影响引入微生物根部定殖的因素

Factors affecting colonization of introduced microorganisms on plant roots

从外界引入的各类有益微生物如生防菌 (BCA)和根际促生菌或增产菌 (PGPR ,YIB)到种子表面随其生根发芽而蔓延或直接到根表沿根分布定殖 .外来微生物在根际定殖的过程为与根尖接触 ,沿根分布 ,最后在根际建立自己的种群 .定殖的位点以PGPR为例 ,是表皮细胞间隙 ,或侧根、根毛基部 .外来微生物在根际定殖动态变化的原因 ,由于根际生物的和非生物的因素引起的 .生物因子除去外来微生物本身的生理特性 ,还有根际土著微生物与外来微生物的相互作用 ,更重要的是植物基因型对微生物定殖的影响 .非生物因子包括土壤环境、土壤结构和含水量 ,土壤温度和土壤 pH值均能影响外来微生物在根部的定殖 .

Microorganisms such as biological control agents (BCA), plant growth promoting rhizobacteria (PGPR) and yield increasing bacteria (YIB) were introduced along growing roots.The colonization process of introduced bacteria was proved that they attached root tipfirst,then distributed along roots,multiplicated there,and survived as certain population size.The colonization location was closely related with root exudates,which was usually at the junction between cortex cells or at the base of lateral roots or root hairs. The variation of colonization by introduced microorganisms in the rhizosphere was caused by biotic and abiotic factors. Biotic factors included the physiological characters of introduced microorganisms and interactions between introduced microorganisms and native microbes. The more important factors were plant genotypes which associated with introduced beneficial microbes and regulated the population and community of those microbes affecting the colonization of introduced microorganisms. Abiotic factors here referred to soil environmental conditions,e.g.,soil texture, water content,soil temperature and pH value.