Abstract：
:Much of the ultraviolet-B radiation (UV-B) research on plants has concentrated on vegetative plant parts, and only a small fraction has dealt with the reproductive system. The present study analyzed pollen grains of 34 taxa germinated and grown under two levels of UV-B radiation (187 and 460 mW/m2) or no UV-B (control group). Visible radiation at 260 mmol/m/s was present in all treatments. Taxa included those with binucleate and trinucleate pollen types. We detected differences among species. A significant reduction in pollen germination occurred in only five species. Pollen tubes of >50% of the species showed significant reduction in length. Trinucleate pollen types were more likely to exhibit tube length reduction than the binucleate types. Proportionately more monocotyledonous species were sensitive to UV-B treatment than dicotyledonous species, and proportionately more wild species were sensitive than cultivated species and pollen collected from plants growing in the field were somewhat more sensitive than pollen collected from plants grown in the greenhouse. Species in which pollination occurred earlier in the season were more likely to be susceptible to UV-B radiation than those for which anthesis took place later in the season, suggesting a possible adaptation to UV-B radiation.
journal_name
Am J Botjournal_title
American journal of botanyauthors
Torabinejad J,Caldwell M,Flint S,Durham Ssubject
Has Abstractpub_date
1998-03-01 00:00:00pages
360issue
3eissn
0002-9122issn
1537-2197pii
85/3/360journal_volume
85pub_type
杂志文章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：: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
pub_type： 杂志文章
doi：
更新日期：2000-11-01 00:00:00
abstract：:Partial cambial mortality is a growth form that is characteristic of Pinus aristata trees. To better elucidate their cambial death pattern, tree size and aspect of cambial death data were gathered from three Pinus aristata forests in central Colorado, USA. Stripping frequency tended to be higher for larger diameter cl...
journal_title：American journal of botany
pub_type： 杂志文章
doi：
更新日期：2001-04-01 00:00:00
abstract：UNLABELLED:• PREMISE OF THE STUDY:Floral traits play important roles in pollinator attraction and defense against floral herbivory. However, plants may experience trade-offs between conspicuousness to pollinators and herbivore attraction. Comparative studies provide an excellent framework to examine the role of multip...
journal_title：American journal of botany
pub_type： 杂志文章
doi：10.3732/ajb.1400171
更新日期：2014-08-01 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：:To our knowledge, xylary reaction tissue has never been reported in a forage crop species. Here we report the discovery of reaction tissue in a transgenic line of Medicago sativa (pC3H, for the gene for p-coumarate-3-hydroxylase) with reduced lignin content and in the wild-type (WT) line. Based on microscopy and biome...
journal_title：American journal of botany
pub_type： 杂志文章
doi：10.3732/ajb.94.6.912
更新日期：2007-06-01 00:00:00
abstract：:A detailed study of ascomal morphology and development in Cercophora palmicola showed that ontogeny is ascohymeniaceous, giving rise to an ostiolate perithecium. Ascomal initials consist of a coiled ascogonium surrounded by several layers of hyphae whose cells become pseudoparenchymatous. The centrum of the young asco...
journal_title：American journal of botany
pub_type： 杂志文章
doi：
更新日期：1999-06-01 00:00:00
abstract：:In volume 97(2) of the American Journal of Botany (pp. 268-275), we published an article entitled "Structural, physiological, and stable carbon isotopic evidence that the enigmatic Paleozoic fossil Prototaxites formed from rolled liverwort mats". Here, we respond to a letter and a commentary on our article in the pres...
journal_title：American journal of botany
pub_type： 杂志文章
doi：10.3732/ajb.1000172
更新日期：2010-07-01 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
pub_type： 杂志文章
doi：10.3732/ajb.90.3.377
更新日期：2003-03-01 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：:Perennial crops represent important fresh and processed food sources worldwide, but advancements in breeding perennials are often impeded due to their very nature. The perennial crops we rely on most for food take several years to reach production maturity and require large spaces to grow, which make breeding new cult...
journal_title：American journal of botany
pub_type： 杂志文章
doi：10.3732/ajb.1400143
更新日期：2014-10-01 00:00:00
abstract：:Although theory has demonstrated rather low levels of gene flow are sufficient to counteract opposing mutation, drift, and selection, widespread recognition of the evolutionary importance of gene flow has come slowly. The perceived role of gene flow as an evolutionary force has vacillated over the last century. In the...
journal_title：American journal of botany
pub_type： 杂志文章,评审
doi：10.3732/ajb.1400024
更新日期：2014-05-01 00:00:00
abstract：UNLABELLED: PREMISE OF THE STUDY:The role of hybridization in plant evolution remains a source of intense debate. Potential consequences range from genetic dead-ends to species fusion or hybrid speciation. While much has been learned from model systems such as Populus, Iris, and Helianthus, many questions remain. Cons...
journal_title：American journal of botany
pub_type： 杂志文章
doi：10.3732/ajb.1300038
更新日期：2013-10-01 00:00:00
abstract：:Field surveys of cynipid gall-inducer occurrences on Quercus species were conducted in Florida, North Carolina, and Pennsylvania, USA. All cynipids demonstrated strong host species and organ fidelity. One result of this specialization is effective niche partitioning among cynipids. The host-association patterns of the...
journal_title：American journal of botany
pub_type： 杂志文章
doi：
更新日期：1998-08-01 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：PREMISE:The cosmopolitan and ecologically important grass subfamily Aristidoideae comprises the widely distributed genus Aristida (250-290 species), Stipagrostis (50 species, with an African-Asian distribution), and Sartidia (five species, Africa and Madagascar). The subfamily includes species with C(3) (Sartidia and a...
