abstract：:When more pollen is present on stigmas than needed to fertilize all ovules, selection among pollen grains may occur due to effects of both pollen donors and maternal plants. We asked whether increasing plant age and flower age, two changes in maternal condition, altered the pattern of seed paternity after mixed pollin...

journal_title：American journal of botany

authors： Marshall DL,Reynolds J,Abrahamson NJ,Simpson HL,Barnes MG,Medeiros JS,Walsh S,Oliveras DM,Avritt JJ

更新日期：2007-03-01 00:00:00

abstract：:We used isozymes (16 loci in 11 enzymatic systems) from Laelia speciosa, an endemic and endangered epiphytic orchid of Mexico, to assess the genetic diversity and population genetic structure in nine populations distributed along its geographic range, as well as to detect those populations that are genetically unique ...

journal_title：American journal of botany

authors： Avila-Díaz I,Oyama K

更新日期：2007-02-01 00:00:00

abstract：:The specific shape of the relationship between plant diversity and productivity and the causal mechanism(s) behind the observed pattern(s) are still highly debated. Recent advances suggest that the relationship depends on several environmental variables and may change with the observational scale. In this study, a mul...

journal_title：American journal of botany

authors： de Lafontaine G,Houle G

更新日期：2007-01-01 00:00:00

abstract：:In contrast to most angiosperms, in which fertilization occurs 1 or 2 days after pollination, in some plant orders, including the Fagales, fertilization is delayed from 4 days to more than 1 year, raising questions regarding why fertilization is delayed and where and how pollen tubes remain in the pistil during the de...

journal_title：American journal of botany

authors： Sogo A,Tobe H

更新日期：2006-12-01 00:00:00

abstract：:Climate changes during glacial periods have had significant effects on the present geographic distribution of plant species. To elucidate the evolutionary history of a plant species with a disjunctive distribution, we investigated the geographic distribution patterns of cpDNA haplotypes in Photinia glabra (Rosaceae) g...

journal_title：American journal of botany

authors： Aoki K,Matsumura T,Hattori T,Murakami N

更新日期：2006-12-01 00:00:00

abstract：:Understanding the role of mother plants as pollen recipients in shaping mating patterns is essential for understanding the evolution of populations and in particular to predict the consequence of habitat fragmentation. Here, we investigated variation in mating patterns due to maternal phenotypic traits, phenological v...

journal_title：American journal of botany

authors： Oddou-Muratorio S,Klein EK,Demesure-Musch B,Austerlitz F

更新日期：2006-11-01 00:00:00

abstract：:Wood, or secondary xylem, is composed mostly of three components-cellulose, hemicelluloses, and lignin. Yet this apparent simplicity is deceiving because the sophisticated arrangement of the components on various structural levels, ranging from intricate molecular architecture to defined cellular arrangements to tissu...

journal_title：American journal of botany

authors： Koehler L,Telewski FW

更新日期：2006-10-01 00:00:00

abstract：:Terrestrial plant leaves are complex structures of composite materials. Resistance to fracture is achieved by a number of mechanisms, which operate at the molecular, cell, tissue, and structural levels. Leaves of dicots have different venation patterns and cell wall volume fractions from those of grasses, and conseque...

journal_title：American journal of botany

authors： Sanson G

更新日期：2006-10-01 00:00:00

abstract：:Plant xylem must balance efficient delivery of water to the canopy against protection from air entry into the conduits via air-seeding. We investigated the relationship between tracheid allometry, end wall pitting, safety from air-seeding, and the hydraulic efficiency of conifer wood in order to better understand the ...

journal_title：American journal of botany

authors： Pittermann J,Sperry JS,Hacke UG,Wheeler JK,Sikkema EH

更新日期：2006-09-01 00:00:00

abstract：:This study shows that structural data, when carefully examined, can provide valuable characters for delimiting monophyletic groups and can complement DNA with observable features to recognize and circumscribe taxa. In the angiosperm order Apiales, traditional classification has relied heavily (often exclusively) on fr...

journal_title：American journal of botany

authors： Liu MR,Plunkett GM,Lowry PP 2nd,Wyk BE,Tilney PM

更新日期：2006-09-01 00:00:00

abstract：:Recent molecular phylogenetic studies of Solanaceae have identified many well-supported clades within the family and have permitted the creation of a phylogenetic system of classification. Here we estimate the phylogeny for Iochrominae, a clade of Physaleae sensu Olmstead et al. (1999), which contains 34 Andean specie...

