重金属镉胁迫臭牡丹根系及其土壤生化指标的变化

Biochemical Indexes Variation of Root System and Soil of Clerodendrum bungei Under Cadmium Stress

为重金属镉污染土壤的植物修复及野生臭牡丹的综合利用提供参考,以野生臭牡丹植株为试验材料,采用盆栽土培法模拟研究不同镉浓度胁迫臭牡丹,对其根系质膜透性、土壤电导率及土壤不同酶活性等的影响。结果表明:随着镉胁迫时间的延长,臭牡丹根系土壤的过氧化氢酶、脲酶和碱性磷酸酶活性均呈先升高后降低趋势。在镉浓度为0.90 mmol/L时,胁迫24d土壤过氧化氢酶活性比胁迫12d的高40.35%;在胁迫36d时,土壤过氧化氢酶的活性明显降低,并表现出明显抑制效应。土壤碱性磷酸酶活性在不同镉浓度胁迫24d时,以镉浓度为0.10mmol/L时最高,比未施镉(CK)升高62.31%。土壤脲酶活性在不同镉浓度胁迫24d时,以镉浓度为0.10mmol/L时最高,比CK升高67.31%,在胁迫36d时比CK降低23.35%。随着镉浓度增加和胁迫时间延长,臭牡丹根系的质膜透性升高,在胁迫36d时,镉浓度为0.90mmol/L的臭牡丹根系质膜透性比CK升高114.71%。土壤电导率在镉胁迫12d时的变化较小,但随着镉胁迫时间延长,其增幅较大;在镉胁迫36d时,喷施镉浓度为0.30 mmol/L、0.60 mmol/L和0.90mmol/L臭牡丹根系质膜的透性增幅明显,比CK分别升高246.27%、256.26%和285.28%。

In order to provide references for phytoremediation of Cd contaminated soil and integrated utilization of Clerodendrum bungei,a pot experiment was conducted to explore the root membrane permeability,soil electrical conductivity and enzyme activities of C.bungei under stress of different Cd concentrations.Results： Under such stress of Cd,the activities of catalase,urease and alkaline phosphatase of C.bungei generally rose first and then fell.When the Cd concen tration was 0.90 mmol/L,soil catalase activity stressed for 24 dwas higher than that stressed for 12 dby 40.35%,which obviously decreased when stressed for 36 d,showing obvious inhibition effect.Alkaline phosphatase activity of soil stressed for 24 dreached the highest when the Cd concentration was 0.10 mmol/L,67.31% higher than CK,while 23.35% lower than CK when stressed for 36 d.With Cd concentration increasing and stress time prolonging,the root membrane permeability of C.bungei increased,114.71% higher than CK under stress of 0.90 mmol/L Cd for 36 d.Soil conductivity varied slightly under Cd stress for 12 d,and increased with stress time;The membrane permeability of C.bungei increased obviously under stress of different concentrations of Cd（0.30 mmol/L,0.60 mmol/L and 0.90 mmol/L）for 36 d,higher than CK by246.27%,256.26% and 285.28%respectively.