The nickel effect on the membrane integrity and lipid composition has been studied in the Mesembryanthemum crystallinum (halophyte) and Brassica juncea leaves. Plants were hydroponically sustained for 21 days at 0, 25, 50, and 100 µM NiCl2. The aim of the present study was to compare the Ni-tolerance of M. crystallinum and B. juncea , through physiological parameters related to membrane lipids. Results indicated that the total lipids (TL) content, as well as the fractions of the lipids such as phospholipids (PL), neutral lipids (NL), and the galactolipids (GL), were reduced more in the leaves of B. juncea than in M. crystallinum , which, however, showed slight changes in the total fatty acid composition. In contrast, there was a significant decrease in the percentage of the tri-unsaturated fatty acid (C18:3) in the leaves of B. juncea . This was associated with a significant increase in the percentage of di-unsaturated fatty acid (C18:2). Ni-treatment led to significant increase in the electrolyte leakage reflecting the metal-induced enhancement of membrane permeability in B. juncea compared to M. crystallinum . The aforementioned results revealed a better aptitude of M. crystallinum to preserve their membrane lipids against the Ni-effect.
Key words: nickel, fatty acids, halophyte, lipids, membrane integrity
Topic: AGRICULTURAL SCIENCES