journal_title：American journal of botany

authors： Smith SD,Baum DA

更新日期：2006-08-01 00:00:00

abstract：:Xylem of the orchids studied provided unusually favorable material to demonstrate how conductive tissue evolves in monocotyledons. In the end walls of tracheary elements of many Orchidaceae, remnants of pit membranes were observed with scanning electron microscopy and minimally destructive methods. The full range from...

journal_title：American journal of botany

authors： Carlquist S,Schneider EL

更新日期：2006-07-01 00:00:00

abstract：:The evolutionary origins of the morphological and taxonomic diversity of angiosperms is poorly known. We used the genus Melianthus to explore the diversification of the southern African flora. Melianthus comprises eight species, and a phylogeny based on one nuclear and two plastid genes, as well as a morphological dat...

journal_title：American journal of botany

authors： Linder HP,Dlamini T,Henning J,Verboom GA

更新日期：2006-07-01 00:00:00

abstract：:Polyploids have significantly influenced angiosperm evolution. Understanding the genetic consequences of polyploidy is advanced by studies on synthetic allopolyploids that mimic natural species. In Nicotiana, Burk (1973) and Kostoff (1938) generated synthetic tobacco (N. tabacum) using the parents ♀N. sylvestris × ♂N....

journal_title：American journal of botany

authors： Lim KY,Souckova-Skalicka K,Sarasan V,Clarkson JJ,Chase MW,Kovarik A,Leitch AR

更新日期：2006-06-01 00:00:00

abstract：:Members of tribe Vandeae (Orchidaceae) form a large, pantropical clade of horticulturally important epiphytes. Monopodial leafless members of Vandeae have undergone extreme reduction in habit and represent a novel adaptation to the canopy environment in tropical Africa, Asia, and America. To study the evolution of mon...

journal_title：American journal of botany

authors： Carlsward BS,Whitten WM,Williams NH,Bytebier B

更新日期：2006-05-01 00:00:00

abstract：:New individuals in clonal populations arise through the recruitment of sexual or clonal offspring. The predominance of one type of regeneration over the other has been correlated with different selective environmental pressures. We compared the reproductive mode (sexual through seeds and vegetative through plantlets o...

journal_title：American journal of botany

authors： Palleiro N,Mandujano MC,Golubov J

更新日期：2006-04-01 00:00:00

abstract：:Breakdown of genetically enforced self-incompatibility (SI), an extremely common and important evolutionary transition in plants, has conventionally been conceived as a qualitative rather than a quantitative change. We evaluated qualitative and quantitative variation in SI for four populations of Witheringia solanacea...

journal_title：American journal of botany

authors： Stone JL,Sasuclark MA,Blomberg CP

更新日期：2006-04-01 00:00:00

abstract：:Caryophyllaceae is a principally holarctic family including around 2200 species often classified into the three subfamilies Alsinoideae, Caryophylloideae, and Paronychioideae. Complex and possibly homoplasious morphological characters within the family make taxa difficult to delimit and diagnose. To explore part of th...

journal_title：American journal of botany

authors： Fior S,Karis PO,Casazza G,Minuto L,Sala F

更新日期：2006-03-01 00:00:00

abstract：:Pinus baileyi from the Paleogene of Idaho was initially related to the bristlecone pine P. longaeva (subgen. Strobus, sect. Parrya, subsect. Balfourianae) from western North America. Unlike the centromucronate condition in P. longaeva, P. baileyi cones have raised umbos that are excentromucronate, i.e., the mucro posi...

journal_title：American journal of botany

authors： Erwin DM,Schorn HE

更新日期：2006-02-01 00:00:00

abstract：:Senna (Leguminosae) is a large, widespread genus that includes species with enantiostylous, asymmetric flowers and species with extrafloral nectaries. Clarification of phylogenetic relationships within Senna based on parsimony analyses of three chloroplast regions (rpS16, rpL16, and matK) provides new insights on the ...

journal_title：American journal of botany

authors： Marazzi B,Endress PK,Queiroz LP,Conti E

更新日期：2006-02-01 00:00:00

abstract：:Oxalate crystals are very common in angiosperms, but few descriptions of their macropattern (crystal types, their tissue distribution, and development) exist. Because unusually large prismatic crystals and druses, are known from pomegranate, we traced the development of crystal macropattern in various-aged leaf sample...

