怀地黄连作对土壤微生物区系的影响

运用传统平板培养方法及变性梯度凝胶电泳(DGGE)分析法对地黄的连作问题进行了研究.结果表明,地黄连作引起土壤根际、根外细菌数量减少;根际放线菌数量增加,根外数量变化不大;真菌种类和数量都有较大变化.DGGE分析表明,头茬和重茬地黄生长过程中根际土壤微生物区系发生了明显变化,细菌数量减幅较大,有些条带消失,说明种群数量减少;放线菌种群没有大的变化,数量有所上升;真菌数量有所增加,种群发生了明显改变,表现为条带的缺失和增加.地黄连作后土壤微生物多样性发生了较大变化,细菌数量减少,木霉和黄曲霉数量增加,土壤生态系统已开始失调,这可能是地黄连作障碍产生的原因.

Effects of Rehmannia glutinosa Libosch.Continuous Cropping on Microbial Communities

The variation of rhizosphere and non-rhizosphere microbial population was analyzed in response to Rehmannia glutinosa continuous cropping problem.Analysis using plate count revealed a reduction trend in the number of culturable bacteria both in rhizosphere and bulk soil as Rehmannia glutinosa continuous cropping problem.Culturable actinomyces increased with the developing of Rehmannia glutinosa.Fungal species and number changed greatly.DGGE analysis about continuous cropping soil revealed a great population shift in rhizosphere microorganisms.Most bacteria populations changed greatly.And some DGGE strip disappear ance showed that some bacteria species diminished.Actinomyces species didn't change too much.But its number rose during Rehmannia glutinosa growth.The fungi number increased.Some DGGE strip lack or increase showed that fungus group had changed differently in rhizosphere and non-rhizosphere soil.In short,microbial diversity in soil changed after Rehmannia glutinosa continuous cropping.Soil ecosystem began to show disorders which may result in continuous cropping obstacles to Rehmannia glutinosa.