Changes in Physiological and Biochemical Parameters in the Kidneys of Siberian Larch during the Change of Phenological Phases in the Middle Taiga of the Komi Republic

The paper includes the results of physiological and biochemical studies of L. sibirica vegetative buds in the taiga zone of the Komi Republic (Russia). The change in the phenological state of L. sibirica during the dormancy period and the transition to vegetative period is accompanied by a significant alteration of metabolism. In the autumn-winter period, the buds of L. sibirica synthesise a large amount of cryoprotective compounds such as soluble sugars, soluble protein and free amino acids. During this period, the buds also contain a considerable quantity of unsaturated fatty acids (about 60% of the sum of all fatty acids), mainly linoleic and oleic fatty acids. The beginning of the sap flow period is marked by a gradual increase in content of sugars and soluble proteins which reach tmaximum values towards the end of April. The fatty acid composition of the buds changed significantly. The content of the unsaturated FAs decreased significantly and the one of the saturated FAs increased, indicating the activation of a fatty acid synthase, the final product of which is palmitic acid. The water content and the share of freezing water in buds decreases to 45% and 16%, respectively, in December. The low water content and the presence of a significant fraction of non-freezing water allows us to be certain about the development of quite sufficient cryo-resistance in larch bud tissues against low negative temperatures in the autumnwinter period. The biochemical changes in the buds adapting to low temperatures are primarily aimed at changing the state of water whereby its phase transitions become relatively safe.