Effect of Pb on leaf antioxidant enzyme activities and ultrastructure of the two ecotypes of Sedum alfredii Hance
Effect of Pb on leaf antioxidant enzyme activities and ultrastructure of the two ecotypes of Sedum alfredii Hance
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DOI：
10.1007/s11183-008-1008-1
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发表时间：
2008
影响因子：
1.4
通讯作者：
D. Liu;T. Q. Li;X. Yang;E. Islam;X. Jin;Q. Mahmood
中科院分区：
文献类型：
--
作者：
D. Liu;T. Q. Li;X. Yang;E. Islam;X. Jin;Q. Mahmood
通过水培试验，研究了铅对东南景天（Sedum alfrediHance）积累型和非积累型生长、叶片抗氧化酶活性及超微结构的影响。AE被认为是更宽容的生长培养基中过量的铅水平。当铅浓度为0.2 mM时，在芽中的AE是1.98倍高于那些在NAE。铅处理后，AE植株叶绿素a和b均未显著下降，而当铅浓度大于0.05 mM时，NAE植株叶绿素a和b显著下降。结果表明，铅胁迫下，AE叶片超氧化物歧化酶（SOD）和过氧化氢酶（CAT）活性升高。而在NAE中，铅处理只提高了SOD活性，而CAT活性则下降。随着铅胁迫水平的增加，两种生态型的丙二醛（MDA）含量均显著增加。表明铅毒害导致了膜脂过氧化和膜损伤，但NAE植株叶片中MDA含量始终高于AE植株。海绵叶肉细胞的超微结构分析表明，过量的铅浓度明显损害细胞膜，叶绿体和线粒体的两个生态型，但损害更严重的NAE。虽然生长，叶片生理和超微结构的两个生态型的铅处理的影响，在NAE的有害影响更为明显。
Hydroponic experiments were conducted to study the effect of Pb on growth, leaf antioxidant enzyme activities, and ultrastructure of the accumulating ecotype (AE) and non-accumulating ecotype (NAE) ofSedum alfrediiHance. AE was found to be more tolerant to excessive Pb levels in growth medium. Concentrations of Pb in the shoots of the AE were 1.98 times higher than those in the NAE when 0.2 mM Pb was supplied. Both chlorophyllaandbdid not decrease significantly in AE plants after Pb treatment, while a significant decrease was noted in chlorophyllaandbof NAE plants treated with Pb concentrations greater than 0.05 mM. The results showed that activities of superoxide dismutase (SOD) and catalase (CAT) were elevated in the leaves of AE under Pb stress. However in NAE, Pb-caused enhancement was noticed only in the activity of SOD while activity of CAT was declined as compared to the control plants. With increased Pb level, malondialdehyde (MDA) content increased significantly in both ecotypes ofS. alfredii, indicating that Pb toxicity led to lipid peroxidation and membrane damage, but MDA content in the leaves of NAE was always higher than in AE plants. The ultrastructural analysis of the spongy mesophyll cells revealed that excessive Pb concentrations obviously damaged the cell membrane, chloroplasts, and mitochondria of both the ecotypes but damage was more severe in NAE. Although growth, leaf physiology, and ultrastructure of both the ecotypes were affected by Pb treatment, deleterious effects were more pronounced in NAE.