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 fulva. Iris hexagona, or Iris brevicaulis. These data demonstrated that the two morphologically variable populations were hybrid associations involving all three of these species and that all three of these species were involved in the origin of I. nelsonii. The distribution of genetic variation in I. nelsonii was significantly different from that present in either of the two hybrid populations. I. nelsonii demonstrated significantly fewer foreign markers than the two hybrid populations. This finding is in accord with the prediction that I. nelsonii is a hybrid species that has undergone stabilization with regard to genetic recombination and segregation. Although the genotypic makeup of I. nelsonii was significantly different from other parental and hybrid populations, individual plants from this species cannot be unequivocally differentiated from either I. fulva or certain hybrid genotypes. This reflects the paradoxical nature of genotypic variation in hybrid species. Thus, a hybrid species may include genotypes that overlap with both parental and contemporary hybrid populations. In the case of I. nelsonii it is necessary to utilize additional information (morphological, chromosomal, ecological) to identify plants belonging to this taxon. One hybrid population (Young's Coulee) is suggested as a paradigm for the progenitor population that gave rise to I. nelsonii.
journal_name
Am J Botjournal_title
American journal of botanyauthors
Arnold MLdoi
10.1002/j.1537-2197.1993.tb13843.xsubject
Has Abstractpub_date
1993-05-01 00:00:00pages
577-583issue
5eissn
0002-9122issn
1537-2197journal_volume
80pub_type
杂志文章abstract::The biological nature of some symbioses is unclear because it is often not easy to discern whether the symbionts obtain any benefits from the association. Mastodia tessellata, a symbiosis between a leafy green alga and a fungus of uncertain phylogenetic position, is among the most investigated, controversial, and poor...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.3732/ajb.0900323
更新日期:2010-05-01 00:00:00
abstract:PREMISE OF THE STUDY:Tetraena simplex is an independently evolved C4 species in the Zygophylloideae (Zygophyllaceae) and a characteristic forb of saline flats in hot and sandy desert habitats. During early ontogeny, the species had a morphological shift from planar cotyledons (dorsiventral symmetry) to terete, succulen...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.1002/ajb2.1087
更新日期:2018-05-01 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::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
pub_type: 杂志文章
doi:10.3732/ajb.93.9.1265
更新日期:2006-09-01 00:00:00
abstract::We present here the first molecular phylogeny of tribe Diseae (Orchidoideae: Orchidaceae). Nuclear ribosomal ITS1, 5.8S rDNA, and ITS2 sequences were compared for 30 Diseae, 20 Orchideae, and four Cranichideae and Diurideae outgroups. ITS - rDNA sequences exhibited a transition:transversion ratio of 1.3 and extensive ...
journal_title:American journal of botany
pub_type: 杂志文章
doi:
更新日期:1999-06-01 00:00:00
abstract::Dispersal is an important life history component. Seed settling velocity may be a useful surrogate for the measurement of dispersal ability in wind-dispersed plants, particularly those whose seeds have plumose dispersal structures. I measured settling velocities on seeds of eight species of Asteraceae, including annua...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.1002/j.1537-2197.1992.tb13702.x
更新日期:1992-10-01 00:00:00
abstract::In the southern Appalachian mountains a subcanopy species, Rhododendron maximum, inhibits the establishment and survival of canopy tree seedlings. One of the mechanisms by which seedlings could be inhibited is an allelopathic effect of decomposing litter or leachate from the canopy of R. maximum (R.m.) on seed germina...
journal_title:American journal of botany
pub_type: 杂志文章
doi:
更新日期:1999-11-01 00:00:00
abstract::The interaction between simulated cotyledon herbivory and interspecific competition was studied in a greenhouse experiment using two species of trees, Acer rubrum and Quercus palustris, which commonly invade abandoned agricultural fields. Herbivory treatments were applied as a gradient of cotyledon removal for A. rubr...
journal_title:American journal of botany
pub_type: 杂志文章
doi:
更新日期:2000-12-01 00:00:00
abstract::Expansion of Typha domingensis into areas previously dominated by Cladium jamaicense in the Florida Everglades has been linked to anthropogenic phosphorus (P) enrichment and increased hydroperiod. The principal stress factor for plants in flooded soils is biochemical reduction, the intensity of which is measured as re...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.3732/ajb.90.5.736
更新日期:2003-05-01 00:00:00
abstract::A spatially explicit, reiterative algorithm (SERA) is presented and used to predict multiple aspects of plant population and community dynamics. Using simple physical principles and empirically derived relationships, SERA provides an analytical venue to test alternative hypotheses about individual functional traits go...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.3732/ajb.0900063
更新日期:2009-08-01 00:00:00
abstract:UNLABELLED:• PREMISE OF THE STUDY:Floral traits play important roles in pollinator attraction and defense against floral herbivory. However, plants may experience trade-offs between conspicuousness to pollinators and herbivore attraction. Comparative studies provide an excellent framework to examine the role of multip...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.3732/ajb.1400171
更新日期:2014-08-01 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
pub_type: 杂志文章
doi:10.3732/ajb.1400316
更新日期:2015-05-01 00:00:00
abstract::Molecular studies of apomictic plant species often detect more genotypic variation than predicted from their assumed reproductive mode. The two most commonly invoked mechanisms to explain these high levels of variation are recombination, via facultative sexuality, and mutation. The potential for sexual reproduction in...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.3732/ajb.91.1.37
更新日期:2004-01-01 00:00:00
