Some trees and trees have evolved to cope with hostile soils rich in metals like nickel and zinc. And scientists believe that hyperaccumulating plants, such as Pycnandra acuminate, could be used to “clean up” soils where, through human activity, there has been an accumulation of poisonous materials. This specific group of metal-absorbing plants, known as hyperaccumulators, has evolved to absorb ordinarily toxic metals through their stems, leaves and even seeds.
A team of researchers has been studying the Pycnandra acuminate tree, which grows on the southern Pacific island of New Caledonia. They believe the tree may be using nickel to defend itself against insects. Its sap also has a very unusual color, blue-green, as it contains up to 25% nickel.
“Pycnandra acuminata is a large, rare, jungle tree and its location is restricted to certain parts of the forest of New Caledonia,” says Dr. Antony van der Ent, a researcher at the University of Queensland, who has been studying these trees.
Metal-absorbing trees could be used to “clean up” soils affected by human activity
Pycnandra and other hyperaccumulators have been analyzed through the X-ray technique at German Electron Synchrotron (DESY).
“If you use a conventional microscope you can see the structures, but you can’t pinpoint what they’re made of,” explains Dr. Kathryn Spiers, who also studies this type of trees.
Researchers have yet to determine why these particular metal-absorbing trees have evolved in this way to cope with hostile soils, but it’s probably not due to human interference in the environment.
“The evolution of metal-absorbing trees (hyperaccumulators) has been seen many times in different families and has probably taken millions of years. These plants were found in soils naturally enriched with metals,” explained Van der Ent.
However, some scientists believe that hyperaccumulators could be used to “clean” soils where, through human activity, there has been an accumulation of toxic materials.