镉胁迫对茶园土壤中养分和微生物区系及生理群的影响

以茶园土壤为研究对象,通过添加外源镉离子(Cd2+)溶液,研究了pH值分别为4和5两种环境下,不同添加量的Cd2+胁迫对茶园土壤中养分和微生物区系及生理群的影响.结果表明:茶园土壤中的速效钾、速效磷等养分呈下降趋势;不同种类的微生物对Cd2+的敏感性不同,Cd2+添加量升至0.4 g/kg时,细菌、亚硝化细菌数量呈快速下降趋势,而放线菌、真菌的数量有增加的趋势;Cd2+添加量继续升高时,细菌、放线菌、真菌的数量都呈缓慢下降趋势,亚硝化菌几乎不能成活,但放线菌、真菌相对能耐受较高浓度的Cd2+;不同的pH环境添加等量的Cd2+,微生物种群数量受抑制程度及变化趋势不同.

Influences of Cd2+ Stress on Nutrients and Flora and Physiological Groups of Microorganism in Tea Garden Soil

Adding exogenous Cd2+ solution to tea garden soil with pH 4 and pH 5 to investigate the influences of different dosages of Cd2+ on nutrients and flora and physiological groups of microorganisms in tea garden soil.The results showed that the nutrients in tea garden soil,such as available potassium,available phosphorus and so on,trended to decrease.Different kinds of microorganism had different sensitivities to Cd2+,when the dosage of Cd2+ was 0.4 g/kg,the number of bacteria and nitrosobacteria declined quickly,while the number of actinomycetes and fungi had a trend of increase;with a further increasing dosage of Cd2+,the number of bacteria,actinomycetes and fungi all slowly decreased,while nitrosobacteria barely survive,but actinomycetes and fungi had better tolerance to high concentration of Cd2+.Adding same dosage of Cd2+ to different pH environments,inhibition degree and variation trend of microbial population number were different.