Additive effects of Trichoderma harzianum and TiO۲ nanoparticles on growth, cadmium stabilization and macroelements absorption of Mentha piperita L. under cadmium stress

Purpose: Nowadays, heavy metal pollution of soils has become a serious environmental concern and a potential threat to human health. Peppermint (Mentha piperita L.) is a medicinal and aromatic plant belonging to Lamiaceae family that its essential oil is used in different pharmaceutical industries. This study focused on the effects of arbuscular mycorrhizal fungi (AMF) and different concentrations of titanium dioxide nanoparticles (TiO۲ NPs) addition on the growth, absorption of macronutrients, migration and bioaccumulation of cadmium in soil- peppermint system. Research Method: A factorial experiment was conducted in a completely randomized design with three factors. The first factor was TiO۲ NPs (۰, ۲۰۰, and ۳۰۰ mg/kg), the second factor included Cd-spiked soil (۰ and ۵۰ mg/kg soil) and third Trichoderma harzianum. Findings: Our results showed cadmium caused negative effects on the growth of peppermint except for shoot and root length. The concentration of all the nutrients assessed (nitrogen and phosphorus) decreased in the presence of cadmium. Mycorrhization under cadmium stress conditions significantly increased nitrogen concentration in roots and shoots by ۱۵% and ۳%, respectively, respect to Cd treatment group. Following mycorrhizal inoculation under cadmium stress conditions, phosphorus concentration significantly increased in roots and shoots by ۳۳% and ۱۲%, respectively, respect to Cd treatment group. Similarly, application of TiO۲ nanoparticles at ۲۰۰ mg/Kg and ۳۰۰ mg/Kg concentrations alone and in combination with mycorrhizal soil amendments in stress as well as non-stress conditions effec­tively enhanced nutrient acquisition. With the addition of TiO۲ NPs and mycorrhiza to soil, the phytoavailability and uptake of Cd by peppermint roots increased. Research limitations: There was no limitation. Originality/Value: Our research demonstrates that applying AMF and TiO۲ NPs could be a sustainable approach to enhancing growth parameters of peppermint plants under Cd stress by improving nutrient acquisition and immobilizing the heavy metal Cd. The results obtained here can provide scientific data for the use of Mentha piperita L. in the remediation of Cd-contaminated soil.

کلیدواژه ها:

Heavy metals ، Inoculation ، Medicinal plants ، Phytoremediation