溶磷细菌和丛枝菌根真菌接种对南方红豆杉生长及根际微生物和土壤酶活性的影响

以南方红豆杉实生苗为材料,采用盆栽实验探讨了高效溶磷细菌草木樨中华根瘤菌(Sinorhizobium meliloti)CHW10B与丛枝菌根真菌缩球囊霉(Glomus constrictum)单独和双接种条件下,其植株生长、根际土壤可培养微生物数量、土壤酶活和土壤微生物功能多样性变化,在微生态水平揭示接种对南方红豆杉生长的影响及其机制。结果表明:(1)各接种处理对南方红豆杉幼苗均有促生长作用,接种处理苗高、地径和生物量均较对照显著增加,并以双接种促进效果最好。(2)各接种处理提高了南方红豆杉根际土壤可培养细菌、真菌和放线菌含量,增加了土壤微生物碳源利用率,改变了土壤中物种的丰富度和均一度,增加了土壤中的生物多样性。(3)各接种处理促进了南方红豆杉根际重要土壤酶(酸性磷酸酶、脱氢酶、转化酶)活力的增加,且双接种的促进作用最为明显。可见,溶磷细菌(草木樨中华根瘤菌CHW10B)和丛枝菌根真菌(缩球囊霉)具有协同作用,两者同时接种可显著提高南方红豆杉根际土壤微生物数量及土壤酶活力,提高土壤微生物碳源利用率和土壤肥力,增加土壤中的生物多样性,从而达到间接促进宿主植物南方红豆杉生长的目的。

Effects of PSB and AMF on Growth,Microorganisms and Soil Enzyme Activities in the Rhizosphere of Taxus chinensis var.mairei Seedlings

In order to make certain the effects of inoculations in the seedlings of Taxus chinensis var.mairei at the micro-ecological level,we studied the number of culturable microorganisms,the enzyme activity and the soil microbial functional diversity of rhizosphere soil,after inoculated with Sinorhizobium meliloti CHW10B (phosphate solubilizing bacteria,PSB) and/or Glomus constrictum (arbuscular mycorrhizal fungi,AMF).The results showed that:(1)inoculation had significant growth-promoting effects in Taxus chinensis var.mairei.The height,ground diameter and biomass of the inoculated groups had significantly increased when compared with the control group.(2)The number of culturable bacteria,fungi and actinomycetes contents in the rhizosphere soil of Taxus chinensis var.mairei were higher obviously compared with those of the control with the extension of time.Inoculation can improved the soil microbial carbon utilization,changed the species richness of soil and increased the soil biodiversity.(3)Inoculation increased the activities of enzymes in the soil,included acid phosphatase,dehydrogease and invertase.All these benefits are especially for co-inoculation treatment.These results indicated there were synergistic benefits between PSB (Sinorhizobium meliloti CHW10B) and AMF (Glomus constrictum).Moreover,the growth-promoting effect of co-inoculation depend on the increase of the number of culturable microorganisms in rhizosphere soil of Taxus chinensis var.mairei,soil enzyme activity and soil biodiversity which lead to soil enhancement of microbial carbon utilization and soil fertility.