Efficacy of Duckweeds for Phytoremediation: Morpho-Physiological and Biochemical Alterations

Phytoremediation is considered as an advanced approach to uptake heavy metals from polluted water and to remediate the contaminated water and soil mediums using plants. Heavy metals including chromium, nickel, cadmium and lead are highly toxic metals, and their concentration is increasing via anthropogenic activities. The study exhibits the response of duckweed under metal stress on plant growth, biochemical attributes and physiology. Duckweed is one of the most suitable plant species that have local adaptation, plant root depth, detoxify heavy metals, fast growth rate and uptake of high concentrations of heavy metals. In this study, we review that heavy metal-stressed duckweed plants uptake and accumulate heavy metals due to their increased biomass. But due to the accumulation of heavy metals in plants, biochemical attributes such as chlorophyll, carotenoid, antioxidant and electrolyte leakage reduced along with the increased production of reactive oxygen species. The present study compiles the data regarding the effects of heavy metals on duckweed plants and their potential to accumulate the heavy metal in their leaves through roots. Further, it has been found that under the application of organic chelators such as citric acid, ascorbic acid and glutamic acid provides support in the development and growth of the plants parallel to increased heavy metals accumulation. Further studies at genetic and molecular level are required to understand the response of duckweed plants to heavy metals stress.