Stomatal response of spring soft wheat plants of different varieties on increasing air water deficiency as a diagnostic sign of drought tolerance selection

In the laboratory and field conditions the authors studied the transpiration activity of plants of several cultivars of spring soft wheat in connection with stomatal response to an increase in air water deficit. It was discovered that plants of Omskaya 20, Bashkirskaya 26 and Kazakhstanskaya 10 varieties at air water deficit closed their stomata, that resulted in a decrease in their transpiration, while plants of Iren' cultivar on the contrary opened their stomata and their transpiration increased further. Maintenance of tissue humidity of plants of Iren' cultivar was achieved due to an increase in hydraulic conductivity of roots and an increase in water flow to shoots. Registration of stomatal reaction to an increase in water deficit in air is proposed to be used as a physiological trait in selection for drought resistance.