Changes in physiological parameters of rapeseed in response to application of 24-epibrassinolide and nano-zinc oxide under salinity stress

This research was conducted to determine the effects of 24-epibrassinolide and zinc oxide nano-particles (ZnO-NPs) on the salinity tolerance capability of canola seedling. In this regard, a factorial potting experiment was carried out based on randomized complete block design with three replications in year 2015. The experimental factors included foliar spray of ZnO-NPs (0, 500 and 1000 ppm), 24-epibrassinolide (0, 15 and 30 mg.ha-1) and salinity stress levels (0, 50 and 100 mM NaCl). According to results, salt stress caused to increase of malondialdehyde and considerable decrease of seedling dry weight and leaf area, membrane stability, quantum yield of photosystem II(Fv/Fm) and catalase and peroxidase activity. Co-application of 24-epibrassinolide and ZnO-NPs alleviated the salt stress mediated oxidative damage. Such that with promotion of antioxidant system, the malondialdehyde content and in contrast, the parameters of dry matter and leaf area, relative water content, membrane stability and Fv/Fm were increased. On the other hand, negative impact of ZnO-NPs at 1000 ppm on dry matter production and membrane stability was observed. According to results, it seems that co-application (30 mg.ha-1 EBL 500 ppm ZnO-NPs) of these two compounds had the best result in order to ameliorate the deleterious impacts of salinity stress.