2,4-D丁酯胁迫下土壤微生物对外源物质的响应

为了解2,4-D对土壤微生物生态特征效应.通过盆栽试验,采用三因素完全随机设计,平板菌落计数法对不同时间土样进行土壤细菌、放线菌、真菌数量的测定.研究了2,4-D胁迫下添加尿素、多效唑对土壤微生物的影响,揭示了土壤细菌、放线菌、真菌在2,4-D胁迫下添加尿素、多效唑的动态变化.结果表明,高浓度2,4-D胁迫下,1～60 d明显抑制了细菌的生长,对放线菌、真菌的生长呈先刺激后抑制的作用,直到第60天3种菌均未恢复到对照水平;低浓度2,4-D胁迫下,1～60 d对细菌、放线菌、真菌均呈抑制效应.添加尿素、多效唑刺激了土壤细菌、放线菌、真菌的繁殖,2,4-D+尿素、2,4-D+尿素+多效唑2种处理对3种菌的刺激效应更为显著,与对照相比,对细菌和放线菌的刺激效应极显著,在1～60 d平均最高激活率达396.5%和125.9%.

The Responses of Soil Microbes to Exogenous Materials Under 2,4-D Stress

This experiment was carried out in pot culture test, by using three - factor completely randomized design and plate culture count to measure the number of soil bacteria, actinomyces and fungus sampled at different time. This re-search studied the influences when adding carbamide and under 2,4-D stress on soil microbes, which revealed the dynam-ic changes of soil bacteria,actinomyces and fungus when adding carbamide and under 2,4-D stress.The results showed that significant inhabitation to growth of soil bacteria were found from one to sixty days under high-concentration 2,4-D stress,but for actinomyces and fungus stimulation at first then inhibition later,three bacteria didn't recovery to the level of control until 60th day;However,under low-concentration 2,4-D stress,inhibiting effects appeared to all these three bacte-ria from 1 to 60 days.So it is concluded that adding carbamide and could stimulate the reproduction of bacteria,actino-myces and fungus,and stimulating effects to the three bacteria of mixed 2,4-D and carbamide or mixed 2,4-D and car-bamide and were more significant, Compared with the control, the stimulating effects to bacteria and actinomyces were sig-nificant at 0.01 level,the average highest activation rate reached 396.5 percent and 125.9 percent from 1 to 60 days.