食细菌线虫对土壤微生物量和微生物群落结构的影响

线虫与微生物的相互作用研究往往是在悉生培养体系 (gnotobiotic microcosm)中进行 ,为了研究在自然或开放土壤条件下土壤线虫与微生物的相互作用 ,作者在开放盆栽体系中接种土壤食细菌线虫 (原小杆线虫 ,Protorhabditis sp) ,研究在小麦不同生育期、在有和无根系作用下食细菌线虫对土壤微生物量和微生物群落结构的影响。结果表明 :接种线虫分别使 SMBC、SMBN、SMBP提高了 2 6 .4 %、32 .9%、2 1.8% ,这种促进作用除个别无根系土和非根际土处理外 ,均达到显著性差异。根际土中的 SMBC、SMBN、SMBP>非根际土 >无根系土。从方差解释比例 v来看 ,SMBN受线虫的影响最大 (v=2 4 % )、其次是 SMBC(v=16 % )、然后是 SMBP(v=12 % ) ,线虫对 SMBC的促进作用在根际土中最突出。接种线虫对土壤细菌、真菌和放线菌的数量有明显的影响。在苗期的无根系土和根际土中 ,接种线虫显著降低了细菌的数量、特别在根际土中尤为突出 ,但在其它处理中却增加了细菌的数量。接种线虫对真菌和放线菌数量的促进作用比对细菌更为明显 ,接种线虫后真菌和放线菌数量的总平均值分别比未接种提高了 4 8.5 %和 6 8.2 % ,而细菌数量的总平均值没有变化。细菌数量与微生物量 C相关散点图表明二者相关性在根际土、非根际土和无根系土中均未

Effect of bacterivorous nematode on soil microbial biomass and microbiocoen-(osis)

Researches on the interaction between nematodes and microbes were usually carried out in gnotobiotic microcosm, in order to know the interaction in open soil system, we inoculated bacterivorous nematode (Protorhabditis sp) into the open soil system with and without wheat to study the effects of bacterivorous nematodes and their interactions with roots on soil microbial biomass and microriocoenosis at different growth stages of wheat. The results indicated that, the inoculation of bacterivorous nematodes increased the content of SMBC, SMBN and SMBP by 26.4%, 32.9% and 21.8% respectively, and the difference were obviously in most treatments except some treatments of bulk soil and soil without plant. The content of SMBC, SMBN and SMBP in rhizosphere soil were much more than that in the bulk soil and soil without plant. The influence of nematode inoculation on SMBC, SMBN and SMBP was in the sequence of SMBN> SMBC> SMBP, and the influence of nematode inoculation on SMBC was most obvious in rhizosphere soil. The inoculation of bacterivorous nematodes had significant effects on bacteria, fungi and actinomycetes number. The bacteria number significantly increased in treatments with nematodes except in rhizosphere soil at seedling stage of wheat. The influence of nematode inoculation on fungi and actinomycetes number was bigger than on bacteria number, the fungi and actinomycetes number were increased by 48.5% and 68.2% respectively. There was no significant correlation between bacteria number and SMBC content in all treatments, while there were significant correlation between fungi number and SMBC content in rhizosphere soil and bulk soil and significant correlation between actinomycetes number and SMBC content in soil without plant.