盐胁迫下镧对水稻幼苗生长的保护效应

通过液培实验，研究水稻幼苗在盐胁迫下，镧对水稻幼苗的保护作用。结果表明：水稻幼苗植株在≤1．5％的盐浓度的盐胁迫下，10mg·L^-1镧能提高幼苗植株超氧化物歧化酶（SOD）和过氧化氢酶（CAT）的活性；降低幼苗植株脂质过氧化产物丙二醛（MDA）的含量和脯氨酸（Pro）的含量；减小质膜透性；提高叶片叶绿素含量和叶绿素a／b的比值；增强根系的活力，进而促进水稻幼苗的生长。10mg·L^-1镧对盐胁迫的缓解作用与盐浓度有关，随着盐浓度增大，镧的缓解作用将逐渐消失。分析表明，在≤1．0％和≥0．5％的盐浓度胁迫下，镧对水稻幼苗的生长存在更有效的防御机制，能够促进水稻幼苗的生长代谢。

The Protective Effects of La on the Growth of Rice Seedlings under Salt Stress

The protective effects of La （ NO3 ） 3 on the growth of rice seedlings under salt stress were evaluated by the nutrient solution culture experiment. The results showed that for the seedlings, 10 mg·L^-1 La（ NO3 ） 3 could improve the activities of protecting enzymes （superoxide dismutase--SOD, catalase--CAT） , decrease content of malondialdehyde （MDA） and proline（Pro） , and the penetrability of cell membrane, raise the content of chlorophyll in the leaves and the ratio of a/b in chlorophyll, improve roots activity in rice seedlings, then promoted the growth of rice seedlings unde stress of ≤1.5 % salts. The relieving function of 10 mg·L^-1 La（NO3）3 on the threats of salts had relation with the concentration of salts. La＇ s relieving function would gradually disappear with the increase of the concentration of salts. Under stress of 0.5 %- 1.0 % salts, there was a defense mechanism of rare earth elements lanthanum on the growth of rice seedlings, and 10 mg·L^-1 La（ NO3 ）3 could promote the metabolism of the plants.