Effect of mercury on early reactions of photosynthesis in Spirulina

Mercury is one of the heavy metal which causes inhibition in photosynthetic electron transport at multiple sites between the two photosystems, PS-II is more sensitive than that of PS-I. Mercury at low concentration causes alterations in absorption as well as fluorescence spectral properties and effects the energy transfer from Phycobilsome to reaction centre. During short term incubation it alters the interaction between chromophore and apo-protien of phycocyanin. Whereas long term incubation leads to the degradation of beta-subunit of phycocyanin