MOE Key Laboratory of Pollution Processes and Environmental Criteria, Tianjin Key Laboratory of Environmental Technology for Complex Trans-Media Pollution, College of Environmental Science and Engineering, Nankai University, Tianjin, 300350, PR China.
Tianjin Research Institute for Water Transport Engineering, Laboratory of Environmental Protection in Water Transport Engineering, Tianjin, 300456, PR China.
Chemosphere. 2020 Jan;239:124794. doi: 10.1016/j.chemosphere.2019.124794. Epub 2019 Sep 6.
Cadmium (Cd) pollution is considered one of the global environmental issues due to its adverse effects on plant and human health. With the rapid development of nanotechnology and the practical application of engineered nanoparticles (ENPs) in agriculture, the mechanisms underlying the interactions between NPs and heavy metal on their uptake, accumulation, and phytotoxicity in crops are still not fully understood. Therefore, the impact of TiO NPs (0, 100, 250 mg/L) and Cd (0, 50 μM) co-exposure on hydroponic maize (Zea mays L.) was determined under two exposure modes. Results showed that root co-exposure to TiO NPs and 100 mg/L Cd significantly enhanced Cd uptake and produced greater phytotoxicity in maize than foliar exposure to TiO NPs. Meanwhile, plant dry weight and chlorophyll content showed a reduction of 45.3% and 50.5%, respectively, when compared with single Cd treatment. In addition, the accumulation of Ti in shoots and roots increased by 1.61 and 4.29 times, respectively when root exposure to 250 mg/L TiO NPs. By contrast, foliar exposure of TiO NPs could markedly decrease shoot Cd contents from 15.2% to 17.8% and had a stronger influence on alleviating Cd-induced toxicity via increasing superoxide dismutase (SOD) and glutathione S-transferase (GST) activities and upregulating several metabolic pathways, including galactose metabolism and citrate cycle, alanine, aspartate and glutamate metabolism, as well as glycine, serine and threonine metabolism. This study provides a new strategy for the application of TiO NPs in crop safety production in Cd contaminated soils.
镉（Cd）污染被认为是全球环境问题之一，因为它对植物和人类健康有不良影响。随着纳米技术的快速发展和工程纳米粒子（ENPs）在农业中的实际应用，纳米粒子与重金属之间相互作用的机制，以及它们在作物中的吸收、积累和植物毒性方面的机制仍未完全理解。因此，确定了 TiO2 NPs（0、100、250 mg/L）和 Cd（0、50 μM）共暴露对水培玉米（Zea mays L.）的影响，采用两种暴露模式。结果表明，与叶面暴露 TiO2 NPs 相比，根暴露于 TiO2 NPs 和 100 mg/L Cd 可显著增强 Cd 的吸收，并对玉米产生更大的植物毒性。同时，与单独 Cd 处理相比，植物干重和叶绿素含量分别降低了 45.3%和 50.5%。此外，当根暴露于 250 mg/L TiO2 NPs 时， shoots 和 roots 中 Ti 的积累分别增加了 1.61 和 4.29 倍。相比之下，叶面暴露 TiO2 NPs 可使 shoots 中的 Cd 含量从 15.2%显著降低到 17.8%，并通过增加超氧化物歧化酶（SOD）和谷胱甘肽 S-转移酶（GST）活性以及上调几种代谢途径，包括半乳糖代谢和柠檬酸循环、丙氨酸、天冬氨酸和谷氨酸代谢以及甘氨酸、丝氨酸和苏氨酸代谢，对缓解 Cd 诱导的毒性有更强的影响。本研究为在 Cd 污染土壤中应用 TiO2 NPs 促进作物安全生产提供了一种新策略。
