Patterns of pigment content in leaves of frost-resistant technical grape varieties depending on varietal characteristics and growing season phases

Abstract. The study of the pigment complex of the main and lateral leaves of three dark-berry frost-resistant grape varieties of domestic breeding Vecherniy, Dmitriy and Kurchanskiy was carried out., The content of chlorophylls (a, b) and carotenoids in the phases of berry growth and ripening was determined using the spectrometric method. Based on the obtained data, the sum of chlorophylls, as well as the ratio of chlorophyll a to chlorophyll b and the sum of chlorophylls to carotenoids were calculated. It was revealed that the pigment content in the leaves depended on varietal characteristics, vegetation phase and leaf type (main, lateral leaves). A general trend towards a decrease in chlorophyll a was observed in the ripening phase of grapes, the control variety Dmitriy had an increase in chlorophyll b, the sum of chlorophylls and a decrease in carotenoids, while the varieties Vecherniy and Kurchanskiy had a decrease in chlorophyll b, the sum of chlorophylls and an increase in carotenoids. During the berry growth phase, the most optimal ratio of chlorophyll a to chlorophyll b was observed in the leaves of the control variety Dmitriy, and during the berry ripening phase – in the leaves of the varieties Vecherniy and Kurchanskiy, which indicates that the plants of these varieties were in a normal physiological state during these periods. In the Vecherniy and Kurchanskiy varieties during the berry growth phase and in the Dmitry variety during the ripening phase, the ratio between the pigment content significantly decreased, which is a sign of a stressful state of the plants. During the berry growth phase, the chlorophylls of the leaves of the control variety Dmitriy were better protected from photooxidation than those of the other two varieties, since the ratio of the sum of chlorophylls to carotenoids was 2.05-3.22 times less than that of the Vecherniy and Kurchanskiy varieties. During the berry ripening phase, for the same reason, the chlorophylls of the Vecherniy and Kurchanskiy varieties were better protected from destruction. The obtained data confirm the fact established by other researchers that the pigment complex of leaves can serve as an indicator of the degree of resistance of the grape plant to stress factors during the growing season. Keywords: grapes, variety, vegetation phases, leaf chlorophylls, leaf carotenoids, stress resistance