菌肥对青稞根际土壤理化性质以及微生物群落的影响

【摘要】应用化学分析、聚合酶链反应-变性梯度凝胶电泳(PCR-DGGE)技术和DNA测序技术,研究了西藏棕色砂壤土中微生物肥料不同施用量和施用期对青稞根际土壤理化性质和细菌群落多样性的影响。结果表明,施用谷特菌肥能显著提高土壤全氮、全磷、全钾、有机质、碱解氮、有效磷和速效钾的水平,如播前施用菌肥浓度750 ml hm-2的处理较不施用菌肥的处理上述指标分别提高13.32%、28.42%、16.20%、9.81%、21.36%、39.35%和30.48%,拔节期施用菌肥浓度2 250 ml hm-2的处理较不施用菌肥的处理分别提高7.25%、29.35%、18.04%、12.86%、15.90%、43.27%和53.99%。DGGE分析表明,相同施用方式中不同施用量土样中微生物的DGGE图谱相似。非加权组平均法(UPGMA)聚类分析将DGGE图谱分为2大类群。Shannon-Wiener指数表明,施用菌肥的土壤细菌多样性先增加后逐渐降低,播前以喷施谷特菌浓度750 ml hm-2时的细菌多样性最高;拔节期则以喷施谷特菌浓度2 250 ml hm-2处理的细菌多样性最高,且两种施用方式土壤养分的释放与Shannon指数的变化规律均为播前﹥拔节期。测序结果表明,不同施肥浓度土样微生物种群分布较为广泛,其中Actinobacteria纲细菌种类略多,少数菌种为未经培养菌种(Uncultured bacterium)。典型对应分析(CCA)表明,DGGE图谱条带分布与土壤理化性质密切相关,碱解氮、全磷和全氮是影响微生物群落的主要环境因子。研究结果表明,施用谷特菌肥可明显改善青稞根际土壤理化性状,提高土壤细菌多样性。

【英文摘要】Chemical analysis, PCR-DGGE and DNA sequencing methods were used to investigate effects of bacterial manure varying in application rate and applied at diffentent time on soil physicochemical properties and microbial community diversity in the rhizosphere of highland barley in Tibet. Results show that application of bacterial manure significantly in- creased total N, total P, total K, organic matter, alkalytic N, available P and readily available K in the soil, for instance, by 13.32% , 28.42% , 16. 20%, 9.81% , 21.36% , 39. 35% and 30. 48% respectively over that in CK when 750 ml hm-z of bacterial manure was applied before sowing; and by 7.25% , 29. 35% , 18.04% , 12.86% , 15.90% , 43.27% and 53.99% , respectively, when 2 250 ml hm-2 of bacterial manure was applied at the jointing stage of the crop. DGGE analysis demonstrates that DGGE atlases of microorganisms in the soils the same in application method, were all quite similar regard- less of application rate. Cluster analysis with UPGMA sorted the DGGE atlases into two clusters. Shannon indices suggest that soil microbial diversity in soils applied bacterial manure increased first and decreased gradually afterwards. Application of 750 ml hm-2 of bacterial manure prior to sowing brought about the highest soil microbial diversity, while application of 2 250 ml hm-2 at the jointing stage did. Moreover, the former was higher than the latter in nutrient releasing and Shannon index as well. DNA sequencing shows that microbial populations were widely distributed and dominated with bacteria of Actinobacteria class, and a few uncultured strains in the soils applied with bacterial manure, regardless of application rate. Canonical corre- spondence analysis （CCA） reveals that the distribution of DGGE fingerprints was strongly related to physical and chemical properties of the soil. AN （ Alkalytic N） , TP and TN were the main environmental factors influencing structure of the micro- bial community. All the findings demonstrate that application of bacterial manure significantly improves physicochemical properties of the soil and microbial community diversity of the rhizosphere soil of highland barley.