Protective role of kartolin-4 in wheat plants exposed to soil draught

Parameters of photosynthesis, heat- resistance, and osmotic pressure of cell exudate of leaves of the drought-sensitive cultivar Lyutestsens 758 of wheat, Triticum aestivum, were studied under conditions of normal water supply, soil drought, and subsequent rehydration. The plants preliminarily treated with kartolin-4 were compared to untreated plants. Kartolin-4, a preparation with cytokinin-like activity, partially prevented the drought-induced inhibition of the photosynthetic assimilation of carbon dioxide and carboxylation activities of ribulose-1,5-bisphosphate carboxylase/oxygenase (EC 4.1.1.39), the key enzyme of carbon metabolism in plants. Upon subsequent rehydration, kartolin-4 stimulated the reparation reactions and facilitated the rapid recovery of normal photosynthetic activity. Kartolin-4 also increased the plant resistance to overheating and water deficiency.