Nanoparticles Pose Risks to Plant Growth and Physiology: Study Finds Chitosan-Proline Nanocomposites to Mitigate Toxicity

A recent study conducted by researchers at the University of Tabriz in Iran has demonstrated the potential risks posed by copper oxide nanoparticles (CuO NPs) to plant growth and physiology. The study found that excessive accumulation of CuO NPs in agricultural soils can induce oxidative stress and metal toxicity, leading to significant reductions in biomass and photosynthesis-linked traits in spearmint plants. However, the researchers also discovered that foliar application of chitosan-proline nanocomposites (Pro-CTS NPs) can mitigate CuO NP-induced phytotoxicity by enhancing physiological resilience and defense mechanisms in spearmint plants.

Key Takeaways:

• Research has shown that excessive accumulation of CuO NPs in agricultural soils poses significant risks to plant growth and physiology.
• Foliar application of chitosan-proline nanocomposites (Pro-CTS NPs) can mitigate CuO NP-induced phytotoxicity in spearmint plants.
• Pro-CTS NPs can enhance physiological resilience and defense mechanisms in spearmint plants, including enzymatic and non-enzymatic antioxidants.
• The study found that Pro-CTS NPs can significantly improve plant growth, restore chlorophyll and carotenoid levels, enhance essential oil yield, and reduce Cu uptake in spearmint plants.
• The observed effects were aligned with induced activities of antioxidant enzymes, including superoxide dismutase, ascorbate peroxidase, and guaiacol peroxidase, as well as higher proline and phenolic contents.
• The study concluded that further research is required to determine whether these benefits extend to other species, stress types, and field environments.

Statistics:

• Increasing CuO NP concentrations (100 and 200 mg kg soil) caused significant reductions in biomass- and photosynthesis-linked traits, along with elevated levels of malondialdehyde (MDA), hydrogen peroxide (H2O2), and Cu accumulation in spearmint plants.
• Foliar treatments with Pro-CTS NPs (25 and 50 mg L) significantly improved plant growth, restored chlorophyll and carotenoid levels, enhanced essential oil yield, and reduced Cu uptake in spearmint plants by 25-50%.
• The study found that Pro-CTS NPs may optimize or redirect metabolic fluxes toward desirable secondary metabolites in spearmint plants.

Sources:

• NewsRx. Reports from University of Tabriz Provide New Insights into Nanoparticles (Nanotechnology showdown: Chitosan-proline nanoparticles improve Mentha spicata L. tolerance against CuO nanoparticle toxicity). Nanotechnology Weekly. November 3, 2025; p 1553.
• International Journal of Biological Macromolecules, 2025:148398.