Phytoremediation is the use of plants to clean up and remove heavy metals from contaminated soil while phytomining refers to the use of plants to recover and extract valuable metals such as nickel, without the need to do open pit mining or other types of extractive activities that can destroy natural habitats.
According to the research published this May in the open access journal PhytoKeys, the Rinorea niccolifera (Violaceae), a shrub endemic to the Philippines, can store up to 18,000 parts per million of nickel in its leaves as part of its diet without getting poisoned.
This ability to store a huge amount of nickel, called hyperaccumulation, is so rare that no more than 1 per cent of plants that thrive on nickel-rich soil exhibit this ability. To date, only 450 species out of the 300,000 vascular plants in the world have this characteristic to “hyperaccumulate” nickel, says Edwino Fernando, lead author of the paper and forest biological sciences professor at the University of the Philippines Los Baños.
“This plant’s capacity to store 1.8 per cent of nickel is similar to the amount of nickel contained in any ordinary spoon or cutlery,” notes Augustine Doronila, co-author of the study and senior research fellow at the University of Melbourne in Australia who specialises in restoration ecology.
He explains to SciDev.Net that the plant has evolved the capacity to siphon huge amounts of nickel from the soil into its tissues so it can thrive in the most unforgiving of environments such as rocky, nickel-rich areas.
Because of the plant’s unique features, Doronila is also interested in further studying its potential applications in medicine. He cites aspirin as an example of a natural plant extract (from the willow tree) that became beneficial in modern medicine.
William Dar, director general of the India-based International Crops Research Institute for the Semi-Arid Tropics, notes that another area worth looking into is the scalability of using the nickel-eating plant for environmental applications and the readiness of the Philippines and other countries in adopting this.
Doronila says a typical study on phytoremediation would involve covering a hectare of land with nickel-eating plants and holding the experiment for three or more years.
It is both labour and financially intensive but doable, Doronila points out. Key to this will be the further development of local scientists trained to identify the plant in the wild, regular funding for research and greater ecological awareness among the local population.
“I hope the discovery of the nickel-eating plant will fuel the hunger for more research on the biodiversity of the Philippines. We need to discover them before they get lost to land conversion,” he stresses.
Link to full paper in PhytoKeys
This article has been produced by SciDev.Net's South-East Asia & Pacific desk.