土壤不同镉水平对马缨丹生长及其抗氧化酶活性的影响

采用盆栽试验方法,分别设置0(对照,不添加镉)、30、60、90、120、150、180、210mg·kg-1共8个土壤镉处理水平,研究土壤不同镉水平对马缨丹(Lantana comara L.)生长及其抗氧化酶活性的影响,以探讨马缨丹对镉胁迫的生理响应机制。结果显示:(1)随着土壤镉处理浓度的升高,马缨丹干重呈先升高后降低的趋势,30mg·kg-1镉处理能促进植株的生长,而浓度高于60mg·kg-1时显著抑制马缨丹的生长。(2)马缨丹叶片和根系中O-·2产生速率、H2O2和MDA含量及电解质渗漏率均随土壤镉处理浓度的升高和胁迫时间的延长逐渐升高,胁迫90d时,叶片和根系中O-·2产生速率、H2O2和MDA含量及电解质渗漏率分别在镉浓度高于60和30mg·kg-1时显著低于对照。(3)叶片和根系抗氧化酶SOD、POD、APX和CAT活性随着土壤镉处理浓度的增加大体呈先升高后降低的趋势,并在镉浓度分别高于90和60mg·kg-1时,叶片和根系抗氧化酶活性显著低于对照。研究表明,低浓度镉处理土壤能促进马缨丹植株生长,而高浓度镉处理土壤显著降低了马缨丹体内抗氧化酶活性,导致活性氧大量积累,引起严重的膜脂过氧化伤害,从而显著抑制马缨丹植株的生长。

Effect of Cadmium on Growth and Antioxidant Enzyme Activities of Lantana comara L.

In this study,a pot experiment was used to investigate the growth and antioxidant enzymes responses of Lantana comara L.under Cd treatment with different concentrations.The results showed that:(1)The dry weight of L.comara L.was increased at first and then decreased with the increasing of Cd concentrations.30 mg·kg^-1 Cd treatment can promote the growth of L.comara L.,but when the Cd concentration was higher than 60 mg·kg^-1,the growth of L.comara L.was inhibited significantly.(2)O^-·₂ production rate,H₂O₂ and MDA contents,and electrolyte leakage rate in leaves and roots of L.comara L.were enhanced by gradually increasing of Cd concentration and stress time.After 90 days of Cd stress,O^-·₂ production rate,H₂O₂ and MDA contents,and electrolyte leakage rate in leaves and roots were significantly lower than those of control when the Cd concentration higher than 60 and 30 mg·kg^-1,respectively.The activities of antioxidant enzymes such as SOD,POD,APX and CAT in roots and leaves of L.comara L.had a decline trend after an initial ascent with increasing of Cd concentration,and which were significantly lower than those of control when the Cd concentration higher than 90 and 60 mg·kg^-1,respectively.The above results revealed that low concentration of Cd treatment can promote the growth of L.comara L.,and the growth of L.comara L.was inhibited significantly under high concentration of Cd treatment.(3)High concentrations of Cd treatment significantly reduced the activities of antioxidant enzymes in L.comara L.,leading to accumulate mass of reactive oxygen species,induced severe membrane lipid peroxidation damage,thus the growth of L.comara L.was significantly inhibited.