Action Spectrum - Red vs blue?

[Dr.Stein]

Chlorophyll absorbs light at either red or blue wavelengths, but there is a definite difference between the two 'peaks' in increased rate of photosynthesis.

Does anyone know why this is? any information would be extremely handy as I cannot seem to find any useful information

They are chlorophyll A and chlorophyll B

[Micky T]

no, i meant the two peaks within chlorophyll, like chlorophyll a had a blue peak and a red peak, as does chlorophyll b. Chlorophyll b will absorb blue more effeciently than red, whereas chlorophyll a will be just as effecient. I was wondering if there was a reason why a particular plant should absorb more blue light than red, and my previous post is the answer i've come up with - it's probably not right.

[MrMistery]

Ok, so
1. We don't know for sure what causes the specific action spectrum of the chlorophyll molecule. Hypothesises are that the specific shape of the molecule, the surrounding molecules and the proteins in the complexes contribute. Don't forget, P680 and P700 are both chl a, but have different absorbtion spectra.
2. The exact composition of pigments varies not only by species, but also by surrounding conditions. In shade, more chl b accumulates to help absorb more light. In intense light, more carotenes accumulate to help protect the plant. It is a very dimanic phenomenon...
Hope this is at least of some help.
Cheers.

[Dr.Stein]

I think it is preferences, I mean such chlorophyll works in a certain wavelenght, which red or blue are there... Pfff how to tell, my English sucks at the moment