MedWorm.com provides a medical RSS filtering service. Over 6000 RSS medical sources are combined and output via different filters. This feed contains the latest items from the 'International Journal of Plant Sciences' source. Wed, 17 Mar 2010 16:30:29 +0100 http://www.medworm.com/index.php?rid=3283001&cid=s_36562_62_f&fid=36562&url=http%3A%2F%2Fwww.journals.uchicago.edu%2Fdoi%2Fabs%2F10.1086%2F650158%3Fai%3Dsl%26mi%3D0%26af%3DR International Journal of Plant Sciences, Volume 171, Issue 3, Page 235-243, March/April 2010. The single‐locus rice blast resistance gene Pi36 is of the coiled‐coil NBS‐LRR (nucleotide binding site–leucine‐rich repeat) type. We have investigated its evolution by resequencing a set of haplotypes (six ssp. indica and four ssp. japonica cultivars and three wild rice accessions) both within and outside the gene’s coding region. It was found that the average nucleotide diversity was ∼4.5%, characteristic of an intermediately diversified pattern. The Ka/Ks ratio and Tajima’s D test were used to show that the gene’s evolution reflects a mixture of purifying and balancing selection. In all, 186 significant gene conversion events were identified across the full coding region... International Journal of Plant Sciences journals http://www.medworm.com/rss/comments.php?id=3283001 Thu, 18 Feb 2010 08:10:12 +0100 3283001 http://www.medworm.com/index.php?rid=3283008&cid=s_36562_62_f&fid=36562&url=http%3A%2F%2Fwww.journals.uchicago.edu%2Fdoi%2Fabs%2F10.1086%2F650202%3Fai%3Dsl%26mi%3D0%26af%3DR In this study, variation in FA was examined at the landscape scale across the whole distributional range of the two oak species Quercus myrtifolia and Quercus chapmanii in Florida. Oak leaf morphology was evaluated in 40 sites covering ∼170,000 km2. Plants growing on coastal/edge sites exhibited significantly higher levels of FA than did plants inhabiting inland/center sites. For myrtle oaks, levels of FA were also spatially structured, and sites were positively spatially autocorrelated at small distances, indicating that sites that were closer exhibited similar levels of environmental stress and FA. Our results have shown that FA, a reliable measurement of plant stress at local scales, can also be used as a biological tool for monitoring the quality of the environment at larger spatial ... International Journal of Plant Sciences journals http://www.medworm.com/rss/comments.php?id=3283008 Wed, 17 Feb 2010 16:18:16 +0100 3283008 http://www.medworm.com/index.php?rid=3283011&cid=s_36562_62_f&fid=36562&url=http%3A%2F%2Fwww.journals.uchicago.edu%2Fdoi%2Fabs%2F10.1086%2F650156%3Fai%3Dsl%26mi%3D0%26af%3DR International Journal of Plant Sciences, Volume 171, Issue 3, Page 332-344, March/April 2010. Permineralized reproductive structures have been known from Antarctica for the past four decades. No formal descriptions have been available for this material, however, leaving a gap in our knowledge of the glossopterid clade. Lakkosia kerasata gen. et sp. nov. is a multiovulate, megasporangiate structure found in silicified peat from the Upper Permian Skaar Ridge locality in the central Transantarctic Mountains. Ovules are borne in depressions on the adaxial surface of the megasporophyll and enclosed in thin strips of tissue that arise from the sporophyll. Transfusion tissue with scalariform wall thickenings is present in the sporophyll and may have acted as storage or conducting tissue. In... International Journal of Plant Sciences journals http://www.medworm.com/rss/comments.php?id=3283011 Wed, 17 Feb 2010 16:18:08 +0100 3283011 http://www.medworm.com/index.php?rid=3283005&cid=s_36562_62_f&fid=36562&url=http%3A%2F%2Fwww.journals.uchicago.edu%2Fdoi%2Fabs%2F10.1086%2F650157%3Fai%3Dsl%26mi%3D0%26af%3DR International Journal of Plant Sciences, Volume 171, Issue 3, Page 275-282, March/April 2010. In many insect‐pollinated angiosperms, stamens are grown with anthers cohered, which might affect pollination processes, but the ecological significance of this fusion of anthers remains unexplored. We studied the breeding system and pollination process of didynamous Campsis grandiflora (Bignoniaceae), with anther fusion in pairs. Pollen removal and deposition were studied in the field for naturally fused versus experimentally separated anthers. Campsis grandiflora flowers were protandrous, with a low pollen:ovule ratio, were mostly outcrossed, and were self‐compatible, with pollinators needed. The main pollinators were pollen‐collecting halictid bees and nectar‐feeding vespid wasps.... International Journal of Plant Sciences journals http://www.medworm.com/rss/comments.php?id=3283005 Wed, 17 Feb 2010 16:17:08 +0100 3283005 http://www.medworm.com/index.php?rid=3283004&cid=s_36562_62_f&fid=36562&url=http%3A%2F%2Fwww.journals.uchicago.edu%2Fdoi%2Fabs%2F10.1086%2F650159%3Fai%3Dsl%26mi%3D0%26af%3DR International Journal of Plant Sciences, Volume 171, Issue 3, Page 267-274, March/April 2010. In the forest canopy, seeds of epiphytic plants encounter heterogeneous environments created by a combination of factors such as solar radiation, humidity, and host characteristics. Germination requirements may explain the species distribution in the canopy; however, more knowledge is essential. Germination of Rhipsalis baccifera, a widespread tropical epiphytic cactus and representative of the humid montane forest in Mexico, was 80% or higher with far red, red, and white light and close to 0 in darkness. Germination was light saturated at very low photon flux density of only 13.5 μmol m−2 s−1. Germination decreased gradually at low water potentials and with increased storage time. Afte... International Journal of Plant Sciences journals http://www.medworm.com/rss/comments.php?id=3283004 Wed, 17 Feb 2010 16:16:38 +0100 3283004 http://www.medworm.com/index.php?rid=3283010&cid=s_36562_62_f&fid=36562&url=http%3A%2F%2Fwww.journals.uchicago.edu%2Fdoi%2Fabs%2F10.1086%2F650153%3Fai%3Dsl%26mi%3D0%26af%3DR This study tests the phylogenetic affinities of 11 South American species of Anemone s.l., including the closely related endemic segregate genera Barneoudia and Oreithales. We analyzed combined sequence data (chloroplast atpB‐rbcL spacer and nuclear ITS regions) for 51 species of Anemone s.l., using both likelihood and cladistic methods. The segregate genera, Oreithales and Barneoudia, nest within Anemone and are included in a clade (subgenus Anemone, sect. Pulsatilloides) consisting largely of South American taxa (Anemone sellowii, Anemone helleborifolia, and Anemone rigida) and other Southern Hemisphere species (e.g., Anemone caffra, Knowltonia vesicatoria, and Anemone crassifolia). As reported previously, Anemone antucensis (Chile and Argentina) is in a separate clade (subgenus and se... International Journal of Plant Sciences journals http://www.medworm.com/rss/comments.php?id=3283010 Wed, 17 Feb 2010 16:16:31 +0100 3283010 http://www.medworm.com/index.php?rid=3283006&cid=s_36562_62_f&fid=36562&url=http%3A%2F%2Fwww.journals.uchicago.edu%2Fdoi%2Fabs%2F10.1086%2F650154%3Fai%3Dsl%26mi%3D0%26af%3DR We examined natural populations of the butterfly pea, Centrosema virginianum, in pine rockland habitat in Everglades National Park (intact habitat) and a pine rockland fragment in suburban Miami‐Dade County to answer the following questions: (1) What is the breeding system of C. virginianum? (2) What are the pollinators of this species in southern Florida pine rocklands? And (3) how are flower herbivores affecting pollinator visitation and subsequent fruit set? Controlled hand‐pollination experiments revealed this species to be self‐compatible but requiring visitation/pollination for fruit set. Cross‐pollinated flowers and open‐pollinated flowers set substantially more seed per fruit than did self‐pollinated flowers. Flowers are visited by a variety of bees (Bombus pensylvanicu... International Journal of Plant Sciences journals http://www.medworm.com/rss/comments.php?id=3283006 Wed, 17 Feb 2010 16:16:08 +0100 3283006 http://www.medworm.com/index.php?rid=3283007&cid=s_36562_62_f&fid=36562&url=http%3A%2F%2Fwww.journals.uchicago.edu%2Fdoi%2Fabs%2F10.1086%2F650155%3Fai%3Dsl%26mi%3D0%26af%3DR International Journal of Plant Sciences, Volume 171, Issue 3, Page 293-302, March/April 2010. We measured the terpenoid chemistry, cone insect distribution, and the relationship between these two parameters in the seed cones of ponderosa pine. Analyses of mono‐, sesqui‐, and diterpenes from four separate sites revealed high amounts of terpenoid diversity and variation. The majority of this variation occurred among trees within sites, but differences were also seen among sites and among cone clusters from individual trees. Cone insect distributions differed substantially in both time and space, with significant differences seen between two points in time and between five sites. Negative correlations existed between levels of cone insect herbivory and both a monoterpene and a diter... International Journal of Plant Sciences journals http://www.medworm.com/rss/comments.php?id=3283007 Wed, 17 Feb 2010 16:15:55 +0100 3283007 http://www.medworm.com/index.php?rid=3283009&cid=s_36562_62_f&fid=36562&url=http%3A%2F%2Fwww.journals.uchicago.edu%2Fdoi%2Fabs%2F10.1086%2F650317%3Fai%3Dsl%26mi%3D0%26af%3DR International Journal of Plant Sciences, Volume 171, Issue 3, Page 310-322, March/April 2010. We tested the effects of hybridization and introgression on the levels of leaf fluctuating asymmetry (FA) in a hybrid zone between Quercus magnoliifolia and Quercus resinosa at the Tequila volcano, Jalisco state, Mexico, in which the species are distributed along an altitudinal gradient ranging from 1400 to 2100 m. Bayesian clustering analysis was performed with STRUCTURE on data for eight nuclear microsatellite loci to assign individuals from reference populations and from the hybrid zone to pure or hybrid genotypic classes. To test the performance of the assignment procedure and to determine optimal thresholds for genetic assignment pure, hybrid and backcrossed genotypes were simulated (fr... International Journal of Plant Sciences journals http://www.medworm.com/rss/comments.php?id=3283009 Wed, 17 Feb 2010 16:15:24 +0100 3283009 http://www.medworm.com/index.php?rid=3283003&cid=s_36562_62_f&fid=36562&url=http%3A%2F%2Fwww.journals.uchicago.edu%2Fdoi%2Fabs%2F10.1086%2F650160%3Fai%3Dsl%26mi%3D0%26af%3DR International Journal of Plant Sciences, Volume 171, Issue 3, Page 258-266, March/April 2010. Using scanning electron microscopy of hand sections of alcohol‐fixed material, microstructure of primary xylem of roots, stems, and rhizomes of Canna was studied. Comparable material of selected other species of Zingiberales, representing five families other than Cannaceae was examined. The appearances present in Canna proved to be shared by other Zingiberaceae. In protoxylem of inflorescence axes, primary walls that experience appreciable elongation bear longitudinally oriented strands facing the lumen. These can be exposed by sectioning and can also be seen in face view on inner surfaces of tracheary elements. Exterior to these strands, primary walls contain reticulate meshworks of cellu... International Journal of Plant Sciences journals http://www.medworm.com/rss/comments.php?id=3283003 Wed, 17 Feb 2010 16:14:57 +0100 3283003 http://www.medworm.com/index.php?rid=3283002&cid=s_36562_62_f&fid=36562&url=http%3A%2F%2Fwww.journals.uchicago.edu%2Fdoi%2Fabs%2F10.1086%2F650161%3Fai%3Dsl%26mi%3D0%26af%3DR International Journal of Plant Sciences, Volume 171, Issue 3, Page 244-257, March/April 2010. Floral development and anatomy were investigated in the monotypic Aextoxicaceae (one species: Aextoxicon punctatum), one of two families of Berberidopsidales, to understand its putative relationship with Berberidopsidaceae and clarify floral evolution in basal core eudicots. Aextoxicon is dioecious, with unisexual flowers that display a late abortion of male and female organs in the respective genders. Flowers are pentamerous or hexamerous and are enclosed by a calyptra derived from the congenital fusion of two bracteoles. Initiation sequence and number of sepals, petals, and stamens are variable and mostly spiral, without clear transition between organ categories, and a single carpel initi... International Journal of Plant Sciences journals http://www.medworm.com/rss/comments.php?id=3283002 Wed, 17 Feb 2010 16:14:36 +0100 3283002 http://www.medworm.com/index.php?rid=3171227&cid=s_36562_62_f&fid=36562&url=http%3A%2F%2Fwww.journals.uchicago.edu%2Fdoi%2Fabs%2F10.1086%2F648986%3Fai%3Dsl%26mi%3D0%26af%3DR International Journal of Plant Sciences, Volume 171, Issue 2, Page 121-146, February 2010. To provide insights into the floral developmental genetics of Nymphaeales (water lilies), we investigated the expression patterns of floral organ identity genes in three genera: Cabomba, Nuphar, and Nymphaea. Additionally, because of the superficial floral similarity between Nymphaea and the early‐diverging eudicot Nelumbo, we conducted the same experiments in the latter taxon. We focused on gene expression associated with (1) perianth differentiation in Nymphaeales, (2) the transition of petaloid staminodes to stamens in Nymphaea, and (3) organ identity in Nymphaea and Nelumbo. In Cabomba, the expression patterns of B‐class gene homologues fit the “sliding boundaries” model, with B‐... International Journal of Plant Sciences journals http://www.medworm.com/rss/comments.php?id=3171227 Wed, 13 Jan 2010 17:19:00 +0100 3171227 http://www.medworm.com/index.php?rid=3171235&cid=s_36562_62_f&fid=36562&url=http%3A%2F%2Fwww.journals.uchicago.edu%2Fdoi%2Fabs%2F10.1086%2F648991%3Fai%3Dsl%26mi%3D0%26af%3DR International Journal of Plant Sciences, Volume 171, Issue 2, Page 221-226, February 2010. The earliest known Asian records of Ulmus fruits are reported based on fossils from the Early Eocene Jijuntun Formation of Fushun coal mine, Liaoning Province, northeastern China. These fruits and associated leaves are morphologically similar to those of Ulmus okanaganensis Denk & Dillhoff, previously described from the late Early Eocene of western Canada. The fruits are small, flattened, and elliptical, with a pair of protruding styles and remnants of a basal calyx, but they do not possess the prominent surrounding wing characteristic of most extant Ulmus species. Fossil fruits from both the Chinese and Canadian Eocene sites are characterized by a short or nonexistent stipe between calyx and t... International Journal of Plant Sciences journals http://www.medworm.com/rss/comments.php?id=3171235 Wed, 13 Jan 2010 17:15:58 +0100 3171235 http://www.medworm.com/index.php?rid=3171231&cid=s_36562_62_f&fid=36562&url=http%3A%2F%2Fwww.journals.uchicago.edu%2Fdoi%2Fabs%2F10.1086%2F648992%3Fai%3Dsl%26mi%3D0%26af%3DR International Journal of Plant Sciences, Volume 171, Issue 2, Page 175-184, February 2010. Recently, the biotic context for sexual and mating system evolution in plants has received special attention; however, the