Table 6.
Limitation and pitfalls of using engineered nanomaterials on plants.
| Engineered nanomaterials | Concentration | Plant species | Adverse effects | References |
|---|---|---|---|---|
| Multiwalled carbon nanotubes (MWCNT) and oxidized-MWCNT | 46×10–3 mg mL–1 | Mustard (Brassica juncea) seeds | Reduced germination rate and plant growth | (Mondal et al., 2011) |
| Carboxy fullerenes (C70(C(COOH)2)2−4) | 0−0.144 mg mL–1 | Tobacco (Nicotiana tabacum) cells | Reduced plant growth | (Liu et al., 2013) |
| Water-soluble graphene | 500–2000 mg L–1 | cabbage (Brassica oleracea), Tomato (Solanum lycopersicum), and spinach (Amaranthus dubius) plants | Reduced growth (Plant height and biomass) | (Begum et al., 2011) |
| Single-bilayer graphene oxide | 0, 100, 200, 400, 800, 1600 mg L−1 | Beans (Vicia faba) | Reduced plant growth and enzymatic activity | (Anjum et al., 2014) |
| Coated (humic acid) and uncoated zinc oxide (ZnO) ENMs | 0, 10, 100, 1000 mg kg–1 soil | Cucumber plants | Reduced plant growth (root and shoot biomass) | (Moghaddasi et al., 2017) |
| Core-shell iron/iron oxide (Fe/Fe3O4) and copper-/copper oxide (Cu/CuO) ENMs | 10, 20 mg L–1 | Lettuce (Lactuca sativa) | Decreased plant growth, water potential, dry weight, and the concentration of several nutrients | (Trujillo-Reyes et al., 2014) |
| Cu/CuO and Zn/ZnO ENMs | 0, 10, 50, 100, 500, 1000 mg L–1 | Cucumber (Cucumis sativus) | Decrease seedling biomass at higher nanoparticle concentrations | (Kim et al., 2012) |
| Cu/CuO ENMs | 0, 20, 80 mg kg–1 | Cilantro (Coriandrum sativum) | Reduced germination, water content, and relative chlorophyll content | (Zuverza-Mena et al., 2005) |
| Cerium oxide (CeO2) and ZnO ENMs | 400–800 mg kg–1 | Cucumber (Cucumis sativus) | Decreased non-reducing sugars, affecting albumin and prolamin fractions | (Zhao et al., 2014a) |
| CuO ENMs | 0, 50, 100, 200, 400, 500 mg L–1 | Green pea (Pisum sativum L.) | Reduced plant growth (shoot and root lengths) | (Raliya et al., 2015) |
| Titanium dioxide (TiO2) (rutile) ENMs | 0, 0.25, 0.5, 1.0, 1.5, 2.0, 2.5, 4.0, 6.0% | Spinach (Spinacia oleracea) | Reduced plant growth rate and crop yield | (Zheng et al., 2005) |
| CuO, aluminum oxide (Al2O3), and TiO2 ENMs | 0, 20, 200, 2000 μg mL−1 | Onion (Allium cepa) | Reduced root length | (Ahmed et al., 2018) |
| Fe₃O₄ and TiO₂ ENMs | (0, 100, 200 mg kg–1 soil) | Soybean (Glycine max) | Decreased plant growth | (Burke et al., 2015) |
| Titanium dioxide (TiO₂) ENMs | 0, 10, 50, 100, 200, 1000, 2000 mg L–1 | Lemna minor | Growth inhibited above 200 mg L–1 | (Song et al., 2012) |
| Silver (Ag) and TiO2 ENMs | 10, 20, 40 ppm Ag-NP and 31, 50, 100 ppm TiO2-NP | Lemna (paucicostata) | Decreased growth rate | (Kim et al., 2011) |