Physiological and biochemical features of the grape leaf in connection with adaptation to drought and high temperatures

Abstract

The issues of grape resistance to drought have acquired particular importance due to the decrease in precipitation during the phenophase of growth and ripening of berries, which reduces their quality and yield. The purpose of these studies was to evaluate grape varieties of various ecological and geographical origin to drought and elevated temperatures according to physiological and biochemical parameters, to identify varieties with high adaptive resistance for cultivation in the conditions of the Anapo-Taman zone of the Krasnodar Krai and use in breeding. The objects of research are grape varieties (interspecific hybrids): European-American origin – Dostoyny, Krasnostop AZOS, Vostorg; Western European – Aligote; Eastern European – Zarif. The control was the Crystal variety of Euro-Amur-American origin. The article presents the results of studying the hydration of leaf tissues, the content of photosynthetic pigments and proline in leaves during the summer growing season 2020-2022. It was found that by the end of summer, the water content of the leaves decreased to the least degree in the varieties Kristall, Krasnostop AZOS, Vostorg, Zarif, in comparison with the varieties Dostoyny and Aligote, in which a decrease was noted by 4.70-4.88 %. Due to the increase in the proportion of carotenoids that perform a photoprotective function in the varieties Crystal, Krasnostop AZOS, Vostorg, Zarif, the lowest values of the chlorophylls/carotenoids ratio (2.8-3.4) were found, indicating their high adaptive ability to drought and elevated temperatures.In contrast to them, the ratio of chlorophylls/carotenoids in the varieties Dostoyny and Aligote was 4.1-4.2, indicating their low adaptive resistance. In all studied varieties, the maximum content of proline in the leaves – 43.27-59.57 μg/g wet weight was found in August in response to extremely high temperatures and lack of precipitation compared to June, when it was 17.83-30.55 μg/g fresh weight, depending on the variety. Grape varieties Crystal, Krasnostop AZOS, Vostorg, Zarif proved to be more resistant to drought and elevated temperatures in comparison with the varieties Dostoyny, Aligote, and are recommended for cultivation in the conditions of the Anapo-Taman zone of the Krasnodar Territory and use in breeding. The indicators of leaf water content, the ratio of chlorophylls/carotenoids pigments, and the proline content can be considered as reliable criteria for the adaptive resistance of grape varieties to summer stress factors.