Effect of Abscisic Acid and Zeatin on Water Stress Induced Photosynthesis and Respiration in Sunflower Leaves

An experiment was conducted to investigate the effect of abscisic acid and zeatin on water potential, stomatal resistance, photosynthesis, respiration, chlorophyll content and transpiration in leaves of sunflower grown under water stress condition in controlled environment. Lowering of ψ_I under water stress condition led to corresponding increase in diffusion resistance, decrease in transpiration, chlorophyll, photosynthesis and dark respiration. Application of ABA resulted in lesser lowering of ψ_I from 3rd day onwards and compared to control (i.e.water stress treatment only) increases diffusion resistance relatively higher while transpiration, total chlorophyll, photosynthesis and dark respiration were lowered. On the other hand opposite trends were seen for kinetin.