Mitigating exogenous cobalt-induced stress in maize plants with biochar and arbuscular mycorrhizal fungi (Rhizophagus intraradices)

Abstract

The natural balance of biological systems, particularly plants, faces strains from various biotic and abiotic stressors. One such concern in agriculture is the accumulation of cobalt (Co) in soil, impacting plant growth and soil microflora adversely. This study delved into the impact of cobalt contamination on maize plants, vital for human and poultry consumption, and explored the potential benefits of soil amendments such as biochar (B) and arbuscular mycorrhizal fungi (AMF) as cost-effective remedies to enhance plant growth in metal-polluted soils. The investigation was conducted through a pot experiment to understand their effects. The experiment evaluated the impact of Rhizophaus intraradices and biochar on maize plants grown under different cobalt concentrations (0, 60, and 120 ppm). A wide range of physiological parameters, including plant height, number of leaves, root and shoot fresh and dry weight, relative water content, electrolyte leakage, chlorophyll and carotenoid content, oxidative stress, cobalt distribution, and nutrient content, were analyzed. The results revealed that cobalt contamination had a negative impact on plant growth, reducing chlorophyll and carotenoid content, increasing oxidative stress, and elevating cobalt accumulation in the shoot while also decreasing nutrient content. However, Rhizophagus intraradices inoculation and biochar application were shown to be effective in reducing cobalt uptake in aerial parts, improving nutrient content, and reducing oxidative stress. This study highlights the potential of AMF and biochar as cost-effective amendments for improving maize growth and mitigating cobalt toxicity in contaminated soils.