Abstract:
:Phylogenetic analysis of DNA sequences of the chloroplast genes rcbL and ndhf revealed a highly supported clade composed of the families Plantaginaceae, Callitrichaceae, and Hippuridaceae in close association with the model organism Antirrhinum majus and other members of family Scrophulariaceae. Plantago has miniature actinomorphic wind-pollinated flowers that have evolved from zygomorphic animal-pollinated precursors. The aquatic Hippuridaceae have reduced windpollinated flowers with one reproductive organ per whorl, and three, rather than four, whorls. In monoecious aquatic Callitrichaceae, further reduction has occurred such that there is only one whorl per flower containing a single stamen or carpel. Optimization of character states showed that these families descended from an ancestor similar to Antirrhinum majus. Recent studies of plant developmental genetics have focused on distantly related species. Differences in the molecular mechanisms controlling floral development between model organisms are difficult to interpret due to phylogenetic distance. In order to understand evolutionary changes in floral morphology in terms of their underlying genetic processes, closely related species exhibiting morphological Variation should be examined. Studies of genes that regulate morphogenesis in the clade described here could aid in the elucidation of a general model tot such fundamental issues as how changes in floral symmetry, organ number, and whorl number are achieved, as well as providing insight on the evolution of dicliny and associated changes in pollination syndrome.
journal_name
Am J Botjournal_title
American journal of botanyauthors
Reeves P,Olmstead Rsubject
Has Abstractpub_date
1998-08-01 00:00:00pages
1047issue
8eissn
0002-9122issn
1537-2197pii
85/8/1047journal_volume
85pub_type
杂志文章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::Leaf habit correlates with multiple physiological traits. Understanding ecophysiology is therefore dependent on knowledge of leaf habit. A variety of leaf habits exists within forest understory plant communities. Oxalis acetosella is one such understory plant and has long been considered a wintergreen, meaning that it...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.3732/ajb.91.9.1371
更新日期:2004-09-01 00:00:00
abstract:UNLABELLED: PREMISE OF THE STUDY:Specific leaf area (SLA) is a critical component of the leaf economics spectrum, and many functional leaf traits have been empirically demonstrated to covary with SLA. However, a complete understanding of how change in leaf size influences SLA has not yet emerged. • METHODS:To help de...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.3732/ajb.1000118
更新日期:2010-11-01 00:00:00
abstract::• Premise of the study: Wild populations of domesticated species constitute a genetic reservoir and are fundamental to the evolutionary potential of species. Wild papaya (Carica papaya) is a rare, short-lived, gap-colonizing, dioecious tree that persists in the forest by continuous dispersal. Theoretically, these life...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.3732/ajb.1400051
更新日期:2014-07-01 00:00:00
abstract::A conspicuous feature of Vochysiaceae flowers is their single fertile stamen. In some genera, the stamen is in front of a petal, whereas in others it is in front of a sepal. This difference has been attributed to two independent reductions, which implies the stamen is not homologous across the family. The observation ...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.3732/ajb.90.11.1548
更新日期:2003-11-01 00:00:00
abstract::The temperature dependence of freezing-induced xylem cavitation was studied in a Chihuahuan desert population of Larrea tridentata (Zygophyllaceae). Field measurements of wood temperature and xylem embolism were combined with anatomical studies and laboratory measurements of embolism in stem and root samples frozen un...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.3732/ajb.89.12.1916
更新日期:2002-12-01 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::Perennial crops represent important fresh and processed food sources worldwide, but advancements in breeding perennials are often impeded due to their very nature. The perennial crops we rely on most for food take several years to reach production maturity and require large spaces to grow, which make breeding new cult...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.3732/ajb.1400143
更新日期:2014-10-01 00:00:00
abstract:PREMISE OF THE STUDY:Plant-herbivore networks are highly specialized in their interactions, yet they are highly variable with regard to the relative importance of specific host species for herbivores. How host species traits determine specialization and species strength in this antagonistic network is still an unanswer...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.3732/ajb.1600045
更新日期:2016-08-01 00:00:00
abstract::The response of axillary buds to floral stimulus activity in stem pieces was examined in two near-isogenic cultivars of tobacco that differ in the recessive maryland mammoth (mm) allele, which confers short-day behavior. All axillary buds from day-neutral plants assayed on six-internode stem pieces made few nodes (les...
