Video shows plants ‘breathe’ through ‘mouths’ that open and close 

It may look like Audrey II from the 1986 film Little Shop of Horrors, but the green mouth opening and closing is a plant’s response to changing carbon dioxide and humidity levels.

Researchers at the University of California San Diego captured a close-up look at a single stomata, a pore found in the epidermis of leaves, opening and closing in a movement that looks like breathing. 

Knowing that plants can signal their ‘mouths’ to respond to changing levels will allow scientists to edit those signals and produce crops that withstand the effects of climate change, said Jared Dashoff, a spokesperson with the National Science Foundation (NSF) that funded the work.

‘The response to changes is critical for plant growth and regulates how efficient the plant can be in using water, which is important as we see increased drought and rising temperatures,’ said Julian Schroeder, who led the new research. 

The changing climate can impact the balance between carbon dioxide entry and water vapor loss through the stomata. 

If plants, particularly crops grown for food, cannot find a balance, they become dried up and useless.

A study in 2021, also funded by NSF, found that global agricultural productivity over the past 60 years is still 21 percent lower than it could have been without climate change.

On the underside of leaves and elsewhere, depending on the plant, are tiny openings called stomata — thousands per leaf with variations by plant species.  

‘Like little castle gates, pairs of cells on the sides of the stomatal pore — known as guard cells — open their central pore to take in the carbon dioxide,’ Dashoff said in a statement.

These proteins signal cells to relax and shit the stomata. 

When the plant senses increased carbon dioxide levels, a second protein blocks the first one from keeping the stomata open and shut. 

‘Finding that the CO2 sensor in plants is made up of two proteins was enlightening and maybe a reason the mechanism hadn’t been identified until now,’ Schroeder said. 

In a low-carbon dioxide 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 up, keeping the stoma open. 

‘However, when stomata are open, the inside of the plant is exposed to the elements and water from the plant is lost into the surrounding air, which can dry out the plant,’ said Dashoff.

‘Plants, therefore, must balance the intake of carbon dioxide with water vapor loss by controlling how long the stomata remain open.’

Richard Cyr, an NSF program director, said: ‘Determining how plants control their stomata under changing CO2 levels creates a different kind of opening — one to new avenues of research and possibilities for addressing societal challenges.’

Dashoff told SWS that the scientists have filed a patent and are examining ways to translate their findings into tools for crop breeders and farmers.

Thousands of stomata are on the surface of the plants. Scientists believe they can edit the signals it receives from plants when there is a change in carbon dioxide levels to breed crops to withstand climate change

While the video looks like Audrey II from the Little Shop of Horrors (pictured), it is a breathtaking shot of stomata responding to changes in carbon dioxide levels 

Plants are known to be carbon dioxide guzzlers, but a study in 2018 found 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 account for what plants do during the photosynthesis-inactive period.

According to the team, previous models fail to consider that plants continue to compete for nutrients in the soil even at night.

By incorporating this, the researchers found that plants can produce an uptake of more carbon dioxide than previously thought.

And soils lose far less nitrous oxide. The new study found the models have been overestimating the soils’ release by roughly 2.4 gigatons of CO2-equivalent per year.

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