Document Type : Research Paper
Department of Plant Production and Genetics, Faculty of Agriculture, Urmia University, P.O. Box 165, Km 11 Nazlou Road, Urmia, Iran
Department of Plant Production and Genetics, Faculty of Agriculture and Natural Resources, Urmia University , Urmia, Iran
Effect of different levels of NaCl (0, 2, 4, 6 and 8 dS/m) were investigated on enzymatic and non-enzymatic activities in C64 and C68 oilseed sunflower genotypes at two times; 3 and 12 days after salinity stress application. Net photosynthesis rate, chlorophyll content and soluble proteins amount decreased by increasing salinity level but proline and malondialdehyde (MDA) contents increased. In genotype C86, the reduction of photosynthesis rate at all studied salinity levels was very high compared to normal condition (0 dS/m) post 3 days; especially at salinity levels of 2, 4 and 6 dS/m, while 12 days later, the decrease rate of photosynthesis rate was moderately at salinity levels of 2 and 4 dS/m but severely at 6 and 8 dS/m salinity levels. The highest amount of proline (31.36%) related to tolerant genotype and the lowest amount (7.72%) related to susceptible one post 12 days application of 2 dS/m salt stress. Considerable MDA was observed in both tolerant and sensitive genotypes 12 days post salt stress application; the highest amount (83%) was observed at salinity level of 8 dS/m. Catalase and ascorbate peroxidase activity increased with increasing salt intensity. The rate of increase in guaiacol peroxidase activity was higher in C86 genotype than C64. Chlorophyll a and total chlorophyll contents decreased in both sunflower genotypes under salinity stress. The lowest amount of total chlorophyll (8.6%) was observed in the salinity level of 8 dS/m in the sensitive line (C64).