外源油菜素内酯对玉米幼苗镉毒害耐受性的影响
Effects of exogenous brassinolide on tolerance to cadmium toxicity in maize seedlings

采用盆栽试验进行玉米幼苗镉胁迫处理，研究了不同浓度（0，0.004%，0.008%，0.012%，0.016%）的油菜素内酯（BR）对镉胁迫下玉米幼苗生长的缓解作用。结果表明：重金属镉明显抑制了玉米幼苗的生长，与对照相比，玉米幼苗叶片的抗氧化酶CAT、POD和SOD活性分别下降了14.61%、7.59%和46.16%；可溶性蛋白、可溶性糖和脯氨酸含量分别降低了49.78%、62.94%和62.69%；叶绿素含量、根系活力分别降低了74.24%和48.38%；而叶片的丙二醛（MDA）含量和电导率增加，分别增加了38.56%和73.83%，这说明重金属镉对玉米幼苗产生一定的毒害作用。而加入一定浓度（0.012%）的油菜素内酯后有一定的缓解作用，与单独镉胁迫处理相比，玉米幼苗的抗氧化酶CAT、POD和SOD活性分别增加了13.98%、4.21%和67.20%；可溶性蛋白、可溶性糖和脯氨酸含量分别增加了98.34%、53.15%和79.28%；叶绿素含量、根系活力分别增加了90.08%和41.08%，而MDA含量和电导率降低，分别下降了30.01%和39.38%。说明油菜素内酯对镉胁迫下玉米幼苗的生长具有缓解作用，以0.012%效果最佳，增强了玉米幼苗的抗性。
Effects of different concentrations (0, 0.004%, 0.008%, 0.012%, 0.016%) of BR on the growth of maize seedlings under Cd stress were assessed by pot test. The results showed that growth of maize seedlings were significantly inhibited Cd tolerance. Comparing to control, activities of CAT, POD and SOD of maize seedlings decreased by 14.61%, 7.59% and 46.16%, respectively; soluble protein, soluble sugar and proline content decreased by 49.78%, 62.94% and 62.69% respectively; content of chlorophyll and root activity decreased by 74.24% and 48.38% respectively; content of MDA and conductivity increased by 38.56% and 73.83% respectively, and the content of chlorophyll and root activity decreased by 49.78%, 62.94% and 62.69% respectively.The findings indicated that Cd had a certain toxic effect on maize seedlings, and adding into certain concentration (0.012%) of BR had some mitigation effect. Comparing to cadmium stress treatment alone, activities of CAT, POD and SOD increased by 13.98%, 4.21% and 67.20% respectively; contents of soluble protein, soluble sugar and proline content increased by 98.34%, 53.15% and 79.28% respectively; chlorophyll content and root activity increased by 90.08% and 41.08% respectively, and the MDA content and conductivity decreased by 30.01% and 39.38% respectively. In conclusion, BR could alleviate the growth of maize seedling under Cd stress, and the best effect was 0.012%, which enhanced the resistance of maize seedlings.