Plant Pores Indicate Growing Carbon Dioxide Levels

Carbon dioxide levels have risen so much in the last 150 years that plant pores, which plants effectively breathe through have decreased in size by up to 34%. As a result plants are restricted in the amount of water vapor that they release into the atmosphere.

The study which was carried out by scientists from the Indiana University Bloomington and Utrecht University is set to be published in an issue of the Proceedings of the National Academy of Sciences and the research suggests that the lack of moisture omitted from plant pores could have an effect on climate change and the environment.

The same scientists suggested that if carbon dioxide was to double in quantity in the atmosphere, water released by the plant life would be dramatically reduced. The samples of plant life that were studied took place in Florida. The majority of plant life use pores known as stomata that are located on the underside of leaves, which are used to absorb carbon dioxide and release moisture. The plant uses the gas to produce sugar, which is in turn transferred into energy. As part of the process the plant transpires or releases water into the atmosphere. Transpiration also helps to keep the plant cool, which is crucial for plant life.

"The increase in carbon dioxide by about 100 parts per million has had a profound effect on the number of stomata and, to a lesser extent, the size of the stomata," said Research Scientist in Biology and Professor Emeritus in Geology, David Dilcher who is the co-author of the paper.

"Our analysis of that structural change shows there's been a huge reduction in the release of water to the atmosphere. The carbon cycle is important, but so is the water cycle. If transpiration decreases, there may be more moisture in the ground at first, but if there's less rainfall that may mean there's less moisture in the ground eventually. This is part of the hyrdrogeologic cycle. Land plants are a crucially important part of it," added Dilcher.

The scientists admitted that there are many potential scenarios and developments that could arise if plant stomata and the moisture they release is reduced. "When plants transpire they cool. So the air around the plants that are transpirating less could be a bit warmer than they have been. But the hydrogeologic cycle is complex. It's hard to predict how changing one thing will affect other aspects. We would have to see how these things play out," said Dilcher.

A drier atmosphere with less water could mean that less water will flow through Florida’s watersheds and this could also occur in other areas around the globe. "Our first paper shows connection between temperature, transpiration, and stomata density. The second paper really is about applying what we know to the future, plant adaptation to rising CO2 is currently altering the hydrological cycle and climate and will continue to do so throughout this century," warned Dilcher.

Photo Credit: Ayacop