Abstract：
:Although theory has demonstrated rather low levels of gene flow are sufficient to counteract opposing mutation, drift, and selection, widespread recognition of the evolutionary importance of gene flow has come slowly. The perceived role of gene flow as an evolutionary force has vacillated over the last century. In the last few decades, new methods and analyses have demonstrated that plant gene flow rates vary tremendously-from nil to very high-depending on the species and specific populations involved, and sometimes over time for individual populations. In many cases, the measured gene flow rates are evolutionarily significant at distances of hundreds and sometimes thousands of meters, occurring at levels sufficient to counteract drift, spread advantageous alleles, or thwart moderate levels of opposing local selection. Gene flow in plants is likely to often act as a cohesive force, uniting individual plant species into real evolutionary units. Also, gene flow can evolve under natural selection, decreasing or increasing. The fact of frequent, but variable, plant gene flow has important consequences for applied issues in which the presence or absence of gene flow might influence the outcome of a policy, regulatory, or management decision. Examples include the unintended spread of engineered genes, the evolution of invasiveness, and conservation. New data-rich genomic techniques allow closer scrutiny of the role of gene flow in plant evolution. Most plant evolutionists now recognize the importance of gene flow, and it is receiving increased recognition from other areas of plant biology as well.
journal_name
Am J Botjournal_title
American journal of botanyauthors
Ellstrand NCdoi
10.3732/ajb.1400024subject
Has Abstractpub_date
2014-05-01 00:00:00pages
737-53issue
5eissn
0002-9122issn
1537-2197pii
ajb.1400024journal_volume
101pub_type
杂志文章,评审abstract：:The American chestnut (Castanea dentata; Fagaceae) was a dominant canopy tree in the Appalachian Mountains of North America. Since the introduction of the chestnut blight fungus (Cryphonectria parasitica; Valsaceae) in America, the American chestnut has been reduced to a predominantly clonal, understory species. Our o...
journal_title：American journal of botany
pub_type： 杂志文章
doi：10.3732/ajb.90.2.207
更新日期：2003-02-01 00:00:00
abstract：PREMISE OF THE STUDY:Tea Unigene-derived MicroSatellite (TUGMS) markers were identified from the publicly available EST data in Camellia sinensis for characterization and future genome mapping studies in tea. METHODS AND RESULTS:One hundred twelve novel TUGMS markers were identified from 4356 unigenes derived by clust...
journal_title：American journal of botany
pub_type： 杂志文章
doi：10.3732/ajb.1000525
更新日期：2011-06-01 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
pub_type： 杂志文章
doi：10.1002/ajb2.1389
更新日期：2019-12-01 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
pub_type： 杂志文章
doi：
更新日期：1998-04-01 00:00:00
abstract：PREMISE OF THE STUDY:Plants adjust their phenology in response to seasonal cues experienced both by their parents and by themselves, and coordinating responses to these cues is necessary for expressing adaptive phenology. We investigated how cues are integrated across time to influence an important progeny phenotype, i...
journal_title：American journal of botany
pub_type： 杂志文章
doi：10.3732/ajb.1600389
更新日期：2017-04-01 00:00:00
abstract：:• Premise of the study: The mechanical properties of a plant are key variables governing the interaction between the plant and its environment. Thus, measuring variables such as the flexural rigidity (bending) of a plant element is necessary to understand and predict the plant-flow interaction. However, plant elements...
journal_title：American journal of botany
pub_type： 杂志文章
doi：10.3732/ajb.1400163
更新日期：2014-06-01 00:00:00
abstract：:Phylogenetic relationships among embryophytes (tracheophytes, mosses, liverworts, and hornworts) were examined using 21 newly generated mitochondrial small-subunit (19S) rDNA sequences. The "core" 19S rDNA contained more phylogenetically informative sites and lower homoplasy than either nuclear 18S or plastid 16S rDNA...
