连作障碍与根际微生态研究Ⅰ.根系分泌物及其生态效应

作物、蔬菜、果树以及苗木长期连作后，皆出现生长衰退和产量降低．许多研究结果表明，连作条件下土壤生态环境对植物生长有很大的影响，尤以植物残体与病原微生物的分解产物，对植物有致毒作用，并影响植物根系分泌物正常代谢，以致于发生自毒作用．本文围绕根系分泌物与根际微生态的相互关系，系统地介绍连作障碍条件下，影响根系分泌物的环境因素（土壤空气、湿度、养分与微生物）、活性物质（自身毒素、残体分解物、微生物产生毒素）、土壤病原菌等的根际效应，为深入研究根系分泌物与连作障碍的相互作用机制提供启示．

Continuous cropping obstacle and rhizospheric microecology I. Root exudates and their ecological effects.

Growth degeneration and yield declination are becoming obvious after a long term continuous cropping of crops, vegetables, fruit trees and nursery seedlings. Many studies show that soil ecological environment greatly affect the growth of plant under continuous cropping, and particularly, the decomposition products of plant residues and pathogenic microbes have a toxic effect to plants and affect the normal metabolism of root exudates, producing an auto toxic effect.In this paper, the rhizospheric effects of soil environmental factors (air,moisture, nutrient and microorganisms), active substances (phytotoxin, residue decomposition substances, microbial toxin), and pathogenic microbes on root exudates under conditions of continuous cropping were systematically introduced, which would afford inspiration for further studying on the interaction mechanism between root exudates and continuous cropping obstacle.