Lead (Pb) contamination is a critical environmental concern that adversely affects plant growth and development. This study investigates the potential of ZnFe₂O₄ nanoparticles (NPs) and plant growth-promoting rhizobacteria to alleviate Pb-induced phytotoxicity in Vigna radiata (mung bean). Seeds were subjected to 30 µM Pb stress alone or in combination with ZnFe₂O₄ NPs and PGPR. Germination parameters including germination percentage, mean germination time, and germination index were significantly impaired under Pb stress, whereas co-application of ZnFe₂O₄ NPs and PGPR restored these traits, resulting in improved and timely seedling emergence. Vegetative growth parameters such as shoot and root length, fresh and dry biomass, and leaf area were notably reduced under Pb exposure. However, the integrated use of ZnFe₂O₄ NPs and PGPR significantly improved plant height (by 29.4%), root length (33.8%), and leaf area (27.9%) compared to Pb-stressed plants. Similarly, fresh and dry biomass values showed marked recovery, indicating improved water and nutrient uptake efficiency in treated plants. Anatomical analysis revealed severe structural damage in Pb-stressed leaves, including reduced epidermal thickness, disrupted mesophyll tissue, and decreased stomatal dimensions. The application of ZnFe₂O₄ NPs and PGPR markedly ameliorated these anatomical deformities, enhancing epidermal integrity, vascular bundle organization, and stomatal morphology. Notably, stomatal length and guard cell dimensions were restored closer to control levels. Overall, the synergistic effect of ZnFe₂O₄ NPs and PGPR substantially mitigated Pb toxicity and promoted normal germination, vegetative development, and anatomical structure in Vigna radiata, suggesting a viable strategy for cultivating crops in contaminated soils.

Department of Botany Government Superior Science College Peshawar Peshawar 25120 Pakistan

Department of Botany University of Peshawar Peshawar 25120 Pakistan

National Culture Collection of Pakistan Park Road Islamabad 45500 Pakistan

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