Adaptation of wheat varieties under combined stress

The article presents the results of studies of adaptive reactions of 10-day-old seedlings of wheat varieties Novosibirskaya 18, Novosibirskaya 44, Sibirskaya 21 and Omskaya 18 under combined stress. The indices of growth, accumulation of wet and dry biomass and permeability of cell membranes by specific electrical conductivity (EC) of leaf extracts under the combined action of chloride salinity (1.3%) and hyperthermia of seeds (43 °C) were studied. Chloride salinization without preliminary heating of seeds caused mainly a decrease in adaptive capacity and a loss of cultivar resistance (a decrease in growth to 57.2%, a decrease in biomass to 35.2%, an increase in EC up to 5.7 times). The most resistant cultivar is Omskaya 18. Preliminary hyperthermia of seeds increased the resistance of seedlings to the subsequent action of chloride salinization (decrease in EC to 56.2%, inhibition of biomass accumulation and growth by up to 14 times). The protective effect of hyperthermia during the subsequent action of salinity is most pronounced in the Sibirskaya 21 variety.