解剖学和形态学
麻醉学
听力与言语-语言病理学
行为科学
心脏和心血管系统
细胞和组织工程学
临床神经病学
危重症监护医学
牙科,口腔外科和医学
皮肤病学
急诊医学
内分泌学和新陈代谢
肠胃学和肝脏学
老人病学和老年医学
卫生保健科学和服务
血液学
免疫学
传染病
综合和补充性医学
医学伦理学
医学信息学
医学实验室技术
医学,全科和内科
医学,法律
医学,研究和试验
神经系统科学
护理
营养学和饮食学
产科医学和妇科医学
肿瘤学
眼科学
整形外科学
耳鼻喉科学
病理学
儿科学
周围血管疾病
药理学和药剂学
生理学
基本医疗保健
精神病学
公共、环境和职业卫生
放射学,核医学和医学成像
康复学
生殖生物学
呼吸系统
风湿病学
运动科学
外科学
毒理学
热带医学
泌尿学和肾脏学
病毒学
老年医学
健康政策和服务
心理学,临床
abstract:PREMISE:Woody plants with photosynthetic stems are common in the drylands of the world; however, we know little about the origin(s) and geographical distribution of photosynthetic stems. Therefore, we set to answer the following questions: (1) Is stem photosynthesis phylogenetically conserved? (2) Do green-stemmed and ...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.1002/ajb2.1572
更新日期:2020-12-06 00:00:00
abstract:PREMISE:The Eocene-Oligocene transition (EOT; 34-33 Ma) was marked by global cooling and increased seasonality and aridity, leading to a shift in North American floras from subtropical forests to deciduous hardwood forests similar to today. This shift is well documented taxonomically and biogeographically, but its ecol...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.1002/ajb2.1580
更新日期:2020-12-01 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:PREMISE:Polyploidy may serve to contribute to range size if autopolyploid cytotypes are adapted to differing ecological conditions. This study aims to establish the geographic distribution of cytotypes within the giant goldenrod (Solidago gigantea), and to assess whether cytotypes exhibit differing ecological tolerance...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.1002/ajb2.1556
更新日期:2020-11-01 00:00:00
abstract:PREMISE:Within closed-canopy forests, vertical gradients of light and atmospheric CO2 drive variations in leaf carbon isotope ratios, leaf mass per area (LMA), and the micromorphology of leaf epidermal cells. Variations in traits observed in preserved or fossilized leaves could enable inferences of past forest canopy c...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.1002/ajb2.1523
更新日期:2020-08-01 00:00:00
abstract:PREMISE:Despite the fast pace of exploration of the patterns and processes influencing Neotropical plant hyperdiversity, the taxa explored are mostly from large groups that are widely distributed, morphologically diverse, or economically important. Vochysiaceae is an example of an undersampled taxon, providing an excel...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.1002/ajb2.1502
更新日期:2020-07-01 00:00:00
abstract:PREMISE:The ecological implications of hyperaccumulation have been investigated at the organismal level, but are poorly understood at the plant community level. Questions addressed here were: Does the presence of selenium (Se) hyperaccumulators affect Se distribution and concentration in their native soil, and do hyper...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.1002/ajb2.1500
更新日期:2020-07-01 00:00:00
abstract:PREMISE:Distylous species possess two floral morphs with reciprocal positioning of stigmas and anthers that is hypothesized to promote disassortative pollination. Theoretical models predict equal morph frequencies, but many populations depart from the expected 1:1 ratio, a pattern that often correlates with asymmetric ...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.1002/ajb2.1478
更新日期:2020-06-01 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:Medullary bundles, i.e., vascular units in the pith, have evolved multiple times in vascular plants. However, no study has ever explored their anatomical diversity and evolution within a phylogenetic framework. Here, we investigated the development of the primary vascular system within Nyctaginaceae showing how...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.1002/ajb2.1471
更新日期:2020-05-01 00:00:00
abstract:PREMISE:Spiny pollen has evolved independently in multiple entomophilous lineages. Sexual selection may act on exine traits that facilitate male mating success by influencing the transfer of pollen from the anther to the body of the pollinator, while natural selection acts to increase pollen survival. We postulated tha...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.1002/ajb2.1428
更新日期:2020-02-01 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:Light is critical in the ability of plants to accumulate chlorophyll. When exposed to far-red (FR) light and then grown in white light in the absence of sucrose, wild-type seedlings fail to green in a response known as the FR block of greening (BOG). This response is controlled by phytochrome A through repressi...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.1002/ajb2.1423