significance of interactions with antagonists has only begun to be revealed. We investigated the effect of florivory on reproduction and inbreeding depression by simulating damage on selfed and outcrossed progeny of hermaphrodites of Fragaria virginiana and recording the response of reproduction, as well as measuring tolerance to florivory. While both florivory and inbreeding affected reproduction, their effects were independent with respect to sexual traits but not an asexual trait; inbreeding depression was florivory and family dependent, specifically, for plantlet produc... International Journal of Plant Sciences journals http://www.medworm.com/rss/comments.php?id=3171231 Wed, 13 Jan 2010 17:15:36 +0100 3171231 http://www.medworm.com/index.php?rid=3171228&cid=s_36562_62_f&fid=36562&url=http%3A%2F%2Fwww.journals.uchicago.edu%2Fdoi%2Fabs%2F10.1086%2F648990%3Fai%3Dsl%26mi%3D0%26af%3DR International Journal of Plant Sciences, Volume 171, Issue 2, Page 147-157, February 2010. Tubular red and pink flowers often indicate bird pollination. Prionotes cerinthoides, a climbing shrub of the temperate rainforest in Tasmania (Australia) and one of only two members of the most primitive clade of the subfamily Styphelioideae (Ericaceae), has such flowers. We tested the hypothesis that P. cerinthoides is bird pollinated using breeding system experiments, observations of flower visitors, and invertebrate trapping. Flowering phenology, nectar availability, and flower damage were also recorded. Prionotes cerinthoides produced little viable seed in the absence of a pollinator but selfed readily when pollination was facilitated. It appears that P. cerinthoides depends largely on the... International Journal of Plant Sciences journals http://www.medworm.com/rss/comments.php?id=3171228 Wed, 13 Jan 2010 17:15:16 +0100 3171228 http://www.medworm.com/index.php?rid=3171232&cid=s_36562_62_f&fid=36562&url=http%3A%2F%2Fwww.journals.uchicago.edu%2Fdoi%2Fabs%2F10.1086%2F648993%3Fai%3Dsl%26mi%3D0%26af%3DR This study represents the most complete phylogenetic analysis of the family to date, with particular focus on the genera and relationships within the large subfamily Alsinoideae, using molecular characters to examine the monophyly of taxa and the validity of the current taxonomy as well as to resolve the obscure origins of divergent taxa such as the endemic Hawaiian Schiedea. Maximum parsimony and maximum likelihood analyses of three chloroplast gene regions (matK, trnL‐F, and rps16) from 81 newly sampled and 65 GenBank specimens reveal that several tribes and genera, especially within the Alsinoideae, are not monophyletic. Large genera such as Arenaria and Minuartia are polyphyletic, as are several smaller genera. The phylogenies reveal that the closest relatives to Schiedea are a pair ... International Journal of Plant Sciences journals http://www.medworm.com/rss/comments.php?id=3171232 Wed, 13 Jan 2010 17:14:41 +0100 3171232 http://www.medworm.com/index.php?rid=3171236&cid=s_36562_62_f&fid=36562&url=http%3A%2F%2Fwww.journals.uchicago.edu%2Fdoi%2Fabs%2F10.1086%2F648994%3Fai%3Dsl%26mi%3D0%26af%3DR International Journal of Plant Sciences, Volume 171, Issue 2, Page 227-234, February 2010. A new genus is described based on fossilized winged fruits from former lake deposits of Wyoming, Utah, Colorado, Oregon, and British Columbia, ranging in age from latest Paleocene to early Middle Eocene. Lagokarpos lacustris McMurran et Manchester gen. et sp. nov. fruits have an elliptical to globose seed body and a conspicuous pair of apical wings with pinnate venation. These wind‐dispersed fruits are compared with and distinguished from similar extant winged fruits such as Dipterocarpus Gaertn f. (Dipterocarpaceae), Gyrocarpus Jacq. (Hernandiaceae), and Alberta E. Meyer (Rubiaceae). No modern fruit was found to exhibit the combination of characters seen in Lagokarpos, and we conclude that i... International Journal of Plant Sciences journals http://www.medworm.com/rss/comments.php?id=3171236 Wed, 13 Jan 2010 17:14:13 +0100 3171236 http://www.medworm.com/index.php?rid=3171229&cid=s_36562_62_f&fid=36562&url=http%3A%2F%2Fwww.journals.uchicago.edu%2Fdoi%2Fabs%2F10.1086%2F649023%3Fai%3Dsl%26mi%3D0%26af%3DR International Journal of Plant Sciences, Volume 171, Issue 2, Page 158-166, February 2010. Colonization may favor self‐compatibility (SC) in invasive plants, a process consistent with Baker’s law. We investigated this hypothesis in invasive eastern North American populations of tristylous Lythrum salicaria L. (purple loosestrife) by controlled self‐ and cross‐pollinations of 124 plants sampled from 12 populations grown under uniform glasshouse conditions. We evaluated whether populations at the northern front of the invasion exhibited higher levels of SC than southern populations, which are closer to source populations for the North American invasion. We also sought evidence for morph‐specific differences in the strength of trimorphic incompatibility. We used the ASTER stat... International Journal of Plant Sciences journals http://www.medworm.com/rss/comments.php?id=3171229 Wed, 13 Jan 2010 17:12:38 +0100 3171229 http://www.medworm.com/index.php?rid=3171230&cid=s_36562_62_f&fid=36562&url=http%3A%2F%2Fwww.journals.uchicago.edu%2Fdoi%2Fabs%2F10.1086%2F648989%3Fai%3Dsl%26mi%3D0%26af%3DR This study offers conclusive evidence of genetic divergence among populations and color forms of M. hypopitys, possibly arising from habitat fragmentation and limitations in gene flow associated with a mycoheterotrophic life history. (Source: International Journal of Plant Sciences) International Journal of Plant Sciences journals http://www.medworm.com/rss/comments.php?id=3171230 Wed, 13 Jan 2010 17:12:16 +0100 3171230 http://www.medworm.com/index.php?rid=3171233&cid=s_36562_62_f&fid=36562&url=http%3A%2F%2Fwww.journals.uchicago.edu%2Fdoi%2Fabs%2F10.1086%2F648988%3Fai%3Dsl%26mi%3D0%26af%3DR This study allows discrimination of true morphological variations from growth stages. The growth habit of Cooksonia is discussed. An emended diagnosis including apomorphic characters is given for the genus, as well as a lectotypification of the genus and the type‐species. (Source: International Journal of Plant Sciences) International Journal of Plant Sciences journals http://www.medworm.com/rss/comments.php?id=3171233 Wed, 13 Jan 2010 17:11:57 +0100 3171233 http://www.medworm.com/index.php?rid=3171234&cid=s_36562_62_f&fid=36562&url=http%3A%2F%2Fwww.journals.uchicago.edu%2Fdoi%2Fabs%2F10.1086%2F648987%3Fai%3Dsl%26mi%3D0%26af%3DR International Journal of Plant Sciences, Volume 171, Issue 2, Page 216-220, February 2010. An updated data set of 25 fossil floras sampling plant communities from the Early Cretaceous (∼123 million years ago) to the Pliocene (∼3 million years ago) is reanalyzed to assess the evolution of a latitudinal gradient in seed size during the radiation of angiosperms and the effect of this gradient on estimations of temporal trends in seed size. There is a significant negative correlation between the median seed size of Tertiary floras and their paleolatitude. As in modern floras, average seed size decreased from the equator toward the poles. Results indicate that previous documentations of a striking increase in within‐flora seed size around the Cretaceous/Tertiary boundary (66 million... International Journal of Plant Sciences journals http://www.medworm.com/rss/comments.php?id=3171234 Wed, 13 Jan 2010 17:10:47 +0100 3171234 http://www.medworm.com/index.php?rid=3092187&cid=s_36562_62_f&fid=36562&url=http%3A%2F%2Fwww.journals.uchicago.edu%2Fdoi%2Fabs%2F10.1086%2F647923%3Fai%3Dsl%26mi%3D0%26af%3DR International Journal of Plant Sciences, Volume 171, Issue 1, Page 1-11, January 2010. Various parts of the anther (walls, tapetum, locular fluid, meiocytes, microspores) cooperate for correct pollen development. To show the different types of relationships possible between these parts, we considered the following characteristics, alone and in combination: types of tapetum, types of pollen‐dispersing unit, form of loculus, amount of locular space and fluid, number of pollen grains in transverse sections of the anther and in the loculus, and hydration status of pollen at dispersal. The different relationships between pollen, loculus, and tapetum should enable uniform nourishment of grains in the loculus and ensure a high percentage of viable grains. Two opposite modes were identifie... International Journal of Plant Sciences journals http://www.medworm.com/rss/comments.php?id=3092187 Tue, 15 Dec 2009 16:50:25 +0100 3092187 http://www.medworm.com/index.php?rid=3092191&cid=s_36562_62_f&fid=36562&url=http%3A%2F%2Fwww.journals.uchicago.edu%2Fdoi%2Fabs%2F10.1086%2F647916%3Fai%3Dsl%26mi%3D0%26af%3DR International Journal of Plant Sciences, Volume 171, Issue 1, Page 53-62, January 2010. Gynodioecy involves the stable co‐occurrence of females and hermaphrodites. Its maintenance theoretically depends on differences in female and male reproductive success among gender morphs. Although many gynodioecious species also include gynomonoecious individuals that carry a mixture of female and perfect flowers, little is known about the male and female fitness of this third morph. Here, we present the first study of the reproductive system of Silene nutans, including females, gynomonoecious plants, and hermaphrodites. By measuring 10 floral traits in controlled conditions, we showed that females bear smaller and lighter flowers than hermaphrodites, with female and perfect flowers of gynomon... International Journal of Plant Sciences journals http://www.medworm.com/rss/comments.php?id=3092191 Tue, 15 Dec 2009 16:45:16 +0100 3092191 http://www.medworm.com/index.php?rid=3092193&cid=s_36562_62_f&fid=36562&url=http%3A%2F%2Fwww.journals.uchicago.edu%2Fdoi%2Fabs%2F10.1086%2F647917%3Fai%3Dsl%26mi%3D0%26af%3DR International Journal of Plant Sciences, Volume 171, Issue 1, Page 73-80, January 2010. Wind is a powerful abiotic influence on plants that is predicted to increase with global warming. The resulting changes to plant function and interaction with herbivores are likely to have significant ecological, forestry, and agricultural consequences. We used a glasshouse manipulative study to test the effects of wind exposure on a range of morphological, functional, and chemical characteristics of seedlings of Eucalyptus tereticornis, a widespread coastal tree. Chronic wind exposure (6 wk of 3 h d−1) resulted in reduced height growth and leaf area, thicker leaf cuticle, slightly higher leaf dry matter, and greater phenolic concentration. Chronic and acute (single 3‐h pulse) exposure to wind... International Journal of Plant Sciences journals http://www.medworm.com/rss/comments.php?id=3092193 Tue, 15 Dec 2009 16:45:08 +0100 3092193 http://www.medworm.com/index.php?rid=3092195&cid=s_36562_62_f&fid=36562&url=http%3A%2F%2Fwww.journals.uchicago.edu%2Fdoi%2Fabs%2F10.1086%2F647918%3Fai%3Dsl%26mi%3D0%26af%3DR International Journal of Plant Sciences, Volume 171, Issue 1, Page 90-106, January 2010. The arctic biome is a relatively young ecosystem with ∼2300 species of vascular plants. We studied the genus Ranunculus as an example of the origin and evolution of the arctic flora. For this purpose we used molecular phylogenetic and clock analyses based on evaluation of nuclear ITS and chloroplast matK‐trnK DNA sequences in 194 taxa of Ranunculus and closely related genera. Taxa occurring in the Arctic arose from seven phylogenetic lineages of Ranunculus and also in the genera Coptidium and Halerpestes. Two clades of Ranunculus are species‐rich in the Arctic, i.e., Ranunculus sect. Ranunculus and R. sect. Auricomus (both from R. subg. Ranunculus), but this is due to a number of arctic “... International Journal of Plant Sciences journals http://www.medworm.com/rss/comments.php?id=3092195 Tue, 15 Dec 2009 16:45:03 +0100 3092195 http://www.medworm.com/index.php?rid=3092189&cid=s_36562_62_f&fid=36562&url=http%3A%2F%2Fwww.journals.uchicago.edu%2Fdoi%2Fabs%2F10.1086%2F647919%3Fai%3Dsl%26mi%3D0%26af%3DR International Journal of Plant Sciences, Volume 171, Issue 1, Page 24-33, January 2010. We investigated changes in floral developmental patterns and sex determination in the PCK (phosphoenolpyruvate carboxykinase) clade using a comparative approach and SEM. We identified variation in patterns of floral development that may be correlated with sex determination. Nine different patterns of floret development were identified, based on sex of the lower floret, sequence of stamen development, and rate of glume and lemma differentiation. Although staminate florets are always formed by the abortion of the gynoecium, the timing of abortion differs among species. Similarly, the formation of sterile lower florets showed different pathways that may operate at the level of floral meristem or orga... International Journal of Plant Sciences journals http://www.medworm.com/rss/comments.php?id=3092189 Tue, 15 Dec 2009 16:44:55 +0100 3092189 http://www.medworm.com/index.php?rid=3092188&cid=s_36562_62_f&fid=36562&url=http%3A%2F%2Fwww.journals.uchicago.edu%2Fdoi%2Fabs%2F10.1086%2F647920%3Fai%3Dsl%26mi%3D0%26af%3DR International Journal of Plant Sciences, Volume 171, Issue 1, Page 12-23, January 2010. A new full‐length cDNA encoding an AP2/EREBP domain‐containing transcription factor named AoDREB was isolated from Asparagus officinalis L. using the RACE‐PCR method. It is a homolog to the dehydration‐responsive element binding protein (DREB) and classified to the A6 subgroup of the DREB subfamily. Using the yeast one‐hybrid system, we conducted a DRE binding assay and demonstrated that AoDREB can bind the DRE element specifically. A transcriptional activity assay showed that AoDREB is a transcription factor capable of activating expression of the reporter gene in yeast. RT‐PCR analysis revealed that expression of the AoDREB gene is induced under 20% PEG and high salinity stress, wher... International Journal of Plant Sciences journals http://www.medworm.com/rss/comments.php?id=3092188 Tue, 15 Dec 2009 16:44:48 +0100 3092188 http://www.medworm.com/index.php?rid=3092190&cid=s_36562_62_f&fid=36562&url=http%3A%2F%2Fwww.journals.uchicago.edu%2Fdoi%2Fabs%2F10.1086%2F647922%3Fai%3Dsl%26mi%3D0%26af%3DR This study contributes to the knowledge of the traffic of substances between tapetum cells and microspores through the localization of pollen proteins during microsporogenesis, by using immunocytochemical techniques with TEM. Because the Oleaceae genera, including Olea and Fraxinus, share a very similar protein profile, an Ole e 1–like protein (which cross‐reacts with the Olea europaea major allergen Ole e 1) was detected in Fraxinus angustifolia pollen grains. From the tetrad to mature–pollen grain stages, distinct labeling intensities were localized in the tapetal cells, anther locule, and orbicules as well as in the microspore and pollen cytoplasms and walls. The localization of this protein in the glycocalyx proves