EFFECTS OF La ON SOLUBLE PROTEIN CONTENT AND PROLINE CONTENT UNDER ACID RAIN STRESS

The effect of lanthanum on the germination of rice seeds was studied under simulated acid rain solutions of pH2.0 ,2.5,3.0,3.5,4.0, 4.5,5.0 and one control (pH=6.5) .Rice seeds pretreated by Lanthanum(1mg·l-1) were placed in culture dishes and kept in normal temperature. The content of soluble protein and proline were investigated under different acid rain stress.The result showed that the content of soluble protein decreased gradually while the content of increased gradually with the increase of the acid rain stress, when time of the intimidation was same. Lanthanum could alleviate the harm of the acid rain when the rice seeds was under the condition of pH5.0 to pH3.0; but when pH values of the acid rain was from 2.5 to 2.0, lanthanum did not have an obvious function of resistance .When pH value of the acid rain was 4.0, the content of soluble protein increased instantly when the acid rain stress was released on the third day and the fifth day, however, they did not have effect on the content of proline.When pH value of the acid rain was 2.5,the acid rain did irreversible harm to the rice seeds because of the long time of intimidation(over 5d);the content of soluble protein was lower than that of the control group (pH6.5) while the content of proline was higher than that of the control group , which showed that rice seeds pretreated by lanthanum did not have an obvious effect of resistance; but when the acid rain stress was released on the third day, the content of soluble protein and proline is much higher than those of the control group , and these two index also increased when rice seeds were pretreated by lanthanum ,which showed that lanthanum had an obvious effect of resistance under this condition .