Frequent pseudogenization and loss of the plastid-encoded sulfate-transport gene cysA throughout the evolution of liverworts.

abstract：:For more than a century, the common ancestor of flowering plants was thought to have had a seven-celled, eight-nucleate Polygonum-type female gametophyte. It is now evident that not one, but in fact three, patterns of female gametophyte development and mature structure characterize the common ancestors of the four mos...

journal_title：American journal of botany

authors： Friedman WE,Ryerson KC

更新日期：2009-01-01 00:00:00

abstract：PREMISE:The genus Arisaema (Araceae) has rapidly diversified in Japan, and multiple species often coexist in the field. Although Japanese Arisaema species hybridize from artificial crossing, hybrid individuals are rare in mixed populations; suggesting the presence of effective pre-pollination barriers. We examined the ...

journal_title：American journal of botany

authors： Matsumoto TK,Miyazaki Y,Sueyoshi M,Senda Y,Yamada K,Hirobe M

更新日期：2019-12-01 00:00:00

abstract：:Isozymatic data taken from 67 Guatemalan collections of maize were subjected to numerical taxonomic analyses to elucidate systematic relationships among the 19 maize races and subraces described for Guatemala by Wellhausen et al. As with Bolivian and Mexican races, isozymatic variation in Guatemalan maize was strongly...

journal_title：American journal of botany

authors： Bretting PK,Goodman MM,Stuber CW

更新日期：1990-02-01 00:00:00

abstract：PREMISE OF THE STUDY:Despite being highly fertile and occupying a large geographic region, the North American heartleaf bittercress (Cardamine cordifolia; Brassicaceae) has a puzzling triploid-like chromosome number (2n = 3x = 24). As most triploids are sterile, we embarked on a detailed analysis of the C. cordifolia g...

journal_title：American journal of botany

authors： Mandáková T,Gloss AD,Whiteman NK,Lysak MA

更新日期：2016-07-01 00:00:00

abstract：UNLABELLED:• PREMISE OF THE STUDY:Mountainous regions support high plant productivity, diversity, and endemism, yet are highly vulnerable to climate change. Historical records and model predictions show increasing temperatures across high elevation regions including the Southern Rocky Mountains, which can have a stron...

journal_title：American journal of botany

authors： Munson SM,Sher AA

更新日期：2015-08-01 00:00:00

abstract：PREMISE OF THE STUDY:A knowledge of pollen characters in early-diverging angiosperm lineages is essential for understanding pollen evolution and the role of pollen in angiosperm diversification. In this paper, we report and synthesize data on mature pollen and pollen ontogeny from all genera of Nymphaeales within a com...

journal_title：American journal of botany

authors： Taylor ML,Cooper RL,Schneider EL,Osborn JM

更新日期：2015-10-01 00:00:00

abstract：:Chromosome numbers and karyotypes of species of Orobanche, Cistanche, and Diphelypaea (Orobanchaceae) were investigated, and 108 chromosome counts of 53 taxa, 19 counted for the first time, are presented with a thorough compilation of previously published data. Additionally, karyotypes of representatives of these gene...

journal_title：American journal of botany

authors： Schneeweiss GM,Palomeque T,Colwell AE,Weiss-Schneeweiss H

更新日期：2004-03-01 00:00:00

abstract：PREMISE:Variation in seedling emergence timing is considered adaptive over the long term in wild populations, but early emergence can result in a fitness advantage. To explore the adaptive significance of seedling emergence timing, it should be studied under realistic conditions and in the context of other traits that ...

journal_title：American journal of botany

authors： Mercer KL,Alexander HM,Snow AA

更新日期：2011-06-01 00:00:00

abstract：:Size, allometry, and mechanical design were measured for trees of three canopy species in a tropical rain forest in French Guiana. Mechanical design was expressed as the safety factor, using the elastic-stability model, and the wind resistance factor, using the constant-stress model. Changes with ontogeny were describ...

journal_title：American journal of botany

authors： Sterck F,Bongers F

更新日期：1998-02-01 00:00:00

abstract：:We assessed the effects of local environment on survival, growth, and development in six clones (genotypes) of Vallisneria americana grown at five sites in the Huron-Erie Corridor. Detrimental effects of local environment on plant performance (rate of clonal growth, leaf and root production, surface area of leaves and...

