Abstract:
:Many plant species contain populations with more than one polyploid cytotype, but little is known of the mechanisms maintaining several cytotypes in a population. Andropogon gerardii cytotypes were compared to evaluate different models of autopolyploid cytotype coexistence. The enneaploid (90 chromosome, 9x) cytotype was found to be larger and taller than the hexaploid (60 chromosome, 6x) cytotype. Seed production is significantly more efficient in hexaploids, but seed production per area was not significantly different. The two cytotypes are not exomorphologically separable in the field because of great plasticity in response to environmental variation and wide variation within each cytotype. These data suggest cytotypic variation is maintained by natural selection.
journal_name
Am J Botjournal_title
American journal of botanyauthors
Keeler KH,Davis GAsubject
Has Abstractpub_date
1999-07-01 00:00:00pages
974-9issue
7eissn
0002-9122issn
1537-2197pii
86/7/974journal_volume
86pub_type
杂志文章abstract::The shoot apical meristem (SAM) produces stem and initiates leaves. Its structure is maintained despite a continuous flow of cells basipetally from the distal portion of the meristem. The apoplasm and symplasm are the obvious means of cell integration, and their role in chemical cell-to-cell signaling is known. Howeve...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.3732/ajb.91.9.1277
更新日期:2004-09-01 00:00:00
abstract:UNLABELLED: PREMISE OF THE STUDY:The Malpighiaceae include ∼1300 tropical flowering plant species in which generic definitions and intergeneric relationships have long been problematic. The goals of our study were to resolve relationships among the 11 generic segregates from the New World genus Mascagnia, test the mon...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.3732/ajb.1000146
更新日期:2010-12-01 00:00:00
abstract::We developed an improved cytological protocol for producing high quality, light microscope images of plant meiotic chromosomes. Because the technique works on species with small genomes and thick microsporocyte cell walls, it should be useful for studying the wild relatives of Arabidopsis and other eudicots with small...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.3732/ajb.94.12.2063
更新日期:2007-12-01 00:00:00
abstract::The taxonomic richness of seed plants at different taxonomic levels was compared between temperate East Asia and North America at both continental and semi-continental scales. In each comparison, land area and latitude range were adjusted to a comparable level between the two continental regions. East Asia is signific...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.3732/ajb.89.11.1818
更新日期:2002-11-01 00:00:00
abstract::A detailed study of ascomal morphology and development in Cercophora palmicola showed that ontogeny is ascohymeniaceous, giving rise to an ostiolate perithecium. Ascomal initials consist of a coiled ascogonium surrounded by several layers of hyphae whose cells become pseudoparenchymatous. The centrum of the young asco...
journal_title:American journal of botany
pub_type: 杂志文章
doi:
更新日期:1999-06-01 00:00:00
abstract:PREMISE OF THE STUDY:Microsatellite markers of an important medicinal plant, Eurycoma longifolia (Simaroubaceae), were developed for DNA profiling and genetic diversity studies. METHODS AND RESULTS:Eighteen polymorphic microsatellite loci were developed for E. longifolia. The primers were designed from a genomic libra...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.3732/ajb.1000469
更新日期:2011-05-01 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
pub_type: 杂志文章
doi:10.1002/ajb2.1580
更新日期:2020-12-01 00:00:00
abstract::Nuclear and chloroplast DNA variation was assayed for two populations of Louisiana irises (Bayou Teche and Young's Coulee) that demonstrated extreme morphological variation and for a sample of the putative hybrid species, Iris nelsonii. The genetic markers examined in this analysis were diagnostic for either Iris fulv...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.1002/j.1537-2197.1993.tb13843.x
更新日期:1993-05-01 00:00:00
abstract:PREMISE:Gynomonoecy is an infrequent sexual system in angiosperms, although widely represented within the Asteraceae family. Currently, the hypothesis of two nuclear loci controling gynomonoecy is the most accepted. However, the genic interactions are still uncertain. Anacyclus clavatus, A. homogamos, and A. valentinus...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.1002/ajb2.1414
更新日期:2020-01-01 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
pub_type: 杂志文章
doi:10.1002/j.1537-2197.1990.tb13547.x
更新日期:1990-02-01 00:00:00
abstract::The evolutionary history of maize (Zea mays subsp. mays) is of general interest because of its economic and scientific importance. Here we show that many cellular traits described previously in developing caryopses of maize are also seen in its wild progenitor teosinte (Zea mays subsp. parviglumis). These features, ea...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.3732/ajb.0900059
更新日期:2009-10-01 00:00:00
abstract::Sex allocation models predict that cosexuality is stabilized by high allocation to attractive structures in pollen-limited species or by high allocation to shared structures that contribute to both genders. High investment in unilateral fixed costs favor the evolution of dioecy or gender change. With these predictions...
journal_title:American journal of botany
pub_type: 杂志文章
doi:
更新日期:2001-10-01 00:00:00
abstract::Paddy fields are one of the dominant anthropogenic sources of methane emission to the atmosphere, and the main passageway of methane from paddy soil is through the rice plant. However, the effect of aquatic weeds on methane emission from rice paddies has not been properly evaluated yet. Methane emission from weeded po...
