Salinity induced changes in the reproductive physiology of wheat plants

The effect of salinity on reproductive physiology of wheat wasinvestigated. One set of wheat plants was subjected to increasingsalt levels up to a certain concentration, whereas another setwas given the same concentration in a single application. Theformer was called "gradual" and latter "shock" treatment. Theireffects on pollen viability, germination and activity of starchsynthetase were studied. Gradual treatment seemed to reducethe toxic effects of salts on the viability of pollen grainsand their germination. Seeds obtained from the two sets weregerminated in the same salinities in which their plants hadbeen growing, and the results were compared with those of seedsobtained from control plants growing in a non-saline medium.The seeds of plants from the gradual treatment were better suitedfor germination on a saline medium than those from the shocktreatment or the control group. Salt treatment also increasedthe activity of starch synthetase at the midmilky stage in developinggrains. This phenomenon was considered essential for synthesisof starch in a saline environment. The increase in Na⁺ and Cl^– and decrease in K⁺ contentsof wheat grains in both treatments suggest that the effect ofsalinity on the physiological phenomenon studied is due to changesin the ionic content of the plants. ¹ In partial fulfilment of a Ph.D. degree from the Universityof Karachi, Pakistan. ² Professor of Botany, Director of Research Projects, Head,Plant Physiology Section, University of Karachi, Pakistan. (Received July 11, 1977; )