Understanding seasonal changes in photosynthetic parameters and stomatal conductance is crucial for modeling long-term carbon uptake and energy fluxes of ecosystems. Gas exchange measurements of CO2 and light response curves on blue oak leaves (Quercus douglasii H. & A.) were conducted weekly throughout the growing season to study the seasonality of photosynthetic capacity (Vcmax) and Ball-Berr...

The short term effects of increased levels of CO(2) on gas exchange of leaves of bigtooth aspen (Populus grandidentata Michx.) were studied at the University of Michigan Biological Station, Pellston, MI. Leaf gas exchange was measured in situ in the upper half of the canopy, 12 to 14 meters above ground. In 1900 microliters per liter CO(2), maximum CO(2) exchange rate (CER) in saturating light ...

according to the drought as the most important environmental factor that limiting agricultural products and using nitrogen as the most consumed nutrition element in farming system, in this study investigates examined the effect of nitrogen on drought tolerance characteristics, including changes in total chlorophyll content, total protein content, leaf area, phosphorus and peroxidase enzyme acti...

Application of water stress to isolated spinach (Spinacia oleracea) chloroplasts by redutcion of the osmotic potentials of CO(2) fixation media below -6 to -8 bars resulted in decreased rates of fixation regardless of solute composition. A decrease in CO(2) fixation rate of isolated chloroplasts was also found when leaves were dehydrated in air prior to chloroplast isolation. An inverse respons...

Fractionation of carbon isotopes by plants during CO(2) uptake and fixation (Delta(leaf)) varies with environmental conditions, but quantitative patterns of Delta(leaf) across environmental gradients at the global scale are lacking. This impedes interpretation of variability in ancient terrestrial organic matter, which encodes climatic and ecological signals. To address this problem, we convert...

Across plant species, leaves vary enormously in their size and their venation architecture, of which one major function is to replace water lost to transpiration. The leaf hydraulic conductance (K(leaf)) represents the capacity of the transport system to deliver water, allowing stomata to remain open for photosynthesis. Previous studies showed that K(leaf) relates to vein density (vein length p...