Grass stomata and climate change

Photo credit: Philippine News Agency

Wheat and other edible grasses have developed pores that make them more drought tolerant. Stanford scientists have studied these pores with an eye toward future climate change. (Image credit: magdasmith / Getty Images) | credit Stanford University | Manila Bulletin


Grass stomata seen as possible lead to crops better surviving climate change

Philippine News Agency (2017)

in Manila Bulletin 2017-03-17 –

The increased efficiency of grass stomata, as confirmed in a new study, may lead to crops that can better survive climate change.

Stomata, the holes in the leaves of land-based plants through which they take in carbon dioxide (CO2) and let out oxygen and water vapor, have remained largely unchanged in the 400 million years since plants colonized the land, according to a resarch paper published in the March 17 issue of the journal Science.

One major exception is grasses, which are better able to withstand drought or high temperatures in large part due to changes in their stomata.

Stomata usually have two so-called “guard cells” with a hole in the middle that opens and closes depending on how a plant needs to balance its gas exchange. If a plant needs more CO2 or wants to cool by releasing water vapor, the stomata open. If it needs to conserve water, they stay closed.

Grasses, which include wheat, corn and rice and make up about 60 percent of the calories people consume worldwide, improved on the original structure by recruiting two extra cells on either side of the guard cells, allowing for a little extra give when the stoma opens. They also respond more rapidly and sensitively to changes in light, temperature or humidity that happen during the day.

The different stomata may have helped grasses spread during a prehistoric period of increased global dryness.

Scientists have assumed grasses’ unusual stomata make these plants more efficient “breathers.” But, spurred by curiosity and a passion for developmental biology, researchers at Stanford University decided to test that theory.

The researchers of the study said they found a mutant of the wheat relative Brachypodium distachyon that had two-celled stomata, compared the stomata from the mutant to the normal four-celled stomata, and confirmed that the four-celled version opens wider and faster.

In addition, they identified which gene creates the four-celled stomata.

“Because it was a grass-specific cell-type, we thought it would be a grass-specific factor as well,” said Michael Raissig, lead author of the paper and a postdoctoral researcher in the lab of Dominique Bergmann, professor of biology. “But it’s not.”

The recruitment of the extra cells seems to be controlled by a well-studied factor which is known to switch other genes on and off. In other plants, that factor is present in guard cells, where it is involved in their development. In grasses, the researchers found that the factor migrated out of guard cells and directly into two surrounding cells, recruiting them to form the four-celled stomata.

Over evolutionary time, humans have bred and propagated plants that produce the kinds of foods we like and that can survive extreme weather.

“When we want something that’s more drought resistant, or something that can work better in higher temperatures, or something that is just able to take in carbon better, often what we are actually doing is selecting for various properties of stomata,” Bergmann, co-author of the paper, was quoted as saying in a news release.

The adaptability and productivity of grass makes understanding this plant family critical for human survival, the researchers said. Whether through genetic modification or selective breeding, these findings may lead to producing other plants with four-celled stomata.

CLIMATE – bibliography

Abdulrahaman A. A., Oladele F. A. (2008)  – Global Warming and Stomatal Complex Types –  Ethnobotanical Leaflets 12: 553-556. 2008 – – (On our blog :
Auckland University (2015) – Study of leaf pores may help scientists predict climate – Scoop Sci-Tech – – (On our blog :

Climate News Network – Plants’ heat response means fiercer heatwaves – – (On our blog :

Philippine News Agency (2017) – Grass stomata seen as possible lead to crops better surviving climate change – Manila Bulletin 2017-09-20 – – (On our blog :


Heat waves and stomata


Photo credit: Eco Business

Researchers have established that extreme heat can alter the atmospheric chemistry unfavourably for plants, and certainly reduce crop yields. Image: Shutterstock

Plants’ heat response means fiercer heatwaves


Asia faces more extreme heat by mid-century as some plant species react unexpectedly to rising average temperatures, new research shows.

Tomorrow’s heat waves could be even hotter than climate scientists have so far predicted. Maximum temperatures across the Asian continent from Europe to China could be 3°C to 5°C higher than previous estimates – because the forests and grasslands will respond in a different way.

Australian scientists report in the journal Scientific Reports that they looked at the forecasts made by the Intergovernmental Panel on Climate Change under the notorious “business-as-usual” scenario, in which the world’s nations go on burning ever more fossil fuels, to release ever more greenhouse gases.

The average global temperatures will rise steadily – but this rise will be accompanied by ever greater and more frequent extremes of heat.

But then Jatin Kala of Murdoch University in Perth, Western Australia, and colleagues factored in the responses of the plants to rising temperatures.

They looked at data from 314 species of plant from 54 research field sites. In particular, they investigated stomatas, tiny pores on the leaves through which plants absorb carbon dioxide and shed water to the atmosphere.

Read the full story: Eco Business

Water loss and heatwaves




Research finds water loss from plants a factor in heatwaves


WATER loss from vegetation could play a key role in the intensity of heatwaves around the world Australian researchers have found.

The research, published in Nature Scientific Reports, investigated why the projected temperature increases are more than half the change forecast by the IPCC under the business-as-usual model.

“We often underestimate the role of vegetation in extreme temperature events as it has not been included in enough detail in climate models up until this point,” said lead author Dr Jatin Kala from Murdoch University.

“These more detailed results are confronting but they help explain why many climate models have consistently underestimated the increase in the intensity of heatwaves and the rise in maximum temperatures when compared to observations.”

