Abstract：
:Nuclear DNA contents (4C) were estimated by Feulgen microdensitometry in 27 species of slipper orchids. These data and recent information concerning the molecular systematics of Cypripedioideae allow an interesting re-evaluation of karyotype and genome size variation among slipper orchids in a phylogenetic context. DNA amounts differed 5.7-fold, from 24.4 pg in Phragmipedium longifolium to 138.1 pg in Paphiopedilum wardii. The most derived clades of the conduplicate-leaved slipper orchids have undergone a radical process of genome fragmentation that is most parsimoniously explained by Robertsonian changes involving centric fission. This process seems to have occurred independently of genome size variation. However, it may reflect environmental or selective pressures favoring higher numbers of linkage groups in the karyotype.
journal_name
Am J Botjournal_title
American journal of botanyauthors
Cox A,Abdelnour G,Bennett M,Leitch Isubject
Has Abstractpub_date
1998-05-01 00:00:00pages
681issue
5eissn
0002-9122issn
1537-2197pii
85/5/681journal_volume
85pub_type
杂志文章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：:Extreme preformation, the initiation of leaves or inflorescences more than 1 yr before maturation and function, is common in arctic and alpine habitats. This extended pattern of development provides a potential means to alleviate an apparent asynchrony between carbon supplied by photosynthesis in the summer and carbon...
journal_title：American journal of botany
pub_type： 杂志文章
doi：10.3732/ajb.90.9.1313
更新日期：2003-09-01 00:00:00
abstract：:Five plant communities in Western Australia, as well as selected desert and Rocky Mountain species of the western USA, were surveyed to evaluate associations among leaf structure, orientational properties, and the sunlight exposure and precipitation characteristic of each community. Selected leaf structural features h...
journal_title：American journal of botany
pub_type： 杂志文章
doi：
更新日期：1998-01-01 00:00:00
abstract：:The desert moss Syntrichia caninervis exhibits one of the most skewed sex ratios in the plant kingdom, with female individuals far outnumbering male individuals (exceeding 14♀:1♂). The "cost of sex hypothesis" derives from allocational theory and predicts that the sex which is most expensive should be the rarer sex. T...
journal_title：American journal of botany
pub_type： 杂志文章
doi：
更新日期：2000-11-01 00:00:00
abstract：:The pitchers of the tropical carnivorous plant Nepenthes alata are highly specialized organs for the attraction and capture of insects and absorption of nutrients from them. This study examined the structure and development of these pitchers, with particular focus on the nectaries and digestive glands. Immature pitche...
journal_title：American journal of botany
pub_type： 杂志文章
doi：
更新日期：1999-10-01 00:00:00
abstract：PREMISE OF THE STUDY:The phenotype of an individual can be modified by the environment experienced by its predecessors, a phenomenon called transgenerational or maternal effects. These effects are studied mostly across sexual generations and are thought to be mediated also by epigenetic variation. However, we do not kn...
journal_title：American journal of botany
pub_type： 杂志文章
doi：10.3732/ajb.1500526
更新日期：2016-09-01 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：:Intensified ultraviolet-B radiation or UV-B (wavelengths between 280 and 320 nm) can delay flowering and diminish lifetime flower production in a few plants. Here we studied the effects of enhanced UV-B on floral traits crucial to pollination and pollinator reproduction. We observed simultaneous flowering responses of...
journal_title：American journal of botany
pub_type： 杂志文章
doi：
更新日期：1999-01-01 00:00:00
abstract：:We examined the effect of inbreeding on fitness (through both male and female functions) and changes in self-fertility in the partially self-incompatible species Campanula rapunculoides. Individuals in natural populations of C. rapunculoides varied extensively in their strength of self-incompatibility (SI). We crossed...
journal_title：American journal of botany
pub_type： 杂志文章
doi：10.3732/ajb.90.12.1736
更新日期：2003-12-01 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：:Accurate estimates of inbreeding depression are necessary in order to predict the evolutionary dynamics of a population, but many studies estimate inbreeding depression based solely on components of female function such as fruit set, seed set, and seed quality. Because total fitness is achieved through both male and f...
journal_title：American journal of botany
pub_type： 杂志文章
doi：10.3732/ajb.92.1.107
更新日期：2005-01-01 00:00:00
abstract：UNLABELLED: PREMISE OF THE STUDY:Vessels are the chief conduit for long-distance water transport in the majority of flowering plants. Vessel length is a key trait that determines plant hydraulic efficiency and safety, yet relatively little is known about this xylem feature. • METHODS:We used previously published stud...
journal_title：American journal of botany
pub_type： 杂志文章
doi：10.3732/ajb.1200140
更新日期：2012-10-01 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：:• 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：:Additional information on the morphology of the vegetative ultimate branches of Archaeopteris roemeriana was obtained by uncovering compression specimens collected in Upper Devonian deposits in Belgium. For the first time, anisophylly, previously inferred from anatomical studies, is demonstrated on one species of the ...
