镉污染对甘蔗生长、土壤微生物及土壤酶活性的影响

摘要

[Objective] To provide a reference for exploring the inner relationship between Cd pollution and sugarcane growth,Cd pollution and microbial properties,the effects of adding different concentrations of exogenous cadmium (Cd) on the growth of sugarcane,the number of soil microbes and the activity of soil enzymes were studied.[Method]The sugarcane plant height,stem diameter,the yield of cane,the soil microbial quantity and enzyme activity were determined by using sugarcane as material treated with different Cd concentration (0,25,50,100,250,500 mg/kg) under potted conditions.[Result] The results showed that the plant height,stem diameter and the yield of sugarcane decreased with the increase of Cd concentration in the soil,the higher the Cd concentration,the more obvious the inhibition effect.The Cd pollution changed the enzyme activity,and the activity of urease and acid phosphatase was significantly decreased with the increase of Cd concentration especially when Cd concentration reached 100 mg/kg.The sensitive order of the two soil enzymes to Cd was urease ＞ acid phosphatase.Cd pollution also changed the soil microbial quantity.Fungi,bacteria and actinomycetes significantly decreased at the Cd concentration level of 100 mg/kg.There were significant and highly significant correlations between Cd contamination concentration and Fungi,bacteria,actinomycetes,activities of urease and acid phosphatase,plant height,stem diameter as well as cane yield.[Conclusion] Under the conditions of potted planted sugarcane,the effects of exogenous Cd pollution on the growth of sugarcane,the number of soil microbes and soil enzyme activities were different.%[目的]研究添加不同浓度外源镉(Cd)对甘蔗生长情况、土壤微生物数量及土壤酶活性的影响,为探讨Cd污染与甘蔗生长、土壤微生物学特性之间的内在关系提供参考.[方法]盆栽条件下,以糖料甘蔗为材料,采用不同Cd浓度(0、25、50、100、250、500 mg/kg)进行污染处理至甘蔗成熟期,测定其株高、茎径、蔗茎产量、土壤微生物数量及土壤酶活性.[结果]甘蔗株高、茎径和蔗茎产量随着土壤中Cd浓度的增加而降低,Cd浓度越高,抑制效应越明显;Cd污染使酶活性发生变化,随着Cd浓度的增大,特别达到100 mg/kg时,脲酶、酸性磷酸酶活性显著下降,2种土壤酶对Cd的敏感顺序为:脲酶＞酸性磷酸酶.Cd污染也使土壤微生物数量发生变化,真菌、细菌和放线菌量在镉浓度100 mg/kg时显著下降.相关性分析表明,真菌、细菌、放线菌、土壤脲酶活性、酸性磷酸酶活性、株高、茎径、蔗茎产量与Cd污染浓度相关显著或极显著.[结论]在盆栽种植甘蔗条件下,外源Cd污染对甘蔗生长情况、土壤微生物数量及土壤酶均产生不同程度地影响.