Aquatic Plant Control Research Program: The Rhizosphere Microbiology of Rooted Aquatic Plants

摘要

The rhizosphere includes the root systems of higher plants and the assemblages of microorganisms associated with them. Plant-microbe interactions in the rhizosphere have not been extensively examined in freshwater plants. However, information based on studies conducted in other environments indicates that these interactions may be important in freshwater systems. This report, based on a review of the literature, examines several aspects of the rhizosphere of rooted aquatic plants. These include: the nature and properties of the rhizosphere; the manner in which plants influence the rhizosphere microflora; the microbial transformations of nutrients in the rhizosphere; and the overall role of the rhizosphereemicroflora in affecting plant growth regulation through influences on nutrient availability, sediment oxidation-reduction status, and gas formation. Sediment is a complex chemical and microbiological environment, even in the absence of plant roots. The presence of anaerobic conditions, accompanied by a low oxidation-reduction potential and often by toxic constituents, places stresses on plants using anaerobic sediments as a rooting medium. Plant roots have developed strategies for coping with life in anaerobic sediments; certain of these strategies directly influence the surrounding sediments and the rhizosphere microflora. Keywords: Aquatic plants; Bacteria; Decomposition; Denitrification; Nitrogen fixation; Phosphorus; Phosphorus solubilization; Plant growth hormone; Plant growth regulator.