This Plant Loves to Soak Up Arsenic, a Chemical That Is Highly Toxic to Humans

Chinese brake fern
The Pteris vittata fern can hyperaccumulate and tolerate high levels of arsenic, making it an effective way to remediate contaminated soil and water. Agricultural Communication photo/Tom Campbell

The Chinese brake fern (Pteris vittata)—which is indigenous to Asia, southern Europe, tropical Africa and Australia—has a unique ability: It can absorb high quantities of the toxic element arsenic from the soil and store the substance in its fronds without dying.

Now, a team of scientists from Purdue University has finally unraveled the mystery of how the plant is able to do this by analyzing the genetic and cellular mechanisms that affect its arsenic tolerance, according to a study published in the journal Current Biology.

The findings could have important implications because soil and groundwater contaminated with arsenic poses a potential risk to hundreds of millions of people around the world.

Currently, cleaning up the toxic heavy metal is a laborious and very expensive process. However, the scientists hope that the Chinese brake fern could hold the keys to a more effective solution.

"Other researchers have shown that this fern, when grown on arsenic-contaminated soils, can remove almost 50 percent of the arsenic in five years," Jody Banks, a professor of botany and plant pathology at Purdue University, in Indiana, said in a statement. "It takes time, but it's cheap."

Furthermore, the team said that the new findings could one day be used to genetically engineer other plants to suck up the toxic substance from the soil more quickly and effectively than the Chinese brake fern, thus providing a solution that could potentially reduce the cost and time of arsenic cleanup.

In general, arsenic is toxic to plants and animals due to the fact that it can cause cell death through oxidative stress or by interfering with a cell's ability to produce ATP, a compound that acts as an energy source.

The Chinese brake fern, however, has special mechanisms that prevent these two processes from occurring, researchers say.

The team identified three genes that exhibit significant activity when the plant comes into contact with arsenic. When the scientists "turned off" these genes in experiments, they found that the plant dies, highlighting their importance in protecting against arsenic's toxic effects.

"These and other genes work together to mop up arsenic inside a cell until it can be stuffed safely away in the cell's vacuole, where it can't do any harm," Banks said.