Effect of glutamate zerovalent iron nanoparticle and benzyl amino purine on physiology of Zea mays L. under induced mercuric chloride stress

Mercury contamination severely threatens maize growth and development, creating gap for effective mitigation practices. The experiment assesses the ameliorative effect of Glutamate-stabilized Zerovalent Iron Nanoparticles (Glu-ZVFeNPs) and Benzyl Amino Purine (BAP), applied individually and in combination, on physiological and biochemical responses of maize exposed to 20 and 40 ppm mercuric chloride (HgCl2) stress. Results showed that HgCl2 significantly reduce growth, biomass accumulation photosynthetic pigment and biochemical traits, particularly under 40 ppm HgCl2, though stress indicators increased. Covertly, BAP and Glu-ZVFeNPs application improved plant performance under stress levels. Their combine application at 20 ppm (T4) resulted maximum shoot fresh weight (5.48 g) shoot dry weight (0.6 g), root fresh weight (1.05 g), root moisture (80.6%), leaf fresh and dry weight (1.74 and 0.23 g), leaf area (76.21 cm2) and SVI (2338). Similar treatments also increased total chlorophyll (0.051 mg/g), carotenoids (5.57 mg/g), sugar (6.55 mg/g) and protein (190.7 mg/g), while reduce proline accumulation compared with stressed plants. Combine application more improved root length, shoot length, germination, leaf dry biomass and moisture content across stress levels. These results concludes that combined BAP and Glu-ZVFeNPs synergistically mitigate HgCl2 toxicity and enhanced maize tolerance through different physiological and biochemical protection mechanisms.