Structural and functional stability of photosystem-II in Moringa oleifera under salt stress

The photosynthetic efficiency in plants is affected by salinity. Focus of this study was to observe the consequences of salinity on the rate of photosynthesis in Moringa (Moringa oleifera L.) plants. Experiment was conducted under field conditions with 3 replicates and data of treated and non-treated plants was collected accordingly. Photosynthetic rate was affected by different levels of salt stress. The change in photosynthetic was attributes were determined by OJIP and light response curve calculations by using Fluor Pen [FP 100-PS (Photon system, Czech Republic)] and DUAL-PAM-100 (Walz, Germany). Salinity stress decreased chlorophyll a fluorescence characteristic. The significant quantity of electron transport (φEo), quantum yield of primary photochemistry (φPo), proficiency per trapped excitation (Ψo) and performance index of photosystem II (PSII). Performance index (PIABS) was also declined with salinity in M. oleifera. Our results showed that electron transport rate and photosynthetic rate were inhibited by salinity in M. oleifera. However, in M. oleifera electron transport pathway of PSII was repressed and found varied in plants which are salt resistant. It was concluded that Y(I), ETR(I), Y(II), ETR(II), and Y(NA) were decreased by increasing salinity while NPQ, Y(ND), Y(NO) and Y(NPQ) increased in plants having resistance to salt stress