Isozyme variability of the wetland specialist Swertia perennis (Gentianaceae) in relation to habitat size, isolation, and plant fitness.

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

authors： Jacobsen AL,Pratt RB,Tobin MF,Hacke UG,Ewers FW

更新日期：2012-10-01 00:00:00

abstract：:Seedling establishment has long been believed to be rare on alpine tundra because of predicted life history trade-offs, the clonality of alpine species, and the harshness of the alpine climate. Contrary to the idea that seedlings are rare on alpine tundra, a 4-yr demographic study of seedlings at Niwot Ridge, Colorado...

journal_title：American journal of botany

authors： Forbis TA

更新日期：2003-08-01 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

authors： Inubushi K,Sugii H,Nishino S,Nishino E

更新日期：2001-06-01 00:00:00

abstract：PREMISE OF THE STUDY:Evolutionary and biogeographic history, including past environmental change and diversification processes, are likely to have influenced the expansion, migration, and extinction of populations, creating evolutionary legacy effects that influence regional species pools and the composition of communi...

journal_title：American journal of botany

authors： Cavender-Bares J,Kothari S,Meireles JE,Kaproth MA,Manos PS,Hipp AL

更新日期：2018-03-01 00:00:00

abstract：:We transplanted Nuphar variegata with submersed leaves only into natural lake sediments in pH-, [CO(2)]-, depth-, and temperature-controlled greenhouse tanks to test the hypotheses that more fertile sediment, lower free [CO(2)], and shallower depth would all stimulate the development of floating leaves. Sediment highe...

journal_title：American journal of botany

authors： Titus JE,Gary Sullivan P

更新日期：2001-08-01 00:00:00

abstract：:Floral morphology of the 13 species of Moringa ranges from actinomorphic flowers with little hypanthium to highly zygomorphic flowers with well-developed hypanthia. Scanning electron and light microscopy were used to identify ontogenetic differences among two actinomorphic and eight zygomorphic species. All species sh...

journal_title：American journal of botany

authors： Olson ME

更新日期：2003-01-01 00:00:00

abstract：:To investigate the relationship between the altitudinal distribution of Quercus laceyi and Q. sideroxyla and their physiological responses to drought, we measured relative water content (RWC), water potentials (Ψ(predawn) and Ψ(midday)), photosynthesis (A(max)), stomatal conductance (g), chlorophyll fluorescence (F(v)...

journal_title：American journal of botany

authors： Poulos HM,Goodale UM,Berlyn GP

更新日期：2007-05-01 00:00:00

abstract：:Clarkia (Onagraceae) is a genus of 42 annual species, mostly native to California, that has served as a model for many studies of plant evolutionary biology, particularly morphological, cytological, and genetic divergence; reproductive isolation; and speciation. Section Sympherica is the largest section with eight dip...

journal_title：American journal of botany

authors： Ford VS,Gottlieb LD

更新日期：2003-02-01 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

authors： Huber J,Dettman DL,Williams DG,Hultine KR

更新日期：2018-10-01 00:00:00

abstract：:Darwin's research on botany and plant physiology was a landmark attempt to integrate plant movements into a biological perspective of behavior. Since antiquity, people have sought to explain plant movements via mechanical or physiological forces, and yet they also constructed analogies between plant and animal behavio...

journal_title：American journal of botany

authors： Whippo CW,Hangarter RP

更新日期：2009-12-01 00:00:00

abstract：:Polyploid speciation is an ongoing, important source of angiosperm diversity. However, the barriers to polyploid speciation and mechanisms of establishment remain poorly understood for all but a few species. Several factors likely to have influenced tetraploid establishment, including barriers to triploid formation, c...

journal_title：American journal of botany

authors： Baack EJ

更新日期：2005-11-01 00:00:00

abstract：:Light propagation and distribution inside leaves have been recognized as important processes influencing photosynthesis. Monochromatic light absorption across the mesophyll was measured using chlorophyll fluorescence generated from illumination of the cut edge (epi-illumination), as well as the adaxial or abaxial surf...

journal_title：American journal of botany

authors： Johnson DM,Smith WK,Vogelmann TC,Brodersen CR

更新日期：2005-09-01 00:00:00

abstract：:Viability of long-distance pollen links ecological models to the genetic structure of forest tree populations, determining how forests will adapt to climate change and how far genes flow from genetically modified (GM) pine plantations. Addressing this landscape-scale inquiry is feasible when the pollen source, the del...

journal_title：American journal of botany

authors： Williams CG

更新日期：2010-05-01 00:00:00

abstract：:Investigations of the Middle Eocene Princeton Chert reveal evidence for the connection of lauraceous flowers to fruits through a developmental series. Youngest fruits are found with attached floral remnants. Later stages show receptacle enlargement, fruit wall thickening, and the development of abundant sclereid clust...

journal_title：American journal of botany

authors： Little SA,Stockey RA,Penner B

更新日期：2009-03-01 00:00:00

abstract：:Floral characteristics such as morphology and flower color have been interpreted as adaptive traits that evolved through selective pressures generated by pollinators. Differences among populations in the expression of floral characters could result from natural selection for their adaptive value to local conditions. W...

