Julian Schroeder, biology professor, said that for each carbon dioxide molecule that was incorporated into plants through photosynthesis, a plant loses about 200 hundred molecules of water through their stomata.
He further explained that because elevated CO2 reduces the density of stomatal pores in leaves, at first sight it was beneficial for plants as they would lose less water, however, the reduction in the numbers of stomatal pores decreases the ability of plants to cool their leaves during a heat wave via water evaporation which could affect crops yield.
Using a combination of systems biology and bioinformatic techniques, the scientists cleverly isolated proteins, which, when mutated, abolished the plant's ability to respond to CO2 stress.
The study found that when plants sense atmospheric CO2 levels rising, they increase their expression of a key peptide hormone called Epidermal Patterning Factor-2, EPF2.
The discovery should help biologists better understand how the steadily increasing levels of CO2 in our atmosphere (which last spring, for the first time in recorded history, remained above 400 parts per million) are affecting the ability of plants and economically important crops to deal with heat stress and drought.
The study is published in the online edition of Nature.