Effect of nitrogen source on wheat response to NaCl salinity stress in hydroponic culture

Abstract EN

Wheat (Triticum aestivum) fcv, Safra Maan) plants were grown in hydroponic culture containing either nitrate or ammonium as the only source for nitrogen with 86 mM NaCl for five days then with 172 mM for the rest of the experimental period and without NaCl.

Relative growth rate, accumulation of dry matter, total soluble carbohydrates, and the amount of chloride, and potassium, were determined in the shoots and roots of the experimented plants.

At the beginning of salt treatment with 172 mM NaCl for one week, nitrate fed plants showed higher relative growth rate than ammonium fed plants.

But upon subjecting the plants to salt stress for longer period (three weeks), both salt treated nitrate and ammonium fed plants exhibited stunted growth to the same extent and showed almost equal accumulation of chloride in the roots and shoots.

During the whole experimental period and in the absence of salt, the nitrate fed plants showed better growth than ammonium fed plants, and exhibited higher dry matter content.

Results indicated that wheat may have better system for using nitrate rather than ammonium (as source for nitrogen) under normal conditions as well as under short term exposure to salt stress conditions, but upon subjecting the plants to NaCl stress for longer period , both salt stressed nitrate and ammonium fed plants showed the same response to the adverse effect of salt.

In addition, this effect of salt stress was not related neither to a stimulatory effect of ammonium, nor to an inhibitory effect of nitrate on the uptake and accumulation of chloride.