A typical mushroom shoots tens of thousands of spores into the atmosphere every second, and until a decade ago nobody knew how.
In the 1990s, Miami University botany professor Nicholas Money decided to look into "one of the great unsolved mysteries in fungal biology," identified a century earlier by mycologist A. H. R. Buller -- whom Money refers to as “the Einstein of Mycology.”
Buller found evidence that the answer had something to do with a drop of liquid that formed on the spore seconds before it shot into the atmosphere. Money and his collaborators developed this theory by using high-speed cameras to prove that the formation and motion of this drop of liquid, known as Buller’s drop, did in fact propel the spores into space, and released their findings in 2005.
A new study led by Money, and published in PLOS ONE last week, takes these findings further with the suggestion that mushrooms can help make it rain. The research shows that in humid environments drops can form on the surfaces of spores, even after the spores are airborne.
Although Money suspected this might be the case, most mycologists, he said, assumed that whatever mechanism created the drop stopped working once the spore was released. As the spores spread into the atmosphere, however, these droplets can grow and grow until they form raindrops, according to the study.
"It's sort of counterintuitive if you think of other kinds of mechanisms," Money said, "like once someone is shot from a cannon they can't be re-shot from a cannon, but in this case these spores can indefinitely form water on their surfaces."
People have often attributed mystical properties to mushrooms, but even Alice’s mushroom didn’t do that. This finding suggests that mushrooms may have evolved an amazing ability to take care of themselves, actually creating the water they need to grow.
But, as Money and his collaborators point out in the paper, the relationship between mushrooms and rain could also trigger a drought cycle: As global warming increasingly causes dry spells, at times when there is less rain fewer mushrooms will grow, and with fewer spores in the atmosphere even less rain may fall.
"I think this is enriching our picture of how humans depend on fungi," Money said.
Perhaps inevitably, people have asked Money about the practical application of the study's findings: Could we somehow harness the power of mushrooms to save farms and forests?
Money is intrigued, but skeptical.
"I think the most important thing that can come out of a study like this is to just increase one’s recognition of the sensitivity of the relationships between biological diversity, and the way that the planet works in a fashion that supports the human condition,” he said.
"If we're cutting down forests or if we’re doing things that might be damaging fungal populations, this doesn't just affect the fungi, it ultimately effects Homo sapiens as well,” Money added.
Arturo Casadevall, a microbiologist at Johns Hopkins University specializing in fungi, who wasn't part of the study, agreed. “Fungal spores are very very prevalent. They are designed by nature to be spread by air,” he said. “The fungal kingdom is the ignored kingdom, but this raises the possibility that fungi are a lot more important than anyone has given them credit for.”