journal_title:American journal of botany
pub_type: 杂志文章
doi:
更新日期:1997-07-01 00:00:00
abstract:PREMISE:Most plants interact with mycorrhizal fungi and animal pollinators simultaneously. Yet, whether mycorrhizae affect traits important to pollination remains poorly understood and may depend on the match between host and fungal genotypes. Here, we examined how ericoid mycorrhizal fungi affected flowering phenology...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.1002/ajb2.1372
更新日期:2019-11-01 00:00:00
abstract:PREMISE OF THE STUDY:New microsatellite primers were developed for testing genetic differentiation within Nothoceros aenigmaticus and their potential use in other Nothoceros species. The microsatellites are designed to investigate partitioning of genetic variation in a taxon with a peculiar sex allopatry in the souther...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.3732/ajb.1100392
更新日期:2012-03-01 00:00:00
abstract:PREMISE OF THE STUDY:Documented fossil floras in the neotropics are sparse, yet their records provide evidence on the spatial and temporal occurrence of taxa, allowing for testing of biogeographical and diversification scenarios on individual lineages. A new fossil Piper from the Late Cretaceous of Colombia is describe...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.3732/ajb.1400427
更新日期:2015-02-01 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::Tropical forest plants are known to be pollinated by a diverse array of animals. Here we report on the pollination of a woody climber species, Uvaria elmeri (Annonaceae), by cockroaches in a lowland mixed-dipterocarp forest in Sarawak, Malaysia. To the best of our knowledge, this is the first report of pollination by ...
journal_title:American journal of botany
pub_type: 杂志文章
doi:
更新日期:1997-02-01 00:00:00
abstract:PREMISE OF THE STUDY:Our goal was to infer the phylogenetic relationships and historical biogeography of the genus Dryopteris with a focus on taxa in sub-Saharan Africa and neighboring islands. In general, little is known about the relationships between African fern species and their congeners in other geographic regio...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.3732/ajb.1600392
更新日期:2017-03-01 00:00:00
abstract::Phylogenetic relationships of 38 species of the Alibertia group (Rubiaceae) and two outgroup species were investigated using the nuclear ribosomal 5S nontranscribed spacer (5S-NTS) and the internal transcribed spacers (ITS). Analysis of the data sets separately and in combination resulted in several well-supported and...
journal_title:American journal of botany
pub_type: 杂志文章
doi:
更新日期:2000-07-01 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::Bamboo is considered useful for controlling landslides, but we observed numerous shallow-slope failures in forests of big node bamboo (Phyllostachys nidularia) in Sichuan, China. Therefore, we inventoried landslide occurrence and vegetation type along one valley. To quantify bamboo root anchorage, we performed uprooti...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.3732/ajb.94.7.1129
更新日期:2007-07-01 00:00:00
abstract:PREMISE OF THE STUDY:Despite being highly fertile and occupying a large geographic region, the North American heartleaf bittercress (Cardamine cordifolia; Brassicaceae) has a puzzling triploid-like chromosome number (2n = 3x = 24). As most triploids are sterile, we embarked on a detailed analysis of the C. cordifolia g...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.3732/ajb.1500452
更新日期:2016-07-01 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::Contact forces are important in maintaining the twining habit of viny stems. A stem twining around a supporting pole puts itself into tension and uses a helical geometry to generate normal loads that are large relative to stem mass per unit length (Silk and Hubbard, Journal of Biomechanics 24(7):599-606, 1991). An ele...
journal_title:American journal of botany
pub_type: 杂志文章
doi:
更新日期:1997-08-01 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::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::In volume 97(2) of the American Journal of Botany (pp. 268-275), we published an article entitled "Structural, physiological, and stable carbon isotopic evidence that the enigmatic Paleozoic fossil Prototaxites formed from rolled liverwort mats". Here, we respond to a letter and a commentary on our article in the pres...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.3732/ajb.1000172
更新日期:2010-07-01 00:00:00
abstract:PREMISE OF THE STUDY:Pollen dispersal is a key process that influences ecological and evolutionary dynamics of plant populations by facilitating sexual reproduction and gene flow. Habitat loss and fragmentation have the potential to reduce pollen dispersal within and among habitat patches. We assessed aquatic pollen di...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.1002/ajb2.1031
更新日期:2018-02-01 00:00:00
abstract::During the crown-building phase, the mechanical architecture of the trunk of Aralia spinosa exhibits considerable ontogenetic variation. All trunks were tapered along their length, and taper was dependent on both ramet size and age; older, larger trunks were more tapered than younger, smaller trunks. Trunk specific gr...
journal_title:American journal of botany
pub_type: 杂志文章
doi:
更新日期:1999-12-01 00:00:00
abstract:UNLABELLED: PREMISE OF THE STUDY:Most studies on orchid hybrids examine separately the effects of hybridization on interactions with pollinators or with mycorrhizal fungi. Here, we simultaneously investigated both interactions in the mediterranean food-deceptive Orchis simia, O. anthropophora, and their hybrid (O. ×be...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.3732/ajb.0900303
更新日期:2010-08-01 00:00:00
abstract::The timing, geographical locations, causes, and consequences of crop domestication have long been major concerns of archaeologists, and agricultural origins and dispersals are currently more relevant than ever to scientists seeking solutions to elusive problems involving food insecurity and global health disparities. ...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.3732/ajb.1400145
更新日期:2014-10-01 00:00:00
abstract::We analyzed the effects of temporal variation in floral display size (number of flowers open at one time on a plant) on the rate of pollen removed and receipt of individual flowers for the sequential blooming plant Narthecium asiaticum (Liliaceae). Because of the acropetal blooming of this species, the display sizes w...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.3732/ajb.89.3.441
更新日期:2002-03-01 00:00:00