THE ROLE OF PROLINE IN STRESS-PROTECTIVE RESPONSES OF GRAPE (VITIS L.) TO LOW TEMPERATURES

Monitoring of the key metabolite, the amino acid proline, in the grape plant is necessary to study the physiological mechanisms underlying the adaptive reactions of grapes in a changing climate. The purpose of this work is to study the dynamics of the content of free proline in various grape varieties, to identify varieties with increased resistance to low temperatures. The objects of research are grape varieties of various genetic origin: Kristall (control), Dostoynyi, Krasnostop AZOS, Vostorg, Aligote, Zarif. The content of proline was determined by capillary electrophoresis on a Kapel 104R device according to a technique based on obtaining an electrophoregram using direct detection of the absorbing components of the sample. In January-February, the varieties Kristall, Krasnostop AZOS, Vostorg had an increased content of proline in comparison with the varieties Dostoynyi, Aligote, Zarif. In the shoots of the varieties Kristall,, Krasnostop AZOS, Vostorg, it was 7.38-8.26 µg/g fresh weight; in Dostoynyi, Aligote, Zarif – 4.12-5.16 µg/g fresh weight. In the buds of the varieties Kristall, Krasnostop AZOS, Vostorg, the content of proline was 7.92-9.21 µg/g fresh weight, in Dostoynyi, Aligote, Zarif – 4.57-5.90 µg/g fresh weight. After artificial freezing in the shoots of the varieties Kristall, Krasnostop AZOS, Vostorg, the proline content increased by 1.13-1.23 times, in other studied varieties it almost did not change. It has been shown that proline plays a significant role in the implementation of the stressprotective reactions of grapes to low temperatures. It has been established that according to the dynamics of the free proline content, the varieties Crystal, Krasnostop AZOS, Vostorg are more resistant to low temperatures in comparison with the varieties Dostoynyi, Aligote, Zarif.