镉胁迫对玉米幼苗抗氧化酶系统及矿质元素吸收的影响

Effects of Cadmium Stress on Antioxidant Enzyme System and Absorption of Mineral Elements in Maize Seedlings

通过水培实验研究了在10-6、10-5、10-4mol·L-1浓度下,Cd2+胁迫对玉米幼苗抗氧化酶系统、丙二醛(MDA)含量、Cd积累及矿质元素吸收的影响,同时讨论了Cd2+毒害的作用机理。结果表明,中、低浓度(10-6、10-5mol·L-1)Cd2+胁迫下,玉米幼苗MDA含量与对照组相比没有显著变化;高浓度(10-4mol·L-1)Cd2+胁迫后,MDA含量显著升高(P<0.05)。Cd2+胁迫初期,超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)活性均升高;随着胁迫时间的延长,除叶片中SOD和CAT活性略有上升外,其他抗氧化酶活性逐渐下降,高浓度组抗氧化酶活性下降最明显。植物吸收的Cd主要积累在根部,Cd2+胁迫能干扰玉米对Fe、Cu、Zn、Mg等养分的吸收。

The effects of different concentrations of Cd2（＋10-6,10-5,10-4 mol·L-1）on antioxidant enzyme system,and malondialdehyde content in maize seedlings were investigated using water culture method,as well as the Cd accumulation and its effects on mineral element uptake by ICP-AES.The results indicated that the content of MDA was not affected significantly when maize seedlings were stressed by 10-6 and 10-5 mol·L-1 of Cd2＋ in comparison with the control,and increased significantly by 10-4 mol·L-1 of Cd2（＋P0.05）.The activities of superoxide dismutase（SOD）,peroxidase（POD）and catalase（CAT）in maize seedlings increased at the early days,and decreased with prolonging duration of Cd treatment except for SOD and CAT in leaves,and decreased the most at the highest concentration.Cadmium absorbed by the seedlings accumulated mostly in roots,and the Cd2＋ stress affected absorption of Fe,Cu,Zn and Mg.The contents of Fe,Cu,Zn of leaves were not affected significantly at 10-6 and 10-5 mol·L-1 of Cd2＋.Cadmium stimulated the absorption of Fe,Cu and Zn in roots,especially Fe in roots.The content of Mg in roots and leaves was stimulated by lower concentration of Cd2＋ and inhibited by higher concentration of Cd2＋.The mechanism of Cd2＋ toxicity was briefly discussed in the end.