The Regulative Effects Of Hydrogen Sulfide On Growth And Cadmium Stress Tolerance Of Oilseed Rape

Cadmium pollution in soil is seriously having affected agricultural production and food safety in China.Oilseed rape is not only an important oil crop in China,but also a feasible soil restoration plant.Hydrogen sulfide(H2S),as a gas signaling molecule,plays an important role in regulating the growth and development of plants and the response to environmental stress.However,the mechanism by which hydrogen sulfide regulates the response of oilseed rape to cadmium stress is still unclear.Therefore,it is of practical significance to study the mechanism of H2S enhancing the cadmium tolerance of rapeseed.In our research,the biomass accumulation,chlorophyll content and the distribution of cadmium in oilseed rape seedlings pretreated with NaHS,as hydrogen sulfide(H2S)donor,under cadmium stress were observed for determining the mitigation effect.Furthermore,the H2S synthetase activity,root cell wall composition and modification of oilseed rape roots were analyzed.The main conclusions were as follows:1)Cadmium stress significantly affected the growth of oilseed rape seedlings,caused the leaf chlorosis,decreased the content of H2S in the roots,decreased the content of pectin and the degree of demethylation of pectin in the cell wall of roots.2)NaHS pretreatment significantly improved growth retardation and leaf chlorosis,indicating that H2S alleviated the damage caused by cadmium toxicity3)NaHS pretreatment significantly increased the activity of L-cysteine desulfhydrase(LCD)and the content of H2S in roots of oilseed rape seedlings.4)NaHS pretreatment significantly improved the tolerance of oilseed rape to cadmium by increasing pectin content and its demethylation,increasing Cd fixation in cell walls,and reducing root-to-shoot Cd translocation.