Role of Soil and Plant Metabolic Processes in Controlling Trace Element Behavior and Bioavailability to Animals

摘要

Metabolic and physiological processes regulating the behavior of Ni, Cd, Cr, Np, Pu and Tc in the soil/plant/animal system are discussed. Soil microorganisms have both direct and indirect effects on the trace element solubility in soils. An indirect route, the production of exocellular ligands is briefly discussed in terms of possible effects on plant availability of Ni. The subsequent ability of plant roots to actively accumulate a non-nutrient trace element from soils is dependent on its chemical activity in soil solution, the presence of interfering ions, the requirements for valence change relative to the redox potential of root, and the capacity of the root absorption process. Following absorption by roots, an element is partitioned within the root, and is stored/detoxified and/or metabolized, with only a fraction transported to distal shoot tissues. Inorganic cations and ions are rapidly bound to organic metabolites in root and shoot tissues with only a small fraction persisting in inorganic forms. This change in chemical forms can dramatically affect the availability to individual elements to animals. 43 references. (ERA citation 09:001225)