The Physiological Role of Proline and Sodium as Osmotic Stress Signal Components of Some Crop Plants

Abstract

The increase of Na + and proline content in maize, wheat, broad bean, cotton and parsley plants indicated that the proline content may act as an indicator of Na + uptake and allow the identification of tolerant plants, which effectively exclude Na + from plant either by exclusion or compartmentalization. In maize and cotton plants while Na + increased in shoots and roots, proline content decreased in these organs of these plants. This concomitant with reduction of dry matter of both organs of the maize and cotton plants. Sodium can be considered as osmotic stress marker component in these plants, especially in shoots of cotton. The percent accumulation of proline in both organs of wheat and parsley plants, shoots of broad bean run parallel with the reduction in dry matter of these plants. This strategy of proline and dry matter was concomitant with the increase of Na + content of these plants. Pytohormonal treatment with either GA 3 or Kinetin 200 ppm was mostly decreased the accumulation of both osmotic stress markers (sodium and proline ) at all levels of salinity in shoots and roots of maize, wheat, cotton, broad bean and parsley plants. Phytohormonal application was significant reduced mostly the accumulation both stress markers sodium ion and proline in shoots and roots of maize, wheat, cotton, broad bean and parsley plants. This can be reflected on the accumulation of metabolities which finally affected on the production of dry matter in shoots and roots of the five tested plants.