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. However, the cell wall apoplasm is most likely also involved in a mechanical integration mode, in which mechanical stress and strains (elastic and plastic strain, i.e., growth) are putative signaling factors. Shoot apex cells grow symplastically and their growth is in general anisotropic. Therefore tensor of growth rates that depends on the displacements caused by growth is the most suitable physical entity to describe growth. The tensor approach introduces the concept of principal directions of growth, i.e., the directions in which growth rates attain extremal values. Because of the symplastic mode of growth, the cell wall pattern within the shoot apical meristem informs us about the sequence and planes of cell divisions and about the deformation of existing walls. In consequence, within the meristem, periclines and anticlines can be recognized, both representing the principal directions of growth.
journal_name
Am J Botjournal_title
American journal of botanyauthors
Kwiatkowska Ddoi
10.3732/ajb.91.9.1277subject
Has Abstractpub_date
2004-09-01 00:00:00pages
1277-93issue
9eissn
0002-9122issn
1537-2197pii
91/9/1277journal_volume
91pub_type
杂志文章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:PREMISE OF THE STUDY:Herbivory can affect a plant's fitness in a variety of ways, including modifying the biotic interactions of the plant. In particular, when herbivory influences floral display, we hypothesize that pollinator visitation will be altered accordingly. Here we studied the indirect effects of feeding by t...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.3732/ajb.1500043
更新日期:2015-05-01 00:00:00
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journal_title:American journal of botany
pub_type: 杂志文章
doi:
更新日期:1997-03-01 00:00:00
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journal_title:American journal of botany
pub_type: 杂志文章
doi:
更新日期:1999-04-01 00:00:00
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journal_title:American journal of botany
pub_type: 杂志文章
doi:10.3732/ajb.1300349
更新日期:2014-02-01 00:00:00
abstract::Iris cristata and I. lacustris differ markedly in geographic distribution, glacial history of current ranges, and ecology. We hypothesized that I. cristata, a widespread species of unglaciated regions of eastern North America, would exhibit genetic diversity typical of other widespread plant species, whereas the threa...
journal_title:American journal of botany
pub_type: 杂志文章
doi:
更新日期:2000-03-01 00:00:00
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journal_title:American journal of botany
pub_type: 杂志文章
doi:10.3732/ajb.1100154
更新日期:2011-11-01 00:00:00
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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::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
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journal_title:American journal of botany
pub_type: 杂志文章
doi:10.1002/ajb2.1146
更新日期:2018-09-01 00:00:00
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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::Up to 22% of plant species are the result of breeding among species-hybridization-directly conflicting with the prediction that hybrids, compared to parental species, are intermediate in character and of low fitness and little consequence. Few studies, however, have compared the fitness of hybrids and parental species...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.3732/ajb.95.2.146
更新日期:2008-02-01 00:00:00
abstract:PREMISE OF THE STUDY:Microsatellite loci were developed in the endangered Pericopsis elata using a combination of low-cost procedures. METHODS AND RESULTS:Microsatellite isolation was performed simultaneously on three distinct species through a newly available procedure that associates multiplex microsatellite enrichm...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.3732/ajb.1100070
更新日期:2011-10-01 00:00:00
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...
