Effects of the Arbuscular Mycorrhizal Fungus Gigaspora albida (Gigasporaceae) on the Physiology, Growth, and Na/K Balance of Creole Corn (Poaceae) Under Different Salinity Levels

Arbuscular mycorrhizal fungi (AMFs) can alleviate salt stress in plants by promoting growth. The mitigating effect of the AMF Gigaspora albida on the physiology, growth, and Na⁺/K⁺ balance in heirloom maize under different dilutions of saline wastewater was evaluated. The study was conducted in a greenhouse under a completely randomized design (CRD) in a 3 × 4 factorial scheme, with six replicates. The treatments consisted of three mycorrhizal conditions (M1—control plants without the AMF; M2—plants inoculated with G. albida; and M3—plants inoculated with G. albida plus the soil microbiota) and four levels of electrical conductivity (ECw): 0.5, 1.8, 3.1, and 4.4 dS m−1. The results indicate that saline wastewater affects the physiology of heirloom maize. The symbiosis in M2 and M3 mitigated the stress in PSII by dissipating heat. The M3 treatment alleviated ionic stress in maize, reduced the Na⁺/K⁺ ratio in the aerial part, and increased the MSPA, MSRA, AP, and DC at ECa levels of 1.8 and 3.1 dS m−1. The M1 plants adapted by investing in root growth to tolerate the high salinity. In M2, the plant–AMF interaction did not mitigate the effects of high salinity, showing the worst growth performance. The saline wastewater reduced the percentage of G. albida colonization. An ECa of 2.9 dS m−1 favored a high spore density.