Grain soaking presowing in ascorbic acid or thiamin versus the adverse effects of combined salinity and drought on wheat seedlings.

Abstract

Some previous experiments were conducted to follow the role of vitamins in alleviating the adverse effects of either salinity or drought on some crop plants. In this work et was intended to test the role of any of the two vitamins (ascorbic acid or thiamin) in alleviating the adverse effects of combined salinity and drought stress on wheat seedlings. In the first group of experiments, the seedlings were subjected to only successively elevated stress of combined salinity and drought. In this plant age, moderate treatments were generally associated with an increase in the rates of photosynthesis and respiration as well as in the contents of photosynthetic pigments. On the contrary the rates of growth and transpiration were lowered in response to these stressing treatments. Soaking of wheat grains presowing for 6 hrs in 100 ppm of either ascorbic acid or thiamin synergistically enhanced the stimulatory effects of combined salinity and drought on net photosynthesis as well as on photosynthetic pigments. On the other side the rate of respiration was comparatively lowered by the application of any of the two vitamins. In addition these vitamin treatments exerted some favorable effects on growth and transpiration of wheat seedlings counteracting the inhibitory effects of combined salinity and drought stress.