A recently discovered, yet already endangered, plant devours nickel from the soil of Luzon Island in the Philippines. Metal-munching plants could clean up pollution and even mine minerals from the soil.
The newly described Rinorea niccolifera plant accumulates nickel in its leaves at levels from 7, 000 to 18, 400 parts per million. This 8-meter-tall plant grows in nickel-rich soils that cover less than 500 square kilometers of Luzon Island.
Nickel and other minerals also attract people who strip-mine the area. Because of the mining threat to the plant’s tiny, fragmented range, botanists regard the plant as endangered under the Red List ranking system of the International Union for Conservation of Nature. The botanists, led by University of the Philippines researchers, described the nickel-loving plant in the journal PhytoKeys.
The nickel-absorbing shrub is a type of plant known as a hyperaccumulator. These plants absorb higher amounts of heavy metals from the soil than most other plants.
Long-term or high-level exposure to heavy metals, such as nickel, cadmium and zinc, can cause health problems in people. Crops can absorb the metals from contaminated soils and store the toxins in edible portions, warned the U.S. Department of Agriculture.
Cleansing metal-laden farm soils carries a heavy price tag. Commercial demand exists for the minerals, but traditional mining from soil is inefficient.
Hyperaccumulator plants could be an inexpensive way to vacuum heavy metals from potential farmland, in a process known as phytoremediation. After harvest, chemists could extract the metals from leaves and shoots.
Photo: Rinorea niccolifera. Credit: Edwino S. Fernando