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 tissues of a parental axis, and they occurred without increase in branch root density. We concluded that ABR are an unrecognized component of undamaged root systems. Using continuous serial sectioning to perform a census of branch roots within parental root axes, we obtained definitive evidence that ABR participate in root turnover. Comparisons of older and younger axes, and the chronology of root formation in older axes fulfilled the expectation that with greater age of parental axis, ABR become increasingly predominant among intact branch roots. We confirmed this trend for one of the species scoring negative in the survey, which means that our survey results were probably influenced by age variation. Thus, any of the six negative results obtained in the survey may have been dependent on the young age and slenderness of the axes that were available for examination in those six species.
journal_name
Am J Botjournal_title
American journal of botanyauthors
Paolillo DJ Jr,Bassuk NLdoi
10.3732/ajb.92.5.802subject
Has Abstractpub_date
2005-05-01 00:00:00pages
802-9issue
5eissn
0002-9122issn
1537-2197pii
92/5/802journal_volume
92pub_type
杂志文章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:Fern spores are unicellular and haploid, making them a potential model system to study factors that regulate lifespan and mechanisms of aging. Aging rates of nongreen spores were measured to compare longevity characteristics among diverse fern species and test for orthodox response to storage tempe...
journal_title：American journal of botany
pub_type： 杂志文章
doi：10.3732/ajb.1100257
更新日期：2012-04-01 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：PREMISE OF THE STUDY:Palaeotropic Derris-like taxa (family Fabaceae, tribe Millettieae) comprise 6-9 genera. They are well known as important sources of rotenone toxin, which are used as organic insecticide and fish poison. However, their phylogenetic relationships and classification are still problematic due to insuff...
journal_title：American journal of botany
pub_type： 杂志文章
doi：10.3732/ajb.1200390
更新日期：2012-11-01 00:00:00
abstract：:Taxonomical classification of higher fungi remains an important challenge and can benefit from the application of molecular analysis. We propose that the ectomycorrhizal (EM) fungal taxa might include a number of cryptic species because there are few morphological characteristics useful for distinguishing among these ...
journal_title：American journal of botany
pub_type： 杂志文章
doi：10.3732/ajb.94.10.1630
更新日期：2007-10-01 00:00:00
abstract：PREMISE OF THE STUDY:Little is known about the effect of environmental conditions on seed dormancy break at the community level or how it could be affected by climate change. This study tested the effects of storage conditions on germination of 489 species from high-elevation natural grasslands on the Tibet Plateau. M...
journal_title：American journal of botany
pub_type： 杂志文章
doi：10.3732/ajb.1000043
更新日期：2011-01-01 00:00:00
abstract：:Phylogenetic relationships were determined in the Araucariaceae, which are now found mainly in the Southern Hemisphere. This conifer family was well diversified and widely distributed in both hemispheres during the Mesozoic era. The sequence of 1322 bases of the rbcL gene of cpDNA was determined from 29 species of Ara...
journal_title：American journal of botany
pub_type： 杂志文章
doi：
更新日期：1998-11-01 00:00:00
abstract：PREMISE OF THE STUDY:Seabirds often cause significant changes to soil properties, and seabird-dominated systems often host unique plant communities. This study experimentally (1) examined species-specific responses to seabird guano gradients, (2) considered the role that differential functional traits among species pla...
journal_title：American journal of botany
pub_type： 杂志文章
doi：10.3732/ajb.1000159
更新日期：2011-02-01 00:00:00
abstract：PREMISE OF THE STUDY:Several members of Selaginella are renowned for their ability to survive extreme drought and "resurrect" when conditions improve. Many of these belong to subgenus Tetragonostachys, a group of ∼45 species primarily found in North and Central America, with substantial diversity in the Sonoran and Chi...
journal_title：American journal of botany
pub_type： 杂志文章
doi：10.3732/ajb.1200426
更新日期：2013-08-01 00:00:00
abstract：PREMISE:The cosmopolitan and ecologically important grass subfamily Aristidoideae comprises the widely distributed genus Aristida (250-290 species), Stipagrostis (50 species, with an African-Asian distribution), and Sartidia (five species, Africa and Madagascar). The subfamily includes species with C(3) (Sartidia and a...
journal_title：American journal of botany
pub_type： 杂志文章
doi：10.3732/ajb.1100103
更新日期：2011-11-01 00:00:00
abstract：PREMISE:Although hybridization has played an important role in the evolution of many plant species, phylogenetic reconstructions that include hybridizing lineages have been historically constrained by the available models and data. Restriction-site-associated DNA sequencing (RADseq) has been a popular sequencing techni...
journal_title：American journal of botany
pub_type： 杂志文章
doi：10.1002/ajb2.1352
更新日期：2019-09-01 00:00:00
abstract：PREMISE OF STUDY:Although there is increasing recognition of the effects of plant intraspecific diversity on consumers, the mechanisms by which such effects cascade-up to higher trophic levels remain elusive. METHODS:We evaluated the effects of plant (lima bean, Phaseolus lunatus) intraspecific diversity on a suite of...
