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Why does an increase in CO2 cause the stomata to close more?

In my head it just makes more sense that the stomata would open more because they would want as much CO2 as possible for photosynthesis. But apparently that's not the case...
Can someone explain please?
Original post by doka13
In my head it just makes more sense that the stomata would open more because they would want as much CO2 as possible for photosynthesis. But apparently that's not the case...
Can someone explain please?

Essentially you would be right to be honest. More CO2 would allow the plant to effectively photosynthesise.
I guess too much would cause the stomata to close due to the fact that if there is more carbon dioxide there is obviously more exchange occurring (and the stomata would be open) which would lead to water being lost so closure of the stomata prevents further water loss.
(edited 1 year ago)
Im pretty sure an excess of CO2 causes the stomata to close as it is just not needed. The stomata only take up the CO2 that they need, if they continuously took up CO2 there would not be enough CO2 for other plants (think about the carbon cycle !)

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