Water content of tissues of vine plants of different сultivars during adaptation to low negative temperatures

The article provides information on the dynamics of the content of the total amount of water and its fractions (bound and free) in the shoots of various grape varieties. The research results showed that the studied grape varieties differed in the degree of adaptation to low negative temperatures. This property can be explained with the state of water in the tissues of the shoots during the period of stress exposure to negative temperatures.

Abstract Introduction. The Rostov region is the northernmost zone of industrial viticulture, where in some years, during the dormant period, there is a decrease in negative temperatures to a critical level. Under such conditions, when cultivating hybrid grape varieties with increased frost resistance without shelter for the winter, there is a high risk of losing not only part or the entire crop due to damage to plants due to exposure to low negative temperatures, but also their complete death.

Object. The object of research was the shoots of grape varieties of different origin and adaptation to low negative temperatures.

Materials and Methods The studies were carried out on the experimental field of the AllRussian Scientific Research Institute of Viticulture and Winemaking, a branch of the Federal State Budgetary Scientific Institution Rostov Federal Agrarian Research Center in accordance with generally accepted methods. The adaptive potential to low negative temperatures of various varieties was assessed by freezing lignified annual shoots in a refrigerator in the following exposures: 18 ° C – 24 hours; -25 °C – 12 hours; -30o C – 8 hours, followed by determination of the number of live and damaged eyes. Previously, they were hardened in natural conditions, and then they were hardened in artificial ones, with a gradual decrease in temperature from -5 ° C to -15 ° C (7 days), followed by determining the number of live and damaged eyes, carried out after gradual thawing plant material. Water fractions (bound and free) were determined by the refractometric method, taking into account the amount of “bound” water remaining in the tissues and using hypertonic sucrose solution at different concentrations.

Results and conclusions. It was revealed that the varieties most adaptive to frost (Kober 5BB, Kristall, Violet early), even when exposed to a temperature of -30 ° C, had up to 8% of fully preserved eyes and 13 ... 25% of partially damaged ones. In other varieties, almost complete death of eyes was observed. By the beginning of the full maturity of the shoots, the water content in them stabilized at the level of 50...61% with a tendency to decrease during the period of stable frosty weather. In winter, the total amount of water decreased compared to the hardening phase, but changed less significantly than the ratio of its fractions (by 2.0-2.8 times). The relationship between the degree of adaptation to low negative temperatures of lignified shoots of different grape varieties and the state of water in them during the dormant period was confirmed (r=0.88…0.92).

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