连作障碍中化感自毒效应及间作缓解机理

连作障碍是典型的土壤-植物负反馈现象,长期以来困扰农业生产的发展,作物连作障碍形成机理与防治一直是国内外学者的研究热点。自毒作用是连作障碍的发生机制之一,连作下土壤中自毒物质累积通过影响作物的营养吸收、光合作用、酶活性等生理过程而抑制作物生长;同时自毒物质还通过改变微生物区系,降低土壤微生物活性和多样性,促进病原菌增殖,加剧土传病害发生而导致连作障碍危害加重。利用植物化感作用而采用的间作模式,可为克服作物连作自毒物质引发的土传病害发生提供环保、经济、有效的防治途径,符合现代农业可持续发展的思路。笔者从营养和生理角度分析间作提高作物的抗性,从根际微生物-自毒物质-病原菌互作角度阐明间作缓解连作自毒效应的机理,为理解间作系统地下部根际生态过程与连作障碍缓解及制定合理的间作模式提供参考,并有助于揭示地上-地下生物多样性互馈机理。

Allelopathy Autotoxcity Effect of Successive Cropping Obstacle and Its Alleviate Mechanism by Intercropping

Successive cropping obstacle is a typical negative plant-soil feedback phenomenon, which has long plagued the development of agricultural production, and the occurrence mechanism and control measures of successive cropping obstacle have been research focuses of domestic and foreign scholars. Autotoxcity is one of the occurrence mechanisms of successive cropping obstacle, the accumulation of autotoxins affects nutrient absorption, photosynthesis and enzyme activity, then inhibits crop growth. Meanwhile, autotoxin decreases soil microbial activity and diversity, enhances the growth of pathogenic bacteria and soil- borne diseases by changing microflora, then leads to an increased degree of soil sickness. Intercropping accords with the idea of sustainable development of modern agriculture, using plant allelopathy can provide nvironmental, economical and effective approaches to control successive cropping obstacle. The authors analyzed resistance enhancing from crop nutritional and hysiological aspects, clarified the mechanism of successive cropping obstacle alleviation by intercropping from the interaction of rhizosphere microorganisms, autotoxins and pathogens. The results could provide references for the understanding of underground ecological processes in intercropping and the release of successive cropping obstacle, to formulate reasonable intercropping mode. The study is helpful to reveal the feedback mechanism between the ground and underground biodiversity.