Effects Of Cd Stress On Carbon And Nitrogen Metabolism Of Cultivated And Wild Soybean

The heavy metal pollution led to crop growth and low yields,which is the problem to be solved urgently.In this experiment,a cultivated soybean(Glycine max)Liaodou 24 and a wild soybean(Glycine soja)1502 were used as experimental materials and Cd concentration of 20,40 and 80 mg/kg was used for treatment.Through the analysis of the shoot length,photosynthesis index(Chl a,Chl b,Car,Pn,Gs,Ci,Ts),protective enzyme activity(SOD,POD,CAT),malondialdehyde(MDA)content,carbon metabolism related index(Soluble sugar,sucrose,starch,invertase,SS,SPS)and nitrogen metabolism related index(nitrate nitrogen,ammonium nitrogen,ureide,free amino acid,total nitrogen,GS,GOGAT),study on growth and carbon and nitrogen metabolism of cultivated soybean and wild soybean under cadmium treatment.The main findings are as follows:1.During the Cd stress period,the plant height of both the cultivated soybean and the wild soybean seedlings were lower than the control,and decreased with the increase of the concentration of cadmium.2.Under cadmium stress,the photosynthetic pigment content of both cultivated soybean and wild soybean seedlings were lower than that of the control.Except in the early period of Cd stress,all of them decreased with the increase of cadmium concentration,and with the increase of cadmium concentration.The effect of wild soybean seedlings was relatively small.The decrease of photosynthesis of cultivated soybean seedlings was caused by non-stomatal factors,while that of wild soybean was mainly caused by stomatal conductance.3.The SOD activity of cultivated soybean was lower than that of control soybean under Cd stress,but the activities of POD and CAT was low promotion and high inhibition.There was no significant effect on the SOD activity of wild soybean with the concentration difference.The POD activity of low promotion and high inhibition.CAT active was weaker than that of the control group.The MDA content of cultivated soybean under cadmium stress was higher than that of control,but the content of MDA in wild soybean was higher than that of control in the late period of stress.4.During cadmium stress,the carbon metabolism of wild soybean seedlings was less affected.In addition to the sucrose content of cultivated soybean seedlings during the later period of stress,the content of soluble sugar,sucrose and starch of cultivated soybean and wild soybean seedlings were lower than that of control.In the middle and late period of soybean cultivation stress and in the early and late period of wild soybean stress,the activities of invertase and sucrose synthase in two soybean seedlings were lower than those of the control.The SPS activitywas lower than that of the control except in the middle period of stress.5.During the stress period,the nitrate nitrogen content of both cultivated soybean and wild soybean seedlings was lower than that of the control,and the decrease of wild soybean was relatively small.The content of ammonium nitrogen of cultivated soybean seedlings was lower than that of control,and that of wild soybean was lower than that of control only at the late stage of stress.The content of ureide and free amino acids in the two soybean varieties increased.Except in the middle of wild soybean stress,the total nitrogen content of the two varieties was lower than that of the control.The NR activity of the two soybean seedlings was lower than that of the control,and the inhibition of wild soybean was weak.In the early and middle period of soybean cultivation stress and in the middle and late period of wild soybean stress,GS activity was lower than that of control.Except for wild soybean,the GOGAT activity of soybean seedlings was lower than that of control.Taken together,compared with cultivated soybean,wild soybean had stronger tolerance to heavy metal cadmium,which could effectively activate antioxidant enzyme activity,reduce damage to membrane system,and reduce carbon metabolism and nitrogen metabolism.Therefore,it is hopeful to cultivate soybean varieties with high cadmium tolerance by using wild soybean.