journal_title：American journal of botany

authors： Biernacki M,Lovett-Doust J

更新日期：1997-12-01 00:00:00

abstract：:Many characteristics of plants and animals scale with body size as described by allometric equations of the form Y = βM(α), where Y is an attribute of the organism, β is a coefficient that varies with attribute, M is a measure of organism size, and α is another constant, the scaling exponent. In current models, the fr...

journal_title：American journal of botany

authors： Koontz TL,Petroff A,West GB,Brown JH

更新日期：2009-05-01 00:00:00

abstract：:Evolutionary relationships among representatives of Apiaceae (Umbelliferae) subfamily Apioideae have been inferred from phylogenetic analyses of nuclear ribosomal DNA internal transcribed spacer (ITS 1 and ITS 2) and plastid rpoC1 intron sequences. High levels of nucleotide sequence variation preclude the use of the I...

journal_title：American journal of botany

authors： Downie S,Ramanath S,Katz-Downie D,Llanas E

更新日期：1998-04-01 00:00:00

abstract：PREMISE:The Eocene-Oligocene transition (EOT; 34-33 Ma) was marked by global cooling and increased seasonality and aridity, leading to a shift in North American floras from subtropical forests to deciduous hardwood forests similar to today. This shift is well documented taxonomically and biogeographically, but its ecol...

journal_title：American journal of botany

authors： Butrim MJ,Royer DL

更新日期：2020-12-01 00:00:00

abstract：PREMISE OF THE STUDY:The classification of the genus Salix has historically been intrinsically difficult due to its propensity toward plasticity and high variation in diagnostic morphological characters. We investigated leaf epidermal characteristics, focusing on the stomatal apparatus because it may provide critical i...

journal_title：American journal of botany

authors： Ghahremaninejad F,Khalili Z,Maassoumi AA,Mirzaie-Nodoushan H,Riahi M

更新日期：2012-04-01 00:00:00

abstract：UNLABELLED: PREMISE OF THE STUDY:Allometric relationships among the dimensions of leaf cells, cell walls, and tissues, and whole-leaf thickness and area are likely to have key implications for leaf construction and function, but have remained virtually untested, despite the explosion of interest in allometric analysis...

journal_title：American journal of botany

authors： John GP,Scoffoni C,Sack L

更新日期：2013-10-01 00:00:00

abstract：PREMISE:Distylous species possess two floral morphs with reciprocal positioning of stigmas and anthers that is hypothesized to promote disassortative pollination. Theoretical models predict equal morph frequencies, but many populations depart from the expected 1:1 ratio, a pattern that often correlates with asymmetric ...

journal_title：American journal of botany

authors： Matias R,Pérez-Barrales R,Consolaro H

更新日期：2020-06-01 00:00:00

abstract：:The geographic distribution of diploid and tetraploid cytotypes and cpDNA haplotypes throughout the entire range of Aucuba japonica was investigated. We measured relative genome size using flow cytometry and sequenced two cpDNA intergenic regions, atpB-rbcL and psbA-trnH (GUG). Two haplotypes include both diploids and...

journal_title：American journal of botany

authors： Ohi T,Kajita T,Murata J

更新日期：2003-11-01 00:00:00

abstract：:Pollinator-mediated natural selection has been shown to act on phenotypic variation in floral morphology, and this variation has often been demonstrated to be heritable, but few details are available concerning the sources of floral variation. We examined phenotypic variation in seven floral traits in wild radish (Rap...

journal_title：American journal of botany

authors： Williams JL,Conner JK

更新日期：2001-09-01 00:00:00

abstract：PREMISE OF THE STUDY:In animal-pollinated plants, autonomous selfing may provide reproductive assurance when pollinators or reproductive partners are limited. Under such circumstances, the contribution of pollinator-mediated seed set to total seed production also may be more variable compared with situations in which p...

journal_title：American journal of botany

authors： Brys R,de Crop E,Hoffmann M,Jacquemyn H

更新日期：2011-11-01 00:00:00

abstract：:The selective maintenance of gynodioecy depends on the relative fitness of the male-sterile (female) and hermaphroditic morphs. Females may compensate for their loss of male fitness by reallocating resources from male function (pollen production and pollinator attraction) to female function (seeds and fruits), thus in...

journal_title：American journal of botany

authors： Williams CF,Kuchenreuther MA,Drew A

更新日期：2000-05-01 00:00:00

abstract：PREMISE OF THE STUDY:Miscanthus, a nonfood plant with high potential as a biofuel, has been used in Europe and the United States. The selection of a cultivar with high biomass, photosynthetic efficiency, and stress resistance from wild populations has become an important issue. New genic microsatellite markers will aid...

