These nanoparticles may be used to support crop growth in heavy metal-contaminated areas, boosting crop yield.
Toxic metals like arsenic, cadmium, and lead have been gaining public attention as it not only poses a threat to the environment and human health, but also affect plant growth, quality, and yield. While plants may have developed efficient strategies to detoxify heavy metals, pollution from human activities has made it difficult to cope. Therefore, a new strategy is needed to help plants manage toxic heavy metals.
Published in the Journal of Nanobiotechnology, researchers from the Xishuangbanna Tropical Botanic Garden (XTBG) of the Chinese Academy of Sciences and Shanxi Agricultural University looked into the mechanisms of nanoparticle-mediated cadmium tolerance in plants.
Engineered nanomaterials have been known to negatively or positively affect plant growth and development attributed to their physiochemical properties, application, and concentrations. Previous works have shown the great potential of nano-based materials in crop improvement under heavy metals. In one study, ferroferric oxide (Fe3O4) nanoparticles affect tobacco seed germination in size- and dosage-dependent manners. Another study showed that while zinc oxide (ZnO) nanoparticles could inhibit plant growth, they could also restore more rapid plant growth.
With these two oxides in mind, the team used a tobacco cultivar “Yunyan 87” (N. tabacum) to investigate the effects of Fe3O4 or ZnO nanoparticles on plant growth and cadmium responses in tobacco seedlings.
They first looked into the effects of cadmium on tobacco seedling growth and observed that treatment with cadmium significantly inhibited plant growth in terms of plant height, shoot fresh weight, root length, and fresh weight.
To confirm if Fe3O4 and ZnO nanoparticles played a part in mediating cadmium response, the team went ahead to expose Fe3O4, ZnO nanoparticles, and ion solutions to the tobacco seedlings. Exposure of the tobacco seedlings’ leaves to Fe3O4 or ZnO nanoparticles displayed great potential in alleviating plant growth under cadmium stress.
When compared to the seedlings that were only treated with cadmium, the metal nanoparticles and ions significantly promoted root growth and fresh weight. These results suggest that Fe3O4 or ZnO nanoparticles might have reprogrammed critical metabolic pathways, including alkaloids, amino acids, flavonoids, and the differentially accumulated metabolites involved in these pathways were significantly correlated with plant growth.
“Our results collectively indicate that metal nanoparticles can serve as plant growth regulators and provide insights into using them for improving crops in heavy metal-contaminated areas,” said Wan Jinpeng of XTBG.
Source: Zou et al. (2022). Comparative physiological and metabolomic analyses reveal that Fe3O4 and ZnO nanoparticles alleviate Cd toxicity in tobacco. Journal of Nanobiotechnology, 20(1), 1-22.