Effect of far-red light on malate and potassium contents in cotton leaves: Relation to drought resistance

Long- or short-term far-red light given before a dark treatment modified the water status and the potassium and malate contents in cotton ( Gossypium hirsutum L. cv. Bou) leaves. Upon a long-term treatment, the leaf water content and the leaf water and osmotic potentials were lower whereas stomatal resistance was greater with a decrease in daily transpiration. There was a parallel increase in potassium and malate, but the calcium content was not significantly changed. This resulted in better water economy with an increase in drought resistance. Upon a short-term treatment, the accumulation of potassium and malate was reversible and the drought resistance was modified accordingly. There was a positive correlation between the ability of a plant to resist water stress and the content of potassium and malate.