摘 要 ：利用平板计数、微生物量碳和末端标记限制性片段长度多态性分析(terminal restriction fragment length polymorphism, T-RFLP)相结合的方法研究了2株生防菌哈茨木霉Th2和T4对甜瓜根围土壤微生态的影响。结果表明,生防菌Th2和T4对根围土壤细菌有明显的促生作用,而对真菌和放线菌有明显的抑制作用。T-RFLP数据统计学分析表明,Th2和T4的引入可以增加土壤细菌的多样性。其中对开花期土壤细菌菌群影响最显著,Th2对TRF251和TRF513菌群有显著的促生作用,含量是对照的3.7倍和4.5倍,T4对TRF251和TRF513菌群含量也比对照高4倍和5.6倍,而2株生防菌对TRF60菌群均有显著的抑制作用,其含量分别为对照的51.6％和64.3%。在果熟期生防菌对土壤细菌菌群的影响减弱,表明土壤的缓冲功能发挥了作用。研究结果还表明,Th2和T4对土壤细菌菌群有着相似的促生和抑制作用,且不会破坏土壤微生态的稳定性。
Abstract:The influence of two biocontrol agents Trichoderma harzianum Th2 and T4 on microecosystem of rhizosphere soil in melon was investigated by using plate culture, microbial mass carbon measurement and terminal restriction fragment length polymorphism(T-RFLP). It was demonstrated that Th2 and T4 can significantly prompted growth of bacteria but had strong growth inhibition effect on actinomycetes and fungi according to the result of plate culture and microbial mass carbon measurement. However, it was showed that introduction of the two biocontrol agents T.harzianum Th2 and T4, will increase the microecological diversity of rhizosphere soil in melon when T-RFLP and statistical method was employed. The both had intensively prompted the microecosystem of rhizosphere soil at blossom time of melon. In Th2 treatment, TRF251 and TRF513 flora was 3.7 and 4.5 times of the control respectively, and T4 treatment 4 and 5.6 times respectively . In addition to that the growth of TRF60 flora was heavily inhibited, TRF60 flora in Th2 and T4 treatment was respectively 51.6% and 64.3% of control. But the both had less effect on microecosystem of rhizosphere soil at fruitage time of melon. Th2 and T4 have similar mechanism of growth prompting or growth inhibition on soil bacteria, and they could not disharmonize the microecosystem of soil.