Question

The idea of two pigment systems in light reaction of photosynthesis was given by

• A. Arnon
• B. Hill
• C. Blackman
• D. None of the above

Answer 1

The correct option is D None of the above

Wavelengths above 700nm are seemingly of low energy to drive any part of photosynthesis so pigments absorbing light becomes inactive above this wavelength of light. So a vast decline has been noticed in productivity at 700nm (red part of visible spectrum). This phenomenon is called as red drop effect. This effect was first of all noticed by Robert Emerson of Illinois University. Emerson etall. also observed that if chlorella plants are given the inefficient far red light and red light of shorter wavelengths in alternate fashion, the quantum yields were more than either colour was provided alone. This enhancement is known as EEE or Emerson Enhancement Effect. This was the first good evidence that there are two photosystems, one absorbs far-red light and other red light and both of them must operate to drive photosynthesis most effectively. So the idea of two pigment system was given by Robert Emerson.