journal_title：American journal of botany

authors： Lersten NR,Horner HT

更新日期：2005-12-01 00:00:00

abstract：:The North American plums are a closely related group that are not easily circumscribed, have overlapping morphologies, and are known to hybridize. We previously showed that the North American plums are a closely related, monophyletic group of taxa with little to no cpDNA sequence divergence between taxa. In that study...

journal_title：American journal of botany

authors： Shaw J,Small RL

更新日期：2005-12-01 00:00:00

abstract：:Polyploid speciation is an ongoing, important source of angiosperm diversity. However, the barriers to polyploid speciation and mechanisms of establishment remain poorly understood for all but a few species. Several factors likely to have influenced tetraploid establishment, including barriers to triploid formation, c...

journal_title：American journal of botany

authors： Baack EJ

更新日期：2005-11-01 00:00:00

abstract：:Ontogenetic changes in architecture, carbohydrate reserves, and resource allocation can constrain the ability of plants to compensate for herbivore damage. To evaluate ontogenetic changes in compensation, saplings and reproductive individuals of the tropical tree Casearia nitida were subjected to three levels of defol...

journal_title：American journal of botany

authors： Boege K

更新日期：2005-10-01 00:00:00

abstract：:The genus Pinguicula is one of the three genera of the carnivorous Lentibulariaceae, comprising approximately 80 species. Phylogeny inference using nucleotide sequences of the chloroplast gene matK and the trnK group II intron, as well as a set of 32 morphological characters revealed five well-supported, major lineage...

journal_title：American journal of botany

authors： Cieslak T,Polepalli JS,White A,Müller K,Borsch T,Barthlott W,Steiger J,Marchant A,Legendre L

更新日期：2005-10-01 00:00:00

abstract：:Light propagation and distribution inside leaves have been recognized as important processes influencing photosynthesis. Monochromatic light absorption across the mesophyll was measured using chlorophyll fluorescence generated from illumination of the cut edge (epi-illumination), as well as the adaxial or abaxial surf...

journal_title：American journal of botany

authors： Johnson DM,Smith WK,Vogelmann TC,Brodersen CR

更新日期：2005-09-01 00:00:00

abstract：:Parsimony, likelihood, and Bayesian analyses of nuclear ITS and plastid trnL-F DNA sequence data are presented for the giant genus Croton (Euphorbiaceae s.s.) and related taxa. Sampling comprises 88 taxa, including 78 of the estimated 1223 species and 29 of the 40 sections previously recognized of Croton. It also incl...

journal_title：American journal of botany

authors： Berry PE,Hipp AL,Wurdack KJ,Van Ee B,Riina R

更新日期：2005-09-01 00:00:00

abstract：:Welwitschiaceae, a family in the Gnetales, is known today from only one extant species, Welwitschia mirabilis. This species is distributed in the Namibian desert, along the western coast of southern Africa, about 10 km inland from the coast. Very little is known about the fossil record of this family. Lower Cretaceous...

journal_title：American journal of botany

authors： Dilcher DL,Bernardes-De-Oliveira ME,Pons D,Lott TA

更新日期：2005-08-01 00:00:00

abstract：:Scaling relationships among photosynthetic rate, foliar nutrient concentration, and leaf mass per unit area (LMA) have been observed for a broad range of plants. Leaf traits of the carnivorous pitcher plant Darlingtonia californica, endemic to southern Oregon and northern California, USA, differ substantially from the...

journal_title：American journal of botany

authors： Ellison AM,Farnsworth EJ

更新日期：2005-07-01 00:00:00

abstract：:The cacti are well-known desert plants, widely recognized by their specialized growth form and essentially leafless condition. Pereskia, a group of 17 species with regular leaf development and function, is generally viewed as representing the "ancestral cactus," although its placement within Cactaceae has remained unc...

journal_title：American journal of botany

authors： Edwards EJ,Nyffeler R,Donoghue MJ

更新日期：2005-07-01 00:00:00

abstract：:Seed size and cotyledon morphology are two key juvenile traits that have evolved in response to changes in plant species life-history strategies and habitat associations. Correlations of these traits with each other and with other juvenile traits were examined for 70 species of trees and shrubs in Kibale National Park...

