Effect of copper on photosynthetic electron transport activities in the, cyanobacterium, Spirulina platensis

Treatment of Spirulina intact cells with different concentrations (10-100 mu M) of CuCl2 caused inhibition in whole chain electron transport as well as PSII catalysed electron transport (H2O ->(P)BQ). The loss observed by 50% in PSII catalysed electron transport at 50 mu M could be due to either alterations at the water oxidation complex or changes in light harvesting complex. Unlike PSII, PSI catalysed electron transport (DCPIPH2 -> MV) is less sensitive to Cu treatment. This loss in PSI catalysed electron transport could be due to alterations in the PSI reaction centre. Thus Cu affects both PSII and PSI in preferential manner.