Scientists Discover Tree That ‘Grows’ Gold in Its Leaves

Scientists in Finland have discovered that a species of tree can literally “grow” gold, as tiny solid particles of the precious metal form within its leaves with help from bacteria.

The groundbreaking study, led by researchers from the University of Oulu and the Geological Survey of Finland, found that bacteria living inside Norway spruce needles can transform dissolved gold in the soil into solid nanoparticles. This was reported by LiveCience. 

Analyzing 138 needle samples from 23 spruce trees near the Kittilä gold mine in northern Finland, researchers detected gold nanoparticles in four trees—embedded within bacterial biofilms inside the needles.

For decades, scientists have known that metals such as gold travel through soil as dissolved ions released from mineral deposits, eventually being absorbed by plant roots. Many plants host microbes that aid survival in harsh environments, including through biomineralization—the natural process of forming minerals within living tissues.

“Our study offers the first indications of how gold moves into plant shoots and forms nanoparticles within spruce needles,” said Dr. Kaisa Lehosmaa, postdoctoral researcher at the University of Oulu and lead author of the study. “In the soil, gold exists in a soluble, liquid form. It is carried by water into the spruce needles, where microbial activity transforms it back into solid, nanosized particles.”

Though invisible to the naked eye—each particle measuring just a millionth of a millimetre—the discovery could revolutionize geological exploration.

“The bacteria associated with spruce needles appear capable of converting soluble gold into solid nanoparticles,” Dr. Lehosmaa added. “By identifying similar bacteria in other plants, we could develop more sustainable and biological techniques for detecting gold deposits.”