journal_title：American journal of botany

authors： Silva-Montellano A,Eguiarte LE

更新日期：2003-03-01 00:00:00

abstract：:Gas exchange was measured in two subalpine herbs during alternating periods of sun and shade that simulated natural cloud patterns. Stomatal conductance (g) in the subalpine herb Helianthella quinquenervis was reduced by as much as 75% during 5-min shade periods that ranged in photosynthetic photon flux density (PPFD)...

journal_title：American journal of botany

authors： Knapp AK,Smith WK

更新日期：1990-02-01 00:00:00

abstract：PREMISE OF THE STUDY:Microsatellite primers were developed in the traditional Tibetan medicinal plant Halenia elliptica D. Don to investigate its genetic diversity and population genetic structure. METHODS AND RESULTS:Using the Fast Isolation by AFLP of Sequences Containing (FIASCO) repeats protocol, 24 primer sets we...

journal_title：American journal of botany

authors： Zhang ZR,Yang J,Sun Y,Gao TG,Li DZ,Xue CY

更新日期：2011-07-01 00:00:00

abstract：PREMISE OF THE STUDY:Generic boundaries and infrageneric relationships among the charismatic temperate magnoliid Asarum sensu lato (Aristolochiaceae) have long been uncertain. Previous molecular phylogenetic analyses used either plastid or nuclear loci alone and varied greatly in their taxonomic implications for the ge...

journal_title：American journal of botany

authors： Sinn BT,Kelly LM,Freudenstein JV

更新日期：2015-05-01 00:00:00

abstract：:Plant xylem must balance efficient delivery of water to the canopy against protection from air entry into the conduits via air-seeding. We investigated the relationship between tracheid allometry, end wall pitting, safety from air-seeding, and the hydraulic efficiency of conifer wood in order to better understand the ...

journal_title：American journal of botany

authors： Pittermann J,Sperry JS,Hacke UG,Wheeler JK,Sikkema EH

更新日期：2006-09-01 00:00:00

abstract：UNLABELLED:• PREMISE OF THE STUDY:Island plants are over-exploited and "under-explored." Understanding the reproductive biology of plants, especially rare species, is fundamental to clarifying their evolution, estimating potential for change, and for creating effective conservation plans. Clarification of sexual syste...

journal_title：American journal of botany

authors： Anderson GJ,Anderson MK,Patel N

更新日期：2015-03-01 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

authors： Douzery EJ,Pridgeon AM,Kores P,Linder HP,Kurzweil H,Chase MW

更新日期：1999-06-01 00:00:00

abstract：:Microelectrodes were used to study the oxygen concentration within Myrica gale L. nodules. Low oxygen concentrations were found only in the region of the mature, nitrogen-fixing endophyte, and appeared to correspond to clusters of infected host cells. The oxygen concentration in the remainder of the nodule was much hi...

journal_title：American journal of botany

authors： Tjepkema JD

更新日期：1983-01-01 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

authors： Hannan GL,Orick MW

更新日期：2000-03-01 00:00:00

abstract：:The evolutionary origins of the morphological and taxonomic diversity of angiosperms is poorly known. We used the genus Melianthus to explore the diversification of the southern African flora. Melianthus comprises eight species, and a phylogeny based on one nuclear and two plastid genes, as well as a morphological dat...

journal_title：American journal of botany

authors： Linder HP,Dlamini T,Henning J,Verboom GA

更新日期：2006-07-01 00:00:00

abstract：:This study examined variation in two components of acorn production. Percentage of bearing ramets (stems) and number of acorns per bearing ramet were examined in five clonal oaks in three xeric habitats of south-central peninsular Florida in relation to ramet size within and between species and vegetative associations...

journal_title：American journal of botany

authors： Abrahamson WG,Layne JN

更新日期：2002-01-01 00:00:00

abstract：:Pollinator-mediated natural selection has been shown to act on phenotypic variation in floral morphology, and this variation has often been demonstrated to be heritable, but few details are available concerning the sources of floral variation. We examined phenotypic variation in seven floral traits in wild radish (Rap...

journal_title：American journal of botany

authors： Williams JL,Conner JK

更新日期：2001-09-01 00:00:00

abstract：:Lxm1-O, a dominant EMS (ethyl methanesulfonate) induced mutation in maize (Zea mays, Poaceae), was originally reported to affect the blade/sheath boundary over the midrib region of the leaf. Here we present a more extensive analysis of the Lxm phenotype in nine different inbred lines. Lxm leaves are longer and narrowe...

journal_title：American journal of botany

authors： Schichnes D,Freeling M

更新日期：1998-04-01 00:00:00

abstract：:Eight ecosystems that were present in the Cretaceous about 100 Ma (million years ago) in the New World eventually developed into the 12 recognized for the modern Earth. Among the forcing mechanisms that drove biotic change during this interval was a decline in global temperatures toward the end of the Cretaceous, augm...

journal_title：American journal of botany

authors： Graham A

更新日期：2011-03-01 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

authors： Hanson R,Zhao XP,Islam-Faridi MN,Paterson A,Zwick M,Crane C,McKnight T,Stelly D,Price HJ

更新日期：1998-10-01 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

authors： Gaynor ML,Marchant DB,Soltis DE,Soltis PS

更新日期：2018-10-01 00:00:00