Gold "grows" on eucalyptus trees

Australian scientists have discovered that deep-rooted eucalyptus trees "steal" gold from underground gold deposits and send it to their leaves, National Geographic has reported.

Researchers have found microscopic gold particles from underground deposits in the leaves of eucalyptus trees whose roots extend up to 40 meters into the ground in a search for water.

These results obtained by a team of scientists led by Mel Lintern from the Australian research organization CSIRO have put an end to a long discussion. Some researchers claimed that gold particles in eucalyptus trees were brought by wind, while others believed they were coming from the roots.
The researchers compared eucalyptus tree leaves at gold prospecting sites in Western Australia with leaves from trees 800 meters away. They also grew eucalyptus trees in greenhouses with potting soil dosed with gold particles, as well as in normal potting soil without gold.

They discovered that the leaves preferentially stored microscopic gold particles about eight micrometers wide on average.

Study authors speculate the particles came from underground, seemingly taken up by the root system of the trees. About 20 leaves needed to be sampled to statistically reveal the presence of gold underneath the trees.

- Gold is probably toxic to plants and is moved to its extremities (such as leaves) or in preferential zones within cells in order to reduce deleterious biochemical reaction - the scientists conclude.

The average concentration of gold in the leaves was only about 46 parts per billion, less than 0.000005 percent of each leaf by weight.

However, study authors believe that eucalyptus trees might offer cheaper, and better, clues to gold deposits.

gold

eucalyptus

Melvin Lintern

CSIRO