Absorption Spectra & Action Spectra
- An absorption spectrum is a graph that shows the absorbance of different wavelengths of light by a particular pigment
- Chlorophylls absorb wavelengths in the blue-violet and red regions of the light spectrum
- Carotenoids absorb wavelengths of light mainly in the blue-violet region of the spectrum
- An action spectrum is a graph that shows the rate of photosynthesis at different wavelengths of light
- The rate of photosynthesis is highest at the blue-violet and red regions of the light spectrum, as these are the wavelengths of light that plants can absorb (ie. the wavelengths of light that chlorophylls and carotenoids can absorb)
- There is a strong correlation between the cumulative absorption spectra of all pigments and the action spectrum:
- Both graphs have two main peaks – at the blue-violet region and the red region of the light spectrum
- Both graphs have a trough in the green-yellow region of the light spectrum