the special role of this layer in ectexine development. At exine ... International Journal of Plant Sciences journals http://www.medworm.com/rss/comments.php?id=3092190 Tue, 15 Dec 2009 16:44:37 +0100 3092190 http://www.medworm.com/index.php?rid=3092192&cid=s_36562_62_f&fid=36562&url=http%3A%2F%2Fwww.journals.uchicago.edu%2Fdoi%2Fabs%2F10.1086%2F647921%3Fai%3Dsl%26mi%3D0%26af%3DR International Journal of Plant Sciences, Volume 171, Issue 1, Page 63-72, January 2010. Many nonnative plants require pollinators to produce the seed needed to establish beyond their native range. Local variation in pollination can cause variation in mating patterns, reproductive output, genetic diversity, and selection, which can influence invasion dynamics. We quantified pollinator visitation, pollen deposition, and pollen limitation of reproduction in the invasive shrub Lonicera maackii in adjacent forest edge and forest interior habitats. Flowers in edge habitats received as many or more pollinator visits than those in interior habitats, resulting in twofold greater pollen deposition and nearly twice as many seeds produced per flower. Supplemental pollination increased seed produ... International Journal of Plant Sciences journals http://www.medworm.com/rss/comments.php?id=3092192 Tue, 15 Dec 2009 16:44:15 +0100 3092192 http://www.medworm.com/index.php?rid=3092194&cid=s_36562_62_f&fid=36562&url=http%3A%2F%2Fwww.journals.uchicago.edu%2Fdoi%2Fabs%2F10.1086%2F647924%3Fai%3Dsl%26mi%3D0%26af%3DR This study tests the hypothesis that habitat differentiation (specifically disturbance) controls the local distribution of triploids and tetraploids. We used flow cytometry to determine the local distribution of cytotypes in four populations. We measured plant morphological traits and environmental characteristics of each microlocation. We performed an experiment to test for differentiation in germination behavior between cytotypes. Tetraploids had higher germination success, were larger, and had a lower stomatal area index than did triploids. Both cytotypes were found in understory and roadside locations, with no relationship between cytotype prevalence and distance from the road. Triploid locations were not significantly different from tetraploid locations for a number of environmental f... International Journal of Plant Sciences journals http://www.medworm.com/rss/comments.php?id=3092194 Tue, 15 Dec 2009 16:43:57 +0100 3092194 http://www.medworm.com/index.php?rid=3092196&cid=s_36562_62_f&fid=36562&url=http%3A%2F%2Fwww.journals.uchicago.edu%2Fdoi%2Fabs%2F10.1086%2F647925%3Fai%3Dsl%26mi%3D0%26af%3DR International Journal of Plant Sciences, Volume 171, Issue 1, Page 107-120, January 2010. A previous study of the Late Devonian cladoxylopsid Denglongia hubeiensis Xue et Hao provided a detailed morphological description, while new material from the type locality of the Huangjiadeng Formation, Hubei Province, China, reported here reveals details of anatomy. Main axes are actinostelic in transverse sections, showing a primary xylem column with five or six xylem ribs separated by deep embayments. First‐order axes have a deeply ribbed primary xylem column with four xylem ribs. Each stelar rib has two permanent, mesarch protoxylem strands near its periphery. Tracheids interpreted as protoxylem show annular or helical thickenings. Metaxylem tracheids have scalariform and elliptical bord... International Journal of Plant Sciences journals http://www.medworm.com/rss/comments.php?id=3092196 Tue, 15 Dec 2009 16:43:25 +0100 3092196 http://www.medworm.com/index.php?rid=2901367&cid=s_36562_62_f&fid=36562&url=http%3A%2F%2Fwww.journals.uchicago.edu%2Fdoi%2Fabs%2F10.1086%2F605927%3Fai%3Dsl%26mi%3D0%26af%3DR International Journal of Plant Sciences, Volume 170, Issue 9, Page iii, November/December 2009. (Source: International Journal of Plant Sciences) International Journal of Plant Sciences journals http://www.medworm.com/rss/comments.php?id=2901367 Fri, 16 Oct 2009 16:34:09 +0100 2901367 http://www.medworm.com/index.php?rid=2901376&cid=s_36562_62_f&fid=36562&url=http%3A%2F%2Fwww.journals.uchicago.edu%2Fdoi%2Fabs%2F10.1086%2F605877%3Fai%3Dsl%26mi%3D0%26af%3DR International Journal of Plant Sciences, Volume 170, Issue 9, Page 1228-1239, November/December 2009. Some Carboniferous seed ferns undergo extensive secondary growth, with secondary vascular tissues occupying increased space within the axis. Mechanisms of accommodating secondary growth in the stem cortex vary significantly between different seed ferns and depend on the degree of secondary growth and position of secondary tissues relative to the cortex. Cortical tissue adjacent to the secondary vascular cylinder is often highly deformed, whereas primary cortex tissue farther away from the secondary growth may be less strained. Developmental patterns of primary and secondary tissues are observed in two species of Calamopitys from the Lower Carboniferous and are compared with patterns ... International Journal of Plant Sciences journals http://www.medworm.com/rss/comments.php?id=2901376 Fri, 16 Oct 2009 15:39:17 +0100 2901376 http://www.medworm.com/index.php?rid=2901377&cid=s_36562_62_f&fid=36562&url=http%3A%2F%2Fwww.journals.uchicago.edu%2Fdoi%2Fabs%2F10.1086%2F648061%3Fai%3Dsl%26mi%3D0%26af%3DR International Journal of Plant Sciences, Volume 170, Issue 9, Page 1240, November/December 2009. (Source: International Journal of Plant Sciences) International Journal of Plant Sciences journals http://www.medworm.com/rss/comments.php?id=2901377 Fri, 16 Oct 2009 15:39:05 +0100 2901377 http://www.medworm.com/index.php?rid=2901373&cid=s_36562_62_f&fid=36562&url=http%3A%2F%2Fwww.journals.uchicago.edu%2Fdoi%2Fabs%2F10.1086%2F605869%3Fai%3Dsl%26mi%3D0%26af%3DR International Journal of Plant Sciences, Volume 170, Issue 9, Page 1183-1194, November/December 2009. The genus Czekanowskia is an important member of the Mesozoic flora and is widespread in the Northern Hemisphere. In China, it is found mostly in Late Triassic and Early and Middle Jurassic sediments of North China. With the exception of a few specimens, all the reports of this genus from China have been based on gross leaf morphology. Abundant Czekanowskia leaves, preserved as compression fossils, were collected from the Middle Jurassic, Zhaogou Formation of Inner Mongolia, China. In this article, two subgenera of Czekanowskia, Harrisella and Vachrameevia, are recognized from Inner Mongolia, China, on the basis of leaf morphology and epidermal characters. Two new species, Czekanows... International Journal of Plant Sciences journals http://www.medworm.com/rss/comments.php?id=2901373 Fri, 16 Oct 2009 15:39:04 +0100 2901373 http://www.medworm.com/index.php?rid=2901370&cid=s_36562_62_f&fid=36562&url=http%3A%2F%2Fwww.journals.uchicago.edu%2Fdoi%2Fabs%2F10.1086%2F605870%3Fai%3Dsl%26mi%3D0%26af%3DR International Journal of Plant Sciences, Volume 170, Issue 9, Page 1120-1131, November/December 2009. Analyses of molecular and quantitative genetic data demonstrate the existence of congruent climate‐related patterns in western white pine (Pinus monticola). Two independent studies allowed comparisons of amplified fragment length polymorphism (AFLP) markers with quantitative variation in adaptive traits. Principal component analyses were conducted on seedling traits in common gardens collected from 58 sites; principal coordinate analyses were conducted on AFLP data from 15 sites. Collection site eigenvector means were regressed on 35 climate variables to produce a genecological prediction for each data set. Both predictions explained a large percentage (>70%) of the genetic variati... International Journal of Plant Sciences journals http://www.medworm.com/rss/comments.php?id=2901370 Fri, 16 Oct 2009 15:38:54 +0100 2901370 http://www.medworm.com/index.php?rid=2901368&cid=s_36562_62_f&fid=36562&url=http%3A%2F%2Fwww.journals.uchicago.edu%2Fdoi%2Fabs%2F10.1086%2F605872%3Fai%3Dsl%26mi%3D0%26af%3DR We examined whether males from artificial‐selection lines differing in floral display (many vs. few flowers) responded differently to stress in the sexually dimorphic dioecious plant Silene latifolia. Males produce more flowers than females, presumably as a consequence of sexual selection for large floral displays. However, ecophysiological traits are genetically correlated with flower production, which may negatively affect many‐flower‐producing males under stressful conditions. To test this premise, we varied water and nutrients and measured flower production, petal size, and pollen production in males. We also measured ovule production in females. Most male traits responded negatively to one or both of the stress treatments. Under high nutrients, pollen production per plant was hi... International Journal of Plant Sciences journals http://www.medworm.com/rss/comments.php?id=2901368 Fri, 16 Oct 2009 15:38:18 +0100 2901368 http://www.medworm.com/index.php?rid=2901369&cid=s_36562_62_f&fid=36562&url=http%3A%2F%2Fwww.journals.uchicago.edu%2Fdoi%2Fabs%2F10.1086%2F605871%3Fai%3Dsl%26mi%3D0%26af%3DR International Journal of Plant Sciences, Volume 170, Issue 9, Page 1109-1119, November/December 2009. Previous studies have suggested that strip‐bark growth in ancient Thuja occidentalis on cliffs in southern Ontario, Canada, may be initiated by root mortality following rockfall. We conducted a long‐term manipulative field study on 65 cliff‐face trees to test whether stem stripping could be experimentally induced by either severing or excavating part of the root system. Further evidence of the proposed mechanism was sought by monitoring the responses of individual branches on timescales ranging from hours to years, including gas exchange, growth, canopy condition, and mortality. The trees were harvested after 5–7 yr to identify and date any stem strips. The results showed tha... International Journal of Plant Sciences journals http://www.medworm.com/rss/comments.php?id=2901369 Fri, 16 Oct 2009 15:38:05 +0100 2901369 http://www.medworm.com/index.php?rid=2901375&cid=s_36562_62_f&fid=36562&url=http%3A%2F%2Fwww.journals.uchicago.edu%2Fdoi%2Fabs%2F10.1086%2F605874%3Fai%3Dsl%26mi%3D0%26af%3DR International Journal of Plant Sciences, Volume 170, Issue 9, Page 1201-1227, November/December 2009. A new species of extinct conifer plants, Emporia royalii sp. nov. Hernandez‐Castillo, Stockey, Mapes et Rothwell (Emporiaceae: Voltziales), is described from the rich fossil biota of the Late Pennsylvanian, Hamilton Quarry, Kansas. This conifer has lateral plagiotropic branches with simple and forked leaves, “age‐dependent heterophylly,” simple pollen cones, and compound ovulate cones. Stems have an endarch eustele, dense wood, and secretory cells arranged in nests or plates in the pith. Leaves are amphistomatic with two adaxial stomatal bands and two longitudinal abaxial rows of stomata with numerous trichome bases. Pollen cones are simple and have helically arranged microsp... International Journal of Plant Sciences journals http://www.medworm.com/rss/comments.php?id=2901375 Fri, 16 Oct 2009 15:37:51 +0100 2901375 http://www.medworm.com/index.php?rid=2901374&cid=s_36562_62_f&fid=36562&url=http%3A%2F%2Fwww.journals.uchicago.edu%2Fdoi%2Fabs%2F10.1086%2F605873%3Fai%3Dsl%26mi%3D0%26af%3DR International Journal of Plant Sciences, Volume 170, Issue 9, Page 1195-1200, November/December 2009. The exine ultrastructure of Williamsoniella coronata Thomas from the Bajocian of Yorkshire (United Kingdom) was investigated with light, scanning electron, and transmission electron microscopy. The pollen averages 16.5 μm along its short axis and 24.5 μm along its long axis and is monosulcate, and the nonapertural sculpturing is distinctly verrucate. The pollen wall is homogeneous, and the sulcus membrane is composed of thin exine with scattered small granules. The pollen grains differ in exine sculpturing and pollen wall ultrastructure from pollen grains of the bennettitalean taxa Cycadeoidea dacotensis (MacBride) Ward and Leguminanthus siliquosis (Leuthardt) Kraeusel. They are si... International Journal of Plant Sciences journals http://www.medworm.com/rss/comments.php?id=2901374 Fri, 16 Oct 2009 15:37:19 +0100 2901374 http://www.medworm.com/index.php?rid=2901372&cid=s_36562_62_f&fid=36562&url=http%3A%2F%2Fwww.journals.uchicago.edu%2Fdoi%2Fabs%2F10.1086%2F605876%3Fai%3Dsl%26mi%3D0%26af%3DR We present detailed chromosomal information on numbers and karyotypes obtained from 394 individuals in 111 populations of 39 Melampodium species and interpret it in the context of a recently developed phylogenetic hypothesis. The distribution of chromosome base numbers (including x=14, reported here for the first time) largely agrees with the circumscription of phylogenetic groups, with the exceptions of x=10, which evolved twice independently, and x=11, the putative ancestral chromosome base number still present in a number of distinct lineages. Polyploidy (tetra‐ and hexaploidy) is known from 17 species, 13 of which are exclusively polyploid, and includes autopolyploids and, more frequently, allopolyploids, with a hotspot in sect. Melampodium. Polyploid karyotypes usually do not underg... International Journal of Plant Sciences journals http://www.medworm.com/rss/comments.php?id=2901372 Fri, 16 Oct 2009 15:37:08 +0100 2901372 http://www.medworm.com/index.php?rid=2901371&cid=s_36562_62_f&fid=36562&url=http%3A%2F%2Fwww.journals.uchicago.edu%2Fdoi%2Fabs%2F10.1086%2F605875%3Fai%3Dsl%26mi%3D0%26af%3DR This study documents unexpectedly diverse floral features for Polemoniaceae, including various corolla aestivation patterns, different types of anther attachment and anther morphology, as well as two types of nectary structure. Prominent features shared by the two families include determinate‐terminal inflorescences, hyaline sepal margins, similar patterns of floral vasculature, late sympetalous corolla development, similar degrees of sympetaly, sterile connective protrusions, short thecal septa, endothecium‐like cells in the connective, trimery in the gynoecium, a stylar canal, parietal, and axile and placentation in the same ovary, similar patterns of ovule arrangement and ovule orientation, distally curved micropylar canals, mesophyll‐type nectaries with stomata, winged seeds, and... International Journal of Plant Sciences journals http://www.medworm.com/rss/comments.php?id=2901371 Fri, 16 Oct 2009 15:36:44 +0100 2901371 http://www.medworm.com/index.php?rid=2785414&cid=s_36562_62_f&fid=36562&url=http%3A%2F%2Fwww.journals.uchicago.edu%2Fdoi%2Fabs%2F10.1086%2F600138%3Fai%3Dsl%26mi%3D0%26af%3DR This study revealed that increased wax accumulation did not have a negative impact on photosynthesis. The physiological analyses indicated that WXP1 is involved not only in wax biosynthesis but also in other physiological responses associated with enhanced drought tolerance that warrant further investigation. (Source: International Journal of Plant Sciences) International Journal of Plant Sciences journals