The Growth And Physiological Response Of Ryegrass To Salt-alkali Stress In The Early Growth Stage

Based on perennial ryegrass（Lolium perenne L.）seeds and seedlings,stress treatment with mixed solutions of different concentrations of Na Cl（A）,Na HCO₃（B）,Na Cl and Na HCO₃（C）,the seed germination indexes of ryegrass were studied with different concentration of neutral salt,alkaline salt and saline-alkali mixture、Physiological parameters of seedlings and the effects of isozyme expression,the salt-alkali tolerance characteristics of ryegrass were analyzed to provide theoretical basis for the subsequent development and utilization of ryegrass resources.The main results of this experiment are as follows:（1）With the increase of stress concentration,the germination rate,germination potential and germination index of ryegrass seeds decreased to varying degrees;when the concentration in A group was 400 m M,the germination rate was only 47.7%of the control;when the B group reached the highest concentration（120 m M）,the seeds of ryegrass did not germinate at all,and the germination rate,germination potential and germination index were all 0,and the relative salt damage rate reached 100%;C group had little effect on the seed germination of ryegrass under 100 m M of stress and when the concentration reached 400 m M,the germination rate of the control was 9.5times higher than that of the control,which seriously inhibited the seed germination.（2）With the increase of stress concentration,the contents of malondialdehyde,proline and soluble sugar in ryegrass seedlings increased;The contents of chlorophyll a、chlorophyll b and chlorophyll（a b）decreased;A、B、C three groups of soluble protein content reached the maximum at 200 m M、60m M、90m M and then decreased;the content of malondialdehyde in C group was higher than that in A、B group,and the content of proline and soluble sugar in A group was higher than that in B、C group.（3）As the stress concentration increased,SOD、POD、CAT activity in ryegrass seedlings varied to varying degrees.A、B、C three groups achieved maximum activity SOD 300 m M、60m M、200m M and the highest at 400 m M、60m M and 200 m M,respectively,A、B the two groups were 200 m M and 60 m M,respectively,the CAT activity was the highest.PAGE analysis showed that saline-alkali stress could induce new bands SOD、POD、CAT isozymes,and there were significant differences in the distribution of main and specific bands.SOD total of 11 bands,mobility range of0.08～0.82,the control group isolated 8 bands,SOD₁is the B group 60 m M～120 and100 m M of the common band;POD a total of 17 bands with a mobility range of0.07～0.74,15 bands were separated from the control group,POD₁were A4 specific bands,POD₁₀were Ck specific bands,and the rest were common bands.CAT total 7bands,mobility range 0.10～0.40,control group separated 2 bands,CAT₁and CAT₄are the special bands in the group,the rest are the common bands.