journal_title：American journal of botany
pub_type： 杂志文章
doi：
更新日期：2001-04-01 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：:Many plant species are characterized by a life cycle with a long-lived, subterranean phase that is completely dependent on mycorrhizal fungal symbionts for fixed carbon. This type of life cycle is both phylogenetically and ecologically widespread and is found in diverse vascular plant lineages from the tropics to suba...
journal_title：American journal of botany
pub_type： 杂志文章
doi：10.3732/ajb.94.7.1248
更新日期：2007-07-01 00:00:00
abstract：PREMISE OF THE STUDY:Drosera peltata var. nipponica, an element of the East Asia warm-temperate vegetation, and D. rotundifolia, a widely distributed boreal species, reach one of their northernmost and southernmost limits, respectively, on the Korean Peninsula. Because the Last Glacial Maximum (LGM)-Holocene dynamics o...
journal_title：American journal of botany
pub_type： 杂志文章
doi：10.3732/ajb.1200486
更新日期：2013-11-01 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：:Fitness of interspecific hybrids is sometimes high relative to their parents, despite the conventional belief that they are mostly unfit. F(1) hybrids between oilseed rape (Brassica napus) and weedy B. rapa can be significantly more fit than their weedy parents under some conditions; however, under other conditions th...
journal_title：American journal of botany
pub_type： 杂志文章
doi：10.3732/ajb.90.4.571
更新日期：2003-04-01 00:00:00
abstract：PREMISE OF THE STUDY:Plant communities may be influenced by toxic secondary metabolites or enhanced plant growth from plant-symbiont interactions. The C:N hypothesis predicts that carbon or nitrogen constrains plant secondary metabolite production, but it does not consider compounds produced by plant symbionts. Locowee...
journal_title：American journal of botany
pub_type： 杂志文章
doi：10.3732/ajb.1100133
更新日期：2011-12-01 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 size and cotyledon morphology are two key juvenile traits that have evolved in response to changes in plant species life-history strategies and habitat associations. Correlations of these traits with each other and with other juvenile traits were examined for 70 species of trees and shrubs in Kibale National Park...
journal_title：American journal of botany
pub_type： 杂志文章
doi：10.3732/ajb.92.6.972
更新日期：2005-06-01 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：:Sequence data from the intron and spacer of the trnL-F chloroplast region elucidate the phylogenetic relationships of the tribe Diseae (Orchidoideae: Orchidaceae). Within Diseae, 41 species of Disa, two of Brownleea, three of Satyrium, and two of Corycium were included, with five species of Habenaria sensu lato (Orchi...
journal_title：American journal of botany
pub_type： 杂志文章
doi：
更新日期：2001-11-01 00:00:00
abstract：:The tribe Genisteae includes genera of great ecological importance in Mediterranean countries because they are dominant elements of many plant communities. Genetic variation and diversification patterns in Stauracanthus (Genisteae) provide information relevant for the study of the processes of diversification in relat...
journal_title：American journal of botany
pub_type： 杂志文章
doi：10.3732/ajb.95.1.98
更新日期：2008-01-01 00:00:00
abstract：:The endodermis of different species of the genus Equisetum has different configurations, two or one continuous layers or a sheath only around the vascular bundles. The question whether the endodermis contributes to the mechanical stability of the aerial shoots is investigated in two ways: In a direct approach, the end...
journal_title：American journal of botany
pub_type： 杂志文章
doi：10.3732/ajb.91.11.1936
更新日期：2004-11-01 00:00:00
abstract：:• Premise of the study: Carpel closure is commonly considered as a key innovation in angiosperms; however, some families continue to exhibit a variety of forms of incomplete carpel closure. The carpel of Sagittaria species contains an unusual structure. In this study, we confirm the closure type of the carpel of Sagit...
journal_title：American journal of botany
pub_type： 杂志文章
doi：10.3732/ajb.1400172
更新日期：2014-07-01 00:00:00
abstract：:For more than a century, the common ancestor of flowering plants was thought to have had a seven-celled, eight-nucleate Polygonum-type female gametophyte. It is now evident that not one, but in fact three, patterns of female gametophyte development and mature structure characterize the common ancestors of the four mos...
journal_title：American journal of botany
pub_type： 杂志文章
doi：10.3732/ajb.0800311
更新日期：2009-01-01 00:00:00
abstract：:Competition and herbivory are ubiquitous environmental challenges that affect most plants. We examined the influence of phenotypic responses to either competition or herbivory on the subsequent response of the plants to the other factor. The stem-elongation response of Chenopodium album to light competition attenuated...
journal_title：American journal of botany
pub_type： 杂志文章
doi：10.3732/ajb.92.1.21
更新日期：2005-01-01 00:00:00
