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用5个级别的人工复合重金属污水处理红树植物木榄Bruguiera gymnorrhiza幼苗,2个月后对其叶片和根系中的保护酶SOD、POD和CAT活性变化以及对膜脂质过氧化作用的影响进行分析。结果显示,当污染级别不大于5倍污水时,根系中SOD活性随污染程度的增加而增加,污染程度再升级其活性迅速下降但仍高于对照组水平;叶片中SOD活性在1倍污水时与对照组相比有所下降,随后的变化与在根系中的变化相似。POD活性在根系和叶片中的变化相对一致,均随污染级别的增加而升高;但在叶片中的变化幅度大于根系中的变化幅度。CAT活性在叶片中不受污染程度的影响,保持平稳,但在高程度污染下活性有下降趋势;而根系中CAT活性在10倍污水时达到最大值,污染程度再升级其活性下降。叶片中膜脂质过氧化作用随污染程度的增加而加剧,MDA的积累增加;但根系中MDA含量在5倍污水时最少,只为对照组的21.98%,其后随着污染程度的增加其MDA含量大幅度积累,膜脂质过氧化作用加剧。从整个试验结果分析认为,木榄在遭受重金属胁迫时具有优先保护根系以增强植物的抗重金属能力。
The effects of five levels of artificial composite heavy metal wastewater treatment of mangrove Bruguiera gymnorrhiza seedlings on the activity of protective enzymes SOD, POD and CAT and their effect on membrane lipid peroxidation in leaves and roots were studied after two months analysis. The results showed that when the pollution level was not more than 5 times of sewage, the activity of SOD in roots increased with the increase of pollution degree. However, the activity of SOD decreased rapidly but was still higher than that of the control. There was a decrease compared with the control group, with subsequent changes similar to those in the root system. The changes of POD activity in roots and leaves were relatively consistent, both increased with the increase of pollution level. However, the changes in POD activity were greater than those in roots. The activities of CAT in the leaves were not affected by the degree of pollution, and remained stable, but the activity decreased with the high degree of pollution. CAT activity in the roots reached the maximum at 10 times of the sewage, and the activity was decreased after the pollution was increased. Membrane lipid peroxidation in leaves increased with the increase of pollution degree, and the accumulation of MDA increased. However, the content of MDA in roots was the least, which was only 21.98% of that in control group, and then increased with the increase of pollution level Significant accumulation of MDA content, membrane lipid peroxidation intensified. According to the results of the whole experiment, the root system of M. przewalskii is preferentially protected when exposed to heavy metal stress so as to enhance the plant’s ability to resist heavy metals.