Response of the cultivated tomato and its wild salt-tolerant relative Lycopersicon pennellii to salt-dependent oxidative stress: The root antioxidative system

The response of the antioxidant system to salt stress was studied in the ro ots of the cultivated tomato Lycopersican esculentum Mill. ev. M82 (Lem) an d its wild salt-tolerant relative L. pennellii (Corr.) D'Arcy accession Ati co (Lpa). Roots of control and salt (100 mM NaCl)-stressed plants were samp led at various times after commencement of salinization. A gradual increase in the membrane lipid peroxidation in salt-stressed root of Lem was accomp anied with decreased activities of the antioxidant enzymes: superoxide dism utase (SOD; EC 1.15.1.1), catalase (CAT; EC 1.11.1.6), ascorbate peroxidase (APX; EC 1.11.1.11) and decreased contents of the antioxidants ascorbate a nd glutathione and their redox states. In contrast, increased activities of the SOD, CAT, APX, monodehydroascorbate reductase (MDHAR; EC 1.6.5.4), and increased contents of the reduced forms of ascorbate and glutathione and t heir redox states were found in salt-stressed roots of Lpa, in which the le vel of membrane lipid peroxidation remained unchanged. It seems that the be tter protection of Lpa roots from salt-induced oxidative damage results, at least partially, from the increased activity of their antioxidative system .