[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.
[Objective] To provide a reference for exploring the relationship between Cd contamination and sugarcane growth and between Cd contamination and microbial properties of soil, the effects of adding different concentrations of exogenous cadmium (Cd) on the growth of sugarcane, the quantities of soil microorganisms and the activity of soil enzymes were studied. [Method] The plant height, stem diameter and cane yield of sugarcane, the soil microbial quantities and enzyme activities were determined by using sugarcane as a material treated with different Cd concentrations (0, 25, 50, 100, 250 and 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, and the higher the Cd concentration, the more obvious the inhibitory effect. The Cd contamination changed the enzyme activity, and the activities of urease and acid phosphatase significantly decreased with the increase of Cd concentration, especially when the Cd concentration reached 100 mg/kg. The sensitivity of the two soil enzymes to Cd ranked as urease>acid phosphatase. Cd contamination also changed soil microbial quantities. 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 and actinomycetes, the activities of urease and acid phosphatase, plant height, stem diameter as well as cane yield. [Conclusion] Under the conditions of potted planted sugarcane, exogenous Cd contamination affected the growth of sugarcane, the quantities of soil microorganisms and soil enzyme activities to different degrees.