The participation of caffeic acid in the regulation of physiological processes of potato plants under conditions of the hypothermia

Among the phenolic compounds related to secondary metabolites, the main role in formation of the sustainability of plant organisms is given the flavonoids. Regarding phenylpropanoids only some information is available. It relates their role in the plant responses, mainly on the action of the biotic factors. The purpose of the research was to study of caffeic acid influence on membrane processes (photochemical activity of isolated chloroplasts, membrane damage rate), activity of the antioxidant system and the growth of potato plants in a 2-hour hypothermia (-2°C) to simulate frosts. The object of research was 21-day-old plants early variety of potato Zhukovsky, grown in the laboratory. As a result of biochemical studies it was revealed that the spraying on 15-day plants with a solution of 0.1 mM of caffeic acid stimulated photochemical activity of chloroplasts in stress-free conditions, and immediately after hypothermia impact. The maximum effect was revealed in stress conditions (37% to 11% compared to control). It was found that the positive effect of caffeic acid on the light reactions of photosynthesis was accompanied by a decrease in the degradation of the membranes installed on the exit of electrolytes and content of malondialdehyde. A substantial reduction in the coefficient of membrane damage in plants rich in caffeic acid (electrolyte leakage decreased in 2.5 times) was showed. Quantity of malondialdehyde was reduced by 25% in the optimal temperature conditions and in stress. The protective effect of caffeic acid on the condition of the membranes was observed against the background of activation of superoxide dismutase is showed. The maximum effect is manifested in conditions of hypothermia (55% vs. 22% compared with stress-free conditions). 10 days after the action of hypothermia a plants showed an increase in weight in variant with caffeic acid (30%). It is concluded about the participation of caffeic acid in the formation of the stability of potato plants to hypothermia.