Poster: Phytoremediation

Abs # 981: Excitation Waves in Hyperaccumulating Plants Due to Phytoextraction

Presenter:	Ranatunga, Don Rufus A., donranatunga@oakwood.edu
Authors	Ranatunga, Don Rufus A. (A)   Edwards, Raginee M. (A)   Volkova, Maia  (A)   Volkov, Alexander G. (A)
Affiliations:	(A): Oakwood College

Phytoextraction refers to the uptake and translocation of metal contaminants in the soil by plant roots into the aboveground portions of the plants. Certain plants considered as hyperaccumulators, have the ability to tolerate high levels of the metal in root and shoot cells, and translocate the metal from roots to shoots at higher rates. Even though several hyperaccumulating plants have been developed based upon accelerated metal removal, the understanding of plant metal tolerance mechanisms is very limited. Plants have a specific property known as excitability in which cells and tissues change their internal condition and external reactions under the influence of various environmental factors. This stimulus-induced change in plasma membrane potential is measured in terms of action and variation potentials. In this work, the propagation of any observed such potentials due to the accumulation of nickel(II) and cadmium(II) in brassica juncea and soybean plants has been investigated as a model study. Action potential data have been collected from plants interfaced with an IBM-compatible computer with a Keithley data acquisition board. After each addition of an aliquot of a standard metal ion solution, data is recorded until a change in the action potential is observed. It is suggested that the free heavy metal ions block the ion channels in the soybean plant resulting a rapid death. A possible mechanism of cadmium/nickel-tolerance in brassica juncea may be due to chelation of such metals by complexing agents within root cells.