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 have been associated previously with photosynthetic function and included shape, thickness, the ratio of thickness to width, stomatal distribution, leaf surface coloration, and the number and distribution of palisade cell layers. Decreases in annual precipitation (<4 to over 15 cm/yr) and increases in total daily sunlight (4.2 to 29.2 mol photons/m1) corresponded strongly to an increase in the percentage of species in a given community with more inclined (more inclined than +/- 45 degrees from horizontal) or thicker leaf mesophyll (>0.4 mm) leaves. Also, the percentage of species with a leaf thickness to width ratio >0.1, which were amphistomatous, or which had palisade cell layers beneath both leaf surfaces, increased from >20% in the highest rainfall and lowest sunlight community to >80% in the community with least rainfall but greatest sunlight exposure. Over 70% of the species in the most mesic, shaded community had lighter abaxial than adaxial leaf surfaces (leaf bicoloration). All of the above structural features were positively associated with a more inclined leaf orientation (r1 = 0.79), except for leaf bicoloration, which was negatively associated (r1 = 0.75). The ratio of adaxial to abaxial light was more strongly associated with leaf bicoloration (r1 = 0.83) and the presence of multiple adaxial and isobilateral palisade cell layers(r1 = 0.80) than with total incident sunlight on just the adaxial leaf surface (r1 = 0.69 and 0.73, respectively). These results provide field evidence that leaf orientation and structure may have evolved in concert to produce a photosynthetic symmetry in leaf structure in response to the amount of sunlight and other limiting factors of the community. This structural symmetry may serve fundamentally to regulate the distribution of both light and CO2 levels inside the leaf and, thus, increase photosynthetic CO2 uptake per unit leaf biomass.
journal_name
Am J Botjournal_title
American journal of botanyauthors
Smith W,Bell D,Shepherd Ksubject
Has Abstractpub_date
1998-01-01 00:00:00pages
56issue
1eissn
0002-9122issn
1537-2197pii
85/1/56journal_volume
85pub_type
杂志文章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
abstract::We used isozymes (16 loci in 11 enzymatic systems) from Laelia speciosa, an endemic and endangered epiphytic orchid of Mexico, to assess the genetic diversity and population genetic structure in nine populations distributed along its geographic range, as well as to detect those populations that are genetically unique ...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.3732/ajb.94.2.184
更新日期:2007-02-01 00:00:00
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...
journal_title:American journal of botany
pub_type: 杂志文章
doi:
更新日期:1998-08-01 00:00:00
abstract:PREMISE OF STUDY:Sequence analyses for Pinaceae have suggested that extant genera diverged in the late Mesozoic. While the fossil record indicates that Pinaceae was highly diverse during the Cretaceous, there are few records of living genera. This description of an anatomically preserved seed cone extends the fossil re...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.3732/ajb.1100568
更新日期:2012-06-01 00:00:00
abstract:UNLABELLED: PREMISE OF THE STUDY:Polyploid speciation has been important in plant evolution. However, the conditions that favor the origination and persistence of polyploids are still not well understood. Here, we examine origins of 16 polyploid species in Mentzelia section Trachyphytum. • METHODS:We used phylogeny r...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.3732/ajb.0900388
更新日期:2010-09-01 00:00:00
abstract::Tribe Macadamieae (91 spp., 16 genera; Proteaceae) is widespread across the southern hemisphere on all major fragments of Gondwana except New Zealand and India. Macadamia is cultivated outside its natural range as a "nut" crop (notably in Hawaii, where it is the principal orchard crop). We sampled seven DNA regions an...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.3732/ajb.0700006
更新日期:2008-07-01 00:00:00
abstract:UNLABELLED:• PREMISE OF THE STUDY:Mountainous regions support high plant productivity, diversity, and endemism, yet are highly vulnerable to climate change. Historical records and model predictions show increasing temperatures across high elevation regions including the Southern Rocky Mountains, which can have a stron...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.3732/ajb.1500156
更新日期:2015-08-01 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::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:PREMISE OF THE STUDY:Microsatellite markers were isolated and characterized from Dacryodes edulis (Burseraceae), a tropical rainforests fruit tree of central Africa. METHODS AND RESULTS:Using an enrichment protocol, six microsatellites loci were developed from Dacryodes edulis. We investigated polymorphism using 45 tr...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.3732/ajb.1000463
更新日期:2011-04-01 00:00:00
abstract::Climate changes during glacial periods have had significant effects on the present geographic distribution of plant species. To elucidate the evolutionary history of a plant species with a disjunctive distribution, we investigated the geographic distribution patterns of cpDNA haplotypes in Photinia glabra (Rosaceae) g...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.3732/ajb.93.12.1852
更新日期:2006-12-01 00:00:00
abstract::When more pollen is present on stigmas than needed to fertilize all ovules, selection among pollen grains may occur due to effects of both pollen donors and maternal plants. We asked whether increasing plant age and flower age, two changes in maternal condition, altered the pattern of seed paternity after mixed pollin...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.3732/ajb.94.3.409
更新日期:2007-03-01 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
pub_type: 杂志文章
doi:
更新日期:1997-12-01 00:00:00
abstract:UNLABELLED: PREMISE OF THE STUDY:Microsatellite primers were developed in Paeonia lactiflora for further population genetic studies. • METHODS AND RESULTS:Ten dinucleotide microsatellite markers were developed using an enriched genomic library. They were identified in 58 individuals, and nine markers were also amplif...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.3732/ajb.1100083
更新日期:2011-09-01 00:00:00
abstract::In an age of rapid global change, it is imperative that we continue to improve our understanding of factors that govern genetic differentiation in plants to inform biologically reasonable predictions for the future and enlighten conservation and restoration practices. In this special issue, we have assembled a set of ...
