Effect of rhizobia on nitrogen metabolism of alfalfa in response to cadmium
To investigate the effects of inoculation with rhizobium on the nitrogen metabolism of alfalfa under cadmium(Cd)stress,two alfalfa cultivars("Victoria"and"WL525HQ")were used as plant materials in a pot experiment,and the effects of Cd(0 mg·kg-1,50 mg·kg-1)treatment in soil were studied.The effects of inoculating rhizobium on key enzyme activities of nitrogen metabolism and nitrogen compounds of two alfalfa cultivars were shown.The results showed that Cd stress affected the nitrogen metabolism of alfalfa,and 50 mg·kg-1 Cd stress had the greatest effect on nitrate reductase activity in the above-ground part of the"WL525HQ"alfalfa uninoculated with rhizobia,which decreased by 85.01%compared with that after 0 mg·kg-1 Cd treatment.When treated with 0 mg·kg-1 Cd,the above-ground glutamate synthetase activity of"WL525HQ"inoculated with rhizobia increased by 95.53%compared with that of the non-inoculated group,and the above-ground asparagine synthetase activity of"Victoria"inoculated with rhizobia increased by 33.30%.Under 50 mg·kg-1 Cd stress,the nitrate reductase activity in the above-ground part of"WL525HQ"inoculated with rhizobia increased the most(164.66%)compared with that without inoculation,and the nitrate reductase activity in the underground part of"Victoria"inoculated with rhizobia increased by 99.46%compared with that without inoculation.Inoculating rhizobium with 50 mg·kg-1 Cd alleviated the inhibition of Cd stress on nitrogen-containing substance accumulation in alfalfa.The soluble protein content of"Victoria"and"WL525HQ"was significantly increased by 6.24%and 5.82%,the free amino acid content increased by 16.10%and 18.70%,and the nitrogen content of"Victoria"increased by 9.48%,respectively,compared with the unvaccinated group.It is indicated that inoculated rhizobacteria can promote the accumulation of nitrogen in alfalfa under Cd stress by regulating the activities of crucial enzymes of nitrogen metabolism towards protein synthesis by translocation,and alleviate the injury of Cd to alfalfa to a certain extent.
国家科技期刊平台
NSTL
万方数据
维普
