An overview of extant conifer evolution from the perspective of the fossil record.

abstract：PREMISE OF THE STUDY:High intraspecific cytogenetic variation in the sedge genus Carex (Cyperaceae) is hypothesized to be due to the "diffuse" or non-localized centromeres, which facilitate chromosome fission and fusion. If chromosome number changes are dominated by fission and fusion, then chromosome evolution will re...

journal_title：American journal of botany

authors： Chung KS,Weber JA,Hipp AL

更新日期：2011-01-01 00:00:00

abstract：PREMISE OF THE STUDY:Recurrent formation of polyploid taxa is a common observation in many plant groups. Haploid, cytoplasmic genomes like the plastid genome can be used to overcome the problem of homeologous genes and recombination in polyploid taxa. Fragaria (Rosaceae) contains several octo- and decaploid species. We...

journal_title：American journal of botany

authors： Dillenberger MS,Wei N,Tennessen JA,Ashman TL,Liston A

更新日期：2018-05-01 00:00:00

abstract：:Herbivore damage is known to cause the premature loss of mature leaves. However, the effects of herbivory on abscission during the early stages of leaf development remain unexplored, even though herbivores frequently prefer unlignified, immature leaves. In a field experiment, we removed 50% of the tissue from leaves a...

journal_title：American journal of botany

authors： Blundell AG,Peart DR

更新日期：2000-11-01 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

authors： Persson C

更新日期：2000-07-01 00:00:00

abstract：PREMISE OF THE STUDY:Land-use change is cited as a primary driver of global biodiversity loss, with myriad consequences for species, populations, and ecosystems. However, few studies have examined its impact on species interactions, particularly pollination. Furthermore, when the effects of land-use change on pollinati...

journal_title：American journal of botany

authors： Skogen KA,Jogesh T,Hilpman ET,Todd SL,Rhodes MK,Still SM,Fant JB

更新日期：2016-11-01 00:00:00

abstract：:Bennettitales is an extinct group of seed plants with reproductive structures that are similar in some respects to both Gnetales and angiosperms, but systematic relationships among the three clades remain controversial. This study summarizes characters of bennettitalean plants and presents new evidence for the structu...

journal_title：American journal of botany

authors： Rothwell GW,Crepet WL,Stockey RA

更新日期：2009-01-01 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

authors： Lu J,Magain N,Miadlikowska J,Coyle JR,Truong C,Lutzoni F

更新日期：2018-07-01 00:00:00

abstract：PREMISE OF THE STUDY:The study of scaling examines the relative dimensions of diverse organismal traits. Understanding whether global scaling patterns are paralleled within species is key to identify causal factors of universal scaling. I examined whether the foliage-stem (Corner's rules), the leaf size-number, and the...

journal_title：American journal of botany

authors： Fajardo A

更新日期：2016-05-01 00:00:00

abstract：:Woody stems comprise a large biological carbon fraction and determine water transport between roots and leaves; their structure and function can influence both carbon and hydrological cycles. While angiosperm wood anatomy and density determine hydraulic conductivity and mechanical strength, little is known about inter...

journal_title：American journal of botany

authors： Zanne AE,Westoby M,Falster DS,Ackerly DD,Loarie SR,Arnold SE,Coomes DA

更新日期：2010-02-01 00:00:00

abstract：PREMISE OF THE STUDY:A prevailing hypothesis in forest succession is that shade-tolerant species grow more slowly than shade-intolerant species, across light conditions, because they prioritize carbon (C) allocation to storage. We examined this hypothesis in a confamilial pair of species, including one of the fastest-g...

journal_title：American journal of botany

authors： Piper FI,Sepúlveda P,Bustos-Salazar A,Zúñiga-Feest A

更新日期：2017-05-01 00:00:00

abstract：PREMISE OF THE STUDY:Areas lacking dominant plants, or gaps, can support high diversity and specialist species. Previous chronosequence research in Florida rosemary scrub showed indistinct gap area patterns with fire and the dependence of certain species on gaps. We hypothesized that fire and gap size would affect exti...

journal_title：American journal of botany

authors： Menges ES,Crate SJH,Quintana-Ascencio PF

更新日期：2017-12-01 00:00:00

abstract：PREMISE OF THE STUDY:Robust markers are required (inter alia) for assessing origins of Calophyllum inophyllum populations on the Bonin Islands, Japan. Therefore, informative expressed sequence tag (EST)-based microsatellite or simple sequence repeat (SSRs) markers in the species were sought. METHODS AND RESULTS:Using ...

journal_title：American journal of botany

authors： Setsuko S,Uchiyama K,Sugai K,Hanaoka S,Yoshimaru H

更新日期：2012-01-01 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：:Members of tribe Vandeae (Orchidaceae) form a large, pantropical clade of horticulturally important epiphytes. Monopodial leafless members of Vandeae have undergone extreme reduction in habit and represent a novel adaptation to the canopy environment in tropical Africa, Asia, and America. To study the evolution of mon...

journal_title：American journal of botany

authors： Carlsward BS,Whitten WM,Williams NH,Bytebier B

更新日期：2006-05-01 00:00:00

abstract：:Cacti are a large and diverse group of stem succulents predominantly occurring in warm and arid North and South America. Chloroplast DNA sequences of the trnK intron, including the matK gene, were sequenced for 70 ingroup taxa and two outgroups from the Portulacaceae. In order to improve resolution in three major grou...

