Investigation the effect of salinity tension on photosynthesis and antioxidant enzymes activity of canola cultivars in vegetative growth stage

This research was carried out in order to investigate the reaction of canola cultivars to salinity tension in a factorial experiment based on randomized complete blocks design with four replications in the research farm of Islamic Azad University, Shoushtar, during 2016-17 cropping year. In the present experiment the reaction of four canola cultivars (Hyola 320, Hyola 330, Option 500 and Sarigol) in vegetative growth stages was investigated in four salinity levels zero(control), 50, 100 and 150 mmol NaCl). The results showed the highest and lowest shoot dry weights were seen at the highest level of salinity tension in Hyola 320 (2.8 g) and Option 500 (1.5 g) and Sarigol bushes cultivars were eliminated at this salinity level. Salinity tension significantly reduced photosynthesis and chlorophyll a and b concentrations of canola cultivars, however at 150 mmol NaCl salinity level, the highest photosynthesis was observed in Hyola 320 and Heyola 330 (9.3 and 8.9 μmol Carbon dioxide per square meter of leaf area per second). Salinity tension reduced sucrose synthase enzyme activity in canola cultivars leaves, while cell membrane degradation in response to salt tension increased and the highest concentration of malondialdehyde was observed in salinity level of 150 mmol NaCl in Option 500 cultivar (0.051 nanomol per gram leaf). The results showed that Hyola 320 and Heulla 330 cultivars had more stability in cell membrane stability, photosynthesis, antioxidant enzymes activity and sucrose synthase enzyme activity compared to Option 500 and Sarigol cultivars.