http://www.medworm.com/rss/comments.php?id=2785414 Fri, 11 Sep 2009 14:13:59 +0100 2785414 http://www.medworm.com/index.php?rid=2785419&cid=s_36562_62_f&fid=36562&url=http%3A%2F%2Fwww.journals.uchicago.edu%2Fdoi%2Fabs%2F10.1086%2F605113%3Fai%3Dsl%26mi%3D0%26af%3DR International Journal of Plant Sciences, Volume 170, Issue 8, Page 1019-1030, October 2009. The Galapagos endemic plants Scalesia aspera, Scalesia crockeri, and Scalesia pedunculata (Asteraceae) grow in distinct parts of Santa Cruz Island. Between them lie morphologically intermediate populations. The putative hybridization of the three species was investigated by means of morphological (leaf characters) and molecular (amplified fragment length polymorphism) measures. The results suggest that the intermediate populations are interspecific hybrids. Artificial hybrids were also made by crossing S. crockeri and S. pedunculata manually. We thus document that reproductive barriers are incomplete and that gene flow occurs between the three different species of Scalesia. (Source: Internatio... International Journal of Plant Sciences journals http://www.medworm.com/rss/comments.php?id=2785419 Fri, 11 Sep 2009 14:12:56 +0100 2785419 http://www.medworm.com/index.php?rid=2785420&cid=s_36562_62_f&fid=36562&url=http%3A%2F%2Fwww.journals.uchicago.edu%2Fdoi%2Fabs%2F10.1086%2F605116%3Fai%3Dsl%26mi%3D0%26af%3DR International Journal of Plant Sciences, Volume 170, Issue 8, Page 1031-1043, October 2009. Evolutionary relationships in Ephedra are difficult to resolve, mainly because there are few informative characters in investigated loci and long distances to outgroups. We address these problems by using a large data set that includes information from seven plastid and nuclear loci and 204 vascular plants. The deepest divergences in Ephedra are weakly supported and differ by analytical method, but they indicate a basal grade of species distributed in the Mediterranean area. New World species are monophyletic, with a South American clade possibly nested within a North American clade. A mainly Asian clade comprises several well‐supported subgroups, of which some are endemic to restricted geog... International Journal of Plant Sciences journals http://www.medworm.com/rss/comments.php?id=2785420 Fri, 11 Sep 2009 14:12:35 +0100 2785420 http://www.medworm.com/index.php?rid=2834010&cid=s_36562_62_f&fid=36562&url=http%3A%2F%2Fwww.journals.uchicago.edu%2Fdoi%2Fabs%2F10.1086%2F644608%3Fai%3Dsl%26mi%3D0%26af%3DR International Journal of Plant Sciences, Volume 170, Issue 8, Page 1102, October 2009. (Source: International Journal of Plant Sciences) International Journal of Plant Sciences journals http://www.medworm.com/rss/comments.php?id=2834010 Fri, 11 Sep 2009 14:12:29 +0100 2834010 http://www.medworm.com/index.php?rid=2785425&cid=s_36562_62_f&fid=36562&url=http%3A%2F%2Fwww.journals.uchicago.edu%2Fdoi%2Fabs%2F10.1086%2F644608%3Fai%3Dsl%26mi%3D0%26af%3DR International Journal of Plant Sciences, Volume 170, Issue 8, Page 1102, October 2009. (Source: International Journal of Plant Sciences) International Journal of Plant Sciences journals http://www.medworm.com/rss/comments.php?id=2785425 Fri, 11 Sep 2009 14:12:29 +0100 2785425 http://www.medworm.com/index.php?rid=2785423&cid=s_36562_62_f&fid=36562&url=http%3A%2F%2Fwww.journals.uchicago.edu%2Fdoi%2Fabs%2F10.1086%2F605117%3Fai%3Dsl%26mi%3D0%26af%3DR International Journal of Plant Sciences, Volume 170, Issue 8, Page 1075-1085, October 2009. Klitzschophyllites choffatii (Saporta sensu Teixeira) emend. is reported from the upper Albian of the Utrillas Formation at the Plou locality, Teruel Province, northeastern Spain. The species shows obovate microphylls; dense, flabellate primary and secondary veins interconnected by fine, reticulate tertiary veins and intersecting with an intramarginal vein; and small glands in sinuses between triangular teeth. It exhibits more affinities with basal eudicots (especially some Ranunculales) than with monocots. Sedimentological and taphonomic evidence, along with morphofunctional features, supports a freshwater hydrophytic habit for K. choffatii. (Source: International Journal of Plant Sciences) International Journal of Plant Sciences journals http://www.medworm.com/rss/comments.php?id=2785423 Fri, 11 Sep 2009 14:12:26 +0100 2785423 http://www.medworm.com/index.php?rid=2785417&cid=s_36562_62_f&fid=36562&url=http%3A%2F%2Fwww.journals.uchicago.edu%2Fdoi%2Fabs%2F10.1086%2F605114%3Fai%3Dsl%26mi%3D0%26af%3DR This study is to examine the effect of stem architecture on biomass allocation between leaf and stem and between leaf size and number in plant twigs of woody species. We investigated leaf size, leaf number, stem length, stem diameter, and mass for 282 woody species of subtropical evergreen broad‐leaved forests in southwest China. Both stem diameter and stem length were positively correlated with individual leaf mass and area but were negatively associated with leaf number per unit stem mass and leaf number per stem length. This suggests that these stem architecture traits can be a physiological mechanism underlying the leaf size versus leaf number trade‐off. The ratio of stem length to stem diameter (LDR) was negatively correlated with leaf size and leaf number per stem length, due to ... International Journal of Plant Sciences journals http://www.medworm.com/rss/comments.php?id=2785417 Fri, 11 Sep 2009 14:12:04 +0100 2785417 http://www.medworm.com/index.php?rid=2785422&cid=s_36562_62_f&fid=36562&url=http%3A%2F%2Fwww.journals.uchicago.edu%2Fdoi%2Fabs%2F10.1086%2F605115%3Fai%3Dsl%26mi%3D0%26af%3DR International Journal of Plant Sciences, Volume 170, Issue 8, Page 1056-1074, October 2009. A new plant concept for the extinct conifer species Emporia lockardii (Mapes & Rothwell) Mapes & Rothwell (Emporiaceae) is developed from fossils collected at the Late Pennsylvanian Hamilton Quarry, Kansas. Emporia lockardii has lateral plagiotropic branches with simple and forked leaves, simple pollen cones, and compound ovulate cones. Stems have an endarch eustele with dense wood surrounding a septate pith. Leaves display position‐dependent heterophylly with forked leaves on penultimate shoots and simple leaves on ultimate shoots. All leaves are amphistomatic with two stomatal bands and papillate epidermal cells on the adaxial surface and two basal stomatal bands and numerous trichome base... International Journal of Plant Sciences journals http://www.medworm.com/rss/comments.php?id=2785422 Fri, 11 Sep 2009 14:11:03 +0100 2785422 http://www.medworm.com/index.php?rid=2785416&cid=s_36562_62_f&fid=36562&url=http%3A%2F%2Fwww.journals.uchicago.edu%2Fdoi%2Fabs%2F10.1086%2F605119%3Fai%3Dsl%26mi%3D0%26af%3DR International Journal of Plant Sciences, Volume 170, Issue 8, Page 990-998, October 2009. Amaranth (Amaranthus hypochondriacus L.) is a plant that produces seed with high protein content, is rich on nutraceutical compounds, and can grow under environmental conditions where most of the basic crops are not able to develop. But little is know about the amaranth stress‐responsive genes/proteins. The aim of this work was to apply the comparative proteomics approach to study the differential expression of amaranth leaf proteins under drought stress. However, the protein extraction from amaranth tissues is difficult as a result of high endogenous concentrations of interfering compounds; we have made some modifications of the classical trichloroacetic acid–acetone precipitation method to... International Journal of Plant Sciences journals http://www.medworm.com/rss/comments.php?id=2785416 Fri, 11 Sep 2009 14:10:45 +0100 2785416 http://www.medworm.com/index.php?rid=2785418&cid=s_36562_62_f&fid=36562&url=http%3A%2F%2Fwww.journals.uchicago.edu%2Fdoi%2Fabs%2F10.1086%2F605118%3Fai%3Dsl%26mi%3D0%26af%3DR International Journal of Plant Sciences, Volume 170, Issue 8, Page 1009-1018, October 2009. The pattern of cell division at shoot apices of Selaginella kraussiana is investigated using laser scanning confocal microscopy. The vegetative shoot possesses a single apical cell with two cutting faces that produce merophytes (apical cell derivatives) in a distichous manner. When the shoot dichotomizes, the apical cell divides into two cells, each of which gives rise to the apical cell of a new axis. Bifurcations of the apical cell occur close together, and by the time the first external signs of a dichotomy are apparent, the next bifurcation of the main axis may have already occurred. New apical cells have the same orientation as their parent, which accounts for the planar and plagiotropic... International Journal of Plant Sciences journals http://www.medworm.com/rss/comments.php?id=2785418 Fri, 11 Sep 2009 14:10:40 +0100 2785418 http://www.medworm.com/index.php?rid=2785421&cid=s_36562_62_f&fid=36562&url=http%3A%2F%2Fwww.journals.uchicago.edu%2Fdoi%2Fabs%2F10.1086%2F605121%3Fai%3Dsl%26mi%3D0%26af%3DR International Journal of Plant Sciences, Volume 170, Issue 8, Page 1044-1055, October 2009. Few studies have addressed the evolutionary relationships within Polygonaceae from a global perspective. The convoluted taxonomic history of Polygonaceae is a major barrier to understanding evolution in this group, and only portions of it have been included in systematic treatments. Phylogenetic studies have been limited in both taxon sampling and amount of data. Our objective is to identify clades within Polygonaceae and to provide a global estimate of phylogenetic relationships in this morphologically diverse and geographically widespread group. We include a total of 75 species representing approximately 40 of the 55 named genera in the family. We use three chloroplast regions (rbcL, matK, a... International Journal of Plant Sciences journals http://www.medworm.com/rss/comments.php?id=2785421 Fri, 11 Sep 2009 14:10:22 +0100 2785421 http://www.medworm.com/index.php?rid=2785415&cid=s_36562_62_f&fid=36562&url=http%3A%2F%2Fwww.journals.uchicago.edu%2Fdoi%2Fabs%2F10.1086%2F605122%3Fai%3Dsl%26mi%3D0%26af%3DR International Journal of Plant Sciences, Volume 170, Issue 8, Page 979-989, October 2009. Maize employs complex mechanisms of gene regulation in response to drought stress. Micro‐RNAs (miRNAs) have emerged as a novel regulatory mechanism of gene expression. Drought induces upregulation and downregulation of numerous genes. However, little is known about the role of miRNAs in maize drought response. In this research, miRNA microarray hybridization showed that 34 miRNAs from 13 plant miRNA families had significantly altered expression after drought treatment. Most of the miRNA‐mediated target genes contained a cis‐acting element that responded to phytohormone (ABA) stimuli during drought stress. Drought stress–upregulated miR474 could downregulate target gene PDH, which is a ne... International Journal of Plant Sciences journals http://www.medworm.com/rss/comments.php?id=2785415 Fri, 11 Sep 2009 14:10:18 +0100 2785415 http://www.medworm.com/index.php?rid=2785424&cid=s_36562_62_f&fid=36562&url=http%3A%2F%2Fwww.journals.uchicago.edu%2Fdoi%2Fabs%2F10.1086%2F605120%3Fai%3Dsl%26mi%3D0%26af%3DR International Journal of Plant Sciences, Volume 170, Issue 8, Page 1086-1101, October 2009. Monetianthus mirus gen. et sp. nov. is described based on a single coalified flower from the Early Cretaceous (Late Aptian‐Early Albian) Vale de Agua locality, western Portugal. The flower is actinomorphic and probably bisexual, with a perianth of nine or 10 tepals, an androecium of 20 stamens, and a syncarpous gynoecium with a partly inferior ovary of 12 carpels arranged radially around a central column. Phyllotaxis of tepals and stamens is uncertain. Nondestructive synchrotron radiation x‐ray tomographic microscopy of internal structures documents laminar placentation with around six anatropous and ascending ovules in each locule. Comparison of Monetianthus with living plants indicates a... International Journal of Plant Sciences journals http://www.medworm.com/rss/comments.php?id=2785424 Fri, 11 Sep 2009 14:09:23 +0100 2785424 http://www.medworm.com/index.php?rid=2690990&cid=s_36562_62_f&fid=36562&url=http%3A%2F%2Fwww.journals.uchicago.edu%2Fdoi%2Fabs%2F10.1086%2F600137%3Fai%3Dsl%26mi%3D0%26af%3DR In this study, transgenic root line Tet3, carrying reporter gene gusA under control of a tetracycline (Tc)‐inducible promoter, was used to study this promoter utility in C. roseus transgenic hairy roots. Three days before the stationary growth stage, different Tc concentrations (0.0, 0.1, 1.0, 5.0, and 10.0 mg/L) were applied in root liquid cultures. Both a GUS‐staining assay and gusA transcript level quantification showed that induction of the gusA gene was dramatically enhanced by an increase of Tc concentration in the root culture. By 96 h after Tc depletion from the liquid culture, gusA transcript levels had dropped to the level of uninduced roots. However, gusA expression leakage in the root tips, especially at the early exponential‐growth stage, limited the inducible‐system a... International Journal of Plant Sciences journals http://www.medworm.com/rss/comments.php?id=2690990 Tue, 11 Aug 2009 19:24:57 +0100 2690990 http://www.medworm.com/index.php?rid=2690992&cid=s_36562_62_f&fid=36562&url=http%3A%2F%2Fwww.journals.uchicago.edu%2Fdoi%2Fabs%2F10.1086%2F599074%3Fai%3Dsl%26mi%3D0%26af%3DR International Journal of Plant Sciences, Volume 170, Issue 7, Page 845-859, September 2009. Although the floral morphology of Oleaceae appears to be simple at first sight, fundamental problems still exist. The most detailed morphological studies date back to the 1920s but do not contain developmental data. Such data, based on the SEM investigation of 15 species out of 10 genera and covering most tribes and subtribes of the family, are presented here. In the dominant floral type, the perianth is tetramerous. The four sepals initiate simultaneously in orthogonal positions on the floral apex. The corolla partly emerges as a continuous ringlike structure from which four petal lobes arise in diagonal positions (early sympetaly). In other cases, the petal primordia emerge separately, fusi... International Journal of Plant Sciences journals http://www.medworm.com/rss/comments.php?id=2690992 Tue, 11 Aug 2009 19:20:13 +0100 2690992 http://www.medworm.com/index.php?rid=2690999&cid=s_36562_62_f&fid=36562&url=http%3A%2F%2Fwww.journals.uchicago.edu%2Fdoi%2Fabs%2F10.1086%2F600134%3Fai%3Dsl%26mi%3D0%26af%3DR International Journal of Plant Sciences, Volume 170, Issue 7, Page 926-940, September 2009. Patterns of tectum ornamentation in pollen of Quercus (oak trees, Fagaceae) are investigated using high‐resolution scanning electron microscopy. Tectum ornamentation is highly consistent at the infrageneric level and can be used to polarize character states within Quercus by comparison with other genera in Fagaceae. In particular, pollen data strongly suggest the recognition of an infrageneric Ilex group and, for the first time, allow definition of the set of taxa that comprise