Physiological responses of two arabidopsis thaliana isolates, N1438 and Col, to different salts

Abstract

Growth inhibition by salt stress in glycophytes like Arabidopsis thaliana is associated with a significant accumulation of Na⁺ and Cl^- in rosette leaves and to a reduction of their supply of essential nutrients such as potassium and calcium. In the present work, we attempted to evaluate the contribution of each of these factors to changes in the physiological functions of the species. The experiments were carried out under greenhouse conditions. Three-week old plants of A. thaliana from Col and N1438 isolates were cultivated for 17 days in a basal medium supplemented with either 12.5 mM Na₂SO₄,12.5 mM K₂SO₄, 25 mM NaCl, or 25 mM KCl. A salt-free medium was used as control. On harvesting, plants were cut into rosette leaves, bolts, and roots, and their fresh and dry weights, water contents, and major nutrient contents were determined. In Col, growth was decreased more by K⁺ salts (KCl and K₂SO₄) than by Na⁺ salts (NaCl and Na₂SO₄), and more by K₂SO₄ than by KCl, whereas in N1438, no difference was observed between the different salt treatments. Sodium was primarily accumulated in shoots, where it was probably compartmentalized into vacuoles, since it seemed to participate in osmotic adjustment. The growth sensitivity of Col to K⁺ salt treatments was associated with excessive accumulation of K⁺ in plant tissues. In conclusion, the variability of salt responses in A. thaliana was more dependent on cations (Na⁺ or K⁺) than on their associate anions (Cl^- or SO₄ ^2-).