化肥减施与外源MeJA对连作草莓根际土壤微生物的影响

Effects of Chemical Fertilizer Reduction and Exogenous MeJA Addition on Rhizosphere Microorganisms in Continuous Cropping Strawberry

【目的】从土壤微生物角度理解化肥减施和外源茉莉酸甲酯(MeJA)消减作物连作障碍的机理。【方法】以连作4年草莓的土壤和红颜草莓为材料,通过分析草莓根际土壤微生物多样性、群落结构和草莓产量,以及土壤微生物群落与土壤理化性质的相关性,探讨化肥减施与外源MeJA对连作草莓根际土壤微生物的影响。【结果】①NMDS分析显示,不同处理土壤细菌群落结构存在差异;②化肥减施和外源MeJA,可以显著提高草莓根际土壤细菌群落的shannon指数、chao1指数和ACE指数;③RDA分析显示,土壤有效钾解释了土壤细菌群落34.5%和土壤真菌群落35.3%的变化;④化肥减施降低了草莓根际土壤的鞘氨醇单胞菌属(Sphingomonas)和芽单胞菌属(Gemmatimonas)的相对丰度(P<0.1),外源MeJA显著降低了芽单胞菌属(Gemmatimonas)的相对丰度;⑤化肥减施并未导致草莓经济产量和生物量显著下降,外源MeJA则显著提高草莓经济产量和生物量。【结论】化肥减施和外源MeJA可以提高连作草莓根际土壤的有机质含量和降低土壤氮磷钾元素含量,因此提高了连作草莓根际土壤的细菌群落丰富度和多样性,但并未明显影响真菌群落的丰富度和多样性。化肥减施和外源MeJA所带来的高肥“细菌型”土壤,可以缓解连作导致的根际土壤微生物区系真菌化,从而消减草莓连作障碍。

【Objective】In order to understand the mechanisms of chemical fertilizer reduction and exogenous methyl jasmonate(MeJA)addition on reducing crop continuous cropping obstacles from the perspective of soil microorganisms.【Method】4-years strawberry continuous cropping soil and"Hongyan"straw⁃berry were used as materials.The strawberry yield and the microbial diversity and community structure of strawberry rhizosphere soil,as well as the correlation between soil microbial community and soil physical and chemical properties were analyzed to explore the effects of chemical fertilizer reduction and exogenous MeJA addition on rhizosphere microorganisms of continuous cropping strawberry.【Result】①NMDS analysis showed that there were differences in soil bacterial community structure among different treatments;②Chemical fertilizer reduction and exogenous MeJA addition can increase the shannon index,chao1 index and ACE index of the strawberry rhizosphere bacterial community(P<0.15);③RDA analysis showed that soil available potassium,total potassium and organic matter explained 34.5%,16.3%and 12.2%of the varia⁃tion in soil bacterial communities,respectively;soil available potassium,alkaline nitrogen and total phospho⁃rus explained 35.3%,13%and 11.6%of the community variation of soil fungi,respectively;④Chemical fer⁃tilizer reduction can decrease the relative abundance of Sphingomonas and Gemmatimonas in the rhizosphere soil(P<0.1),and exogenous MeJA addition can significantly reduce the relative abundance of Gemmatimo⁃nas;⑤Chemical fertilizer reduction did not lead to a significant decrease in the economic yield and biomass of strawberry,while exogenous MeJA addition significantly increased the economic yield and biomass of straw⁃berry.【Conclusion】Fertilizer reduction and exogenous MeJA addition increased the organic matter con⁃tent and reduced the soil nitrogen,phosphorus and potassium content in inter-root soils of continuous strawberries.As a result,those applications increased the bacterial community richness and diversity in the inter-root soil of continuous strawberry,but did not significantly affect the fungal community.The high-fertilizer"bacterial"soils resulting from fertilizer reduction and exogenous MeJA addition can miti⁃gate the fungalization of the inter-root soil microbiota caused by continuous cropping,thus reducing the obstacles of strawberry continuous cropping.