Photosynthetic Pigments

Photosynthetic Pigments

  • Leaves exhibit various shades of green due to the presence of different pigments. 
  • Separation of leaf pigments through paper chromatography reveals four main pigments:

- Chlorophyll a (bright or blue-green)

- Chlorophyll b (yellow-green)

- Xanthophylls (yellow)

- Carotenoids (yellow to yellow-orange). 

  • Roles of Pigments in Photosynthesis

- Pigments are substances capable of absorbing light at specific wavelengths.

- The most abundant plant pigment is chlorophyll. 

  • Chlorophyll a Absorption Spectrum

- Chlorophyll a's absorption spectrum indicates its ability to absorb light at specific wavelengths.

- Maximum absorption occurs in the blue and red regions of the spectrum.

- Another absorption peak may occur at a different wavelength. 

 

 

  • Photosynthesis and Chlorophyll a

- Maximum photosynthesis coincides with the wavelengths where chlorophyll a absorbs light most efficiently.

- Chlorophyll a is the primary pigment associated with photosynthesis.

- However, there is not a complete one-to-one overlap between chlorophyll a's absorption spectrum and the action spectrum of photosynthesis. 

 

 

 

  • Accessory Pigments

- Other pigments like chlorophyll b, xanthophylls, and carotenoids act as accessory pigments.

- They absorb light and transfer energy to chlorophyll a.

- Accessory pigments broaden the range of wavelengths utilized for photosynthesis and protect chlorophyll a from photo-oxidation.