Data on changes in the energy status and pro-/antioxidant metabolism activity at different stages of the dormancy and upon emergence from it in L. buds were obtained. A significant degree of water content (70–75%) and a low proportion of free water (50%) during the overwintering of buds were demonstrated. The freezing temperature of free water ranged from –6°C to –8°C, reflecting the high degree of meristematic tissues adaptation to low temperatures. During autumn-winter morphogenesis (from August to January), buds demonstrated stable rates of heat generation and O uptake, and a high proportion of cytochrome respiration (more than 70%). In January, compared to autumn, a significant increase in the rate and efficiency of energy storage and an increase in provxidant levels (the content of thiobarbituric acid reactive substances (TBARS) and HO content) were observed. During dormancy emergence in spring, an increase in rate of heat production and respiratory capacity, but a decrease in the energetically efficiency of respiration were observed. Compared to the autumn-winter period, the activity of energetically inefficient alternative respiration increased 4.5 times in spring, suggesting the involvement of alternative oxidase in maintaining pro-/antioxidant metabolism and plant adaptation to spring temperature fluctuations and increased insolation. In spring, compared to the dormant period, we observed a peak in provxidants accumulation and antioxidant enzymes activity. The maximal diversity and activity of SOD isoforms during spring morphogenesis may be related to the accumulation of HO in various cellular compartments, as a stable ROS and an important signaling molecule. We concluded that plants adapted to more favorable conditions do not exhibit the deep, organic dormancy which is characteristic of natural conditions. Energy metabolism parameters, the capacity and ratio of the cytochrome and alternative respiratory pathways, provxidants content and antioxidant enzymes activity can serve as physiological and biochemical markers of dormancy maintenance and emergence in buds.
S.P. Maslova (Wed,) studied this question.