Researchers from Mahatma Gandhi University, Kerala, identified a plant that can remove lead from soil, eventually cleaning the environment from toxic metal contents.
A native roadside plant, Eclipta prostrate, was found to accumulate lead at about 12,000 microgram/g of dry weight in the root and 7,000 microgram/g of dry weight in its shoot. The researchers demonstrated the accumulation of lead by plants using a soluble salt of lead. The findings were published in the journal Ecotoxicology and Environmental Safety in January 2019.
Dr. Joseph George Ray, researcher from the School of Biosciences at the University and corresponding author of the work, said: “These plants grow in soils that are continuously exposed to lead from vehicle exhausts. Though lead additives in petrol and diesel are banned now, some low-quality fuels still have a huge percentage of lead.”
The study claims that Eclipta prostrate has the highest lead tolerance capacity. The plant is known as False Daisy, or Bhringraj’ (Karisalankanni in Tamil), is a hair growth stimulant and is found across the Indian subcontinent.
“Hi-tech microscopic analysis showed that the lead travelled to the leaves and was deposited as lead nanoparticles in its cell wall, cytoplasm, and chloroplast. Though we noticed a little distortion in the structure of these organelles no toxicity was seen,” explains Chandana Chandrasekhar, the first author of the paper.
The researchers found that Eclipta prostrate has lead hyperaccumulator and suitable biochemical machinery. The researchers suggest an innovative method of clearing toxic lead metal from soil, by burning the plant once it has accumulated enough lead content in the roots and shoots.