水稻和杂草稻对镉胁迫反应的比较研究

采用水培实验,研究不同浓度Cd2+胁迫对水稻和杂草稻植株的生长、色素含量、抗氧化酶的活性、丙二醛含量、相对电导率以及脯氨酸含量的影响。结果表明:(1)Cd2+胁迫条件下,水稻和杂草稻植株地上部分外观伤害随着Cd2+浓度的升高而加重。(2)水稻和杂草稻的叶绿素a、叶绿素b和叶绿素总量含量均表现为Cd2+胁迫浓度<0.5 mg.L-1时升高,Cd2+胁迫浓度>0.5 mg.L-1时降低的现象;水稻和杂草稻的类胡萝卜素含量也都表现出Cd2+胁迫浓度<0.5 mg.L-1时降低,然后升高,最后在Cd2+胁迫浓度>1 mg.L-1时降低的现象。(3)水稻的SOD、POD、CAT活性表现出在Cd2+浓度<1 mg.L-1时升高,在Cd2+浓度>1 mg.L-1时降低的现象;杂草稻的SOD、CAT活性表现出在Cd2+浓度<2 mg.L-1时升高,在Cd2+浓度>2 mg.L-1时降低的现象,杂草稻的POD活性表现出随着Cd2+浓度的升高而升高的现象;抗氧化酶活性随着Cd2+浓度升高的变化幅度是水稻>杂草稻。(4)Cd2+胁迫使水稻和杂草稻的丙二醛含量、相对电导率以及脯氨酸含量显著增加,且增加幅度是水稻>杂草稻,说明水稻产生了较严重的膜脂过氧化。总之,对于Cd2+胁迫,在敏感性上水稻>杂草稻,在抗性上杂草稻>水稻。

Response of Rice and Weedy Rice Subjected to Cadmium Stress: A Comparative Study

The effects of Cd2+ on growth,chlorophyll content,MDA content,proline content,relative electric conductivity and activities of anti-oxidative enzymes in rice and weedy rice were examined hydroponically.The results suggested that,(1)apparent damage of aerial parts of rice and weedy rice exposed to Cd enhanced with increasing Cd2+ concentration.(2)Contents of chlorophyll a,chlorophyll b and total chlorophyll in leaves of rice and weedy rice increased at Cd2+ concentration below 0.5 mg·L-1,while their contents decreased at concentration above 0.5 mg·L-1.Carotenoid content decreased at Cd2+ concentration below 0.5 mg·L-1,but attenuated later on.The Carotenoid content increased again at Cd2+ concentration above 1.0 mg·L-1.(3)Activities of SOD,POD and CAT in rice exposed to Cd2+ increased when Cd2+ concentration was below 1 mg·L-1,but decreased when Cd2+ concentration was above 1 mg·L-1.Activities of SOD and CAT in weedy rice increased when Cd2+ concentration was below 2 mg·L-1,but decreased when Cd2+ concentration was above 2 mg·L-1.POD activity in weedy rice increased with increasing Cd2+ concentration.(4)Subjected to Cd2+ treatment,MDA content in both rice and weedy rice increased,while relative electric conductivity and proline content significantly increased,and the amplitude increased in rice was higher than those in weedy rice,suggesting that rather severe membrane lipid peroxidation has been occurred in rice.Taken together,rice was more sensitive to Cd2+ stress than weedy rice in terms of susceptibility,while with reference to resistance,weedy rice was more resistant to Cd2+ stress than rice.