萌妹社区

(萌妹社区Org.com) -- Remarkable bacteria that resist arsenic could greatly enhance cleanups of toxic environments and potentially boost agricultural production, according to a new University of Florida study.

The bacteria were isolated from arsenic-contaminated soil surrounding the Chinese brake fern, a plant known for its ability to remove arsenic from the environment.

The carcinogen contaminates soils around the world and is deadly to most organisms.

Arsenic levels above state-set minimum standards were reported in residential areas in Miami and Gainesville, according to a 2003 study co-authored by Lena Ma, a UF soil and water science professor.

The new findings, published in this month鈥檚 issue of Bioresource Technology, could lead to improved phytoremediation 鈥� the process of using plants to remove environmental contaminants 鈥� in which the bacteria are added around the roots of the Chinese brake fern to increase arsenic absorption.

In the study, the bacteria broke arsenic down into a more easily absorbed form and increased the fern鈥檚 arsenic uptake ability by more than 900 percent.

The bacteria also caused the plant to grow bigger, with a nearly 100 percent increase in root size.

鈥淚 really didn鈥檛 expect that the plant would grow better,鈥� said Ma, an author of the study. 鈥淏ut the arsenic-resistant bacteria increased plant biomass.鈥�

In 2001, Ma was the first to report the fern鈥檚 extraordinary arsenic accumulation abilities.

Wanting to further increase the plant鈥檚 arsenic absorption capabilities, Ma, fellow UF Institute of Food and Agricultural Sciences member Bala Rathinasabapathi and soil and water science doctoral candidate Piyasa Ghosh, began examining bacteria living in the soil around the plant. Ghosh is the study鈥檚 lead author.

鈥淲e thought that there could be bacteria associated with the fern that could be useful in one way or another,鈥� said Rathinasabapathi, a UF horticultural sciences associate professor.

The researchers collected soil near the fern and the fern鈥檚 root zone from different places in Florida contaminated with arsenic.

After the scientists isolated bacteria from the soil, they added it to the fern鈥檚 growing environment in the laboratory where it broke arsenic down into a more available form readily absorbed by the fern. In addition to the increase in arsenic absorption, they also noted a gain in the uptake of the nutrient phosphorus by the fern, which led to better growth.

Rathinasabapathi said more studies are needed to explore whether the bacteria can be widely used in agriculture.

The fern is licensed to and sold by a company based in Manhattan, Kan.