EFFECTS OF ZN AND K NUTRITIONAL STATUS ON PROTEIN CONTENT, LIPID PEROXIDATION AND ANTIOXIDATIVE ENZYME ACTIVITIES UNDER THE SALINITY STRESS IN DIFFERENT WHEAT GENOTYPES

A solution culture experiment was conducted with different zinc (Zn) (2x10(-8) M and 10(-6) M) and potassium (K) (100 mu M and 2 mM) level using two bread wheat (Triticum aestivum L.), Dagdas and ES-14 and two durum wheat (Triticum durum L.), Kunduru-1149 and Selcuklu-97 genotypes. After 7 days, nutrient solution was salinized by two NaCl levels (0 and 150 mM NaCl) and the effect of Zn and K supplements on protein content, lipid peroxidation (LPX) level, ascorbate peroxidase (APX) and catalase (CAT) activities were evaluated on the 8th day after salinization. Salinity stress led to significant increases in LPX and decreases in protein content. Salinity-induced levels of LPX were significantly reduced by Zn and K supplements and especially by Zn-K supplement in combine. This effect was more significant in durum wheat genotypes. Zinc and K supplements either alone or together elevated the protein content of plants; however this effect was more significant under Zn supplements and in durum wheat genotypes. It was found that, salinity stress significantly enhanced the activities of APX and CAT. Under salinity stress, Zn deficiency significantly stimulated activities of APX and CAT however, such an effect was not found with K. Results showed that detrimental effects of salinity stress in plants could be mitigated with K and Zn supplements by limiting the lipid peroxidation and protein degradation.