Silver nanoparticles strengthen Zea mays against toxic metal-related phytotoxicity via enhanced metal phytostabilization and improved antioxidant responses

Abstract

This study investigated the phytostabilization and plant-promoting abilities of silver nanoparticles (AgNPs). Twelve Zea mays seeds were planted in water and AgNPs (10, 15 and 20 mg mL⁻¹) irrigated soil for 21 days on soil containing 0.32 ± 0.01, 3.77 ± 0.03, 3.64 ± 0.02, 69.91 ± 9.44 and 13.17 ± 0.11 mg kg⁻¹ of As, Cr, Pb, Mn and Cu, respectively. In soil treated with AgNPs, the metal contents were reduced by 75%, 69%, 62%, 86%, and 76%. The different AgNPs concentrations significantly reduced accumulation of As, Cr, Pb, Mn, and Cu in Z. mays roots by 80%, 40%, 79%, 57%, and 70%, respectively. There were also reductions in shoots by 100%, 76%, 85%, 64%, and 80%. Translocation factor, bio-extraction factor and bioconcentration factor demonstrated a phytoremediation mechanism based on phytostabilization. Shoots, roots, and vigor index improved by 4%, 16%, and 9%, respectively in Z. mays grown with AgNPs. Also, AgNPs increased antioxidant activity, carotenoids, chlorophyll a and chlorophyll b by 9%, 56%, 64%, and 63%, respectively, while decreasing malondialdehyde contents in Z. mays by 35.67%. This study discovered that AgNPs improved the phytostabilization of toxic metals while also contributing to Z. mays’ health-promoting properties.

NOVELTY STATEMENT

Enhanced phytoremediation strategies, which use nanoparticles to boost and facilitate the phytoremediation capacity of plants, are being recommended due to the limitations of traditional phytoremediation employing hyperaccumulating plants alone. Nanoparticles enhance phytoremediation potentials by directly reducing phytoavailable pollutants and promoting plant growth. Silver nanoparticles (AgNPs) are recognized as possessing the ability to enhance the phytoremediation of heavy metals HMs by converting them to a less toxic form and immobilizing the remaining phytoavailable HMs. This is in addition to their potential to modify plant biochemical and physiological properties to counteract HM toxicity.

Keywords:

• Germination index
• metal tolerance index
• phytostabilization
• translocation factor
• Zea mays

Disclosure statement

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper