Wow, plants remember things, how so? The key player here is an internal signaling molecule called GABA (gamma-aminobutyric acid) that was identified in this project by researchers. Using a model plant called Arabidopsis thaliana, they found that GABA accumulates in so-called guard cells when a plant experiences drought. Guard cells play a key role in regulating how much water a plant loses. How? Plant leaves contain numerous small pores called stomata which control the flow of gases in and out as well as the loss of water molecules during transpiration (the process of converting water into gas). Each stoma is composed of a pair of guard cells with a pore in between. Sensing light, the guard cells open the pores and close them when darkness falls and GABA plays a role in this signaling mechanism.
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