نتایج جستجو برای: having produced smaller leaves leaf size
تعداد نتایج: 1321637 فیلتر نتایج به سال:
• Paleobotanists have long used models based on leaf size and shape to reconstruct paleoclimate. However, most models incorporate a single variable or use traits that are not physiologically or functionally linked to climate, limiting their predictive power. Further, they often underestimate paleotemperature relative to other proxies. • Here we quantify leaf-climate correlations from 92 globall...
Outbreaks of Escherichia coli O157:H7 infections have been linked increasingly to leafy greens, particularly to lettuce. We present here the first evidence that this enteric pathogen can multiply on the leaves of romaine lettuce plants. The increases in population size of E. coli O157:H7 in the phyllosphere of young lettuce plants ranged from 16- to 100-fold under conditions of warm temperature...
Freshwater ecosystems are positioned at low levels in the landscape and receive large inputs of diverse plant-based detritus, a major source of energy for consumers in aquatic ecosystems. We conducted Þeld experiments in Urbana, IL to determine the independent and combined effects of leaves of common tree species including thenorthern redoak (Quercus rubraL.), sugarmaple (Acer saccharumMarshall...
The main objective of this thesis was to examine the effects of climate change and simulated herbivory (artificial foliage damage) on growth responses and leaf characteristics (chemical and morphological structure and consequent palatability) of silver birch (Betula pendula) seedlings. In order to achieve this target, seedlings were grown in climate controlled closed-top chambers under ambient ...
Quantitative levels of indole-3-acetic acid (IAA) were determined in leaf blades of two sugarbeet cultivars by a double standard isotope dilution assay using column chromatography followed by reverse phase C(18) high performance liquid chromatography and gas-liquid chromatography with nitrogen thermionic detection. The double standard method was validated as a quantitative tool by gas chromatog...
BACKGROUND Although the effect of elevated carbon dioxide (CO2) concentration on pollen production has been established in some plant species, impacts on fungal sporulation and antigen production have not been elucidated. OBJECTIVE Our purpose was to examine the effects of rising atmospheric CO2 concentrations on the quantity and quality of fungal spores produced on timothy (Phleum pratense) ...
Common purslane is a widely distributed summer annual weed. It can vegetatively reproduce from stem cuttings by forming adventitious roots from the cut end of the stem. Apart from large stem cuttings, it is unclear if purslane cuttings of various plant tissues differ in their ability to asexually reproduce. The objective of the study was to determine the survival and asexual reproductive capaci...
Although leaf size is one of the most responsive plant traits to environmental change, the functional benefits of large versus small leaves remain unclear. We hypothesized that modification of leaf size within species resulting from differences in irradiance can allow leaves to acclimate to different photosynthetic or evaporative conditions while maintaining an efficient balance between hydraul...
The effect of leaf age on photosynthetic capacity, a critical parameter in the theory of optimal leaf longevity, was studied for two tropical pioneer tree species, Cecropia longipes and Urera caracasana, in a seasonally dry forest in Panama. These species continuously produce short-lived leaves (74 and 93 d, respectively) during the rainy season (May-December) on orthotropic branches. However, ...
A pattern of seasonal changes in the morphological and anatomical leaf traits is reported for Potentilla argentea L. var. tenuiloba (Jord.) Sw. of temperate-climate areas in central Poland. Leaf area, perimeter, dry mass and lamina thickness were measured in summer and autumn leaves of the same individuals. Dissection index, density and specifi c leaf area were calculated. Signifi cant differen...
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