Investigating the Effect of Sodium Hydrosulfide Pretreatment on the Biochemical and Enzymatic Properties of Brassica napus L under Arsenic Toxicity

Hydrogen sulfide is one of the most important signaling molecules involved in many processes of plant stress resistance. Thereby and in an attempt to investigate the priming effect of sodium hydrosulfide, hydrogen sulfide-releasing compound, on reducing arsenic in Canola seed, a factorial experiment in a completely randomized design with three replications was conducted in the research laboratory of Kerman University of Shahid Bahonar in 2015. The experiment included two factors i.e., the use of sodium hydrosulfide (including the application and non-application of Sodium hydrosulfide) and different concentrations of arsenic (including 0, 100, and 200 μM). The results showed that increasing the concentrations of arsenic and shoot fresh weight reduced the Chlorophyll content in canola plants, while the amount of MDA, proline, hydrogen peroxide and the activity of the antioxidant enzymes of catalase, ascorbate peroxidase and guaiacol peroxidase increased. The pretreatment of the plants with sodium hydrosulfide compared to its non-application condition resulted in an increase in the fresh weight, the amount of photosynthetic pigments, proline, the activity of antioxidant enzymes; while it reduced the amount of malondialdehyde and hydrogen peroxide in canola plants. Possibly, hydrogen sulfide increases the activity of anti-oxidative enzymes through connecting with nitric oxide and as a result protects the plant against oxidative damage caused by the toxicity of arsenic.