间作绿肥对香蕉生长与根际土壤微生物群落结构的影响

Effects of intercropping green manure on growth and rhizosphere soil microbial community structure of banana

  • 摘要: 【目的】探究间作绿肥对香蕉生长和根际土壤微生物群落结构影响,为香蕉间作绿肥模式推广应用提供理论依据。【方法】以皇帝蕉及红三叶、假花生、蟛蜞菊和尖叶猪屎豆4种绿肥为试验材料,测定小区香蕉移栽1、2和3个月后间作4种绿肥的抽蕾期香蕉地上部和根系生物量及单株养分累积量,对大田2个月苗龄香蕉间作4种绿肥近根系区域和香蕉—绿肥根系共生区土壤微生物群落进行α多样性分析、土壤微生物群落主坐标(PCoA)分析和操作分类学单元(OTUs)聚类分析,并分析土壤细菌和真菌门和属水平结构组成、相对丰度及根系分泌物种类数和分布。【结果】小区试验结果显示,与小区香蕉单作(CK1)相比,移栽2个月间作猪屎豆分别显著提高香蕉地上部分生物量、根系生物量、单株氮和钾累积量61.69%、117.72%、38.71%和64.81%(P<0.05,下同),移栽3个月显著提高47.97%、67.79%、34.53%和52.04%。大田试验结果显示,香蕉—绿肥土壤细菌和真菌群落结构与大田香蕉单作(CK2)明显分离,共生区较CK2提高土壤细菌群落ACE指数5.53%~26.93%和Shannon指数8.78%~14.52%,而近根系区降低ACE指数23.69%~32.21%和Shannon指数11.70%~18.85%;与CK2相比,种植绿肥放线菌门相对丰度提高17.97%~73.97%,根系共生区变形菌门丰度降低12.32%~27.92%;香蕉间作假花生和蟛蜞菊的芽孢杆菌属(Bacillus)相对丰度分别提高82.09%~260.14%和0.85%~25.20%;香蕉间作绿肥降低了真菌病原菌柄锈菌属(Puccinia)相对丰度94.48%~99.37%。间作绿肥与CK2相比,近根系区酸类物质含量比根系共生区高7.06%~41.84%;间作红三叶和猪屎豆近根系区糖类物质含量与根系共生区分别高88.11%和64.19%。【结论】香蕉移栽后不同时期间作绿肥对香蕉地上部分、根系生长和养分累积影响不同,猪屎豆适合香蕉移栽后2个月间作,红三叶、蟛蜞菊和假花生适合香蕉移栽后3个月间作,香蕉间作绿肥可降低共生区有机酸含量和变形菌门相对丰度,提高放线菌门和芽孢杆菌属相对丰度,促进香蕉根系生长并增强抗病性。

     

    Abstract: 【Objective】 This research studied the effects of intercropping green manure on the growth of banana and rhizosphere soil microbial community structure, to provide theoretical basis for the application and introduction of banana intercropping green manure model.【Method】 The experiment was conducted to study the aboveground part biomass, root part biomass and nutrient accumulation per plant of banana at bud stage which intercropped with four green manuresTrifolium pratense L., Arachis duranensis Krap.et Greg, Sphagneticola calendulacea(L.) Pruski, Crotalaria pallida Ait. at the stage after 1, 2, 3 months of transplanting. Analysis of α diversity, principal coordinate analysis(PCoA) and operational taxonomic units(OTUs) cluster analysis were conducted for soil microbial community in banana-green manure symbiotic area, with banana at 2 months intercropping with four green manures in the field. The horizontal fungus structure composition, relative abundance, species number and distribution of root exudates of phylum and genus levels were analyzed.【Result】 Plot experiment showed that, compared with banana monoculture in plot(CK1), the above-ground part biomass, root part biomass and nitrogen and potassium accumulation per plant of bananas intercropped with C. pallida after 2 months of transplanting significantly improved by 61.69%, 117.72%, 38.71% and 64.81% respectively(P<0.05, the same below). Those of bananas intercropped with C. pallida after 3 months of transplanting significantly increased by 47.97%, 67.79%, 34.53% and 52.04% respectively. Through field experiment, it was found that the community structure of bacteria and fungi in banana-green manure soil was obviously separated from monoculture banana in field (CK2). Compared with CK2, the ACE index and Shannon index of soil bacterial community increased by 5.53%-26.93% and 8.78%-14.52% in the symbiotic area, and ACE index decreased by 23.69%-32.21% and shannon index decreased by 11.70%-18.85% in the near-root area. Compared with CK2, the relative abundance of Actinobacteria increased by 17.97%-73.97% by planting green manure, and the relative abundance of Proteobacteria in root symbiotic area decreased by 12.32%-27.92%. The relative abundance of Bacillus was increased by 82.09%-260.14% and 0.85%-25.20% by intercropping with A. duranensis and S. calendulacea respectively. The relative abundance of Puccinia decreased by 94.48%-99.37% by intercropping with green manure. Intercropping green manure compared with CK2, the content of acids in near-root area was 7.06%-41.84% higher than that in root symbiotic area. The content of carbohydrates substances in the near-root area of intercropping with T. pratense and C. pallida was 88.11% and 64.19% higher than that in symbiotic area respectively.【Conclusion】 The effects of intercropping green manure on the banana growth of above-ground part, root part and nutrient accumulation are differentat diverse stage after banana transplanting.C. pallidais suitable for intercropping 2 months after banana transplanting.T. pratense, S. calendulacea and A. duranensisare suitable for intercropping 3 months after banana transplanting. Banana intercropping green manure can reduce the organic acid contents and the relative abundance of Proteobacteria, increase the relative abundance of Actinobacteria and Bacillusin the symbiotic area, promoting banana root growth and improving banana disease resistance.

     

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