journal_title：American journal of botany
pub_type： 杂志文章
doi：
更新日期：1999-03-01 00:00:00
abstract：PREMISE OF THE STUDY:The evolution of metal tolerance in plants is an important model for studies of adaptation to environment, population genetics, and speciation. Here, we investigated nickel tolerance in the North American serpentine endemic Caulanthus amplexicaulis var. barbarae in comparison with its nonserpentine...
journal_title：American journal of botany
pub_type： 杂志文章
doi：10.3732/ajb.1200382
更新日期：2012-11-01 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：: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
pub_type： 杂志文章
doi：10.3732/ajb.92.8.1294
更新日期：2005-08-01 00:00:00
abstract：PREMISE OF THE STUDY:The genus Hoya (Apocynaceae; Asclepiadoideae) is characterized by a set of complex floral characters unique among the asclepiads, but their role in pollination is poorly understood. Here, we report a new mechanism of asclepiad pollination in the wax plant Hoya carnosa: the pollinaria are transferre...
journal_title：American journal of botany
pub_type： 杂志文章
doi：10.3732/ajb.1700078
更新日期：2017-06-01 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：PREMISE OF THE STUDY:Ferns and lycophytes are the only extant land plants with two free-living generations (sporophytes and gametophytes); hence, a single species may have two different distributions. The distribution of the gametophytes of most fern species, which are much smaller in size than sporophytes, are almost ...
journal_title：American journal of botany
pub_type： 杂志文章
doi：10.3732/ajb.1200555
更新日期：2013-04-01 00:00:00
abstract：PREMISE:Although polyploidy has been studied since the early 1900s, fundamental aspects of polyploid ecology and evolution remain unexplored. In particular, surprisingly little is known about how newly formed polyploids (neopolyploids) become demographically established. Models predict that most polyploids should go ex...
journal_title：American journal of botany
pub_type： 杂志文章
doi：10.1002/ajb2.1466
更新日期：2020-05-01 00:00:00
abstract：PREMISE OF THE STUDY:The presence or absence of a functional copy of a plastid gene may reflect relaxed selection, and may be phylogenetically significant, reflecting shared ancestry. In some liverworts, the plastid gene cysA is a pseudogene (inferred to be nonfunctional). We surveyed 63 liverworts from all major clade...
journal_title：American journal of botany
pub_type： 杂志文章
doi：10.3732/ajb.1100010
更新日期：2011-08-01 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
pub_type： 杂志文章
doi：10.3732/ajb.92.7.1085
更新日期：2005-07-01 00:00:00
abstract：PREMISE OF THE STUDY:Fossilized seeds similar to Cissus (Vitaceae) have been recognized from the Miocene of Kenya, though some were previously assigned to the Menispermaceae. We undertook a comparative survey of extant African Cissus seeds to identify the fossils and consider their implications for the evolution and bi...
journal_title：American journal of botany
pub_type： 杂志文章
doi：10.3732/ajb.1600177
更新日期：2016-09-01 00:00:00
abstract：PREMISE OF THE STUDY:Herbivory affects pollination success and reproductive output in plants. However, the different stages in the process from pollination to seed maturation have hardly been investigated within the context of herbivory. Herbivory might affect these stages via its effect on geitonogamous pollination an...
journal_title：American journal of botany
pub_type： 杂志文章
doi：10.3732/ajb.1500291
更新日期：2015-12-01 00:00:00
abstract：:The fresh weights of suspension cultures of pear (Pyrus communis) and quince (Cydonia oblonga) increased exponentially for 30 to 40 days after subculturing. Transferring pear cultures to media in which quince cultures had grown for 10 days resulted in a 70% inhibition of callus growth. Transferring quince cultures to ...
