Question

Why does the rate of photosynthesis plateau when the concentration of carbon dioxide increases to a certain point?

Answer 1

Well we need to consider other factors as well...

Explanation:

Consider the photosynthesis equation:

`6CO_2(g)+6H_2O(l)stackrel("sunlight")stackrel("chlorophyll")->C_6H_12O_6(aq)+6O_2(g)`

Usually, increase the carbon dioxide content would increase the rate of reaction right? But also to a certain extent, where we need to consider other necessities, such as water and sunlight amount. If we just give the plant tons of `CO_2` but no water, the photosynthesis reaction can't happen, because water is the limiting reactant.

If we just give the plant carbon dioxide and also water but no sunlight, the plant won't have enough activation energy, and so the reaction cannot happen.

It doesn't mean just increasing the carbon dioxide amount would increase the rate of photosynthesis, because we also need to consider amount of other requirements as well.

Hope this helps!