淡紫拟青霉在烤烟根际定殖能力分析

通过盆栽试验,确定了烟草根结线虫生防菌淡紫拟青霉IPC菌株在烤烟K326和云85根际的生长和定殖情况及其对根际微生物的影响.结果表明,施入菌剂2周和4周时淡紫拟青霉IPC菌株能在烤烟K326外根际、根表分离到,根内则不能分离到;而不同时期在烤烟云85的外根际、根表和内根际都能分离到.在6周时2种烤烟的外根际、根表和根内的分离数达到最大,8周时分离数减少.每个时期在2种烟草根际分离到IPC菌株的菌落繁殖单位(CFU)都是外根际最大,其次是根表,内根际最小.IPC菌剂处理后烤烟根际细菌、真菌和放线菌的数量在2周比对照减少,4周时比对照增多,6周和8周时与对照接近.表明生防菌淡紫拟青霉IPC菌株可以在烟草外根际、根表定殖和生长,而在根内则较困难,菌剂施用2周时对根际土壤微生物具有一定的抑制作用,4周后抑制作用减弱.

Studies on the interactions of Paecilomyces Lilacinus (Thom) samson IPC and tobacco rhizosphere

By using pot experiment, the growth and the colonization of Paecilomyces lilacinus (Thom) Samson IPC on the rhizosphere of flue-cured tobacco K326 and Yun85 and its influence on the rhizospheric microbes were determined. The results indicated that IPC were isolated from rhizoplane and ectorhizosphere of flue-cured tobacco K326 but could not be from its endorhizosphere in the second and fourth weeks post inoculation respectively. However, it could be isolated from rhizoplane, ectorhizosphere and endorhizosphere of Yun85 at different periods. The colony forming units of IPC on rhizoplane, ecterhizosphere and endorhizosphere of two flue-cured tobacco reached the biggest volume in the sixth week. By eighth week, the colony volume decreased. In each period, the CFU isolated of two flue-cured tobacco reached the biggest volume on the rhizoplane, less on ectorhizosphere, and least on the endorhizosphere. The amount of fungi, bacteria and actinomyces on tobacco rhizosphere after IPC treatment decreased in the second week, increased in the fourth week and reached nearly the same level to that of the control at six and eight weeks. This study suggested that the biocontrol strain P. lilacinus IPC could colonize and grow on rhizoplane and ectorhizosphere of tobacco, which inhibited soil microbes at early stage.