I like to Google search strings that were used to access this site to see what else is available on the subject. Today I Googled the string "mycorrhizal fungi for carbon circulation", which was used to access this old post here: Nitrogen Transport.
It's a good post that featured this MSU news release: Digging in the dirt for life’s biochemical foundations. The referenced study is worth a second look, especially if you missed it a year ago or had forgotten about it.
It seems a mighty feat for a microscopic fungus built from threadlike filaments. But collectively, these spindly mushroom relatives help move several billion tons of nutrients out of the soil and into plants each year. . .The above photo shows the microscopic fungal threads of arbuscular mycorrhiza attached to a plant root. Mycorrhiza means "fungus root" and arbuscular refers to the treelike appearance. Photo by: Mark Brundrett, Department of Environment, Western Australia. There is an interesting quote on Shachar-Hill's web site: “The mycorrhiza rather than the root is the chief organ of nutrient uptake” Smith and Read 1997.The fungus-plant partnership is one of the planet’s oldest and dates back more than 400 million years, when plants began to move out of the oceans and onto land. Plants trade a bit of their sunlight-made sugars for building block nutrients that fungi wring from the soil. Scientists have understood broad outlines of this evolutionary bargain for years, but specific details remained fuzzy, especially those related to nitrogen.
To learn more about nutrient uptake, MSU researchers led by Shachar-Hill, along with collaborators at New Mexico State University and the U.S. Department of Agriculture research center near Philadelphia, tagged nitrogen with easy-to-spot atomic markers and then watched as it traveled from soil to fungus to plant roots.
Many had assumed that the fungus would play a modest role. The team found, however, that the fungus acts more like a four-lane highway than a two-track country road in shuttling the nitrogen into plant roots. More than a third of the total nitrogen taken up by the plants came by way of the fungus, Shachar-Hill and his collaborators report in the June 9 issue of Nature.
“The really fascinating part is the mechanism underlying the transfer process,” says Maria Harrison, a plant biologist at Cornell University’s Boyce Thompson Institute and an expert on fungus-facilitated movement of other soil nutrients into plant roots. “Dr. Shachar-Hill and his colleagues were able to show that the fungus acquires the nitrogen from the soil and then links it to carbon and moves this combination molecule towards the plant. Then just before delivery to the plant cell, it unhitches the carbon and releases only the nitrogen to the plant.”
Field work remains to be done, to show that these lab results happen outside controlled environments. I haven't seen more recent work that confirms the results, but it's only been a year.
I wish I could see the tiny things in the soil and monitor functions. I'd like an instrument, perhaps something like a multi-meter, that could give me precise information on spot checks. I want a tri-corder sort of gizmo. That would be a cool tool.