Authors: V. E. SOFRONOVA, candidate of chemical sciences, senior researcher, V. A. CHEPALOV, candidate of biological sciences, researcher, K. A. PETROV, doctor of biological sciences, leading researcher, Institute for Biological Problems of Cryolithozone of the Yakut Scientific Centre of the SB RAS (41 Lenina Av., 677000, Yakutsk), O. V. DYMOVA, candidate of biological sciences, senior researcher, T. K. GOLOVKO, doctor of biological sciences, professor, chief researcher, Institute of Biology of Komi Scientific Centre of the UB RAS (28 Kommunisticheskaya, 167982, Syktyvkar)
Keywords: oats, sowing dates, autumn vegetative plants, low temperatures, cryofodder, chlorophylls, carotenoids, xan- thophylls.
Abstract: The influence of a late sowing date on the pigment content of an autumn vegetative plant in Central Yakutia (62°15′ N, 129°37′ E) has been studied for the first time. The experiments were carried out using spring oat, Avena sativa L., cultivar (cv) Pokrovsky, commonly used in the preparation of cryofodder, the seeds of which were planted according to the optimal (17 June) and late (25 July) sowing dates. It was established that till the end of the first decade of September the content of chlorophylls (15-16 mg/g dry weight) and carotenoids (2,9 mg/g dry weight) in the leaves of late sowing plants were higher by 11–13 % compared to control plants at the same phases of growth and development. Autumn decrease in temperature from the second half of September until the beginning of October (from +7…+8 °C to near-zero) led to a gradual reduction of chlorophylls (a + b) content by 40 %. The ratio Chl a/Chl b remained almost constant, a significant increase of which was noted only at near-zero temperatures due to a greater degradation of Chl b than Chl a. At the same time, carotenoids showed greater resistance to low temperatures. When green plants in the milk ripeness phase went under snow in October, the total carotenoid content was 2,2 mg/g dry weight. The proportion of individual carotenoids in the total pool of yellow pigments of late sowing plants did not depend on the phenological phases of growth and development, as well as on seasonal temperature decrease. The share of β-carotene accounted for 26–30 % of the carotenoids sum, xanthophylls lutein and zeaxanthin make up 39–40 %, violaxanthin ‒ 17–21 %, neoxanthin ‒ 9–10 %, antheraxanthin ‒ 4–5 %. Losses of carotenoids did not exceed 20 % and their ratio remained almost unchanged during winter storage of green mass of frozen plants in rolls.