journal_title:American journal of botany
pub_type: 杂志文章,评审
doi:10.3732/ajb.1400024
更新日期:2014-05-01 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
pub_type: 杂志文章
doi:10.3732/ajb.90.11.1645
更新日期:2003-11-01 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
pub_type: 杂志文章
doi:
更新日期:1998-02-01 00:00:00
abstract::Marchantia inflexa, a dioecious thallose liverwort, is sexually dimorphic in clonal expansion traits. We used selection analyses to measure the magnitude and direction of selection on clonal fitness to uncover possible mechanisms for the maintenance of preadult sexually dimorphic characters. We planted replicates of g...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.3732/ajb.89.4.592
更新日期:2002-04-01 00:00:00
abstract:PREMISE OF THE STUDY:Large phylogenies can help shed light on macroevolutionary patterns that inform our understanding of fundamental processes that shape the tree of life. These phylogenies also serve as tools that facilitate other systematic, evolutionary, and ecological analyses. Here we combine genetic data from pu...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.1002/ajb2.1019
更新日期:2018-03-01 00:00:00
abstract:PREMISE OF THE STUDY:Autopolyploidy, or whole-genome duplication within a species, leads to closely related cytotypes in one geographic location. One hypothesized mechanism by which autopolyploids become established is climatic niche divergence from their diploid progenitor. Here we tested this hypothesis in diploid, t...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.1002/ajb2.1161
更新日期:2018-10-01 00:00:00
abstract:PREMISE OF THE STUDY:Koelreuteria (Sapindaceae) has four extant deciduous tree species, disjunctly distributed in eastern Asia and the Fiji Islands. While K. paniculata is widely cultivated, the biogeographic origin and evolutionary history of Koelreuteria remain unclear. METHODS:Fruits, pollen, wood, and leaves of cl...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.3732/ajb.1200415
更新日期:2013-02-01 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:UNLABELLED: PREMISE OF THE STUDY:Fungal plant pathogens exert much of their effect on plant cells through alterations in the host cell walls. However, obtaining biochemical proof for this change is difficult because of the relatively small number of cells that are affected by the pathogen relative to the bulk of host ...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.3732/ajb.1000099
更新日期:2010-12-01 00:00:00
abstract::The plastid trnL-F region has proved useful in molecular phylogenetic studies addressing diverse evolutionary questions from biogeographic history to character evolution in a broad range of plant groups. An important assumption for phylogenetic reconstruction is that data used in combined analyses contain the same phy...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.3732/ajb.94.6.1003
更新日期:2007-06-01 00:00:00
abstract:PREMISE:Outcomes of species interactions, especially mutualisms, are notoriously dependent on environmental context, and environments are changing rapidly. Studies have investigated how mutualisms respond to or ameliorate anthropogenic environmental changes, but most have focused on nutrient pollution or climate change...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.1002/ajb2.1404
更新日期:2020-02-01 00:00:00
abstract:PREMISE OF THE STUDY:Bio-ontologies are essential tools for accessing and analyzing the rapidly growing pool of plant genomic and phenomic data. Ontologies provide structured vocabularies to support consistent aggregation of data and a semantic framework for automated analyses and reasoning. They are a key component of...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.3732/ajb.1200222
更新日期:2012-08-01 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
pub_type: 杂志文章
doi:10.3732/ajb.1200608
更新日期:2013-10-01 00:00:00
abstract:PREMISE OF THE STUDY:It has been hypothesized that two flower types permit flexible allocation of resources to female and male functions, yet empirical evidence for the sex-allocation hypothesis remains scarce in gynomonoecious species. To characterize resource allocation to pistillate and perfect flowers and allocatio...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.3732/ajb.1600397
更新日期:2017-03-01 00:00:00
abstract:UNLABELLED: PREMISE OF THE STUDY:Phenolic compounds exuded by roots have been implicated in allelopathic interactions among plants. Root enzymes that destroy phenolics may protect plants against allelopathic inhibition and thus may aid in invasiveness. Phenolic-degrading enzymes are chiefly found in aboveground plant ...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.3732/ajb.0900337
更新日期:2010-07-01 00:00:00
abstract::Propagule banks are assumed to be able to store considerable genetic variability. Bryophyte populations are expected to rely more heavily on stored propagules than those of seed plants due to the vulnerability of the haploid gametophyte. This reliance has important implications for the genetic structure and evolutiona...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.3732/ajb.2007283
更新日期:2008-05-01 00:00:00
abstract:UNLABELLED: PREMISE OF THE STUDY:Sphagnum dominates vast expanses of wetland habitats throughout the northern hemisphere and species delimitation within the genus is important because floristic changes associated with a warming global climate may have measureable impacts on large-scale ecological processes. Most north...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.3732/ajb.1200630
更新日期:2013-06-01 00:00:00