journal_title：American journal of botany

authors： Ho CW,Wu TH,Hsu TW,Huang JC,Huang CC,Chiang TY

更新日期：2011-08-01 00:00:00

abstract：PREMISE OF THE STUDY:Microsatellite markers were developed for Petunia integrifolia subsp. depauperata with an intent to clarify taxonomic questions on the P. integrifolia complex, and to identify a purple-flowered parent of P. hybrida. METHODS AND RESULTS:We characterized 11 microsatellite loci by screening primers d...

journal_title：American journal of botany

authors： Kriedt RA,Ramos-Fregonezi AM,Beheregaray LB,Bonatto SL,Freitas LB

更新日期：2011-10-01 00:00:00

abstract：UNLABELLED: PREMISE OF STUDY:Phylogenetic relationships of the papilionoid legumes (Papilionoideae) reveal that the early branches are more highly diverse in floral morphology than are other clades of Papilionoideae. This study attempts for the first time to comprehensively sample the early-branching clades of this ec...

journal_title：American journal of botany

authors： Cardoso D,de Queiroz LP,Pennington RT,de Lima HC,Fonty E,Wojciechowski MF,Lavin M

更新日期：2012-12-01 00:00:00

abstract：:The degree to which plants self-fertilize may impact their potential for genetic adaptation. Given that the mating system influences genetic processes within and among populations, the mating system could limit or promote local adaptation. I conducted a literature survey of published reciprocal transplant experiments ...

journal_title：American journal of botany

authors： Hereford J

更新日期：2010-02-01 00:00:00

abstract：PREMISE OF THE STUDY:Generic boundaries and infrageneric relationships among the charismatic temperate magnoliid Asarum sensu lato (Aristolochiaceae) have long been uncertain. Previous molecular phylogenetic analyses used either plastid or nuclear loci alone and varied greatly in their taxonomic implications for the ge...

journal_title：American journal of botany

authors： Sinn BT,Kelly LM,Freudenstein JV

更新日期：2015-05-01 00:00:00

abstract：:Intensified ultraviolet-B radiation or UV-B (wavelengths between 280 and 320 nm) can delay flowering and diminish lifetime flower production in a few plants. Here we studied the effects of enhanced UV-B on floral traits crucial to pollination and pollinator reproduction. We observed simultaneous flowering responses of...

journal_title：American journal of botany

authors： Sampson BJ,Cane JH

更新日期：1999-01-01 00:00:00

abstract：PREMISE OF THE STUDY:Uplift of the tropical Andes had a significant impact on the diversification of South American flora and fauna. Recent biogeographic inquiries have established patterns of Andean divergence, but investigations on ferns are scant. The fern genus Polystichum Roth (Dryopteridaceae) combines widespread...

journal_title：American journal of botany

authors： McHenry MA,Barrington DS

更新日期：2014-02-01 00:00:00

abstract：:Yucca glauca is a C(3) evergreen rosette species locally common in the C(4)-dominated grasslands of the central Great Plains. Most congeners of Y. glauca are found in deserts, and Y. glauca's morphological similarities to desert species (steeply angled leaves, evergreen habit) may be critical to its success in grassla...

journal_title：American journal of botany

authors： Maragni LA,Knapp AK,McAllister CA

更新日期：2000-02-01 00:00:00

abstract：:• Premise of the study: Wild populations of domesticated species constitute a genetic reservoir and are fundamental to the evolutionary potential of species. Wild papaya (Carica papaya) is a rare, short-lived, gap-colonizing, dioecious tree that persists in the forest by continuous dispersal. Theoretically, these life...

journal_title：American journal of botany

authors： Chávez-Pesqueira M,Suárez-Montes P,Castillo G,Núñez-Farfán J

更新日期：2014-07-01 00:00:00

abstract：UNLABELLED: PREMISE OF THE STUDY:Taxonomic groups have often been recognized on the basis of geographic distinctions rather than accurately representing evolutionary relationships. This has been particularly true for temperate and tropical members from the same family. Polygonaceae exemplifies this problem, wherein th...

journal_title：American journal of botany

authors： Burke JM,Sanchez A,Kron K,Luckow M

更新日期：2010-08-01 00:00:00