镉处理对油菜生长和抗氧化酶系统的影响

通过盆栽实验研究了Cd处理对油菜生长和抗氧化酶系统的影响.结果表明,油菜整株鲜重、叶鲜重随Cd胁迫呈显著降低趋势.逐步回归表明,叶鲜重下降导致油菜整株鲜重下降.油菜叶细胞膜渗透性和MDA随Cd胁迫增大而增加.Cd处理浓度为20 mg·kg^-1时，叶细胞膜渗透性和MDA分别增加29.68％和15.19％，叶细胞膜渗透性和 MDA呈显著正相关，相关系数为0.823^*.Cd处理浓度为5 mg·kg^-1时，叶绿素a、b和a+b含量达到峰值，分别比对照高23.97%、33.63%和26.45%；Cd胁迫对类胡萝卜素含量无显著影响.几种色素对Cd敏感顺序为：叶绿素b>叶绿素a>叶绿素a+b>类胡萝卜素；3种抗氧化酶对Cd敏感顺序为：POD>CAT>SOD.各生理指标IC50表明,油菜只适宜种植在Cd含量小于5 mg·kg^-1的土壤中.

Effects of Cd on rape growth and antioxidant enzyme system

The study with pot experiment showed that the fresh weights of rape plant and leaf decreased with increasing Cd concentration, and the decrease of leaf fresh weight resulted in the decrease of whole plant fresh weight. The permeability of cell membrane and the content of MDA increased with increasing Cd concentration. When the concentration of Cd was 20 mg x kg(-1), compared with the control, cell membrane permeability and MDA content were increased by 29.68% and 15.19% respectively, and there was a significant correlation between these two indices. When the Cd concentration was 5 mg x kg(-1), the contents of chlorophyll a, b and a + b reached their peaks, and were 23.97%, 33.63% and 26.45% higher than the control, respectively. Cd stress had no significant effect on carotenoid content. The sensibility of the pigments to Cd stress was chlorophyll b> chlorophyll a> chlorophyll a + b> carotenoid, and that of protective enzymes was POD>CAT>SOD. The IC50 of test physiological indices suggested that rape could only grow well on the soil with < 5 mg x kg(-1) Cd.