journal_title：American journal of botany

authors： Nyffeler R

更新日期：2002-02-01 00:00:00

abstract：:Dispersal is an important life history component. Seed settling velocity may be a useful surrogate for the measurement of dispersal ability in wind-dispersed plants, particularly those whose seeds have plumose dispersal structures. I measured settling velocities on seeds of eight species of Asteraceae, including annua...

journal_title：American journal of botany

authors： Andersen MC

更新日期：1992-10-01 00:00:00

abstract：:We assessed the effects of local environment on survival, growth, and development in six clones (genotypes) of Vallisneria americana grown at five sites in the Huron-Erie Corridor. Detrimental effects of local environment on plant performance (rate of clonal growth, leaf and root production, surface area of leaves and...

journal_title：American journal of botany

authors： Biernacki M,Lovett-Doust J

更新日期：1997-12-01 00:00:00

abstract：PREMISE OF THE STUDY:Geographic differences in flower visitor assemblages might lead to among-population differences in the magnitude and pattern of floral integration. However, the role of current pollinator visitation in shaping the magnitude and pattern of floral trait correlations is still controversial. METHODS:W...

journal_title：American journal of botany

authors： Lázaro A,Santamaría L

更新日期：2016-02-01 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：:In contrast to most angiosperms, in which fertilization occurs 1 or 2 days after pollination, in some plant orders, including the Fagales, fertilization is delayed from 4 days to more than 1 year, raising questions regarding why fertilization is delayed and where and how pollen tubes remain in the pistil during the de...

journal_title：American journal of botany

authors： Sogo A,Tobe H

更新日期：2006-12-01 00:00:00

abstract：PREMISE OF THE STUDY:Large genera provide remarkable opportunities to investigate patterns of morphological evolution and historical biogeography in plants. A molecular phylogeny of the species-rich and morphologically and ecologically diverse genus Mimosa was generated to evaluate its infrageneric classification, reco...

journal_title：American journal of botany

authors： Simon MF,Grether R,de Queiroz LP,Särkinen TE,Dutra VF,Hughes CE

更新日期：2011-07-01 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

authors： O'Brien AM,Yu ZH,Luo DY,Laurich J,Passeport E,Frederickson ME

更新日期：2020-02-01 00:00:00

abstract：:Primarily known only by the edible fruits of Citrus, Rutaceae comprise a large (c. 160 genera and 1900 species), morphologically diverse, cosmopolitan family. Of its extraordinary array of secondary chemical compounds, many have medicinal, antimicrobial, insecticidal, or herbicidal properties. To assist with the much-...

journal_title：American journal of botany

authors： Groppo M,Pirani JR,Salatino ML,Blanco SR,Kallunki JA

更新日期：2008-08-01 00:00:00

abstract：:Recent molecular phylogenetic studies of Solanaceae have identified many well-supported clades within the family and have permitted the creation of a phylogenetic system of classification. Here we estimate the phylogeny for Iochrominae, a clade of Physaleae sensu Olmstead et al. (1999), which contains 34 Andean specie...

journal_title：American journal of botany

authors： Smith SD,Baum DA

更新日期：2006-08-01 00:00:00

abstract：:The biogeography of plant-animal interactions is a novel topic on which many disciplines converge (e.g., reproductive biology, biogeography, and evolutionary biology). Narrative reviews have indicated that tropical columnar cacti and agaves have highly specialized pollination systems, while extratropical species have ...

journal_title：American journal of botany

authors： Munguía-Rosas MA,Sosa VJ,Ojeda MM,De-Nova JA

更新日期：2009-10-01 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

authors： Briand CH,Campion SM,Dzambo DA,Wilson KA

更新日期：1999-12-01 00:00:00

abstract：:Yucca glauca is a C(3) evergreen rosette species locally common in the C(4)-dominated grasslands of the central Great Plains. Most congeners of Y. glauca are found in deserts, and Y. glauca's morphological similarities to desert species (steeply angled leaves, evergreen habit) may be critical to its success in grassla...

journal_title：American journal of botany

authors： Maragni LA,Knapp AK,McAllister CA

更新日期：2000-02-01 00:00:00

abstract：:Self-incompatibility (SI) is an effective method for limiting self-fertilization in flowering plant species, but there are circumstances in which an otherwise functional SI system may fail. One of the most intriguing of these is the induction of selfing by mixed loads of self and heterospecific pollen (the mentor effe...

journal_title：American journal of botany

authors： Desrochers A,Rieseberg L

更新日期：1998-06-01 00:00:00

abstract：:• Premise of the study: Tropical forests are the most species-rich terrestrial communities on Earth, and understory trees and shrubs comprise a large fraction of their plant species diversity, especially at high rainfalls. The mechanisms responsible for generating such high levels of diversity remain unknown. One hypo...

journal_title：American journal of botany

authors： Theim TJ,Shirk RY,Givnish TJ

更新日期：2014-07-01 00:00:00

abstract：:The direct and indirect effects of vegetative herbivory on the mating system of Impatiens capensis were analyzed through a survey of herbivory in natural I. capensis populations and manipulation of leaf damage in the field. Across 10 wild populations of I. capensis proportion of cleistogamous flowers had a significant...

journal_title：American journal of botany

authors： Steets JA,Ashman TL

更新日期：2004-07-01 00:00:00