journal_title：American journal of botany
pub_type： 杂志文章
doi：10.1002/j.1537-2197.1986.tb09673.x
更新日期：1986-01-01 00:00:00
abstract：PREMISE:Root-associated fungi provide a wide range of functions for their host plants, including nutrient provisioning, pathogen protection, and stress alleviation. In so doing, they can markedly influence host-plant structural and physiological traits, although the degree to which these effects vary within particular ...
journal_title：American journal of botany
pub_type： 杂志文章
doi：10.1002/ajb2.1573
更新日期：2020-12-01 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
pub_type： 杂志文章
doi：10.3732/ajb.93.4.505
更新日期：2006-04-01 00:00:00
abstract：PREMISE OF THE STUDY:Direct tests of a species distribution model (SDM) were used to evaluate the hypothesis that the northern and southern edges of Mimulus bicolor's geographical range are limited by temperature and precipitation. METHODS:Climatic suitability was predicted using an SDM informed only by temperature an...
journal_title：American journal of botany
pub_type： 杂志文章
doi：10.3732/ajb.1600414
更新日期：2017-06-01 00:00:00
abstract：:Multicellularity has evolved at least once in every major eukaryotic clade (in all ploidy levels) and numerous times among the prokaryotes. According to a standard multilevel selection (MLS) model, in each case, the evolution of multicellularity required the acquisition of cell-cell adhesion, communication, cooperatio...
journal_title：American journal of botany
pub_type： 杂志文章,评审
doi：10.3732/ajb.1300314
更新日期：2014-01-01 00:00:00
abstract：:Species of Collinsia and Tonella, the two sister genera of self-compatible annuals that constitute tribe Collinsieae, show extensive variation in floral size and morphology and in patterns of stamen and style elongation during the life of the flower (anthesis). We used a nuclear ribosomal ITS phylogeny, independent co...
journal_title：American journal of botany
pub_type： 杂志文章
doi：10.3732/ajb.89.1.37
更新日期：2002-01-01 00:00:00
abstract：:Seed mass is considered to be the least plastic component of reproductive yield. Yet, in invasive populations of garlic mustard, Alliaria petiolata, seed mass was highly variable (eightfold among populations, 2.5-7.5 fold within populations, two-threefold within individuals, and 1.4-1.8 fold within fruits). Variation ...
journal_title：American journal of botany
pub_type： 杂志文章
doi：
更新日期：2000-01-01 00:00:00
abstract：:Chrysothamnus nauseosus (Asteraceae) is a complex polymorphic shrub species widely distributed in western North America. In a study of 86 populations belonging to 15 subspecies, achene mass varied among populations over a sevenfold range. Achene mass was closely correlated with capitulum size at the subspecies level, ...
journal_title：American journal of botany
pub_type： 杂志文章
doi：
更新日期：1997-04-01 00:00:00
abstract：PREMISE OF THE STUDY:Areas lacking dominant plants, or gaps, can support high diversity and specialist species. Previous chronosequence research in Florida rosemary scrub showed indistinct gap area patterns with fire and the dependence of certain species on gaps. We hypothesized that fire and gap size would affect exti...
journal_title：American journal of botany
pub_type： 杂志文章
doi：10.3732/ajb.1700175
更新日期：2017-12-01 00:00:00
abstract：PREMISE OF THE STUDY:Productivity in drylands may depend on the sensitivity of interactions between plants and biocrusts. Given future climate variability, it is essential to understand how interactions may be context-dependent with precipitation regime. Furthermore, little is known about the additional interactions of...
journal_title：American journal of botany
pub_type： 杂志文章
doi：10.1002/ajb2.1120
更新日期：2018-07-01 00:00:00
abstract：:Patterns of biodiversity are ultimately the product of speciation and extinction. Speciation serves as the biodiversity pump while extinction serves as the agent that culls global to local levels of biodiversity. Linking these central processes to global and local patterns of biodiversity is a key challenge in both ec...
journal_title：American journal of botany
pub_type： 杂志文章,评审
doi：10.3732/ajb.1000289
更新日期：2011-03-01 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
