Влияние засухи на содержание хлорофилла и активность ферментов антиоксидантной системы в листьях трех сортов пшеницы, различающихся по продуктивности
2010
Nikolaeva, M.K. | Maevskaya, S.N. | Shugaev, A.G. | Bukhov, N.G., Russian Academy of Sciences, Moscow (Russian Federation). The K.A. Timiryazev Institute of Plant Physiology
Seedlings of 3 wheat varieties (Triticum aestivum L.) - highly productive cv. Ballada, moderately productive cv. Belchanka and low productive cv. Beltskaya—were exposed to progressive soil drought (cessation of watering for 3, 5 and 7 days). Then they were analyzed for chlorophyll content and activities of ferredoxin-NADP+ oxidoreductase (FNR), glutathione reductase (GR) and ascorbate peroxidase (AscP). The proline content and the extent of lipid peroxidation were examined also. During the 1 period of water limitation a water loss from leaves was slight for the all wheat cultivars, that could be characteristic of drought-resistant varieties. After 7-day drought the leaf water content decreased by 5.2–6.8%. The total chlorophyll content expressed per unit dry weight increased insignificantly during the first 2 periods of drought but later decreased by 13–15%. That decrease was not accompanied by changes in chlorophyll a/b ratio. Plant dehydration did not induce significant changes in FNR activity. Activities of GR and AscP in leaves of Ballada and Belchanka increased on the 3 and 5 days of drought. The lipid peroxidation rate remained at nearly the control level observed in water-sufficient plants. The activities of GR and AscP reduced in parallel with the increase in malonic dialdehyde (MDA) content when the dehydration period was prolonged to 7 days, indicating that the antioxidant enzyme defense system was weakened and lipid peroxidation enhanced. Beltskaya did not exhibit the increase in GR and AscP activities unlike Ballada and Belchanka, during progressive soil drought. The increase in MDA content by 16% in this cultivar was only observed after a 7-day drought period. The proline content in leaves of all the wheat cultivars increased substantially during drought treatment. Thus, different responses of the defense systems were mobilized to implement plant protection against water stress. The activities of antioxidant enzyme defense system depended on a wheat cultivar, a duration of drought and a stage of leaf development.
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