VARIATIONS BETWEEN THE PHYSIOLOGICAL RESPONSES OF BREAD WHEAT, DURUM WHEAT, BARLEY, RYE AND OAT UNDER SALINITY STRESS

Physiological responses of bread wheat (Triticum aestivum L. cv. Dagdas), durum wheat (Triticum durum L. cv. Selcuklu), barley (Hordeum vulgare, cv. Kiral). rye (Secale cereale L., cv. Aslim) and oat (Avena sativa L. cv. Faik Bey) to salinity stress were researched. After the germinating in perlite, seedlings were transferred to pots with nutrient solution. At 6th day of growth, the plants were exposed to 0, 100, 150 mM NaCl with gradual increases. On the 8th day of salt treatment, leaves were sampled to analyze protein content. malondialdehyde (MDA) content and antioxidative enzyme activities (ascorbate peroxidase-APX, and catalase-CAT). Salinity stress remarkably increased the MDA content and the antioxidative enzymes activities, hut decreased protein contents. The highest average MDA accumulation was determined in lye (3289 nmol.g(-1) protein), while the lowest was recorded in bread wheat (1125 nmol.g(-1) protein). The highest increase in MDA was found in rye; followed by oats, durum, barley and bread wheat. The most severe decrease in protein content was found in rye, barley, bread wheat, durum wheat and oat, respectively at 150 mM NaCl. Antioxidative enzyme activities increased due to an increase in salinity. While the highest increase in APX activity was determined in barley. the highest increase in CAT activity was observed in oats. It was concluded that increased enzyme activities have a significant effect in alleviating oxidative damage, caused by salinity stress with important variations among the cereal species.