Responses of photosynthesis and carbohydrate accumulation in sunflower leaves to short-term water stress
1995
Plesnicar, M. | Sakac, Z. | Pankovic, D. | Cupina, T. (University of Novi Sad, Novi Sad (Yugoslavia). Institute of Field and Vegetable Crops)
Water stress was experimentally induced by holding leaf, petiole submerged for 24 hours in 0; 0.05; 0.1; 0.2; 0.5 and 1.0 M sorbitol solutions. Increased concentrations of sorbitol, up to 0.2 M, induced a rapid decrease of relative water content (RWC) in leaves of studied sunflower hybrids. Rapidly applied water stress significantly reduced CO2 and light-saturated photosynthesis in the leaves already at 0.05 M sorbitol. The decline in net photosynthesis at decreased RWC in leaves was accompanied by a substantial decline in the apparent quantum yield. Primary photochemical reactions and electron transport appeared to be less affected by low RWC in leaves. Accumulation of carbohydrates was increased under the effect of rapid water stress. The increased sucrose content could affect, through a feedback mechanism, the inhibition of photosynthesis.
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