The research predicts heatwaves from Europe to China are likely to be more intense and result in maximum temperatures that are 3°C to 5°C warmer than previously estimated by the middle of the century – all because of the way plants on the ground respond to carbon dioxide in the atmosphere.

The biggest temperature changes were projected to occur over needleleaf forests, tundra and agricultural land used to grow crops.

To get their results the researchers looked at data from 314 plant species across 56 field sites. In particular, they investigated stomata, small pores on plant leaves that take in carbon dioxide and lose water to the atmosphere.

Previously, most climate models assumed all plants trade water for carbon in the exactly same way, ignoring experimental evidence showing considerable variation among plant types. By not accounting for these differences, models have likely over-estimated the amount of water lost to the atmosphere in some regions.

If plants release less water there is more warming and a consequent increase in heat wave intensity.

The study is unique because, for the first time, it used the best available observations to characterise different plants water-use strategies within a global climate model.

Read the full article: Daily Examiner

A heatwave and stomata




Heatwave surprise: Plants’ response will make events more intense than thought


by Peter Hannam

Environment Editor, The Sydney Morning Herald

Heatwaves in the northern hemisphere may become as much as 5 degrees warmer than previously estimated by mid-century because plants’ response to higher carbon dioxide levels has been miscalculated, according to new research by Australian scientists.

As atmospheric levels of the greenhouse gas increase, plant stomata – the tiny pores on leaves that open to take in CO2 and let out water vapour – won’t need to open as much.

“There’s less water vapour being lost so you have a net warming effect,” said Jatin Kala, a lecturer from Murdoch University and lead author of the paper that was published Monday inNature Scientific Reports.

“During a heatwave, it makes it a lot worse” not to have that evaporative cooling effect, he said.

The researchers used data from 314 plant species across 56 field sites to examine how plants responded. Existing climate models had assumed all plants would trade water for carbon in exactly the same way.

Needle-leaf forests, tundra and agricultural land used for crops would likely suffer the biggest temperature increases. Heatwaves from Europe to China were likely to become 3-5 degrees hotter than the already higher base expected from global warming, Dr Kala said.

Read the full article: Sydney Morning Herald

Stomata to help build better climate models

Photo credit: Google × 300Search by image

Like the Lorax, the University of Auckland’s Cate Macinnis-Ng speaks for the trees.

Study of leaf pores may help scientists predict climate

by Auckland University (2015)

in Scoop Sci-Tech


A major global research project to help build better climate models is using data collected from plants at 56 sites around the world including kauri trees at Auckland’s Waitakere Ranges.
Data for the project was crowd-sourced from scientists in 15 countries. Samples were taken from the leaf pores – or stomata – of 314 plant species in different regions of the globe, from wild Arctic tundra to tropical rain forests.

Leaf pores of plants are highly responsive to environmental conditions such as humidity and soil moisture. Plants use stomata to control water loss and the intake of carbon during photosynthesis.

Because plants trade water for carbon, the data is important to understanding the carbon and water exchange between plants and the atmosphere. These water and carbon cycles are fundamental to a better understanding of how the Earth’s climate might be changing.

School of Biological Sciences lecturer Dr Cate Macinnis-Ng, who took part in the study, says it was good to see New Zealand data being included in the project.

“We contributed data from kauri trees growing in the Waitakere Ranges and it’s fantastic to see New Zealand being included is such a big global project,” she says.

“We sometimes get left out because of our small size. But so many of New Zealand’s plants are found nowhere else so it’s important our ecosystems are represented in climate models.”

Overall the study found that plants use water wisely, indicating that plants have adapted their water-use strategies to their environments.

Stomata and global warming


Global Warming and Stomatal Complex Types

by Abdulrahaman A. A., Oladele F. A. (2008)

in Ethnobotanical Leaflets 12: 553-556. 2008.



In relation with this, plants that possessed stomata with many subsidiary cells (e.g. tetracytic and anomocytic types) will play an important role in reducing greenhouse gases especially carbondioxide. To proof this fact, Obiremi and Oladele (2001) and Oyeleke et al (2004) studied the relationship between the stomatal complex types and transpiration rate in some selected Citrus species and some afforestation tree species respectively.

In both studies, stomatal complex types with many subsidiary cells transpired higher than those with less number. This translates to mean that the latter opens faster to allow carbon dioxide to enter the leaves and water vapour to escape to the atmosphere via the stomatal openings than the former. More over the other aspect of stomatal opening that favour water loss to the atmosphere (i.e. encouraging high rate of transpiration) is also advantageous by humidifying the atmospheric air.

Amaranthus stomata -
Amaranthus stomata –

Amaranthus stomata -
Amaranthus stomata –

However, to achieve reasonable atmospheric purification, plants with hypostomatic nature of the leaves (i.e. stomata being found or located on the abaxial surface only), lower frequency of stomata with many subsidiary cells (e.g. anisocytic, tetracytic and anomocytic), higher frequency of stomata with frequency of stomata with little subsidiary cells (e.g. cyclic, paracytic and diacytic), less heterogeneous composition of stomatal complex types, less stomatal density and index (i.e. less distribution of stomata on the surface of leaves), and lastly, probably occurrence of trichome (Figures 9 – 11) may be more suitable for afforestation in dry locations. Plants with opposite conditions of the above stomatal features may be more suitable for afforestation in wet environments. These conditions had earlier identified by Oyeleke et al. (2004) and AbdulRahaman and Oladele (2003; 2004).

Read the full story: Ethnobotanical Leaflets