Chlorophyll Fluorescence Parameters and Chlorophyll Content in Mangrove Species Grown in Different Salinity

Leaf chlorophyll fluorescence parameters as well as chlorophyll content were compared in three dominant mangrove species grown in two zones with different salinity in the Bhitarakanika National Park. The accumulation of dry matter and chlorophyll content in leaves decreased under high saline conditions. Quantification and de-convolution of chlorophyll fluo-rescence transient into several phenomenological and biophysical parameters (JIP-test) revealed that maximum fluorescence (Fm), maximum quantum yield of primary photochemistry (Fv/Fm), area above the fluorescence curve between Fo and Fm, electron transport and active reaction centers per cross section decreased in the leaves of all species at high saline ambience compared to the low salinity zone. In contrast, a significant increase in the minimal fluorescence (Fo) was noticed in the leaves of A. officinalis and H. fomes in the highly saline zones. Among the fluorescence parameter studied, the area above the fluorescence curve between Fo and Fm was found to be more sensitive to salinity. Thus, salinity induced functional alterations in PS II and led to down-regulation of PS II activity.