journal_title：American journal of botany

authors： Zanne AE,Chapman CA,Kitajima K

更新日期：2005-06-01 00:00:00

abstract：:Based on positive results for 11 of 17 species included in an anatomical survey of tree roots, we concluded that the origin of adventitious branch roots (ABR) on established, undisturbed woody parental root axes is a widespread occurrence. ABR were morphologically indistinguishable from branch roots formed in primary ...

journal_title：American journal of botany

authors： Paolillo DJ Jr,Bassuk NL

更新日期：2005-05-01 00:00:00

abstract：:Multiply sired fruits provide unambiguous evidence that pollen from two or more donors was deposited on a stigma and successfully fertilized ovules. Such multiple paternity within fruits can have important consequences for both parental and offspring fitness, but little is known about the frequency of multiple paterni...

journal_title：American journal of botany

authors： Mitchell RJ,Karron JD,Holmquist KG,Bell JM

更新日期：2005-05-01 00:00:00

abstract：:Incarvillea is a herbaceous and temperate member of Bignoniaceae, previously divided into four subgenera, Niedzwedzkia, Amphicome, Incarvillea, and Pteroscleris. Niedzwedzkia and Amphicome have in the past been treated as independent genera. Different relationships have been proposed for the four subgenera. Here, maxi...

journal_title：American journal of botany

authors： Chen S,Guan K,Zhou Z,Olmstead R,Cronk Q

更新日期：2005-04-01 00:00:00

abstract：:Sphenobaiera huangii (Sze) Hsü is typical Early Mesozoic fossil foliage of Ginkgoales in China. It has been recorded from the Upper Triassic to the Lower Jurassic. The cuticular anatomy is investigated based on material from the type locality, Lower Jurassic Hsiangchi Formation, Zigui County, Hubei Province. The speci...

journal_title：American journal of botany

authors： Wang Y,Guignard G,Thévenard F,Dilcher D,Barale G,Mosbrugger V,Yang X,Mei S

更新日期：2005-04-01 00:00:00

abstract：:In monocarpic plants, reproduction is closely associated with senescence, which is itself often correlated to specific environmental signals. Floerkea proserpinacoides (Limnanthaceae) is a spring ephemeral annual of the deciduous forests of eastern North America. The phenology of its growth and reproduction is conside...

journal_title：American journal of botany

authors： Mokhtar IB,Houle G

更新日期：2005-03-01 00:00:00

abstract：:Tacca, a genus of tropical herbs, possesses near black flowers, conspicuous involucral bracts and whisker-like filiform bracteoles. These features have been assumed to function as a "deceit syndrome" in which reproductive structures resemble decaying organic material attracting flies that facilitate cross-pollination ...

journal_title：American journal of botany

authors： Zhang L,Barrett SC,Gao JY,Chen J,Cole WW,Liu Y,Bai ZL,Li QJ

更新日期：2005-03-01 00:00:00

abstract：:Detailed investigations on Lower Cretaceous Ephedra L. fossils (Gnetopsida) reveal morphological characters similar to those of extant Ephedra rhytidosperma Pachomova, including articulate branches with many fine longitudinal striations, a dichasial branching pattern, uni- or bi-ovulate cones with paired bracts, cones...

journal_title：American journal of botany

authors： Yang Y,Geng BY,Dilcher DL,Chen ZD,Lott TA

更新日期：2005-02-01 00:00:00

abstract：:Molecular phylogenetic studies of seven plastid DNA regions were used to resolve circumscriptions at generic and infrageneric levels in subfamily Tillandsioideae of Bromeliaceae. One hundred and ten tillandsioid samples were analyzed, encompassing 10 genera, 104 species, and two cultivars. Two species of Bromelioideae...

journal_title：American journal of botany

authors： Barfuss MH,Samuel R,Till W,Stuessy TF

更新日期：2005-02-01 00:00:00

abstract：:Competition and herbivory are ubiquitous environmental challenges that affect most plants. We examined the influence of phenotypic responses to either competition or herbivory on the subsequent response of the plants to the other factor. The stem-elongation response of Chenopodium album to light competition attenuated...

journal_title：American journal of botany

authors： Kurashige NS,Agrawal AA

更新日期：2005-01-01 00:00:00