Chapter 14 - Physiological basis of arsenic accumulation in aquatic plants

Abstract

Aquatic plants exhibit capacity to remove arsenic (As) from the water and soil sediments. Uptake of As varies for plant species and depends upon its chemical species, namely, arsenate, arsenite, or methylated As. Arsenic removal in aquatic plants occurs primarily by physicochemical processes such as adsorption onto surface of roots or leaves. Iron plaques present on the root surface assist in uptake of metals. Uptake of As primarily by passive route (via apoplast), active route (via symplast), or direct transcellular transport is followed by reduction to arsenite in cytosol of roots and further translocation to shoots. Accumulation and translocation of As depend upon its concentration in the medium, efficiency of transport system, and physiological factors such as root pressure and leaf transpiration rate. Study of translocation and accumulation mechanisms can prove useful in developing phytoremediation technologies for removal of As from the environment.