Effects of salt stress on ion accumulation and activity of some antioxidant enzymes in melon (Cucumis melo L.)

The changes in ion acumulation and the possible involvement of the antioxidant system in relation to the tolerance of salt stress was investigated in melon (Cucumis melo L.). Four local Turkish varieties (Besni, Midyat, Yuva and Semame), three cultivars (Ananas, Galia C8 and Galia F1) and C. melo var. flexuosus were grown in hydroponic culture. The 4-5 true leaf stages of melon seedlings were subjected to 100 mM NaCl for 8 days. In Galia C8 and Galia Fl cultivars and Midyat and Besni varieties level of Cl ion accumulation was lower, but activities of superoxide dismutase (SOD; EC 1.15.1.1) and catalase (CAT; EC 1.11.1.6) were inherently higher than in Ananas, Yuva and C. flexuosus. These results possibly suggest that 'Galia C8' and 'Galia F1' exhibit a better protection mechanism against oxidative damage by maintaining a higher inherited and induced activity of antioxidant enzymes than the relatively sensitive plants of the melon.