this group. The infrageneric Ilex group displays a relatively simple tectum ornamentation exclusively found in this group of oaks, in Fagus, and in extinct lineages related to Trigonobalanus, Colombobalanus, and Form... International Journal of Plant Sciences journals http://www.medworm.com/rss/comments.php?id=2690999 Tue, 11 Aug 2009 19:19:34 +0100 2690999 http://www.medworm.com/index.php?rid=2690995&cid=s_36562_62_f&fid=36562&url=http%3A%2F%2Fwww.journals.uchicago.edu%2Fdoi%2Fabs%2F10.1086%2F600133%3Fai%3Dsl%26mi%3D0%26af%3DR International Journal of Plant Sciences, Volume 170, Issue 7, Page 885-893, September 2009. Self‐fertilization can provide reproductive assurance during periods of low or unreliable pollinator visitation. Therefore, periods of low pollen receipt may favor evolutionary shifts from cross‐fertilization to self‐fertilization. Although reproductive assurance is hypothesized to be important in mating system evolution, it has been quantified in relatively few species. Leptosiphon jepsonii shows variation in the mode of selfing, with transient self‐incompatibility conferring delayed selfing seen in some individuals and early self‐compatibility present in others. Autofertility, reproductive assurance, and pollen limitation were quantified in three populations of L. jepsonii that var... International Journal of Plant Sciences journals http://www.medworm.com/rss/comments.php?id=2690995 Tue, 11 Aug 2009 19:14:16 +0100 2690995 http://www.medworm.com/index.php?rid=2690996&cid=s_36562_62_f&fid=36562&url=http%3A%2F%2Fwww.journals.uchicago.edu%2Fdoi%2Fabs%2F10.1086%2F600149%3Fai%3Dsl%26mi%3D0%26af%3DR International Journal of Plant Sciences, Volume 170, Issue 7, Page 894-905, September 2009. A few generalizations have been made about the amount of genetic diversity and life‐history traits in plants, and a number of studies have reported contrasting results, indicating that these generalizations are not necessarily reliable. Six Govenia species belonging to three groups characterized by different pollinator attraction strategies were studied: (a) small inflorescences with three to eight whitish or greenish flowers, (b) medium‐sized inflorescences with 15–30 white flowers, and (c) large inflorescences with 30–50 or more yellowish flowers. Genetic variation was assessed using starch gel electrophoresis to resolve 17 allozyme loci in 13 populations, to determine the level and ... International Journal of Plant Sciences journals http://www.medworm.com/rss/comments.php?id=2690996 Tue, 11 Aug 2009 19:04:42 +0100 2690996 http://www.medworm.com/index.php?rid=2691000&cid=s_36562_62_f&fid=36562&url=http%3A%2F%2Fwww.journals.uchicago.edu%2Fdoi%2Fabs%2F10.1086%2F600148%3Fai%3Dsl%26mi%3D0%26af%3DR International Journal of Plant Sciences, Volume 170, Issue 7, Page 941-950, September 2009. Fossil fruits document the former presence of Sloanea L. (Elaeocarpaceae) in Greenland and midlatitude North America during the early Tertiary. First described as Castanea ungeri by Heer in 1869 from the Paleocene of Greenland, the distinctive spiny fruits have since been discovered at several Paleocene to lower Eocene sites in Colorado, Wyoming and Montana. The fruits are 3–5‐valved capsules 2.5–3.5 cm in diameter, borne on long pedicels. Immature, unopened capsules show a single persistent style. The capsules open from the apex with valves separating to the lower 10% of the fruit. Each valve has a smooth inner surface with a pronounced median septum and is ornamented dorsally with clos... International Journal of Plant Sciences journals http://www.medworm.com/rss/comments.php?id=2691000 Tue, 11 Aug 2009 19:04:19 +0100 2691000 http://www.medworm.com/index.php?rid=2690998&cid=s_36562_62_f&fid=36562&url=http%3A%2F%2Fwww.journals.uchicago.edu%2Fdoi%2Fabs%2F10.1086%2F600140%3Fai%3Dsl%26mi%3D0%26af%3DR International Journal of Plant Sciences, Volume 170, Issue 7, Page 918-925, September 2009. Endemic plant species are often thought to be restricted to marginal habitats as a result of a trade‐off between fitness in high‐stress environments and competitive ability in benign environments. Here we provide a unique test of this hypothesis by manipulating competition and habitat quality across a gradient and contrasting closely related species that differ in their habitat specializations. We compared the competitive abilities of five Cirsium species that co‐occur in northern California and range from an endemic species to a noxious invader. The endemic species Cirsium fontinale var. fontinale is restricted to low‐nutrient serpentine habitats. We conducted a greenhouse experiment ... International Journal of Plant Sciences journals http://www.medworm.com/rss/comments.php?id=2690998 Tue, 11 Aug 2009 19:01:49 +0100 2690998 http://www.medworm.com/index.php?rid=2691001&cid=s_36562_62_f&fid=36562&url=http%3A%2F%2Fwww.journals.uchicago.edu%2Fdoi%2Fabs%2F10.1086%2F600139%3Fai%3Dsl%26mi%3D0%26af%3DR International Journal of Plant Sciences, Volume 170, Issue 7, Page 951-967, September 2009. The third of three whole‐plant cordaitaleans we reconstructed from a single Early Permian locality in northern China is Shanxioxylon taiyuanense. The name is based on the stem S. taiyuanense B. Tian & S.‐J. Wang emend. S.‐J. Wang & J. Hilton, which has a large septate pith and endarch cauline bundles that generate mesarch leaf traces that dichotomize at the pith margin. The comparatively small, elongate leaves with few veins and thickened margins are assigned to Cordaites taiyuanensis S.‐J. Wang & B. Tian emend. S.‐J. Wang and J. Hilton, which is here nomenclaturally typified after a previous invalid publication. Fertile axes are diamond shaped in transverse section, bearing in a tet... International Journal of Plant Sciences journals http://www.medworm.com/rss/comments.php?id=2691001 Tue, 11 Aug 2009 19:01:29 +0100 2691001 http://www.medworm.com/index.php?rid=2690991&cid=s_36562_62_f&fid=36562&url=http%3A%2F%2Fwww.journals.uchicago.edu%2Fdoi%2Fabs%2F10.1086%2F600136%3Fai%3Dsl%26mi%3D0%26af%3DR International Journal of Plant Sciences, Volume 170, Issue 7, Page 834-844, September 2009. DRGs are highly conserved GTP binding proteins. All eukaryotes examined contain DRG1 and DRG2 orthologs. The first experimental evidence for GTP binding by a plant DRG1 protein and by DRG2 from any organism is presented. DRG1 antibodies recognized a single ∼43‐kDa band in plant tissues, whereas DRG2 antibodies recognized ∼45‐, 43‐, and 30‐kDa bands. An in vitro transcription and translation assay suggested that the 45‐kDa band represents full‐length DRG2 and that the smaller bands are specific proteolytic products. Homogenates from pea roots and root apices were used to produce fractions enriched in cytosolic and microsomal monosomes and polysomes. DRG1 and the 45‐ and 43‐k... International Journal of Plant Sciences journals http://www.medworm.com/rss/comments.php?id=2690991 Tue, 11 Aug 2009 19:00:36 +0100 2690991 http://www.medworm.com/index.php?rid=2690993&cid=s_36562_62_f&fid=36562&url=http%3A%2F%2Fwww.journals.uchicago.edu%2Fdoi%2Fabs%2F10.1086%2F600135%3Fai%3Dsl%26mi%3D0%26af%3DR In this study, the fronds of the most ancient fossil fern, Psalixochlaena antiqua, and the most ancient reconstructed seed plant, Elkinsia polymorpha, are characterized and compared with leaves of modern plants in order to identify the sequence in which features of leaves in two distinct clades of euphyllophytes arose. While both fronds show a combination of characters attributable to ancestral vegetative axes and characters attributable to leaves, each plant displays different combinations of those characters. These data document dissimilar sequences of character originations and, therefore, the independent evolution of developmental mechanisms in seed plants and ferns. (Source: International Journal of Plant Sciences) International Journal of Plant Sciences journals http://www.medworm.com/rss/comments.php?id=2690993 Tue, 11 Aug 2009 19:00:12 +0100 2690993 http://www.medworm.com/index.php?rid=2690994&cid=s_36562_62_f&fid=36562&url=http%3A%2F%2Fwww.journals.uchicago.edu%2Fdoi%2Fabs%2F10.1086%2F604743%3Fai%3Dsl%26mi%3D0%26af%3DR International Journal of Plant Sciences, Volume 170, Issue 7, Page 869-884, September 2009. New data are presented on shoot architecture and branching pattern in one of the two perennial species of Hydatellaceae (Nymphaeales), Trithuria filamentosa, in the first detailed comparative study that covers both development and anatomy. Perennial rhizomes of T. filamentosa bear vegetative leaves and leafless stalks of reproductive units. Rhizome growth is sympodial. Each shoot produces four to nine vegetative leaves and in its distal part one or two lateral shoots and one to three reproductive units. Lateral shoots develop in the axils of vegetative leaves. The two first leaves of each lateral shoot lie in a transversal plane, with a divergence angle close to 180°; they are interpreted as ... International Journal of Plant Sciences journals http://www.medworm.com/rss/comments.php?id=2690994 Tue, 11 Aug 2009 18:58:44 +0100 2690994 http://www.medworm.com/index.php?rid=2690997&cid=s_36562_62_f&fid=36562&url=http%3A%2F%2Fwww.journals.uchicago.edu%2Fdoi%2Fabs%2F10.1086%2F599238%3Fai%3Dsl%26mi%3D0%26af%3DR International Journal of Plant Sciences, Volume 170, Issue 7, Page 906-917, September 2009. Climate change will test the evolutionary potential of many narrowly distributed plants, especially in alpine environments. We test for adaptation to elevation of an alpine forb, Craspedia lamicola, across three narrow replicated elevation transects and compare findings with a recent study in the grass Poa hiemata across the same range. Low‐elevation plants exhibited larger (yet fewer in number) leaves per plant compared with high‐elevation plants. Reciprocal transplant and common garden experiments indicated that differences due to elevation were predominantly environmentally determined, with only a small heritable component for leaf number. Plants did not exhibit a native‐site advantag... International Journal of Plant Sciences journals http://www.medworm.com/rss/comments.php?id=2690997 Tue, 11 Aug 2009 18:57:05 +0100 2690997 http://www.medworm.com/index.php?rid=2503858&cid=s_36562_62_f&fid=36562&url=http%3A%2F%2Fwww.journals.uchicago.edu%2Fdoi%2Fabs%2F10.1086%2F599788%3Fai%3Dsl%26mi%3D0%26af%3DR International Journal of Plant Sciences, Volume 170, Issue 6, Page 699, July/August 2009. (Source: International Journal of Plant Sciences) International Journal of Plant Sciences journals http://www.medworm.com/rss/comments.php?id=2503858 Tue, 23 Jun 2009 19:27:18 +0100 2503858 http://www.medworm.com/index.php?rid=2503865&cid=s_36562_62_f&fid=36562&url=http%3A%2F%2Fwww.journals.uchicago.edu%2Fdoi%2Fabs%2F10.1086%2F599077%3Fai%3Dsl%26mi%3D0%26af%3DR In this study, we have estimated the phylogeny for 534 Rubiaceae taxa from 329 genera with up to five different chloroplast regions by Bayesian analysis. It resulted in a highly resolved tree with many strongly supported nodes. There is strong support for the three subfamilies (Cinchonoideae, Ixoroideae, Rubioideae) and most of the 44 included tribes. A scaled‐down data set of 173 Rubiaceae taxa was used with a Bayesian approach to estimate divergence times for clades classified as tribes and subfamilies. Four fossils were used as minimum age priors, one inside each subfamily and one for Rubiaceae as a whole (Faramea‐type pollen, Scyphiphora pollen, Cephalanthus pusillus fruits, and Paleorubiaceophyllum eocenicum leaves). The estimated lineage (stem) divergence time for Rubiaceae is... International Journal of Plant Sciences journals http://www.medworm.com/rss/comments.php?id=2503865 Tue, 23 Jun 2009 18:45:41 +0100 2503865 http://www.medworm.com/index.php?rid=2503867&cid=s_36562_62_f&fid=36562&url=http%3A%2F%2Fwww.journals.uchicago.edu%2Fdoi%2Fabs%2F10.1086%2F599076%3Fai%3Dsl%26mi%3D0%26af%3DR International Journal of Plant Sciences, Volume 170, Issue 6, Page 814-828, July/August 2009. Pteridosperms are common in the Permian floras of China and are known from both vegetative and fertile organs in adpression assemblages and as dispersed ovules and seeds in permineralized assemblages. In contrast, reports of vegetative organs from permineralized assemblages are limited, and in all cases, accounts have not been verified by detailed descriptions nor illustration. Here we report four taxa of pteridosperm stem or rachis from the Permian permineralized floras of China. Coal balls from the Asselian‐Sakmarian (Cisuralian) Taiyuan Formation are shown to contain specimens of a medullosan and a lyginopterid pteridosperm. The medullosan rachis has a distinctive collateral organizatio... International Journal of Plant Sciences journals http://www.medworm.com/rss/comments.php?id=2503867 Tue, 23 Jun 2009 18:43:45 +0100 2503867 http://www.medworm.com/index.php?rid=2503861&cid=s_36562_62_f&fid=36562&url=http%3A%2F%2Fwww.journals.uchicago.edu%2Fdoi%2Fabs%2F10.1086%2F599075%3Fai%3Dsl%26mi%3D0%26af%3DR International Journal of Plant Sciences, Volume 170, Issue 6, Page 724-734, July/August 2009. We conducted a paternity analysis within a population of the Neotropical tree Platypodium elegans using microsatellite markers to determine rates of gene flow and to investigate whether postpollination selection affects male reproductive success. Paternity was assigned for three early life stages (aborted fruit, mature seeds, and seedlings) of five adult trees. The rate of pollen immigration into the population was high (>40%). Significant heterogeneity in pollen allele frequencies was discovered among families but subsequently declined across life stages. Comparisons of parentage among the three life stages showed no significant differences in the number of progeny resulting from immigrant ... International Journal of Plant Sciences journals http://www.medworm.com/rss/comments.php?id=2503861 Tue, 23 Jun 2009 18:41:01 +0100 2503861 http://www.medworm.com/index.php?rid=2503860&cid=s_36562_62_f&fid=36562&url=http%3A%2F%2Fwww.journals.uchicago.edu%2Fdoi%2Fabs%2F10.1086%2F599073%3Fai%3Dsl%26mi%3D0%26af%3DR International Journal of Plant Sciences, Volume 170, Issue 6, Page 701-723, July/August 2009. Figures from independent studies of 1941 suggested a similarity in the initiation of the vascular system of the arborescent palms and the unrelated and herbaceous lily turf, Ophiopogon. In order to compare more rigorously the vascular pattern of Ophiopogon with the intensively studied vascular system of the palms, cross sections of the rhizome of Ophiopogon were serially analyzed. All procambial strands were mapped in the 1.5‐mm‐long tip of a rhizome of Ophiopogon containing the insertions of 18 leaves. Charting procambia effected a description of the origins of the three major traces and the two intermediate traces associated with each leaf. All traces arise by merger of originally isol... International Journal of Plant Sciences journals