[Pigment degradation in Synechocystis aquatilis under nitrogen starvation with varying illumination]

When the cells of Synechocystis aquatilis are incubated in a medium without nitrogen, the degradation of pigments in the conditions of illumination occurs in two stages: (i) during the first day and (ii) after three days of the incubation. The degree of degradation increases with the intensity of illumination and correlates with the rate of cell death. The pigments are not degraded in the dark. When chlorotic cells are transferred to a medium containing nitrogen, their number increases stepwise by a factor of 1.2 after 7--8 hours and rises exponentially after 14 hours; the synthesis of phycocyanin starts after 7 hours and the synthesis of chlorophyll only after 12 hours when the chlorophyll-to-phycocyanin ratio reaches its normal value (1. 1).