journal_title:American journal of botany
pub_type: 杂志文章
doi:
更新日期:2001-06-01 00:00:00
abstract::Axillary meristems play a fundamental role in inflorescence architecture. Maize (Zea mays) inflorescences are highly branched panicles because of the production of multiple types of axillary meristems. We used auxin transport inhibitors to show that auxin transport is required for axillary meristem initiation in the m...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.3732/ajb.94.11.1745
更新日期:2007-11-01 00:00:00
abstract:PREMISE OF THE STUDY:We developed the first set of microsatellite markers for the passion fruit, Passiflora cincinnata, to provide tools for further study of its genetic diversity and to support current conservation and genetic studies. METHODS AND RESULTS:We used a microsatellite-enriched library approach to isolate ...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.3732/ajb.1100477
更新日期:2012-04-01 00:00:00
abstract::The boreotropical flora concept suggests that relictual tropical disjunctions between Asia and the Americas are a result of the expansion of the circumboreal tropical flora from the middle to the close of the Eocene. Subsequently, temperate species diverged at high latitudes and migrated to other continents. To test t...
journal_title:American journal of botany
pub_type: 杂志文章
doi:
更新日期:2001-12-01 00:00:00
abstract:PREMISE OF THE STUDY:The ecological and evolutionary significance of natural epigenetic variation (i.e., not based on DNA sequence variants) variation will depend critically on whether epigenetic states are transmitted from parents to offspring, but little is known on epigenetic inheritance in nonmodel plants. METHODS...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.1002/ajb2.1074
更新日期:2018-04-01 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
pub_type: 杂志文章
doi:10.3732/ajb.92.5.802
更新日期:2005-05-01 00:00:00
abstract:PREMISE:Spiny pollen has evolved independently in multiple entomophilous lineages. Sexual selection may act on exine traits that facilitate male mating success by influencing the transfer of pollen from the anther to the body of the pollinator, while natural selection acts to increase pollen survival. We postulated tha...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.1002/ajb2.1428
更新日期:2020-02-01 00:00:00
abstract::This paper reports the frequency of spontaneous amphiploids or neopolyploids in experimental interspecific hybrids in two annual sections of Gilia (Polemoniaceae, sects. Arachnion and Gilia, x = 9). In each section the species were intercrossed in numerous hybrid combinations to obtain an array of F1 hybrid types; sev...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.3732/ajb.89.8.1197
更新日期:2002-08-01 00:00:00
abstract::Darwin's research on botany and plant physiology was a landmark attempt to integrate plant movements into a biological perspective of behavior. Since antiquity, people have sought to explain plant movements via mechanical or physiological forces, and yet they also constructed analogies between plant and animal behavio...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.3732/ajb.0900220
更新日期:2009-12-01 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
pub_type: 杂志文章
doi:10.3732/ajb.92.1.21
更新日期:2005-01-01 00:00:00
abstract::Traditional farming communities frequently maintain high levels of agrobiodiversity, so understanding their agricultural practices is a priority for biodiversity conservation. The cultural origin of agave spirits (mezcals) from west-central Mexico is in the southern part of the state of Jalisco where traditional farme...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.3732/ajb.0800176
更新日期:2009-02-01 00:00:00
abstract:PREMISE OF THE STUDY:Population genetic structuring over limited timescales is commonly viewed as a consequence of spatial constraints. Indirect approaches have recently revealed reproductive isolation resulting from flowering time (so-called isolation by time, IBT). Since phenological processes can be subject to selec...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.3732/ajb.1200147
更新日期:2012-09-01 00:00:00
abstract:UNLABELLED: PREMISE OF THE STUDY:Microsatellite primers were developed in the introduced shrub Rhamnus cathartica L., to investigate potential hybridization events with related taxa as a stimulus of invasive spread. • METHODS AND RESULTS:Using a non-radioactive protocol, 15 primer sets were identified in North Americ...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.3732/ajb.0900394
更新日期:2010-03-01 00:00:00
abstract:UNLABELLED: PREMISE OF THE STUDY:Invasive plant species threaten native plants in multiple ways, one of which is genetic assimilation through hybridization. However, information regarding hybridization between related alien and native plant species is generally lacking. In Hawaii, the invasive Central American species...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.3732/ajb.1300018
更新日期:2013-06-01 00:00:00
abstract::Gregor Mendel was a 19(th) century priest and botanist who developed the fundamental laws of inheritance. The year 2000 marked a century since the rediscovery of those laws and the beginning of genetics. Although Mendel is now recognized as the founder of genetics, significant controversy ensued about his work through...
journal_title:American journal of botany
pub_type: 杂志文章
doi:
更新日期:2001-05-01 00:00:00
abstract::The pattern of DNA, RNA, and protein synthesis during lateral root initiation in Marsilea quadrifolia L. was monitored by autoradiography of incorporated of 3H-thymidine, 3H-uridine, and 3H-leucine, respectively. DNA synthesis was associated with the enlargement of the lateral root initial prior to its division. Con...
journal_title:American journal of botany
pub_type: 杂志文章
doi:
更新日期:1991-01-01 00:00:00
abstract::This paper presents the first broad overview of three main features of microsporogenesis (male meiosis) in angiosperms: cytokinesis (cell division), intersporal wall formation, and tetrad form. A phylogenetic comparative approach was used to test for correlated evolution among these characters and to make hypotheses a...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.3732/ajb.0800110
更新日期:2008-11-01 00:00:00
abstract::Microscopic structures (petrofilaments) may develop during palynological laboratory processing procedures that are superficially similar to secondary wall thickenings and elaters. These filaments form from angular bodies that resemble fungal spores and resin bodies. The angular bodies are a type of hydrocarbon called ...
journal_title:American journal of botany
pub_type: 杂志文章
doi:
更新日期:2000-05-01 00:00:00