http://www.medworm.com/rss/comments.php?id=2503860 Tue, 23 Jun 2009 18:40:17 +0100 2503860 http://www.medworm.com/index.php?rid=2503863&cid=s_36562_62_f&fid=36562&url=http%3A%2F%2Fwww.journals.uchicago.edu%2Fdoi%2Fabs%2F10.1086%2F599072%3Fai%3Dsl%26mi%3D0%26af%3DR International Journal of Plant Sciences, Volume 170, Issue 6, Page 748-758, July/August 2009. Fagus japonica is generally known as one of two beech species native to Japan. It forms intermediate temperate forests that are vertically distributed from the lower part of the cool temperate zone into the upper part of the warm temperate zone, mostly along the Pacific side of Japan. We have studied the genetic diversity and population genetic structure in 16 F. japonica populations distributed throughout its range, using 13 nuclear microsatellite markers. Genetic diversity within populations was found to be high (average $H_{\mathrm{E}\,}=0.659$), whereas population differentiation was low ($F_{\mathrm{ST}\,}=0.023$; $R_{\mathrm{ST}\,}=0.025$). However, we detected significant isolation by... International Journal of Plant Sciences journals http://www.medworm.com/rss/comments.php?id=2503863 Tue, 23 Jun 2009 18:37:51 +0100 2503863 http://www.medworm.com/index.php?rid=2503864&cid=s_36562_62_f&fid=36562&url=http%3A%2F%2Fwww.journals.uchicago.edu%2Fdoi%2Fabs%2F10.1086%2F599241%3Fai%3Dsl%26mi%3D0%26af%3DR International Journal of Plant Sciences, Volume 170, Issue 6, Page 759-765, July/August 2009. We investigated the population genetic structure of the invasive plant Hieracium aurantiacum (Asteraceae), a facultative apomict. We generated amplified fragment length polymorphism fingerprints for H. aurantiacum samples from across its invasive range in North America ($N=226$) and from six other North American native and invasive Hieracium species ($N=60$). Almost no genetic variability was found in the North American H. aurantiacum across locations from Alaska and Oregon to Pennsylvania and Ontario ($\mathrm{clonal}\,\,\mathrm{diversity}\,=0.035$). In contrast, other Hieracium species showed a range of clonal diversities ($\mathrm{range}\,=0.154{\mbox{--}} 1.0$). The single H. aurantiacum... International Journal of Plant Sciences journals http://www.medworm.com/rss/comments.php?id=2503864 Tue, 23 Jun 2009 18:37:30 +0100 2503864 http://www.medworm.com/index.php?rid=2503862&cid=s_36562_62_f&fid=36562&url=http%3A%2F%2Fwww.journals.uchicago.edu%2Fdoi%2Fabs%2F10.1086%2F599240%3Fai%3Dsl%26mi%3D0%26af%3DR International Journal of Plant Sciences, Volume 170, Issue 6, Page 735-747, July/August 2009. We investigated whether dynamic photosynthesis of understory Quercus rubra L. (Fagaceae) seedlings can acclimate to the altered pattern of sunflecks in forest patches with Rhododendron maximum L. (Ericaceae), an understory evergreen shrub. Maximum photosynthesis (A) and total CO2 accumulated during lightflecks was greatest for 400‐s lightflecks, intermediate for 150‐s lightflecks, and lowest for 50‐ and 75‐s lightflecks. For the 400‐s lightflecks only, maximum A and total CO2 accumulated were significantly lower for seedlings in forest patches with shrubs present (SF) than for seedlings in forest patches without shrubs (F). These effects were found only when A was calculated on a l... International Journal of Plant Sciences journals http://www.medworm.com/rss/comments.php?id=2503862 Tue, 23 Jun 2009 18:37:15 +0100 2503862 http://www.medworm.com/index.php?rid=2503866&cid=s_36562_62_f&fid=36562&url=http%3A%2F%2Fwww.journals.uchicago.edu%2Fdoi%2Fabs%2F10.1086%2F599239%3Fai%3Dsl%26mi%3D0%26af%3DR This study addresses the infrafamilial relationships of Dilleniaceae with nucleotide sequence data from the plastid loci rbcL, infA, rps4, and the rpl16 intron. Analyses of these data using maximum parsimony and Bayesian methods resolve Tetracera, the only pantropical genus in the family, as sister to all other Dilleniaceae. Within the clade of Dilleniaceae exclusive of Tetracera, the New World endemic genera form a clade that is sister to a clade composed of the Old World endemic genera. The latter contains two major subclades: (1) a clade containing Acrotrema, Dillenia, and Schumacheria and (2) a clade containing Hibbertia and its satellite genera, Adrastaea and Pachynema, which are embedded within Hibbertia. Ancestral‐state reconstructions of six morphological characters of both biolo... International Journal of Plant Sciences journals http://www.medworm.com/rss/comments.php?id=2503866 Tue, 23 Jun 2009 18:36:34 +0100 2503866 http://www.medworm.com/index.php?rid=2503859&cid=s_36562_62_f&fid=36562&url=http%3A%2F%2Fwww.journals.uchicago.edu%2Fdoi%2Fabs%2F10.1086%2F599237%3Fai%3Dsl%26mi%3D0%26af%3DR International Journal of Plant Sciences, Volume 170, Issue 6, Page 699-700, July/August 2009. (Source: International Journal of Plant Sciences) International Journal of Plant Sciences journals http://www.medworm.com/rss/comments.php?id=2503859 Tue, 23 Jun 2009 18:34:48 +0100 2503859 http://www.medworm.com/index.php?rid=2402528&cid=s_36562_62_f&fid=36562&url=http%3A%2F%2Fwww.journals.uchicago.edu%2Fdoi%2Fabs%2F10.1086%2F597817%3Fai%3Dsl%26af%3DR We examined early development of fibers, including abundance and placement on seed surface, nucleus position, presence of vacuoles, and fiber size and shape. Four species were studied using microscopic, morphometric, and statistical methods: Gossypium raimondii (wild D genome), Gossypium herbaceum (cultivated A genome), Gossypium hirsutum (wild tetraploid), and Gossypium hirsutum (cultivated tetraploid). Early fiber development is highly asynchronous in G. raimondii but more synchronous in other taxa. Significant changes associated with domestication include pronounced synchronization of fiber development in G. hirsutum relative to other taxa studied, implicating unconscious selection that shaped early molecular and cellular events, and a delay in some developmental features in fibers of G... International Journal of Plant Sciences journals http://www.medworm.com/rss/comments.php?id=2402528 Fri, 08 May 2009 22:18:03 +0100 2402528 http://www.medworm.com/index.php?rid=2402533&cid=s_36562_62_f&fid=36562&url=http%3A%2F%2Fwww.journals.uchicago.edu%2Fdoi%2Fabs%2F10.1086%2F597785%3Fai%3Dsl%26af%3DR International Journal of Plant Sciences, Volume 170, Issue 5, Page 627-643, June 2009. Molecular phylogenetics has revolutionized our understanding of the Caryophyllales, and yet many relationships have remained uncertain, particularly at deeper levels. We have performed parsimony and maximum likelihood analyses on separate and combined data sets comprising nine plastid genes (∼12,000 bp), two nuclear genes (∼5000 bp), and the plastid inverted repeat (∼24,000 bp), giving a combined analyzed length of 42,006 bp for 36 species of Caryophyllales and four outgroups. We have recovered strong support for deep‐level relationships across the order. Two major subclades are well supported, the noncore and core Caryophyllales; Rhabdodendron followed by Simmondsia are sisters to the core... International Journal of Plant Sciences journals http://www.medworm.com/rss/comments.php?id=2402533 Fri, 08 May 2009 21:58:55 +0100 2402533 http://www.medworm.com/index.php?rid=2402531&cid=s_36562_62_f&fid=36562&url=http%3A%2F%2Fwww.journals.uchicago.edu%2Fdoi%2Fabs%2F10.1086%2F597786%3Fai%3Dsl%26af%3DR International Journal of Plant Sciences, Volume 170, Issue 5, Page 599-608, June 2009. The impact of the horizontally transmitted endophyte Balansia henningsiana on the growth of C4 grass Panicum rigidulum was examined in the greenhouse under control and drought‐stress conditions. Tiller number, leaf number, and the root:shoot ratio were higher and shoot height and leaf area were lower for infected (E+) than for uninfected (E−) plants. Under control conditions, the total biomass was similar for E+ and E− plants. Under drought‐stress conditions, however, E+ plants had less biomass. In response to drought stress, E+ plants reduced leaf growth and increased leaf senescence more than E− plants. After recovery, E+ plants responded by more rapid leaf growth and allocated more res... International Journal of Plant Sciences journals http://www.medworm.com/rss/comments.php?id=2402531 Fri, 08 May 2009 21:58:43 +0100 2402531 http://www.medworm.com/index.php?rid=2402529&cid=s_36562_62_f&fid=36562&url=http%3A%2F%2Fwww.journals.uchicago.edu%2Fdoi%2Fabs%2F10.1086%2F597781%3Fai%3Dsl%26af%3DR International Journal of Plant Sciences, Volume 170, Issue 5, Page 575-583, June 2009. Allocation trade‐offs are predicted to affect evolutionary dynamics, including the evolution of sexual dimorphism. In gynodioecious species, where populations have both females and hermaphrodites, selection may result in sexual dimorphism in individual traits or trait correlations because, in contrast to females, hermaphrodites acquire fitness through both male and female function. Using the gynodioecious species Silene vulgaris, we measured reproductive traits (ovule number, ovule size, anther size, and floral traits related to display) and a vegetative trait (internode length) among plants growing under full sun and foliar shade treatments. We tested for sex‐specific correlation structures as... International Journal of Plant Sciences journals http://www.medworm.com/rss/comments.php?id=2402529 Fri, 08 May 2009 21:57:47 +0100 2402529 http://www.medworm.com/index.php?rid=2402535&cid=s_36562_62_f&fid=36562&url=http%3A%2F%2Fwww.journals.uchicago.edu%2Fdoi%2Fabs%2F10.1086%2F597782%3Fai%3Dsl%26af%3DR International Journal of Plant Sciences, Volume 170, Issue 5, Page 657-665, June 2009. Cynepteris bolichii is proposed as a new species of the monogeneric fern family Cynepteridaceae on the basis of a single, well‐articulated specimen from the Upper Triassic Chinle Formation in Petrified Forest National Park, Arizona. The specimen consists of an erect rhizome with at least eight attached fronds. As for the other three known Cynepteris species, C. bolichii pinnae exhibit reticulate venation and scattered, solitary, exindusiate sporangia on their abaxial surfaces. Each sporangium is ovoid to pyriform with a short, thick stalk and a complete, apical, caplike annulus consisting of a single row of cells surrounding a multicellular distal plate. These sporangial features are similar to t... International Journal of Plant Sciences journals http://www.medworm.com/rss/comments.php?id=2402535 Fri, 08 May 2009 21:57:42 +0100 2402535 http://www.medworm.com/index.php?rid=2402534&cid=s_36562_62_f&fid=36562&url=http%3A%2F%2Fwww.journals.uchicago.edu%2Fdoi%2Fabs%2F10.1086%2F597784%3Fai%3Dsl%26af%3DR International Journal of Plant Sciences, Volume 170, Issue 5, Page 644-656, June 2009. Permineralized Vertebraria roots from the late Permian of the Central Transantarctic Mountains, Antarctica, are investigated to understand the unusual vascular anatomy of the genus. The specimens range from ∼1 mm to several centimeters in diameter and illustrate all the stages of secondary growth. Our observations confirm previous hypotheses on the development of these roots and suggest that their unique anatomy is the result of a change in developmental timing. Vertebraria is characterized by a vascular cambium that remains discontinuous through several growth seasons, leading to the formation of lacunae alternating in cross section with wedges of secondary vascular tissues. The bifacial nature ... International Journal of Plant Sciences journals http://www.medworm.com/rss/comments.php?id=2402534 Fri, 08 May 2009 21:57:37 +0100 2402534 http://www.medworm.com/index.php?rid=2402536&cid=s_36562_62_f&fid=36562&url=http%3A%2F%2Fwww.journals.uchicago.edu%2Fdoi%2Fabs%2F10.1086%2F597799%3Fai%3Dsl%26af%3DR International Journal of Plant Sciences, Volume 170, Issue 5, Page 666-698, June 2009. Historically collected specimens of the Pennsylvanian pteridosperm Eremopteris artemisiaefolia have been reinvestigated to provide detailed information on its morphology and cuticular anatomy and to enable some of the external features of the plant to be reconstructed. The stem bore a distal crown of helically arranged compound leaves that show evidence they were actively abscissed from the plant. The blade consists of a main rachis that is straight or curved and may be undivided or show a single overtopped or occasionally dichotomous division. Secondary foliar segments are once or twice divided, with ultimate segments consisting of an elongate lanceolate blade, sometimes with one or two pairs of s... International Journal of Plant Sciences journals http://www.medworm.com/rss/comments.php?id=2402536 Fri, 08 May 2009 21:57:10 +0100 2402536 http://www.medworm.com/index.php?rid=2402532&cid=s_36562_62_f&fid=36562&url=http%3A%2F%2Fwww.journals.uchicago.edu%2Fdoi%2Fabs%2F10.1086%2F597780%3Fai%3Dsl%26af%3DR International Journal of Plant Sciences, Volume 170, Issue 5, Page 609-626, June 2009. Eleven highly polymorphic microsatellite markers were used to determine the genetic structure and levels of diversity in 51 natural populations of Pinus oocarpa across its geographic range of 3000 km in Mesoamerica. The study also included 17 populations of Pinus patula and Pinus tecunumanii chosen for their resistance or susceptibility to the pitch canker fungus based on previous research. Seedlings from all 68 populations were screened for pitch canker resistance, and results were correlated to mean genetic diversity and collection site variables. Results indicate that P. oocarpa exhibits average to above‐average levels of genetic diversity ($A=19.82$, $A_{\mathrm{R}\,}=11.86$, $H_{\mathrm{E... International Journal of Plant Sciences journals http://www.medworm.com/rss/comments.php?id=2402532 Fri, 08 May 2009 21:56:54 +0100 2402532 http://www.medworm.com/index.php?rid=2402530&cid=s_36562_62_f&fid=36562&url=http%3A%2F%2Fwww.journals.uchicago.edu%2Fdoi%2Fabs%2F10.1086%2F597269%3Fai%3Dsl%26af%3DR International Journal of Plant Sciences, Volume 170, Issue 5, Page 584-598, June 2009. Evolutionary shifts from insect to wind pollination involve a host of modifications to floral structure and phenology, but little is known about how floral modifications that facilitate pollination might affect the fertilization process. Within the water lily family Cabombaceae, there is evidence that wind pollination arose recently in Brasenia, whereas the sister genus Cabomba became specialized for fly pollination. Both species have an apomorphic stylar extension, which in Brasenia became greatly elongated to produce a much larger stigmatic surface. Consequently, pollen tubes in Brasenia must travel much farther to reach ovules, and because mean pollen tube growth rates are similar (750–950 μm... International Journal of Plant Sciences journals http://www.medworm.com/rss/comments.php?id=2402530 Fri, 08 May 2009 21:56:20 +0100 2402530 http://www.medworm.com/index.php?rid=2340008&cid=s_36562_62_f&fid=36562&url=http%3A%2F%2Fwww.journals.uchicago.edu%2Fdoi%2Fabs%2F10.1086%2F597270%3Fai%3Dsl%26af%3DR International