Researchers Discover That Plants Have Mouths That Open And Close In A Breathing-Like Motion
Researchers at the University of California San Diego took a close look at one stomata, pores in the skin of leaves that open and close in a breathing-like motion.
Knowing that plants can signal their "mouths" to respond to changing levels will allow scientists to modify those signals and produce crops that can withstand the effects of climate change, said Jared Dashoff, a spokesman for the National Science Foundation (NSF), which funded the work.
"Responding to changes is critical to plant growth and regulates how efficiently the plant uses water, which is important because we see increasing droughts and rising temperatures," said Julian Schroeder, who led the new research.
A changing climate could affect the balance between the entry of carbon dioxide and the loss of water vapor through stomata.
And if plants, especially crops grown for food, cannot find balance, they become dry and useless. A 2021 study, also funded by the National Science Foundation, found that global agricultural productivity over the past 60 years is still 21 percent lower. % of what it would be without climate change.
On the undersides of leaves and elsewhere, depending on the plant, are tiny openings called stomata — thousands per leaf with variations according to plant species.
"Like the gates of a small castle, pairs of cells on the sides of the oral pores - known as guard cells - open their central pores to absorb carbon dioxide," Dashoff said in a statement.
These proteins signal the cells to relax and close the stomata. When the plant senses increased carbon dioxide levels, the second protein prevents the first from keeping the stomata open and closed.
"The discovery that the carbon dioxide sensor in plants consists of two proteins was beneficial and may be a reason why the mechanism has not yet been identified," Schroeder said.
In a low-carbon environment where the plant needs to keep the stomata open longer to get the amount it needs for photosynthesis, a protein known as HT1 activates an enzyme that forces the guard cells to swell, keeping the stomata open.
"However, when the stomata are open, the interior of the plant is exposed to the elements and water from the plant is lost to the surrounding air, which can lead to dehydration of the plant," Dashoff said.
Therefore, plants must balance carbon dioxide uptake with water vapor loss by controlling how long the stomata remain open.
"Identifying how plants control their stomata under changing carbon dioxide levels creates a different kind of opener - one to new avenues of research and possibilities for addressing societal challenges," said Richard Seyr, NSF program director.
Plants are known to consume large amounts of carbon dioxide, but a 2018 study found that they take in more than previously thought.
In the study, researchers from the Department of Energy's Lawrence Berkeley National Laboratory developed a new model to calculate what plants do during their photosynthetic inactivity period.
According to the team, previous models failed to consider that plants continue to compete for nutrients in the soil even at night.
By combining this, the researchers found that plants can produce more carbon dioxide uptake than previously thought.
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