A Random Question About Plants?

Question

Ok so I know how photosynthesis works but I have this question about it. If it is a cloudy day, can plants still make photosynthesis because of the UVA and UVB rays, or do they need the actual sun?

Answer 1

Different plants use light of different wavelength to photosynthesize, some need bright sunshine, some like/suffer shadow.

Here you find a diagram:

"Light and photosynthesis"

http://www.botany.uwc.ac.za/ecotree/phot...

You see the rate of photosynthesis differs but it`s the most time higher than zero.

The rate of photosynthesis at the different wavelengths of visible (!) light shows two peaks which roughly correspond to the absorption peaks of chlorophyll a, the most common chlorophyll..

Plants do not depend only on chlorophyll a in their light harvesting machinery but also have other pigments (accessory pigments) which absorb light of  different wavelengths

So plants need visible light ( actual sun ), but even on a cloudy day there is sufficient light in spectrum of required wavelengths.

Answer 2

Some UVA and UVB rays can penetrate clouds depending on their thickness.