Fruit growing
and viticulture of South Russia

Annotation

Climate change on the planet is characterized by increased aridity in the regions where grapes are traditionally cultivated, the grapes is one of the most important crop in the world. Grapes vegetation takes a place at high temperatures, soil and atmospheric drought. Under such conditions, the plants are affected by a combination of abiotic and biotic stresses, causing the defensive reactions that are unique to each combination of stress factors. The aim of the research is to study the changes in the activity of antioxidant enzymes of various grape varieties under the influence of osmotic and high-temperature stresses. The objects of study were the leaves of different grape varieties, under the influence of simulated drought and high temperature. To simulate a drought, the leaves were dried for 2 hours at room temperature. To simulate the high-temperature stress, the grape leaves in the glasses with distilled water were kept n a thermostat for 2 hours at a temperature of +50 º�. Different enzyme isoforms have different activity when the environmental conditions change, so the formation of several isoenzymes with differtnt molecular weights may show the adaptive response of plants to stress. It is found that for the most of the studied grape varieties, short-term exposure to stress led to decrease in the number of peroxidase isoforms, and decrease in the activity of superoxide dismutase and a phenolic oxidizing peroxidase. The activity of ascorbate peroxidase changed less than the activity of the other two enzymes. The content of MDA, which indirectly characterizes the development of secondary oxidative stress, was markedly increased in all studied grape varieties. This reaction may be associated with the activation of signaling cascades in the grape plants, which requires an increase in the level of secondary oxidative stress, for the further formation of protective reaction. Our study have shown that different grape varieties are sensitive to different types of stress. These research will continue to study the reactions of grape plants at a longer exposure time of studied stress factors.