ABSTRACT
The term ‘rhizosphere’ has been derived from the Greek word ‘rhiza’, meaning root, and ‘sphere’, meaning field of influence. The rhizosphere is the zone surrounding the roots of plants in which complex relationships exist among the plant, the soil microorganisms and the soil itself. The plant roots and the biofilm associated with them can profoundly influence the chemistry of the soil, including pH and nitrogen transformations. The term rhizosphere was coined for the first time by German agronomist and plant physiologist Lorenz Hiltner in 1904. The active reaction zone of a wetland plant is the root zone or the rhizosphere. The rhizosphere is also known to be a hot spot of microbial activities, in which physicochemical and biological processes take place that are induced by the interaction of plants, microorganisms, the soil and pollutants (Stottmeister et al. 2003). Phytoremediation efforts have largely focused on the use of plants to accelerate degradation of organic contaminants, usually in concert with root rhizosphere microorganisms, or to remove hazardous heavy metals from soils and water. Plants have been used for wastewater treatment applications over the past 300 years and began to be used for treatment of slurries and metal contamination in the mid-1970s. The wetland technology, an ecofriendly green technology, has an important influence on the biological degradation and removal mechanism of contaminants.
