The discovery on an island in the Philippines of a rare plant, Rinorea niccolifera, that eats metal could have beneficial effects in helping create a greener environment and also help miners. The shrub, discovered by scientists from the University of the Philippines, eats nickel. It can consume over 18,000 parts per million (ppm) of nickel and not be poisoned by the metal. That’s 1,000 times more nickel than can be found in most other plants.
There are, according to National Geographic, 450 vascular plants in the world out of approximately 300,000 which have the ability to hyperaccumulate, or eat large amounts of, heavy metals. Less than one percent of plants living in places around the world that have soil rich in nickel can live in these areas.
Luzon Island is where Rinorea niccolifera was discovered by the scientists. It’s an area rich in heavy metals like nickel. Finding a plant like Rinorea niccolifera that can thrive in such an area that is a hostile environment to most other plants could have a beneficial effect on greening up areas of the world that have become dumping grounds for heavy metals, in a process called “phytomediation.” Also, they can be useful in “phytomining,” that is, they can aid in leading people who have an interest in mining nickel to regions that have nickel rich soil. The plants, themselves, can then be “mined” for their nickel. To do “mining” of the plants, their leaves would get burned, and the ashes would then be collected and processed in a refinery or smelter.
Using plants like Rinorea niccolifera for these purposes is a much greener method to mine heavy metals and also to green up land where heavy metal is unwanted. The scientists involved in the research project published their results in the journal Phytokeys that came out just this past Friday. They received funding from the Department of Science and Technology — Philippine Council for Industry, Energy, and Emerging Technology Research and Development.
The heavy metals “consumed” by plants that hyperaccumulate metal don’t harm the plants because they’re contained in microscopic structures called vacuoles in the plants’ cells. The vacuoles seal up and contain the metal, preventing it from harming the rest of the plant.
David E. Salt, associate professor of plant molecular physiology at Purdue University, has hit on a method of cloning the genes that let plants like Rinorea niccolifera hyperaccumulate heavy metals. This finding could result in the development of new crop varieties that can live in a wider variety of soils, and also be sued to cleanse soils of heavy metals.
Why do plants like Rinorea niccolifera hyperaccumalte heavy metals?
Some scientists believe that certain plants like Rinorea niccolifera developed the ability to hyperaccumulate, or eat, heavy metal for other reasons than the ability to thrive without competition from other plants. For instance, the plants likely use this ability as a way to defend themselves from predators. Many insect and animal species probably find the taste of the heavy metal infused leaves of the plants distasteful, or poisonous.
Other types of plants that are known to hyperaccumulate heavy metals have gained fame for being the friends of miners. For example, there is the Viscaria aplina plant, whose flowers prospectors spotted, which lead them to discover a mine in Sweden that is named after them, the former Viscaria copper mine.
Also, gold has been found in the leaves of certain eucalyptus trees and miners could use them to locate gold rich areas where they could mine gold without doing as much damage to the environment as by using other mining methods.
The ability of plants like the shrub Rinorea niccolifera to hperaccumulate, or eat, nickel, for whatever reason or reasons it evolved, can prove to be very useful in both mining enterprises and in greening up the environment. The cloned genes of plants like it can also, one day, help create crop plants that can grow in conditions that would kill other varieties of crops.
Written by: Douglas Cobb