Heat shock is considered an abiotic stress for plant growth, but the effects of heat shock on physiological responses of cucumber plant leaves with and without downy mildew disease are still not clear. In this study, cucumber seedlings were exposed to heat shock in greenhouses, and the responses of photosynthetic properties, carbohydrate metabolism, antioxidant enzyme activity, osmolytes, and d...

The photosynthetic efficiency of C3 grasses declines with increasing temperature and C4 grasses are predicted to be advantaged at temperatures above 15 °C. We demonstrated an above-ground productivity difference in a commongarden experiment with Alloteropsis semialata and show that it is related more to differences in life-history than to photosynthesis. Frost caused leaf mortality in the C4 bu...

We exposed Populus tremuloides Michx. and Acer saccharum Marsh. to a factorial combination of ambient and elevated atmospheric CO2 concentrations ([CO2]) and high-nitrogen (N) and low-N soil treatments in open-top chambers for 3 years. Our objective was to compare photosynthetic acclimation to elevated [CO2] between species of contrasting shade tolerance, and to determine if soil N or shading m...

this study investigated the variation between two sugar beet (beta vulgaris l.) cultivars with respect to growth parameters and photosynthetic rates of individual attached leaves during salinization. sugar beet plants grown in sand culture were gradually exposed to different levels of salinity (0, 50, 150 , 250, and 350 mm, nacl+cacl2 in 5:1 ratio). salt concentrations significantly decreased a...

The effects of gibberellic acid (GA3) on growth, physiology and yield of salt-stressed mustard (Brassica juncea L. Czern & Coss) cv. Varuna plants were studied. The stress imposed by 25 or 50 mM NaCl reduced substantially leaf area, dry mass, leaf chlorophyll content, stomatal conductance and net photosynthetic rate 50 days after emergence. At harvest, although other yield components were gener...

Since leaves are essentially energy-gaining organs, the arrangement of leaves in time (leaf phenology) and in space (canopy architecture) in both seasonal and nonseasonal environments can be viewed as a central element in plant strategies for carbon gain. Interrelationships among leaf longevity, leaf habit, and leaf-emergence pattern together with shoot architecture affect plant productivity. L...

Sugar beets (Beta vulgaris L. cv F58-554H1) were grown hydroponically in a 16-h light, 8-h dark period at a photosynthetic photon flux density of 0.5 mmol m-2 s-1 for 4 weeks in half-Hoagland culture solution containing only nitrate-nitrogen. Half of the plants were then transferred to half-Hoagland solution with ammonium-nitrogen (7.35mM), while the other half continued on 7.5 mM nitrate. Grow...