更新日期:2020-02-01 00:00:00
abstract:PREMISE:Gynomonoecy is an infrequent sexual system in angiosperms, although widely represented within the Asteraceae family. Currently, the hypothesis of two nuclear loci controling gynomonoecy is the most accepted. However, the genic interactions are still uncertain. Anacyclus clavatus, A. homogamos, and A. valentinus...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.1002/ajb2.1414
更新日期:2020-01-01 00:00:00
abstract:PREMISE:Inbreeding depression is traditionally considered a major factor favoring outcrossing in hermaphrodites. Recent experiments have shown that environmental conditions can influence the magnitude of inbreeding depression, but their relevance in natural populations is unclear. To investigate this, we studied the cl...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.1002/ajb2.1410
更新日期:2020-01-01 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: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:Hyperaccumulation of heavy metals in plants has never been documented from Central America or Mexico. Psychotria grandis, P. costivenia, and P. glomerata (Rubiaceae) have been reported to hyperaccumulate nickel in the Greater Antilles, but they also occur widely across the neotropics. The goals of this research...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.1002/ajb2.1362
更新日期:2019-10-01 00:00:00
abstract:PREMISE:Understanding plant hydraulic functioning and water balance during drought has become key in predicting species survival and recovery. However, there are few insightful studies that couple physiological and morphological attributes for many ecosystems, such as the vulnerable Tropical Montane Cloud Forests (TMCF...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.1002/ajb2.1356
更新日期:2019-10-01 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:Declines in reproductive capabilities with increasing age are common across the tree of life. However, in plants, mating system traits have rarely been tested for signs of senescence. Since reproduction is often resource limited, we might expect outcrossing and selfing taxa to allocate these resources different...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.1002/ajb2.1346
更新日期:2019-09-01 00:00:00
abstract:PREMISE:Closely related species occurring in sympatry may experience the negative consequences of interspecific pollen transfer if reproductive isolation (RI) barriers are not in place. We evaluated the importance of pre- and post-pollination RI barriers in three sympatric species of Achimenes (Gesneriaceae), including...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.1002/ajb2.1324
更新日期:2019-07-01 00:00:00
abstract:PREMISE:Despite the efforts to understand the processes that shape neotropical biodiversity, the complexity of certain biomes, such as the Atlantic Forest (AF), prevents the generalization of patterns. Initially, ecological niche modeling (ENM), with phylogeographic studies, identified past stable areas in the central ...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.1002/ajb2.1317
更新日期:2019-07-01 00:00:00
abstract:PREMISE:Adaptation to harsh edaphic substrates has repeatedly led to the evolution of edaphic specialists and generalists. Yet, it is unclear what factors promote specialization versus generalization. Here, we search for habitat use patterns associated with serpentine endemics (specialists) and serpentine tolerators (g...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.1002/ajb2.1285
更新日期:2019-05-01 00:00:00
abstract:PREMISE OF THE STUDY:A key question in evolutionary biology is why some clades are more successful by being widespread geographically, biome diverse, or species-rich. To extend understanding of how shifts in area, biomes, and pollinators impact diversification in plants, we examined the relationships of these shifts to...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.1002/ajb2.1268
更新日期:2019-04-01 00:00:00
abstract:PREMISE OF THE STUDY:Climate cycles of the Quaternary have impacted plants at a global scale, leaving behind a complex genetic legacy. Species of the northern Rocky Mountains of North America were exposed to more uniform glacial patterns than the central and southern ranges, where synergistic relationships between temp...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.1002/ajb2.1259
