Plant leaves and absorbtion of CO2

jeremy v

Guru Class Expert
Apr 17, 2008

I was wondering if the CO2 uptake rate at a certain plant leaf is based on the total light hitting the entire plant (and the plant as a whole determining the uptake rates for all the leaves), or if it is more of a cause/effect or reactionary response that is set independently for each leaf based on the amount of light hitting that particular leaf only.

I am wondering, because if a plant leaf absorbs CO2 solely based on the light that particular leaf receives, wouldn't the fact that the CO2 levels might not be as high down in the plant beds or in the middle of a bunch of stem plants make less of a difference overall, because the leaves that are in those locations wouldn't be able to process/require as much CO2 (since they would be at a much lower light level) anyways?

If the process of absorption of nutrients and CO2 is based on an overall demand set by the plant as a whole for all the leaves, then the CO2 levels in the middle of a dense grouping of plants would be very important to maintain at higher levels even though almost no light reaches those areas.

Have a good one, Jeremy

Tom Barr

Staff member
Jan 23, 2005
So can a plant allocate nutrients, as a whole organism or a semi autonomus organism with a variety of organs like leaves, stems and roots??

Where might they store resources?

Are leaves not storage organs in some cases?
Demand for CO2 is highest where new growth occurs typically.

An old mature leaf already is "grown", and needs few nutrients etc, just enough for maintenance.

so your question also depends a lot on the developmental stage of the leaf, which is not satisfied, can lead to curled twisted leaves etc, and have nothing to do with Calcium etc. Might have had poor CO2.

The other issue here, what about species to species differences in the ability to take up CO2? Say Myriophyllum vs a sword(different leaf shape) ? Egeria vs Tonia, both have the same type of leaf shape?

Surface area ratios make a different as well.

Tom Barr