Journal of Plant Sciences, Volume 170, Issue 4, Page 429-443, May 2009. Sensitivity cycling to physical dormancy (PY) break in seeds is known to occur in some Fabaceae and Convolvulaceae species. PY in seeds of species of Convolvulaceae and of some other angiosperm plant families can be broken by storing them dry. However, the mechanism of opening the water gap in the seed coat (dormancy break) during dry storage has not been investigated. In research reported here, we determined whether sensitivity cycling occurs in seeds of Ipomoea hederacea (Convolvulaceae) and investigated the effect of dry storage on opening of the water gap. Seeds can cycle between insensitive and sensitive states to dormancy break, and dormancy can be broken in sensitive seeds by storing them dry... International Journal of Plant Sciences journals http://www.medworm.com/rss/comments.php?id=2340008 Mon, 06 Apr 2009 19:12:44 +0100 2340008 http://www.medworm.com/index.php?rid=2340010&cid=s_36562_62_f&fid=36562&url=http%3A%2F%2Fwww.journals.uchicago.edu%2Fdoi%2Fabs%2F10.1086%2F597783%3Fai%3Dsl%26af%3DR International Journal of Plant Sciences, Volume 170, Issue 4, Page 457-466, May 2009. Hand sections of root and stem xylem of diverse species of Nymphaea (including Ondinea) were studied with SEM in order to explore the diversity of wall structure within the genus. Lateral walls of root tracheary elements are untextured at the magnifications used, but end wall structure suggests that lysis of pit membranes leaves a cellulosic network with a large reticulum. Stem tracheids have lateral walls that are untextured or have a few prominent fibrils, but end walls have a dense accretion of coarse fibrils. These fibrils form a spongiform or compressed network overlying the pit membranes. In addition, on the lumen side of pit membranes, coarse fibrils cross the pits in an axial direction. Thes... International Journal of Plant Sciences journals http://www.medworm.com/rss/comments.php?id=2340010 Mon, 06 Apr 2009 19:12:12 +0100 2340010 http://www.medworm.com/index.php?rid=2340009&cid=s_36562_62_f&fid=36562&url=http%3A%2F%2Fwww.journals.uchicago.edu%2Fdoi%2Fabs%2F10.1086%2F597273%3Fai%3Dsl%26af%3DR International Journal of Plant Sciences, Volume 170, Issue 4, Page 444-456, May 2009. Multicellular glandular trichomes form on gynoecia of wild annual Glycine species, annual soybean cultivars, and wild perennial Glycine species. These trichomes occur from the ovary base to the style base and, in perennial species, along the style as well. Trichomes form at least 2 d before anthesis, and new trichomes develop throughout flowering and also on young seed pods. Trichome structure is similar in all taxa examined, usually five to seven linearly arranged cells. Stalk cells with callose walls become highly vacuolate, and their cytoplasms have reduced numbers of Golgi bodies and endoplasmic reticulum. During secretion, two to four distal cells develop dense cytoplasms containing both promin... International Journal of Plant Sciences journals http://www.medworm.com/rss/comments.php?id=2340009 Mon, 06 Apr 2009 19:11:25 +0100 2340009 http://www.medworm.com/index.php?rid=2340013&cid=s_36562_62_f&fid=36562&url=http%3A%2F%2Fwww.journals.uchicago.edu%2Fdoi%2Fabs%2F10.1086%2F597271%3Fai%3Dsl%26af%3DR International Journal of Plant Sciences, Volume 170, Issue 4, Page 496-504, May 2009. Isoëtes L. is critically endangered in areas of East Asia, including Taiwan, Japan, and South Korea. The genetic diversity and the population structure of six Isoëtes species from East Asia were evaluated by using amplified fragment length polymorphism (AFLP). Three AFLP‐selective primer combinations generated a total 923 amplification products, of which 919 (99.6%) were polymorphic. The levels of genetic diversity of two diploid species (I. taiwanensis [percentage of polymorphic loci $( \mathrm{PPL}\,) =33.1\% {\mbox{--}} 38.3\% $] and I. asiatica [$\mathrm{PPL}\,=49.0\% $]) are higher than those of polyploid species (tetraploid: I. jejuensis [$\mathrm{PPL}\,=9.3\% {\mbox{--}} 29.3\% $] and I. ... International Journal of Plant Sciences journals http://www.medworm.com/rss/comments.php?id=2340013 Mon, 06 Apr 2009 19:11:14 +0100 2340013 http://www.medworm.com/index.php?rid=2340015&cid=s_36562_62_f&fid=36562&url=http%3A%2F%2Fwww.journals.uchicago.edu%2Fdoi%2Fabs%2F10.1086%2F597272%3Fai%3Dsl%26af%3DR In this study four types of floral phyllotaxis were recovered: Fibonacci spiral, simple-whorled (decussate), complex-whorled, and irregular. Whorled and spiral phyllotaxis co‐occur in all families except Gomortegaceae and even vary within a species in some Mollinedioideae (Monimiaceae). Complex‐whorled floral phyllotaxis with two or more organs in a position where only one is expected and changes in merism are especially prominent in Atherospermataceae and Monimiaceae. The most elaborate complex‐whorled phyllotaxis pattern (leading to 8‐merous whorls) is present in flowers with a flat floral base. Presence of a hyperstigma is correlated with double positions in the perianth. Flowers with low organ number commonly have simple‐whorled phyllotaxis; flowers with high organ number ha... International Journal of Plant Sciences journals http://www.medworm.com/rss/comments.php?id=2340015 Mon, 06 Apr 2009 19:10:06 +0100 2340015 http://www.medworm.com/index.php?rid=2340012&cid=s_36562_62_f&fid=36562&url=http%3A%2F%2Fwww.journals.uchicago.edu%2Fdoi%2Fabs%2F10.1086%2F597268%3Fai%3Dsl%26af%3DR International Journal of Plant Sciences, Volume 170, Issue 4, Page 476-495, May 2009. Many epacrids (Ericales: Ericaceae: Styphelioideae) possess the highly unusual character of variable sterility of some members of the pollen tetrad, producing tetrads, triads, dyads, and monads. In Leucopogon and Styphelia (Styphelioideae: Styphelieae), remarkably, three of the four cells produced by meiosis regularly degenerate. In this article, pollen structure was examined using TEM in nine species of Styphelioideae from five different tribes, together with pollen development in Leucopogon parviflorus. Both living and rehydrated herbarium material was used. Data on pollen units in Ericaceae, on the basis of these original observations and the results of an extensive literature survey, were optimi... International Journal of Plant Sciences journals http://www.medworm.com/rss/comments.php?id=2340012 Mon, 06 Apr 2009 19:08:49 +0100 2340012 http://www.medworm.com/index.php?rid=2340014&cid=s_36562_62_f&fid=36562&url=http%3A%2F%2Fwww.journals.uchicago.edu%2Fdoi%2Fabs%2F10.1086%2F597267%3Fai%3Dsl%26af%3DR International Journal of Plant Sciences, Volume 170, Issue 4, Page 505-521, May 2009. Molecular and morphological data were used to reconstruct the phylogeny of Camphorosmeae (Chenopodiaceae) in Australia, a tribe adapted to and widespread in the temperate arid and semiarid areas of the continent. A total of 71 species, representing nearly half of the species and all 14 currently recognized endemic genera, were sampled. Of seven molecular markers tested (ETS, ITS, the trnL‐trnF spacer, the trnP‐psaJ spacer, the rpS16 intron, the rpL16 intron, and the trnS‐trnG spacer), only the nuclear ETS and ITS provided enough variation for phylogenetic studies in the group. Phylogenetic hypotheses inferred from molecular data do not support the current taxonomy of Camphorosmeae in Australia... International Journal of Plant Sciences journals http://www.medworm.com/rss/comments.php?id=2340014 Mon, 06 Apr 2009 19:08:10 +0100 2340014 http://www.medworm.com/index.php?rid=2340011&cid=s_36562_62_f&fid=36562&url=http%3A%2F%2Fwww.journals.uchicago.edu%2Fdoi%2Fabs%2F10.1086%2F597266%3Fai%3Dsl%26af%3DR In this study, we examined the effects of pollen load and donor diversity on variation in seed and fruit mass of outcrossing senita cacti (Pachycereus schottii) in the Sonoran Desert. By massing all individual seeds per fruit from pollen supplementation and donor diversity experiments, we were able to examine their effects on seed and fruit mass, compared with intra‐ and interplant variation. Seed and fruit mass showed up to 13‐ and 15‐fold variations, respectively. Pollen load did statistically increase seed and fruit mass, but it explained (Source: International Journal of Plant Sciences) International Journal of Plant Sciences journals http://www.medworm.com/rss/comments.php?id=2340011 Mon, 06 Apr 2009 19:07:45 +0100 2340011 http://www.medworm.com/index.php?rid=2340016&cid=s_36562_62_f&fid=36562&url=http%3A%2F%2Fwww.journals.uchicago.edu%2Fdoi%2Fabs%2F10.1086%2F596335%3Fai%3Dsl%26af%3DR International Journal of Plant Sciences, Volume 170, Issue 4, Page 551-560, May 2009. Sixty trigonal fagaceous fruits have been identified in the calcareous nodules from the Eocene Appian Way locality of Vancouver Island, British Columbia, Canada. The anatomically preserved fruits are known at various developmental stages. In transverse section, fruits are triangular, with lateral ridges that vary in shape from rounded to sharply angled. In longitudinal section, the nuts show a broad base and a tapered apex. The ovary is partitioned into three locules at the apex, and placentation is axile, with two ovules per locule. Locules merge near the base, giving the appearance of a three‐lobed ovarian cavity. This area is occupied by a single seed at maturity. The inner wall of the endocarp... International Journal of Plant Sciences journals http://www.medworm.com/rss/comments.php?id=2340016 Mon, 06 Apr 2009 19:07:18 +0100 2340016 http://www.medworm.com/index.php?rid=979664&cid=s_36562_62_f&fid=36562&url=http%3A%2F%2Fwww.journals.uchicago.edu%2Fcgi-bin%2Frssresolve%3Fijps%2BIJPS30540 This study shows that each samaroid structure in Amphipterygium is a few-flowered cyme and that the teeth at the entrance of the cupule are the subtending bracts of the flowers. A comparison of Amphipterygium with Pistacia also shows that both genera share with Rhus and other genera of Anacardioideae a tricarpellate, pseudomonomerous gynoecium with a unilocular ovary and a single crassinucellar and (hemi)anatropous ovule with a ponticulus. However, the ovules in both Amphipterygium and Pistacia are outstanding in being unitegmic (though sometimes with traces of a second integument on the convex side) and having a massive funicle with unique lateral and median outgrowths, which becomes much larger than the ovule after anthesis. The funicle is also proportionally much larger and more complic... International Journal of Plant Sciences journals http://www.medworm.com/rss/comments.php?id=979664 Thu, 25 Oct 2007 18:46:30 +0100 979664 http://www.medworm.com/index.php?rid=979663&cid=s_36562_62_f&fid=36562&url=http%3A%2F%2Fwww.journals.uchicago.edu%2Fcgi-bin%2Frssresolve%3Fijps%2BIJPS30522 A new species, Millerocaulis preosmunda, is established based on specimens collected from the Lanqi Formation (Middle Jurassic) near Changgao, Liaoning Province, China, and provides evidence for tracing the evolution of living Osmunda subg. Osmunda. The specimens represent two stems surrounded by a mantle of stipular petiole bases and adventitious roots. The stems, 10–13 mm in diameter, consist of siphonostele and a two-layered cortex containing 32–35 leaf traces. When departing from the stele, the leaf traces are a flattened C shape, with an endarch protoxylem that bifurcates at the base of the petiole. Sclerenchyma rings are heterogeneous and change from an abaxial band at the base of stipular petiole bases to two lateral strands at the top. A heterogeneous sclerenchyma mass is prese... International Journal of Plant Sciences journals http://www.medworm.com/rss/comments.php?id=979663 Thu, 25 Oct 2007 18:46:30 +0100 979663 http://www.medworm.com/index.php?rid=979662&cid=s_36562_62_f&fid=36562&url=http%3A%2F%2Fwww.journals.uchicago.edu%2Fcgi-bin%2Frssresolve%3Fijps%2BIJPS30558 Data on the reproductive biology of the Annonaceae are rather fragmentary, particularly for paleotropical species. The pollination ecology and breeding system of the Sri Lankan endemic Xylopia championii (Annonaceae) are described in detail. The pollination ecology was investigated using a diverse range of approaches, including (1) observations of flower-level and population-level phenology, (2) assessments of floral visitors and effective pollinators, (3) monitoring of floral temperature in situ using a digital data logger, and (4) analysis of scent chemistry using solid-phase microextraction sampling and gas chromatography–mass spectrometry identification of volatiles. The breeding system was evaluated using pollen/ovule ratios and field-based controlled-pollination experiments. Intraf... International Journal of Plant Sciences journals http://www.medworm.com/rss/comments.php?id=979662 Thu, 25 Oct 2007 18:46:30 +0100 979662 http://www.medworm.com/index.php?rid=979661&cid=s_36562_62_f&fid=36562&url=http%3A%2F%2Fwww.journals.uchicago.edu%2Fcgi-bin%2Frssresolve%3Fijps%2BIJPS30600 Ovule development in Ginkgo biloba is examined. Ovulate stalks are initiated in leaf axils, and each stalk primordium dichotomizes to produce two ovule primordia. Integument development appears circumferential and during micropyle formation becomes slightly lobed. Primary nucellar tissues are derived from periclinal divisions in the hypodermal layer, which is limited to several apically located cells of the nucellus and remains active through pollen chamber formation. One spore mother cell differentiates in the sporangial tissues; others differentiate as tapetum. The epidermal layer does not contribute directly to development of the primary nucellus but does contribute to secondary nucellar tissues. Secondary parietal tissues are divided into regions based on their growth patterns and loca... International Journal of Plant Sciences journals http://www.medworm.com/rss/comments.php?id=979661 Thu, 25 Oct 2007 18:46:30 +0100 979661 http://www.medworm.com/index.php?rid=979660&cid=s_36562_62_f&fid=36562&url=http%3A%2F%2Fwww.journals.uchicago.edu%2Fcgi-bin%2Frssresolve%3Fijps%2BIJPS30615 This study identifies four major lineages within the family, each strongly supported as a monophyletic group. Two large genera, Dryopteris and Polystichum, as traditionally defined, are shown to be polyphyletic and need to be revised in the future. (Source: International Journal of Plant Sciences) International Journal of Plant Sciences journals http://www.medworm.com/rss/comments.php?id=979660 Thu, 25 Oct 2007 18:46:30 +0100 979660 http://www.medworm.com/index.php?rid=979659&cid=s_36562_62_f&fid=36562&url=http%3A%2F%2Fwww.journals.uchicago.edu%2Fcgi-bin%2Frssresolve%3Fijps%2BIJPS30378 Tenuisa frasniana gen. et sp. nov. is reported from the Late Devonian (Frasnian) Hunan Province of South China. Its axes are naked and narrow. Fertile stem is pseudomonopodial in branching and bears distichous lateral units. Fertile lateral units are subopposite and pseudomonopodial in the proximal part of stem, while they are alternate and isotomous two to four times in the distal