Rhizosphere Populations

Abstract

The quantitative und qualitative nature of microbial populations in the rhizosphere and rhizoplane are related either directly or indirectly to root exudates and thus will vary somewhat according to the same environmental factors that influence exudation. These fluctuating populations constitute part of what we term the rhizosphere effect, this effect diminishing with increasing distance from the root surface. Populations are made up of components of both the microflora (bacteria, actinomycetes, fungi, and algae) and the micro- and mesofauna (protozoa, nematodes, mites, and insects). The microflora has received by far the greater research attention by soil microbiologists, plant pathologists, and ecologists; the fauna, except for nematodes, has been largely neglected.