中国生态农业学报2017，Vol.25Issue(5)：730-739,10.DOI:10.13930/j.cnki.cjea.160792
连作番茄根区病土对番茄生长及土壤线虫与微生物的影响
Effect of sick rhizosphere soil under tomato continuous cropping on soil nematodes, microbes and tomato growth
摘要
Abstract
Continuous cropping of tomato is a widespread practice that severely restricts sustainable tomato production. The interac-tion between soil nematodes, soil microbes and plants may be related with root-knot nematode disease due to continuous cropping.However, a little attention has been paid to the interrelatedness of these factors or the effect of continuous cropping on the relation-ship among soil and other 3 factors. Thus, this study explored the effects of sick soil (root-knot nematode infecting soil) on tomato root-knot disease, mechanism of micro-ecological obstacles and plant growth of continuously cropped tomato with a pot experiment. The abundances and communities of microbes and nematodes in root-zone soils and the activities of defensive enzymes in seedling leaves of tomato were analyzed to determine what pathogenic mechanism existed in such cropping systems. Compared with healthy soil, sick soil caused the following changes: (1) at seedling stage, root-knot nematodes began to infect roots and therefore root-knots appeared on tomato roots. Compared with the healthy soil, silk soil increased the abundance of soil nematode by 390.4%. At maturity, the infection rate of root-knot nematode was 62.7% and the related disease index was 80.0%. (2) The growth of tomato was re-strained and the activities of defense enzymes reduced. The dates of blossoming and fruiting delayed too. Fresh biomass of shoot and root at maturity significantly (P< 0.05) decreased by up to 50.2% and 33.1%, respectively. Also the quantity and fresh mass of fruit significantly (P< 0.05) decreased by up to 59.7% and 68.2%, respectively. While compared with healthy soil, PPO activity of seed-ling leaves significantly (P< 0.05) decreased (by 15.8%), and POD activity significantly (P< 0.05) increased (by 24.0%) for silk soil. (3) Tomato roots became easily infected by harmful bacteria (Pseudomonas brassicacearum). The number of pathogenic bacteriaP. brassicacearumin tomato roots in sick soils was 463 times greater than that in healthy soils. The total number of bacteria, fungi and actinomycetes in rhizosphere soils increased by 46.3%, 94.5% and 134.0%, respectively. (4) The abundance of soil nematodes in-creased nearly 3 times, among which the abundance of fungi-feeding nematodes, bacteria-feeding nematodes and plant-parasitic nematodes increased by 1.6, 3.3 and 7.3 times, respectively. The abundance and diversity of plant-parasitic nematodes greatly in-creased, of which root-knot nematode accounted for 95.6%. In conclusion, the inoculation of sick soils from the root-zone under continuous tomato cropping had complex effects on root-zone soil ecology. It inhibited tomato growth and increased the incidence of root-knot nematode disease by influencing the abundance and diversity of microbes and nematodes in root-zone soils and also by influencing biochemical metabolism of tomato. Mass propagation of plant parasitic nematodes and plant pathogenic bacteria de-creased defensive enzyme activity and stress resistant ability of tomato, which in turn led to more severe root-knot nematode infec-tion with significant inhibitory effect on tomato production. The negative effects of continuous cropping on tomato growth were caused by the interactions among root-zone soil microbes, root endophytes and soil nematodes.关键词
番茄/连作/根结线虫/微生物/防御酶/病原菌Key words
Tomato/Continuous cropping/Root-knot nematode/Soil microbe/Defensive enzyme/Pathogenic bacteria分类
农业科技引用本文复制引用
马媛媛,李玉龙,来航线,郭俏,薛泉宏..连作番茄根区病土对番茄生长及土壤线虫与微生物的影响[J].中国生态农业学报,2017,25(5):730-739,10.基金项目
"十二五"国家科技支撑计划课题(2012BAD14B11)及陕西省2016年科技统筹创新工程计划(2016KTZDNY03-03-02)资助 This work was supported by the National Key Technology R&D Program of China (2012BAD14B11), and the Sci. & Tech. Innovation Project of Shaanxi Province, China (2016KTZDNY03-03-02). （2012BAD14B11）