更新日期:2019-03-01 00:00:00
abstract:PREMISE OF THE STUDY:Nutrient resorption is essential for plant nutrient conservation. Large-bodied plants potentially have large nutrient sink pools and high nutrient flux. Whether and how nutrient resorption can be regulated by plant size and biomass allocation are yet unknown. METHODS:Using the herbaceous plant Ama...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.1002/ajb2.1246
更新日期:2019-03-01 00:00:00
abstract:PREMISE OF THE STUDY:Over one-third of the native flowering plant species in the Hawaiian Islands are listed as federally threatened or endangered. Lack of sufficient pollination could contribute to reductions in populations, reproduction, and genetic diversity among these species but has been little studied. METHODS:...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.1002/ajb2.1233
更新日期:2019-02-01 00:00:00
abstract:PREMISE OF THE STUDY:Phenological mismatch has received attention in plant-pollinator interactions, but less so in seed dispersal mutualisms. We investigated whether the seasonal availability of myrmecochorous seeds is well matched to the seasonal activity patterns of seed-dispersing ants. METHODS:We compared seasonal...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.1002/ajb2.1214
更新日期:2019-01-01 00:00:00
abstract:PREMISE OF THE STUDY:Variation in demographic parameters reflects the life-history strategies of plants in response to specific environments. We aimed to investigate the intraspecific variation in life-history traits of a clonal alpine herb, Gentiana nipponica, in various snowmelt conditions. METHODS:Individual ramets...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.1002/ajb2.1186
更新日期:2018-11-01 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: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:PREMISE OF THE STUDY:Giant cacti species possess long cylindrical stems that store massive amounts of water and other resources to draw on for photosynthesis, growth, and reproduction during hot and dry conditions. Across all giant cacti taxa, stem photosynthetic surface area to volume ratio (S:V) varies by several fol...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.1002/ajb2.1166
更新日期:2018-10-01 00:00:00
abstract:PREMISE OF THE STUDY:General relationships among functional traits have been identified across species, but the forces shaping these relationships remain largely unknown. Adopting an approach from evolutionary biology, we studied similarities and differences in intrapopulation trait correlations among locally co-occurr...
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
abstract:PREMISE OF THE STUDY:Conifers are an important living seed plant lineage with an extensive fossil record spanning more than 300 million years. The group therefore provides an excellent opportunity to explore congruence and conflict between dated molecular phylogenies and the fossil record. METHODS:We surveyed the curr...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.1002/ajb2.1143
更新日期:2018-09-01 00:00:00
abstract:PREMISE OF THE STUDY:The apical meristem generates indeterminate apical growth of the stem and root of vascular plants. Our previous examination showed that shoot apical meristems (SAMs) can be classified into two types based on plasmodesmatal networks (PNs), which are important elements in symplasmic signaling pathway...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.1002/ajb2.1153
更新日期:2018-09-01 00:00:00
abstract:PREMISE OF THE STUDY:The fossil record of Agathis historically has been restricted to Australasia. Recently described fossils from the Eocene of Patagonian Argentina showed a broader distribution than found previously, which is reinforced here with a new early Paleocene Agathis species from Patagonia. No previous phylo...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.1002/ajb2.1127
更新日期:2018-08-01 00:00:00
abstract:PREMISE OF THE STUDY:Inclusion of fossils in phylogenetic analyses is necessary in order to construct a comprehensive "tree of death" and elucidate evolutionary history of taxa; however, such incorporation of fossils in phylogenetic reconstruction is dependent on the availability and interpretation of extensive morphol...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.1002/ajb2.1123
更新日期:2018-08-01 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: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