Foliar use of TiO2-nanoparticles for okra (Abelmoschus esculentus L. Moench) cultivation on sewage sludge-amended soils: biochemical response and heavy metal accumulation

Investigation on effects of TiO2 on cucumber seedlings using ICP-OES and LA-ICP-MS

With the expansion of TiO2 applications in various fields, TiO2 inevitably enters the soil, increasing the possibility of plant roots being exposed to high concentrations of TiO2. Therefore, it is important to study plant growth under TiO2 exposure conditions. In this study, the combination method of inductively coupled plasma emission spectroscopy (ICP-OES) and laser ablation inductively coupled plasma mass spectroscopy (LA-ICP-MS) was used to evaluate the effect of TiO2 on the content and distribution of nutrient elements in different parts of cucumber seedlings. The results showed that the low concentrations (50 mg/L, 100 mg/L and 200 mg/L) of TiO2 had gradually enhanced the growth of cucumber seedlings, while the high concentration (500 mg/L) of TiO2 had a significant inhibitory effect on the plant. The contents of elements (Ti, K, Ca, Mg, Mn, Fe, Zn, and Cu) in cucumber seedling roots, stems and leaves incubated with 200 mg/L TiO2 were determined by ICP-OES, and the results showed that the uptake of TiO2 increased the content of nutrient elements in the plant. High-resolution imaging of Ti, Ca, Mg, Mn, Fe, Zn, and Cu in roots, stems, and leaves using LA-ICP-MS showed that Ti accumulated mainly at the margins of the leaves. Ca, Mg, Mn, Fe, Zn, and Cu in the leaves were mainly concentrated in the main veins and lateral veins. By evaluating the content and distribution of elements in the plant with ICP-OES and LA-ICP-MS, it provides a new idea to study the mechanism of nanoparticles in the plant. It provides a theoretical basis for the correct use of nanomaterials, which is of great significance in promoting the sustainable development of agriculture.

Nano-enabled agrochemicals: mitigating heavy metal toxicity and enhancing crop adaptability for sustainable crop production

The primary factors that restrict agricultural productivity and jeopardize human and food safety are heavy metals (HMs), including arsenic, cadmium, lead, and aluminum, which adversely impact crop yields and quality. Plants, in their adaptability, proactively engage in a multitude of intricate processes to counteract the impacts of HM toxicity. These processes orchestrate profound transformations at biomolecular levels, showing the plant's ability to adapt and thrive in adversity. In the past few decades, HM stress tolerance in crops has been successfully addressed through a combination of traditional breeding techniques, cutting-edge genetic engineering methods, and the strategic implementation of marker-dependent breeding approaches. Given the remarkable progress achieved in this domain, it has become imperative to adopt integrated methods that mitigate potential risks and impacts arising from environmental contamination on yields, which is crucial as we endeavor to forge ahead with the establishment of enduring agricultural systems. In this manner, nanotechnology has emerged as a viable field in agricultural sciences. The potential applications are extensive, encompassing the regulation of environmental stressors like toxic metals, improving the efficiency of nutrient consumption and alleviating climate change effects. Integrating nanotechnology and nanomaterials in agrochemicals has successfully mitigated the drawbacks associated with traditional agrochemicals, including challenges like organic solvent pollution, susceptibility to photolysis, and restricted bioavailability. Numerous studies clearly show the immense potential of nanomaterials and nanofertilizers in tackling the acute crisis of HM toxicity in crop production. This review seeks to delve into using NPs as agrochemicals to effectively mitigate HM toxicity and enhance crop resilience, thereby fostering an environmentally friendly and economically viable approach toward sustainable agricultural advancement in the foreseeable future.

Accumulation and migration of microplastics and its influencing factors in coastal saline-alkali soils amended with sewage sludge

Coastal saline-alkali soil can be transformed to agricultural soil with sewage sludge amendment. However, sewage sludge contains a large number of microplastics (MPs), and the fate of MPs in sludge-treated saline-alkali soil needs to be studied. Therefore, we investigated the accumulation and migration of MPs, and their influencing factors in saline-alkali soil after one-time sewage sludge application (0, 25, 50, 100 and 200 t ha-1 SSA). The results indicated that sewage sludge input contributed to MP accumulation in soil, and the MP abundance in 20-40 cm soil was significantly lower than that in 0-20 cm soil. Fragments and fibers were the most abundant MPs in soil, and the proportions of fragments and 50-200 µm MPs in 20-40 cm soil were lower than those in 0-20 cm soil, while the < 50 µm MP proportion was higher than that in 0-20 cm soil. Correlation analysis showed that MP accumulation rate (0-40 cm) and migration rate (20-40 cm) were negatively correlated with soil organic matter (SOM) content and SSA, but positively correlated with soil pH. Stepwise regression analysis further showed that SOM and SSA were the main factors affecting MP accumulation rate, which explained 47.7% and 46% of its variation, respectively, while pH was the crucial factor affecting the migration rate of MPs, followed by EC and SSA. In conclusion, SSA caused MP accumulation in saline-alkali soil, and SSA primarily affected the MP abundance, while soil OM, pH and EC directly affected MP migration in soil.