In vivo fluorescence kinetics of Gracilaria spp. subjected to different salinities

Gracilaria species were subjected to different salinities under laboratory conditions and changes in the photosynthetic oxygen evolution and fluorescence kinetics were followed. The plants which were subjected to more or less the normal salinity conditions exhibited low values of variable fluorescence and quantum yield. Prolonged treatment increased the quantum yield but the pigment content and the photosynthetic rate reduced significantly Among the two species tested, Gracilaria edulis was found to be very sensitive to low salinity (15 ppt) and G. crassa to higher salinity (45 ppt).