journal_title:American journal of botany
pub_type:
doi:10.3732/ajb.1500515
更新日期:2016-01-01 00:00:00
abstract::Long-distance transplantation of seed material as done in restoration programs has raised concerns about the risks associated with the introduction of maladapted genotypes that may hybridize with neighboring native conspecifics and decrease local population fitness (outbreeding depression). We studied the consequences...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.3732/ajb.0900103
更新日期:2010-01-01 00:00:00
abstract:PREMISE OF THE STUDY:Most pollen walls are interrupted by apertures, thin areas providing access to stigmatic fluids and exit points for pollen tubes. Unexpectedly, pollen tubes of Arabidopsis thaliana are not obligated to pass through apertures and can instead take the shortest route into the stigma, passing directly ...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.3732/ajb.1600031
更新日期:2016-06-01 00:00:00
abstract:PREMISE OF THE STUDY:Intertidal macroalgae must resist extreme hydrodynamic forces imposed by crashing waves. How does frond flexibility mitigate drag, and how does flexibility affect predictions of drag and dislodgement in the field? METHODS:We characterized flexible reconfiguration of six seaweed species in a recirc...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.3732/ajb.1100541
更新日期:2012-05-01 00:00:00
abstract::The cacti are well-known desert plants, widely recognized by their specialized growth form and essentially leafless condition. Pereskia, a group of 17 species with regular leaf development and function, is generally viewed as representing the "ancestral cactus," although its placement within Cactaceae has remained unc...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.3732/ajb.92.7.1177
更新日期:2005-07-01 00:00:00
abstract::Zeuxine gracilis, Zeuxine strateumatica, and Eulophia sinensis are wild orchids with different breeding systems and colonizing abilities. Zeuxine gracilis is an outcrosser with restricted distribution, whereas S. strateumatica is an apomictic colonizer found only in newly available open habitats. Eulophia sinensis is ...
journal_title:American journal of botany
pub_type: 杂志文章
doi:
更新日期:2001-12-01 00:00:00
abstract::Isozymatic data taken from 67 Guatemalan collections of maize were subjected to numerical taxonomic analyses to elucidate systematic relationships among the 19 maize races and subraces described for Guatemala by Wellhausen et al. As with Bolivian and Mexican races, isozymatic variation in Guatemalan maize was strongly...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.1002/j.1537-2197.1990.tb13547.x
更新日期:1990-02-01 00:00:00
abstract::This study shows that structural data, when carefully examined, can provide valuable characters for delimiting monophyletic groups and can complement DNA with observable features to recognize and circumscribe taxa. In the angiosperm order Apiales, traditional classification has relied heavily (often exclusively) on fr...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.3732/ajb.93.9.1357
更新日期:2006-09-01 00:00:00
abstract:PREMISE OF THE STUDY:Elucidating the factors that determine the abundance and distribution of species remains a central goal of ecology. It is well recognized that genetic differences among individual species can affect the distribution and species interactions of dependent taxa, but the ecological effects of genetic d...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.3732/ajb.1100137
更新日期:2011-10-01 00:00:00
abstract::The utility of the PCR-based AFLP technique (polymerase chain reaction; amplified fragment length polymorphisms) was explored in elucidating details of polyploid evolution in the Eurasian orchid genus Dactylorhiza. We emphasized Swedish taxa but also included some material from the British Isles and elsewhere in Europ...
journal_title:American journal of botany
pub_type: 杂志文章
doi:
更新日期:2001-10-01 00:00:00
abstract::Biogeographical patterns and diversification processes in Andean and Patagonian flora are not yet well understood. Calceolaria is a highly diversified genus of these areas, representing one of the most specialized plant-pollinator systems because flowers produce nonvolatile oils, a very unusual floral reward. Phylogen...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.3732/ajb.0900165
更新日期:2009-12-01 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
pub_type: 杂志文章
doi:10.3732/ajb.93.12.1748
更新日期:2006-12-01 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::Wind is a major ecological factor for plants and a major economical factor for forestry. Mechanical analyses have revealed that the multimodal dynamic behavior of trees is central to wind-tree interactions. Moreover, the trunk and branches influence dynamic modes, both in frequency and location. Because of the complex...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.3732/ajb.0800161
更新日期:2008-12-01 00:00:00
abstract:PREMISE OF THE STUDY:Reintroductions may be essential to prevent extinction of many critically endangered species. Ideally, reintroduction efforts rely on adjacent source populations, but limited source material may necessitate crossing individuals from different and possibly distant populations. To determine the conse...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.3732/ajb.1400271
更新日期:2014-11-01 00:00:00
abstract:PREMISE OF THE STUDY:The ability of insect visitors to learn to manipulate complex flowers has important consequences for foraging efficiency and plant fitness. We investigated learning by two butterfly species, Danaus erippus and Heliconius erato, as they foraged on the complex flowers of Asclepias curassavica, as wel...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.3732/ajb.1700040
更新日期:2017-08-01 00:00:00