Effects of Drought Stress on the Growth and Heavy Metal Accumulation by Chromolaena odorata Grown in Hydroponic Media.

This study aimed to investigate the effects of drought stress on cadmium (Cd) and zinc (Zn) accumulation in Chromolaena odorata grown in an artificially contaminated nutrient solution for 15 days. Polyethylene glycol (5% PEG) was used as a drought stressor. The presence of PEG did not affect the chlorophyll content and photochemical efficiency, while drought stress induced by PEG caused a decrease in water content in the plant tissues. The bioaccumulation factor (BAF) of Cd were higher than the BAF of Zn and accumulated mainly in the roots of C. odorata. The highest concentrations (4273.7 mg/kg Cd, 2135.4 mg/kg Zn) were found in the 20 mg/L treatment. The results suggested that Cd and Zn accumulation in C. odorata was not affected by PEG, while a translocation factor (TF) value < 1 was caused by either PEG or contaminants. Based on the hydroponic BAF criterion, the study confirmed that C. odorata was useful for phytoremediation of Cd with low drought stress.