abstract:PREMISE OF THE STUDY:Factors shaping spatiotemporal patterns of associations in mutualistic systems are poorly understood. We used the lichen-forming fungi Peltigera and their cyanobacterial partners Nostoc to investigate the spatial structure of this symbiosis at an intrabiome scale and to identify potential factors s...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.1002/ajb2.1119
更新日期:2018-07-01 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
pub_type: 杂志文章
doi:10.3732/ajb.93.7.963
更新日期:2006-07-01 00:00:00
abstract:PREMISE OF THE STUDY:Although our awareness of ploidy diversity has expanded with the application of flow cytometry, we still know little about the extent to which cytotypes within mixed-ploidy populations are genetically differentiated across environmental gradients. METHODS:To address this issue, we reared 14 popula...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.3732/ajb.1500146
更新日期:2016-01-01 00:00:00
abstract:PREMISE OF THE STUDY:Microsatellite loci were developed from Imperata cylindrica, a traditional medicinal herb in Asia and among the top 10 worst invasive weeds in the world, to aid in the identification of the limits of asexual clonal individuals. METHODS AND RESULTS:A total of 21 microsatellite markers, including 18...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.3732/ajb.1200152
更新日期:2012-11-01 00:00:00
abstract:PREMISE OF THE STUDY:Male-biased herbivory in dioecious species is expected as a consequence of selection for increased resistance (reduced attack) in the sex with higher reproductive costs-females. Empirical support of this prediction is taxonomically restricted and fraught with exceptions. Phenological changes in res...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.3732/ajb.1200603
更新日期:2013-02-01 00:00:00
abstract:PREMISE OF THE STUDY:Geographic differences in flower visitor assemblages might lead to among-population differences in the magnitude and pattern of floral integration. However, the role of current pollinator visitation in shaping the magnitude and pattern of floral trait correlations is still controversial. METHODS:W...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.3732/ajb.1500336
更新日期:2016-02-01 00:00:00
abstract::Bumble bee pollinated Chamaecrista fasciculata provides pollen as the sole reward to its pollinators. Male sterility, expressed as an absence or nearly complete absence of pollen production, occurs in low frequency in populations of C. fasciculata. Here we describe experiments, using C. fasciculata, to examine frequen...
journal_title:American journal of botany
pub_type: 杂志文章
doi:
更新日期:1998-09-01 00:00:00
abstract:PREMISE OF THE STUDY:Land-use change is cited as a primary driver of global biodiversity loss, with myriad consequences for species, populations, and ecosystems. However, few studies have examined its impact on species interactions, particularly pollination. Furthermore, when the effects of land-use change on pollinati...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.3732/ajb.1600302
更新日期:2016-11-01 00:00:00
abstract::The genus Caltha (Ranunculaceae) consists of 10 species of low-growing, perennial herbs distributed throughout the moist temperate and cold regions of both the Northern and Southern Hemispheres. Traditionally, the species have been divided into two sections: section Psychrophila in the Southern Hemisphere with diploph...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.3732/ajb.91.2.247
更新日期:2004-02-01 00:00:00
abstract::The micromorphology of pits in tracheary elements was examined in 35 species representing 29 genera of Rosaceae and related families to evaluate the assumption that angiosperm pits are largely invariant. In most Rosaceae, pit membranes between fibers and tracheids frequently appear to have amorphous thickenings with a...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.3732/ajb.94.4.503
更新日期:2007-04-01 00:00:00
abstract::Zeuxine gracilis, Zeuxine strateumatica, and Eulophia sinensis are wild orchids with different breeding systems and colonizing abilities. Zeuxine gracilis is an outcrosser with restricted distribution, whereas S. strateumatica is an apomictic colonizer found only in newly available open habitats. Eulophia sinensis is ...
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 correct assessment of homology is an important prerequisite for reconstructing phylogenetic relationships and character evolution. Old World Papaveroideae (Papaver, Meconopsis, Roemeria, Stylomecon) show substantial diversity in gynoecium and capsule morphology. In particular, capsules can have...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.3732/ajb.1100066
更新日期:2011-08-01 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
pub_type: 杂志文章
doi:
更新日期:1997-12-01 00:00:00
abstract:PREMISE OF THE STUDY:The perennial feather moss Hylocomium splendens is one of the most widely distributed and common bryophytes in the Northern Hemisphere and has, because of its capacity to grow under a wide range of environmental conditions, been used as a biomonitor for atmospheric metal deposition in Europe. METH...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.3732/ajb.1200028
更新日期:2012-09-01 00:00:00
abstract::Megaspore and microspore massulae of Paleoazolla patagonica gen. et sp. nov. are described from the Upper Cretaceous of La Colonia Formation, Chubut Province, Argentina. The new fern possesses megaspore complexes with three to four glochidiate floats attached directly to the megaspore; a columella-like structure appea...
journal_title:American journal of botany
pub_type: 杂志文章
doi:
更新日期:1999-08-01 00:00:00
abstract::The hollow stem of Equisetum giganteum owes its mechanical stability to an outer ring of strengthening tissue, which provides stiffness and strength in the longitudinal direction, but also to an inner lining of turgid parenchyma, which lends resistance to local buckling. With a height >2.5 m isolated stems are mechani...
journal_title:American journal of botany
pub_type: 杂志文章
doi:
更新日期:1998-03-01 00:00:00
abstract::Six of 14 species of Triteleia were studied. All possess septal nectaries, raphides in the ovary wall, an anatropous and crassinucellate ovule with a micropyle formed by the inner integument only, and parietal cells. A short and thick nucellus, which is not penetrated by the embryo sac, has a one-layered apical epider...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.3732/ajb.90.6.937
更新日期:2003-06-01 00:00:00