Photosynthetic responses of durum wheat to chemical/microbiological fertilization management under salt and drought stresses

The current research was carried out to evaluate the stress tolerance potential of durum wheat plants, in response to the inoculation of native plant growth-promoting bacteria (PGPB), through assessing PSII photochemistry and photosynthetic traits, as well as grain yield and plant height, and to investigate the possibility of using PGPB as a sustainable alternative or in combination with traditional fertilization plans. A greenhouse experiment included chemical/microbiological fertilization and stress (salinity and drought) treatments. The results indicated that the application of bacterial consortium of four PGPB markedly augmented some biochemical and functional traits in photosystem II, such as effective quantum yield of PSII photochemistry (Y(II)), electron transport rate of PSII (ETR), photosynthesis capacity, transpiration rate and stomatal conductance in unstressed plants, and prevented severe changes in the mentioned traits under drought and salinity conditions. The application of PGPB contributed to enhanced grain yield, too. Furthermore, a better performance of the PGPB inoculation was found in combination with half-dose of the recommended chemical fertilizers. In conclusion, PGPB inoculants maintain or improve the photosynthesis efficiency of durum wheat, grain yield and plant height, particularly under stress conditions, and can help to minimize the consumption of chemical fertilizers.