Fruit growing
and viticulture of South Russia

Annotation

The wintering period and exit from dormancy are of great importance for the subsequent vital activity of grape plants. Induced dormancy is characterized by a number of specific physiological and biochemical changes. The aim of this study was to characterize the photosynthetic parameters, the carbohydrate composition of chlorophyll-containing vine tissue in the period of exit from dormancy. Studies were conducted on grape hybrids of TANA 33 (intraspecific hybrid V. vinifera), TANA 42 (interspecific hybrid V. vinifera and V. amurensis), TANA 68 (interspecific hybrid of V. vinifera and American varieties). TANA 42 and TANA 68 are non-freeze-sensitive hybrids, and TANA 33 is freeze-sensitive hybrid. The studies were carried out in February and March. Content of carbohydrates, photosynthetic pigments, the photochemical activity and the content of MDA in the vines were obtained. Physiological differences between grape hybrids with different freeze resistance during the induced dormancy were revealed. The lowering of the air temperature to moderate negative values have had a weak influence the manifestation of oxidative stress in non-freeze-sensitive hybrids, and a steady increase in the content of MDA was observed in freeze- sensitive TANA 33. The content of photosynthetic pigments in the vines cannot serve as an indicator of freeze- tolerance but this parameter was closely associated with the temperature changes. The effective quantum yield of PS Ⅱ in February was significantly lower for the freeze-sensitive TANA 33, however, the differences between the varieties disappeared after the onset of sap flow. The quantum yield of PS Ⅱ was depended on the temperature changes. The adaptation of non-tolerant grapes probably accompanied with the transformation of starch into soluble carbohydrates, which was not typical for frost-resistant varieties.