The possible alleviating effects of salicylic acid on protection of cowpea (Vigna unguiculata) cv. Parastu under water stress conditions were investigated in the University of Zanjan Agriculture Research Station during 2008. Water stress was imposed by withholding irrigation at 50% flowering (flowering water stress, FWS) and when 50% of the pods grew 2-3cm (pod-formation water stress, PFWS). Sa...

Experiments are described further indicating that 02-resistant photosynthesis observed in a tobacco (Nicotiana tabacum) mutant with enhanced catalase activity is associated with decreased photorespiration under conditions of high photorespiration relative to net photosynthesis. The effects on net photosynthesis of (a) increasing O2 concentrations from 1% to 42% at low CO2 (250 microliters CO2 p...

The response of respiration, photosynthesis, and calcification to elevated pCO2 and temperature was investigated in isolation and in combination in the Mediterranean crustose coralline alga Lithophyllum cabiochae. Algae were maintained in aquaria during 1 year at near-ambient conditions of irradiance, at ambient or elevated temperature (+3°C), and at ambient (ca. 400 μatm) or elevated pCO2 (ca....

A previously developed model for radiation-use efficiency (RUE) for gross photosynthesis and net carbon accumulation by wheat before anthesis [Agric. Forest Meteorol. 101 (2000) 217], with some improvement, has been applied to maize, sorghum, and rice during their vegetative period under unstressed conditions. The objective of the present study is to assess the extent to which the model can pro...

Global modeling efforts indicate semiarid regions dominate the increasing trend and interannual variation of net CO2 exchange with the atmosphere, mainly driven by water availability. Many semiarid regions are expected to undergo climatic drying, but the impacts on net CO2 exchange are poorly understood due to limited semiarid flux observations. Here we evaluated 121 site-years of annual eddy c...

We have evaluated the effects of short-term changes in incident irradiance and temperature on oxygenic photosynthesis and oxygen consumption in a hypersaline cyanobacterial mat from the Ebro Delta, Spain, in which Microcoleus chthonoplastes was the dominant phototrophic organism. The mat was incubated in the laboratory at 15, 20, 25 and 30 degrees C at incident irradiances ranging from 0 to 1,0...

The effects of aminoacetonitrile (a competitive inhibitor of glycine oxidation) on net photosynthesis, glycolate pathway intermediates, and ribulose-1,5-bisphosphate (RuBP) levels have been investigated at different O(2) and CO(2) concentrations with soybean (Glycine max)[L] Merr. cv Pioneer 1677) leaf discs floated on 25 millimolar aminoacetonitrile (AAN) for 50 minutes prior to assay.At 2% O(...

Glycidate (2,3-epoxypropionate) increased CO(2) photoassimilation in intact spinach (Spinacia oleracea L.) chloroplasts in the presence of various inhibitors of photosynthesis, including O(2), arsenite, azide, iodo-acetamide, and carbonylcyanide 3-chlorophenylhydrazone. Although the mechanism by which glycidate enhances photosynthesis is obscure, the stimulatory effect cannot be ascribed to eit...

the possible alleviating effects of salicylic acid on protection of cowpea (vigna unguiculata) cv. parastu under water stress conditions were investigated in the university of zanjan agriculture research station during 2008. water stress was imposed by withholding irrigation at 50% flowering (flowering water stress, fws) and when 50% of the pods grew 2-3cm (pod-formation water stress, pfws). sa...