Arbuscular Mycorrhizal fungi alleviate salinity stress in Avicennia marina through morphophysiological and biochemical modulation
Abstract
Increasing salinity threatens coastal mangrove ecosystems worldwide by impairing plant growth, physiological function, and biochemical processes, ultimately reducing productivity and survival. The present study was conducted to examine the impact of arbuscular mycorrhizal fungi (AMF) on Avicennia marina under different salt concentrations (9, 14, and 19 dS/m). This study included four treatments i.e. negative control (only salt: T1), species consortium of Glomus (T2), species consortium of Gigaspora (T3), consortium of both Glomus and Gigaspora spp. (T4) along with positive control (T0). The AMF inoculation found to be effective in reducing the negative effects of salt stress by improving plant growth, biomass, photosynthetic pigments, glomalin-related soil proteins, osmolyte accumulation, antioxidant enzymes as well as regulating malondialdehyde (MDA) and hydrogen peroxide (H₂O₂). Consortium inoculation significantly increased chlorophyll a and total chlorophyll contents under 14 and 9 dS/m salinity, while anthocyanin accumulation was highest in Glomus spp. inoculated seedlings under 19 dS/m concentration. Although Gigaspora spp. inoculation progressively improved shoot, root, and leaf biomass, the combined application of both AMF strains resulted in a more pronounced enhancement of other parameters including plant growth, easily extractable glomalin-related soil protein (EE-GRSP) accumulation, proline content, and the improvement of antioxidants, particularly catalase (CAT), acid phosphatase (ACP), alkaline phosphatase (AKP), and dehydrogenase along with significant reduction of oxidative damage parameters i.e. MDA and H₂O₂, indicating a stronger contribution of AMF synergy toward improving stress tolerance and physiological performance. Overall, consortium-based application was found superior, demonstrating its potential as a sustainable approach to enhance mangrove establishment.