Glomus versiforme and Micrococcus yunnanensis reduce the negative effects of salinity stress by regulating the redox state and ion homeostasis in Brassica napus L. crops

Abstract

Salinity stress is a major threat that negatively affects plant growth and production in arid and semi- arid regions. Application of biofertilizers could mitigate this stress. Accordingly, a pot experiment was conducted on rapeseed grown under salinity stress (0, 5, 10, and 15 dS m−1) while considering the following additives: (1) AMF (non-inoculated and inoculated with Glomus versiforme) and (2) PGPR (non-inoculated and inoculated with Micrococcus yunnanensis). The present results showed that salinity stress led to significant reductions in growth, yield, yield components, and physiological attributes, while raising the Na+/K+ ratio. However, with the application of PGPR and AMF, the increased salinity tolerance of rapeseed resulted in a significant improvement in redox status and ion homeostasis. They considerably improved antioxidant enzymatic activity and plant nutrition status. Furthermore, the co-inoculation of PGPR and AMF increased chlorophyll a, chlorophyll b, carotenoids, photosynthesis rate, and percentage of rapeseed oil under 15 dS m−1 1.7-, 1.8-, 2.3-, 2.0- and 1.3-times, respectively, compared with the non-inoculation treatment. These findings indicate that the integral application of PGPR and AMF is essential for alleviating salinity stress.