乙酸添加对狗牙根抗氧化酶及土壤性质的影响

The Effect of Acetic Acid Addition on the Antioxidant Enzymes and Soil Properties of Cynodon dactylon

为探究在重金属污染土壤中,耐性植物对外源低分子量有机酸(LMWOAs)的生理响应及根际效应,该文通过盆栽试验,在500 mg/kg重金属铅污染的土壤中添加不同浓度的乙酸,分析狗牙根叶和根的抗氧化酶活性和根际土壤氮、磷含量和酶活性的变化。结果表明:(1)乙酸浓度为2.5 mmol/L时,狗牙根叶的超氧化物歧化酶(SOD)活性为对照组的1.52倍,此浓度下,叶中铅含量最低,较对照下降37.44%;(2)乙酸浓度为5 mmol/L时,叶的谷胱甘肽-S转移酶(GST)活性为对照组的1.6倍,根际土壤全磷含量较对照组升高18.35%;(3)乙酸浓度为7.5 mmol/L时,根的GST活性为对照组的1.72倍,根际土壤有效磷含量和酸性磷酸酶活性最高,较对照组分别升高50.23%和35.92%;(4)乙酸浓度为10 mmol/L时,根的过氧化物酶(POD)活性为对照组的1.5倍,根的铅含量最低,较对照下降61.96%,此浓度下根际土壤硝态氮含量最高,较对照组升高77.78%;(5)土壤添加乙酸后狗牙根根际土壤蔗糖酶活性都显著高于对照组。乙酸能有效提高狗牙根抗氧化酶系统的活性,降低狗牙根对铅的吸收富集量,显著提高了狗牙根根际土壤有效磷、硝态氮的含量以及土壤酸性磷酸酶和蔗糖酶的活性。通过使用乙酸处理污染土地或农田,在不影响环境安全及人畜健康前提下有效降低重金属及其他毒害元素对于作物以及环境造成危害,同时也为重金属污染土壤修复提供理论基础。

This study investigated the physiological responses and rhizosphere effects of tolerant plants to exogenous low mo⁃lecular weight organic acids(LMWOAs)in heavy metal contaminated soils.The antioxidant enzyme activities of Cynodon dactylon leaves and roots,and the changes of nitrogen,phosphorus,and enzyme activities in rhizosphere soil were studied by adding acetic acid at different concentrations in soil polluted by 500 mg/kg lead in a pot experiment.The results showed that after supplementing 2.5 mmol/L acetic acid,the activity of superoxide dismutase(SOD)in leaves was 1.52 times higher than that of the control,and Pb content in the leaves of Cynodon dactylon was the lowest,which was 37.44%lower than that of the control.The activity of glutathione-s transferase(GST)in the leaves of Cynodon dactylon was 1.6 times higher than that of the control,and the content of total phosphorus in rhizosphere soil increased by 18.35%compared with the control.The activity of GST in the roots of Cynodon dactylon was 1.72 times higher than that of the control,and the content of available phosphorus and the activity of acid phosphatase in rhizosphere soil were the highest,compared with the control group,increas⁃ing by 50.23%and 35.92%,respectively.When the concentration of acetic acid was 10 mmol/L,the peroxidase(POD)activity of the root was 1.5 times higher than that of the control group,and the content of Pb in roots of Cynodon dactylon was the lowest,which decreased by 61.96%compared with the control group.At this concentration,the content of nitrate nitrogen in rhizosphere soil was the highest,increasing by 77.78%compared with the control.The sucrase activity in the rhizosphere soil of Cynodon dactylon was significantly higher than that of the control after supplementing acetic acid with lead-contaminated soil.Acetic acid can effectively increase the activity of the antioxidant enzyme system of Cynodon dactylon and decrease the absorption and accumulation of Pb by it.The contents of available phosphorus,nitrate nitrogen,soil acid phosphatase,and sucrase activity in the rhizosphere soil of Cynodon dactylon were significantly increased.By using acetic acid to treat polluted land or farmland,it is possible to effective reduce the harm caused by heavy metals and other toxic elements to crops and the environment without compromising environmental safety and human and animal health,which also provides a theoretical basis for the remediation of heavy metal-contaminated soil.