journal_title：American journal of botany
pub_type： 杂志文章
doi：10.3732/ajb.1100103
更新日期：2011-11-01 00:00:00
abstract：PREMISE OF THE STUDY:Documented fossil floras in the neotropics are sparse, yet their records provide evidence on the spatial and temporal occurrence of taxa, allowing for testing of biogeographical and diversification scenarios on individual lineages. A new fossil Piper from the Late Cretaceous of Colombia is describe...
journal_title：American journal of botany
pub_type： 杂志文章
doi：10.3732/ajb.1400427
更新日期：2015-02-01 00:00:00
abstract：:Molecular phylogenetic studies of seven plastid DNA regions were used to resolve circumscriptions at generic and infrageneric levels in subfamily Tillandsioideae of Bromeliaceae. One hundred and ten tillandsioid samples were analyzed, encompassing 10 genera, 104 species, and two cultivars. Two species of Bromelioideae...
journal_title：American journal of botany
pub_type： 杂志文章
doi：10.3732/ajb.92.2.337
更新日期：2005-02-01 00:00:00
abstract：PREMISE OF THE STUDY:Mixotrophy is a strategy whereby plants acquire carbon both through photosynthesis and heterotrophic exploitation of mycorrhizal fungi. In Euro-American Pyroleae species studied hitherto, heterotrophy levels vary according to species, sites of study, and possibly light conditions. We investigated m...
journal_title：American journal of botany
pub_type： 杂志文章
doi：10.3732/ajb.1100546
更新日期：2012-07-01 00:00:00
abstract：:Phylogenetic relationships were determined in the Araucariaceae, which are now found mainly in the Southern Hemisphere. This conifer family was well diversified and widely distributed in both hemispheres during the Mesozoic era. The sequence of 1322 bases of the rbcL gene of cpDNA was determined from 29 species of Ara...
journal_title：American journal of botany
pub_type： 杂志文章
doi：
更新日期：1998-11-01 00:00:00
abstract：UNLABELLED: PREMISE OF THE STUDY:Microsatellite primers were developed in the introduced shrub Rhamnus cathartica L., to investigate potential hybridization events with related taxa as a stimulus of invasive spread. • METHODS AND RESULTS:Using a non-radioactive protocol, 15 primer sets were identified in North Americ...
journal_title：American journal of botany
pub_type： 杂志文章
doi：10.3732/ajb.0900394
更新日期：2010-03-01 00:00:00
abstract：:Trichomanes intricatum, the sporophyte-less filmy fern of the eastern United States, has been considered to be a species whose sporophyte generation has become extinct or is possibly still present among the many species of Trichomanes s.l. in the new world tropics but unable to grow in a temperate climate. A close rel...
journal_title：American journal of botany
pub_type： 杂志文章
doi：10.3732/ajb.0800122
更新日期：2008-12-01 00:00:00
abstract：:Tropical forest plants are known to be pollinated by a diverse array of animals. Here we report on the pollination of a woody climber species, Uvaria elmeri (Annonaceae), by cockroaches in a lowland mixed-dipterocarp forest in Sarawak, Malaysia. To the best of our knowledge, this is the first report of pollination by ...
journal_title：American journal of botany
pub_type： 杂志文章
doi：
更新日期：1997-02-01 00:00:00
abstract：:The eudicot order Malpighiales contains ∼16000 species and is the most poorly resolved large rosid clade. To clarify phylogenetic relationships in the order, we used maximum likelihood, Bayesian, and parsimony analyses of DNA sequence data from 13 gene regions, totaling 15604 bp, and representing all three genomic com...
journal_title：American journal of botany
pub_type： 杂志文章
doi：10.3732/ajb.0800207
更新日期：2009-08-01 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：:Understanding the role of geography and ecology in species divergence is central to the study of evolutionary diversification. We used climatic, geographic, and biological data from nine wild Andean tomato species to describe each species' ecological niche and to evaluate the likely ecological and geographical modes o...
journal_title：American journal of botany
pub_type： 杂志文章
doi：10.3732/ajb.0900216
更新日期：2010-04-01 00:00:00
abstract：:The timing, geographical locations, causes, and consequences of crop domestication have long been major concerns of archaeologists, and agricultural origins and dispersals are currently more relevant than ever to scientists seeking solutions to elusive problems involving food insecurity and global health disparities. ...
journal_title：American journal of botany
pub_type： 杂志文章
doi：10.3732/ajb.1400145
更新日期：2014-10-01 00:00:00
abstract：:The circumscription and relationships of genera within the tribe Melanthieae (29 representative taxa) were evaluated using parsimony analyses of ITS (nuclear ribosomal) and trnL-F (plastid) DNA sequence data, alone and in combination. Proposed new generic circumscriptions, strongly supported by the tree statistics and...
journal_title：American journal of botany
pub_type： 杂志文章
doi：
更新日期：2001-09-01 00:00:00
abstract：PREMISE OF THE STUDY:Phylogenetic incongruence between "gene trees" and "species trees" has been widely acknowledged in phylogenetic research. Conflicts may emerge from several processes including paralogy, hybridization, and incomplete lineage sorting. Although phylogenetic incongruence appears common, its impact on m...
journal_title：American journal of botany
pub_type： 杂志文章
doi：10.3732/ajb.1400527
更新日期：2015-04-01 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
pub_type： 杂志文章
doi：10.3732/ajb.1100299
更新日期：2012-01-01 00:00:00