part. They have tiny terminal sporangia that are paired and fusiform and that possess pedicels. Sterile ultimate units are dichotomous and terminate in tips recurving oppositely. Tenuisa resembles Psilophyton in pseudomonopodial fertile stem with alternate and dichotomous lateral units terminated by paired and vertically elongate sporangia. However, fertile lateral units are subopposite and pseudomonopodial on t... International Journal of Plant Sciences journals http://www.medworm.com/rss/comments.php?id=979659 Thu, 25 Oct 2007 18:46:30 +0100 979659 http://www.medworm.com/index.php?rid=979658&cid=s_36562_62_f&fid=36562&url=http%3A%2F%2Fwww.journals.uchicago.edu%2Fcgi-bin%2Frssresolve%3Fijps%2BIJPS30583 Capsule dehiscence, seed dispersal, and seed dormancy and germination were examined in Oenothera triloba and Oenothera macrocarpa. The hygrochastic capsules of O. triloba, resembling splash cups, opened, and seeds were dispersed during rain. Capsules retained viable seeds for at least 1 yr, and the seeds were nondormant and could germinate at any time of the year as long as temperatures were ca. 15°/6°C or higher. In contrast, the xerochastic capsules of O. macrocarpa, which also mature by July, opened during late autumn and winter with moisture and temperatures ≤5°C. As opposed to O. triloba capsules, O. macrocarpa capsules were fully expanded when dried after rain. Seeds of O. macrocarpa required cold stratification for release from dormancy, which occurred while the capsules were g... International Journal of Plant Sciences journals http://www.medworm.com/rss/comments.php?id=979658 Thu, 25 Oct 2007 18:46:30 +0100 979658 http://www.medworm.com/index.php?rid=979657&cid=s_36562_62_f&fid=36562&url=http%3A%2F%2Fwww.journals.uchicago.edu%2Fcgi-bin%2Frssresolve%3Fijps%2BIJPS30580 Members of Simaroubaceae comprise a clade of 22 genera and ca. 100 species in the Sapindales. Previous phylogenetic analyses of the family were limited to a single gene and seven genera, and relationships among the genera remain poorly understood. Molecular data from three plastid genes (rbcL, atpB, and matK) and a nuclear gene (phyC), totaling ca. 6000 bp, are used to reconstruct the phylogeny of Simaroubaceae and clarify generic limits, employing maximum parsimony (MP) and Bayesian approaches. Individual analyses of genes are largely congruent, and both MP and Bayesian analyses of combined data produce well-supported phylogenies. Nothospondias, an African genus of uncertain affiliation, is found to be a member of the family. A clade composed of Picrasma, Holacantha, and Castela is sister... International Journal of Plant Sciences journals http://www.medworm.com/rss/comments.php?id=979657 Thu, 25 Oct 2007 18:46:30 +0100 979657 http://www.medworm.com/index.php?rid=979656&cid=s_36562_62_f&fid=36562&url=http%3A%2F%2Fwww.journals.uchicago.edu%2Fcgi-bin%2Frssresolve%3Fijps%2BIJPS30480 This article records a diverse assemblage of fossil leaves of another major scleromorphic group, the epacrids (subfamily Styphelioideae of Ericaceae, formerly known as Epacridaceae). The fossils are from Stony Creek Basin, in the western uplands of Victoria, Australia, and are of earliest Pleistocene age (ca. 1.6 million years old). They include 19 forms sufficiently distinct as to constitute different species. This diversity is considerably greater than the extant diversity of epacrids in the region. Published taphonomic data are used to argue that the actual diversity of the source vegetation of the fossil flora may have been significantly greater and comparable to the current local species richness of the centers of diversity. Ten of the fossil species are assigned to the largest extant... International Journal of Plant Sciences journals http://www.medworm.com/rss/comments.php?id=979656 Thu, 25 Oct 2007 18:46:30 +0100 979656 http://www.medworm.com/index.php?rid=979655&cid=s_36562_62_f&fid=36562&url=http%3A%2F%2Fwww.journals.uchicago.edu%2Fcgi-bin%2Frssresolve%3Fijps%2BIJPS30596 We investigated genetic variation within and among 11 populations of Iris hexagona at its southern limits in the Florida peninsula by using 19 microsatellite loci. All of the populations contain varying numbers of identical multilocus genotypes, indicative of clonal reproduction. Two population samples consist largely of one clonal lineage and two clonal lineages: the first from the Caloosahatchee drainage west of Lake Okeechobee and the other from the Big Cypress Swamp. The populations are predominantly outcrossing, with high levels of heterozygosity, and show a highly significant pattern of isolation by distance that fits a modified stepping-stone model. This pattern breaks down at the local level, however, where metapopulation dynamics or asymmetrical gene flow may exert a stronger effe... International Journal of Plant Sciences journals http://www.medworm.com/rss/comments.php?id=979655 Thu, 25 Oct 2007 18:46:30 +0100 979655 http://www.medworm.com/index.php?rid=979654&cid=s_36562_62_f&fid=36562&url=http%3A%2F%2Fwww.journals.uchicago.edu%2Fcgi-bin%2Frssresolve%3Fijps%2BIJPS30606 Grasses infected with endosymbiotic ascomyceteous fungi (family Clavicipitaceae) often show increased growth and vigor; however, when resources are limited, the costs of being infected may outweigh the advantages. We grew multiple genotypes of two grasses species (Lolium perenne and Lolium arundinaceum) infected (or uninfected) with Neotyphodium sp. under limited light or water availability and measured both biomass and relative growth rates. There was a significant interaction between water stress and infection in L. perenne, while in L. arundinaceum, there were significant differences between infected and uninfected plants but no significant interaction. In both species, there were significant interactions between light level and infection. At full sun, infected plants were larger, while... International Journal of Plant Sciences journals http://www.medworm.com/rss/comments.php?id=979654 Thu, 25 Oct 2007 18:46:30 +0100 979654 http://www.medworm.com/index.php?rid=953112&cid=s_36562_62_f&fid=36562&url=http%3A%2F%2Fwww.journals.uchicago.edu%2Fcgi-bin%2Frssresolve%3Fijps%2BIJPS30524 Distinct leaf laminar growth dynamics have been found previously in some filicalean ferns and angiosperm seed plants: a discrete zone of marginal growth versus diffuse intercalary growth throughout the leaf without a conspicuous marginal growth zone. The fern pinnules for which marginal growth is known are also morphologically distinct from dicots: one or two orders of dichotomizing veins ending only along the margin versus many orders that include internally directed veins and endings dispersed throughout the leaf. Both of those morphological alternatives have evolved many times among extant and fossil plants, but whether similar developmental processes underlie each recurrence of a particular laminar morphology has not been investigated. Here, marginal growth is demonstrated in two indep... International Journal of Plant Sciences journals http://www.medworm.com/rss/comments.php?id=953112 Fri, 07 Sep 2007 22:12:10 +0100 953112 http://www.medworm.com/index.php?rid=953111&cid=s_36562_62_f&fid=36562&url=http%3A%2F%2Fwww.journals.uchicago.edu%2Fcgi-bin%2Frssresolve%3Fijps%2BIJPS30462 We tested two hypotheses for how vessel evolution in angiosperms influenced xylem function. First, the transition to vessels decreased resistance to flow—often considered the driving force for their evolution. Second, the transition to vessels compromised safety from cavitation—a constraint emerging from the “pit area hypothesis” for vulnerability to cavitation. Data were obtained from branch wood of 17 basal taxa with vessels and two eudicots possessing “primitive” perforation plates. Results were compared with previous data from vesselless angiosperms and eudicots with simple perforation plates. Contrary to the first hypothesis, basal taxa did not have significantly lower sapwood-specific resistivity than vesselless angiosperms, despite vessels being wider than tracheids. Eud... International Journal of Plant Sciences journals http://www.medworm.com/rss/comments.php?id=953111 Fri, 07 Sep 2007 22:12:10 +0100 953111 http://www.medworm.com/index.php?rid=953110&cid=s_36562_62_f&fid=36562&url=http%3A%2F%2Fwww.journals.uchicago.edu%2Fcgi-bin%2Frssresolve%3Fijps%2BIJPS30461 Two structure-function hypotheses were tested for vesselless angiosperm wood. First, vesselless angiosperm wood should have much higher flow resistance than conifer wood because angiosperm tracheids lack low-resistance torus-margo pits. Second, vesselless wood ought to be exceptionally safe from cavitation if the small cumulative area of pits between tracheids confers safety (the pit area hypothesis). Data were obtained from branch wood of 19 vesselless angiosperms: Amborella trichopoda, Trochodendron aralioides, Tetracentron sinense, and 16 Winteraceae from Tasmannia, Zygogynum, Bubbia, Pseudowintera, and Drimys. Contrary to the first hypothesis, vesselless and conifer species with narrow tracheids (below ca. 18 μm) had similar area-specific resistivities. The reason was that vesselless ... International Journal of Plant Sciences journals http://www.medworm.com/rss/comments.php?id=953110 Fri, 07 Sep 2007 22:12:10 +0100 953110 http://www.medworm.com/index.php?rid=953109&cid=s_36562_62_f&fid=36562&url=http%3A%2F%2Fwww.journals.uchicago.edu%2Fcgi-bin%2Frssresolve%3Fijps%2BIJPS30437 Although broccoli is moderately tolerant to salt stress, the tolerance mechanism is still unknown. Therefore, in this article, the uptake and transport of nutrients and water in relation to the changes in root anatomy (phi thickening appearance) caused by salinity stress have been studied. The effect of phi thickening in the response of these plants to salinity was studied by comparing two methods of measuring root hydraulic conductance, pressurizing roots and natural exudation, and analyzing the nutrient concentrations in the xylem. The permeability properties of phi thickening were tested by a tracer that moves only via the apoplastic pathway. Brassica oleracea L. var. Italica plants, grown under different levels of NaCl (0, 40, and 80 mM), showed modifications in the cell wall of the co... International Journal of Plant Sciences journals http://www.medworm.com/rss/comments.php?id=953109 Fri, 07 Sep 2007 22:12:10 +0100 953109 http://www.medworm.com/index.php?rid=953108&cid=s_36562_62_f&fid=36562&url=http%3A%2F%2Fwww.journals.uchicago.edu%2Fcgi-bin%2Frssresolve%3Fijps%2BIJPS30472 This study provides a new temporal framework for ligule acquisition and early diversification of heterosporous lycopsid lineages and implies that homosporous, ligulate lycopsid lineages (i.e., Leclercqia of Protolepidodendrales) and heterosporous, ligulate lycopsid lineages (i.e., Selaginellales and Isoetales) had diverged by the late Middle Devonian. (Source: International Journal of Plant Sciences) International Journal of Plant Sciences journals http://www.medworm.com/rss/comments.php?id=953108 Fri, 07 Sep 2007 22:12:10 +0100 953108 http://www.medworm.com/index.php?rid=953107&cid=s_36562_62_f&fid=36562&url=http%3A%2F%2Fwww.journals.uchicago.edu%2Fcgi-bin%2Frssresolve%3Fijps%2BIJPS30354 The mechanical architecture of the Carboniferous seed fern Lyginopteris oldhamia is investigated from development stages including naturally decorticated stems. The growth form shows a relatively long semi-self-supporting phase of growth, with prolonged retention of the primary outer “dictyoxylon” cortex contributing significantly during early and mature growth. The outer cortex is retained on the stem despite significant secondary vascular growth via radial and tangential expansion and proliferation of interstitial parenchyma and longitudinal division of the radial bands of fibers. In the final stages of development, the outer “mechanical dictyoxylon” cortex is sloughed from the stem after periderm development in the inner cortex. Loss of the outer cortex results in a decrease in ... International Journal of Plant Sciences journals http://www.medworm.com/rss/comments.php?id=953107 Fri, 07 Sep 2007 22:12:10 +0100 953107 http://www.medworm.com/index.php?rid=953106&cid=s_36562_62_f&fid=36562&url=http%3A%2F%2Fwww.journals.uchicago.edu%2Fcgi-bin%2Frssresolve%3Fijps%2BIJPS30482 Cashew nuts have been identified among compression fossils from the early Middle Eocene lake sediments of Messel, Germany. These fossil fruits confirm that the cashew genus, Anacardium, was formerly distributed in Europe, remote from the modern native distribution in Central and South America. Anacardium germanicum sp. n. shows that the characteristic inflated pedicel, or “cashew apple,” which facilitates biotic dispersal of cashew nuts, evolved at least 47 million yr ago. It was previously proposed that Anacardium and its African sister genus, Fegimanra, diverged from their common ancestor when the landmasses of Africa and South America separated. However, the paleobotanical data indicate a connection via the Northern Hemisphere with Europe as an important footstep in the spread of th... International Journal of Plant Sciences journals http://www.medworm.com/rss/comments.php?id=953106 Fri, 07 Sep 2007 22:12:10 +0100 953106 http://www.medworm.com/index.php?rid=953105&cid=s_36562_62_f&fid=36562&url=http%3A%2F%2Fwww.journals.uchicago.edu%2Fcgi-bin%2Frssresolve%3Fijps%2BIJPS30425 Bandulskaia aestuaria gen. et sp. nov. is described from Early Eocene estuarine sediments in Tasmania. It is represented by an incomplete leaf with a finely toothed margin and well-preserved cuticle. Despite the absence of such teeth in more than 2500 known species of fossil and extant Lauraceae, the fossil cuticle exhibits traits that in combination are found only in the family. These include the derived characters of sunken, paracytic stomata with small, apparently embedded guard cells, stomata confined to small areoles, and stomatal positions that are marked by slitlike abaxial surface apertures, as well as the presence of persistent resin bodies and simple, uniseriate trichomes with thickened, poral bases. Although monimioid teeth occur widely in other lauralean families, the teeth in ... International Journal of Plant Sciences journals http://www.medworm.com/rss/comments.php?id=953105 Fri, 07 Sep 2007 22:12:10 +0100 953105 http://www.medworm.com/index.php?rid=953104&cid=s_36562_62_f&fid=36562&url=http%3A%2F%2Fwww.journals.uchicago.edu%2Fcgi-bin%2Frssresolve%3Fijps%2BIJPS30517 The increasing number of pseudogenic internal transcribed spacer (ITS) regions (ITS1, 5.8S rDNA, ITS2) reported for plant taxa raises questions—for example, concerning the proportion of functional copies. Our application of quantitative PCR (qPCR) with genomic DNA under stringent conditions revealed that (Source: International Journal of Plant Sciences) International Journal of Plant Sciences journals http://www.medworm.com/rss/comments.php?id=953104 Fri, 07 Sep 2007 22:12:10 +0100 953104