Table 5.
Phytotoxicity of nanoparticles based on ZnO
| Plant | Type of nanoparticle, particle size (nm) | Particle concentration | Comment | Observed effect | References |
|---|---|---|---|---|---|
| Glycine max | ZnO NPs <50 nm | 500 ppm | Effect of ZnO NPs on soybean seedlings was studied | Decrease in root growth (length and weight), loss of root cell viability, accumulation of superoxide and decrease in leaf weight, down regulation of oxidative cascade related genes | [89] |
| Pisum sativum | Bare ZnO NPs 10 nm, Al2O3/ZnONPs 15 nm, KH550/ZnO NPs 20 nm | 250, 1000 mg L−1 of soil | Pea plants were grown for 65 days in soil amended with three types of ZnO NPs | Al2O3/ZnO NPs at 250 mg kg−1 significantly increased chlorophyll-a and carotenoid concentrations. Al2O3/ZnO NPs at 1000 mg kg−1 significantly increased sucrose concentration of green peas | [90] |
| Zea mays, Oryza sativa | ZnO NPs <50 nm | 500, 1000, 2000 mg L−1 | Seed germination was investigated | ZnO NPs inhibited root elongation at 2000 mg L−1 (50.45% for maize and 66.75% for rice) of two crop plants | [91] |
| Brassica pekinensis | Spheric ZnO NPs 30 nm, spheric ZnO NPs 50 nm, columnar ZnO NPs 90 nm, hexagon rod-like ZnO NPs 150 nm | 1, 5, 10, 20, 40, 80 mg L−1 | There were no significant differences in observed effects between different NPs | ZnO NPs inhibited the root and shoot elongation of Chinese cabbage seedlings. The highest inhibition of root elongation at 80 mg L−1 was observed | [92] |
| Pisum sativum | ZnO NPs <50 nm | 250, 500, 750, 1000 mg L−1 | No impact on germination | ZnO NPs (500–1000 mg L−1) significantly inhibited root elongation | [93] |
| Vigna unguiculata | ZnO NPs <100 nm | 25 mg L−1 | More pronounced effects were observed with ZnCl2 than with ZnO NPs | Significant decrease in biomass production of roots and leaves observed in solution culture, but not observed in soil culture | [94] |
| Arabidopsis thaliana | ZnO NPs <100 nm | 100 mg L−1 | Effect of ZnO NPs on gene expression in plant roots were studied | Induction of stress responsive genes, down regulation of genes involved in cell organization and biogenesis | [94] |
| (Glycine max) | ZnO NPs 10 nm | 50, 100, and 500 mg kg−1 of soil | ZnO NPs were added to the soil | Zn bioaccumulated in all tissues and especially in the leaves | [96] |
| (Fagopyrum esculentum) | ZnO NPs <50 nm | 10, 100, and 1000 mg kg−1 of soil | ZnO NPs were added to the soil and growth of plant seedlings were observed | Inhibition of shoot growth | [21] |
| Triticum aestivum | ZnO NPs <100 nm | 500 mg kg−1 sand | ZnO NPs were added to the sand | Reduced root growth, increased lipid peroxidation and oxidized glutathione in roots. Bioaccumulation of Zn and decreased chlorophyll content in the shoots | [67] |
| Cucumis sativus | ZnO NPs 50 nm | 10, 50, 100, 500, 1000 mg L−1 | Hydroponic experiments | Decrease in seedling biomass. ZnO NPs adhered to the root cell wall, and some of them were observed in the root cells | [97] |
| Allium sativum | ZnO NPs 3–5 nm | 10, 20, 30, 40, 50 mg L−1 | Hydroponic experiments | Concentration-dependent inhibition of root length, observed mitotic aberrations | [98] |
| Zea mays | ZnO NPs 370–410 nm | 20 mg L−1 | ZnO NPs were added to the sandy loam soil or to the water | ZnO NPs aggregates penetrated the root epidermis and cortex. Some of the NPs aggregates were also present in xylem vessels | [112] |