Some trees 'farm' bacteria to help supply nutrients

July 29, 2010

Some trees growing in nutrient-poor forest soil may get what they need by cultivating specific root microbes to create compounds they require. These microbes are exceptionally efficient at turning inorganic minerals into nutrients that the trees can use. Researchers from France report their findings in the July 2010 issue of the journal Applied and Environmental Microbiology.

"In acidic forest soils, availability of inorganic nutrients is a tree-growth-limiting factor. A hypothesis to explain sustainable forest development proposes that tree roots select involved in central biogeochemical processes, such as mineral weathering, that may contribute to nutrient mobilization and tree nutrition," says Stéphane Uroz, an author on the study.

Certain microbes are efficient at breaking down into nutrients. This process, called mineral weathering, is especially important in acidic forest soils where tree growth can be limited by access to these nutrients. Mineral-weathering bacteria can release necessary nutrients such as iron from minerals. This gives with increased concentrations of mineral-weathering microbes an advantage over other trees.

Distinct impacts of the tree species on the soil bacterial community structure have been previously reported, suggesting that the composition and activity of soil bacterial communities depend on tree physiology and notably on its impact on the soil physicochemical properties and nutrient cycling. However, no study has ever addressed the question of the impact of tree species on the structure of forest soil bacterial communities involved in mineral weathering.

"This question regarding the impact of tree species on the functional diversity of the bacterial communities remains a major issue in forestry, especially in the context of today's climate change, which will give rise to a shift in the spatial distribution of forest tree species" says Uroz.

The researchers took soil samples from the root areas of beech, oak and Norway spruce trees and cultured them to determine the bacterial populations. They observed heightened levels of mineral-weathering bacteria in the samples near the roots of oak and beech trees compared to surrounding soil samples. This difference was not seen in the Norway spruce samples.

"Our results suggest that certain tree species have developed indirect strategies for mineral weathering in nutrient-poor soils, which lie in the selection of bacterial communities with efficient mineral weathering potentials" says Uroz.

Explore further: Why do autumn leaves bother to turn red?

Related Stories

Can you rescue a rainforest? The answer may be yes

March 27, 2008

Half a century after most of Costa Rica's rainforests were cut down, researchers from the Boyce Thompson Institute took on a project that many thought was impossible - restoring a tropical rainforest ecosystem.

Probing Question: Can logging be done sustainably?

April 3, 2008

In an era of ever-increasing environmental awareness, few industries receive more scrutiny than logging. For decades, environmental groups have claimed that commercial logging practices result in devastating consequences, ...

Tree species composition influences nitrogen loss from forests

March 16, 2009

Throughout the world, nitrogen compounds are released to the atmosphere from agricultural activities and combustion of fossil fuels. These pollutants are deposited to ecosystems as precipitation, gases, and particles, sometimes ...

Recommended for you

Genomes uncover life's early history

August 24, 2015

A University of Manchester scientist is part of a team which has carried out one of the biggest ever analyses of genomes on life of all forms.

Rare nautilus sighted for the first time in three decades

August 25, 2015

In early August, biologist Peter Ward returned from the South Pacific with news that he encountered an old friend, one he hadn't seen in over three decades. The University of Washington professor had seen what he considers ...

Study shows female frogs susceptible to 'decoy effect'

August 28, 2015

(Phys.org)—A pair of researchers has found that female túngaras, frogs that live in parts of Mexico and Central and South America, appear to be susceptible to the "decoy effect." In their paper published in the journal ...

Why a mutant rice called Big Grain1 yields such big grains

August 24, 2015

(Phys.org)—Rice is one of the most important staple crops grown by humans—very possibly the most important in history. With 4.3 billion inhabitants, Asia is home to 60 percent of the world's population, so it's unsurprising ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.