Bioactive chemicals and biological-biochemical activities and their functions in rhizospheres of wetland plants

Wetland soils provide anoxia-tolerant plants with access to ample light, wa ter, and nutrients, Intense competition, involving chemical strategies, ens ues among the plants. The roots of wetland plants are prime targets for roo t-eating pests, and the wetland rhizosphere is an ideal environment for man y other organisms and communities because it provides water, oxygen, organi c food, and physical protection. Consequently, the rhizosphere of wetland p lants is densely populated by many specialized organisms, which considerabl y influence its biogeochemical functioning. The roots protect themselves ag ainst pests and control their rhizosphere organisms by bioactive chemicals, which often also have medicinal properties. Anaerobic metabolites, alkaloi ds, phenolics, terpenoids, and steroids are bioactive chemicals abundant in roots and rhizospheres in wetlands. Bioactivities include allelopathy, gro wth regulation, extraorganismal enzymatic activities, metal manipulation by phytosiderophores and phytochelatines, various pest-control effects, and p oisoning. Complex biological-biochemical interactions among roots, rhizosph ere organisms, and the rhizosphere solution determine the overall biogeoche mical processes in the wetland rhizosphere and in the vegetated wetlands. T o comprehend how wetlands really function, it is necessary to understand th ese interactions. Such understanding requires further research.