journal_title：American journal of botany
pub_type： 杂志文章
doi：10.3732/ajb.1600234
更新日期：2016-10-01 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：PREMISE OF THE STUDY:Chloroplast microsatellites were developed in Theobroma cacao to examine the genetic diversity of cacao cultivars in Trinidad and Tobago. METHODS AND RESULTS:Nine polymorphic microsatellites were designed from the chloroplast genomes of two T. cacao accessions. These microsatellites were tested in...
journal_title：American journal of botany
pub_type： 杂志文章
doi：10.3732/ajb.1100306
更新日期：2011-12-01 00:00:00
abstract：:Temporal and demographic aspects of the growth of Botrychium gallicomontanum and B. mormo were studied for 2 yr. A total of 219 B. gallicomontanum and 412 B. mormo plants were monitored in a prairie and maple-basswood forest, respectively. Growth events were divided into four stages: leaf emergence, leaf separation, s...
journal_title：American journal of botany
pub_type： 杂志文章
doi：10.3732/ajb.89.10.1624
更新日期：2002-10-01 00:00:00
abstract：:Studies of developmental stability can provide insights into the amount of genetic or environmental stress experienced by individuals or populations. In the present study, we used young plants of Acer platanoides (Norway maple) and Betula pendula (silver birch), two distantly related tree species with widely different...
journal_title：American journal of botany
pub_type： 杂志文章
doi：10.3732/ajb.90.8.1107
更新日期：2003-08-01 00:00:00
abstract：:We sequenced the nuclear small subunit ribosomal DNA coding region from 20 members of the Bangiophycidae and from two members of the Florideophycidae to gain insights into red algal evolution. A combined alignment of nuclear and plastid small subunit rDNA and a data set of Rubisco protein sequences were also studied t...
journal_title：American journal of botany
pub_type： 杂志文章
doi：
更新日期：2001-08-01 00:00:00
abstract：:Chloroplast DNA (cpDNA) restriction enzyme site analysis was used to test hypotheses of series and superseries affiliations of 76 taxa, representing 11 of the 13 South American series (material unavailable for two series) of wild potatoes (Solanum sect. Petota) recognized in the latest classification by Hawkes. The cl...
journal_title：American journal of botany
pub_type： 杂志文章
doi：
更新日期：1997-05-01 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：:Cleistogamous capitula formed by Centaurea melitensis display a number of morphological and functional changes with respect to chasmogamous capitula that ensure self-fertilization. Because no studies have hitherto addressed the evolution of cleistogamy in Asteraceae, it was considered useful to ascertain whether these...
journal_title：American journal of botany
pub_type： 杂志文章
doi：
更新日期：2000-07-01 00:00:00
abstract：:Very little is known regarding how repetitive elements evolve inpolyploid organisms. Here we address this subject by fluorescent insitu hybridization (FISH) of 20 interspersed repetitive elements tometaphase chromosomes of the cotton AD-genome tetraploid Gossypiumhirsutum and its putative A- and D-genome diploid ances...
journal_title：American journal of botany
pub_type： 杂志文章
doi：
更新日期：1998-10-01 00:00:00
abstract：PREMISE OF THE STUDY:Astragalus sect. Humillimi is distributed across the southwestern United States and contains two endangered taxa, A. cremnophylax var. cremnophylax and A. humillimus. The former was originally described from the South Rim of the Grand Canyon. Analysis of individuals discovered on the North Rim of t...
journal_title：American journal of botany
pub_type： 杂志文章
doi：10.1002/ajb2.1157
更新日期：2018-10-01 00:00:00
abstract：UNLABELLED:• PREMISE OF THE STUDY:Polymorphic microsatellite primers were developed in the seagrass Halophila ovalis to investigate genetic variation. • METHODS AND RESULTS:Ten polymorphic microsatellite loci were developed in Halophila ovalis. The number of alleles per locus ranged from 2 to 12 across 80 H. ovalis i...
journal_title：American journal of botany
pub_type： 杂志文章
doi：10.3732/ajb.1000111
更新日期：2010-06-01 00:00:00
abstract：:Understanding the role of geography and ecology in species divergence is central to the study of evolutionary diversification. We used climatic, geographic, and biological data from nine wild Andean tomato species to describe each species' ecological niche and to evaluate the likely ecological and geographical modes o...
journal_title：American journal of botany
pub_type： 杂志文章
doi：10.3732/ajb.0900216
更新日期：2010-04-01 00:00:00
abstract：PREMISE OF THE STUDY:Pollinator shifts have been implicated as a driver of divergence in angiosperms. We tested the hypothesis that there was a transition from bird- to butterfly pollination in the African genus Clivia (Amaryllidaceae) and investigated how floral traits may have been either modified or retained during ...
journal_title：American journal of botany
pub_type： 杂志文章
doi：10.3732/ajb.1300363
更新日期：2014-01-01 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：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：:The circumscription and relationships of genera within the tribe Melanthieae (29 representative taxa) were evaluated using parsimony analyses of ITS (nuclear ribosomal) and trnL-F (plastid) DNA sequence data, alone and in combination. Proposed new generic circumscriptions, strongly supported by the tree statistics and...
journal_title：American journal of botany
pub_type： 杂志文章
doi：
更新日期：2001-09-01 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
pub_type： 杂志文章
doi：10.3732/ajb.92.10.1632
更新日期：2005-10-01 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
