Adaptation of Pinus sylvestris Forms with Seeds of Different Colours under Conditions of Excessively Moist Soils

Adaptive changes in biochemical parameters of different pine forms under conditions of constant excessive soil moisture in the northern latitudes of the European part of Russia have been studied. The influence of seasonal variability on the dynamics of the photosynthetic pigment complex of pine forms with different seed colours has been shown. It has been established that elevated temperatures in early autumn contribute to the accumulation of chlorophyll, and this can negatively affect the hardening of trees in preparation for overwintering. The proportion of chlorophylls localized in the light-harvesting complexes of chloroplasts fluctuates from May to November from 43 to 60 %, which is associated with the adaptation of the photosynthetic apparatus of trees of different forms to the light conditions of high latitudes and other environmental factors. It has been determined that anthocyanins accumulate significantly more in pine needles in autumn, which increases their antioxidant role in this season. It has been revealed that peroxidase activity in 1-year-old needles increases in the autumn period. This can be considered as a protective reaction of different forms of pine, preventing the development of uncontrolled processes with a limited oxygen supply to the organs. A significant new formation of water-soluble proteins in pine needles with dark-coloured seeds has been detected due to the deterioration of weather conditions. This form, compared to pine with light seeds, probably reacts more strongly to the effect of stress factors that increase hypoxia of the root system. It has been concluded that the concentration of proline in needles is a very variable indicator, reacting sharply to the action of stress factors. No general trends in the seasonal dynamics of the indicator have been identified. It has been established that the content of ascorbic acid in the needles of trees of different forms of pine in late spring is significantly lower than in the summer and autumn seasons. This indicates the development of protective mechanisms to prevent oxidative stress under adverse weather conditions.