Department of Microbiology, College of Basic Sciences and Humanities, Punjab Agricultural University, Ludhiana, 141004, India.
Electron Microscopy and Nanoscience Laboratory, Department of Soil Science, College of Agriculture, Punjab Agricultural University, Ludhiana, 141004, India.
Chemosphere. 2022 Aug;301:134629. doi: 10.1016/j.chemosphere.2022.134629. Epub 2022 Apr 18.
Titanium dioxide (TiO) nanoparticles (NPs) are the most widely used nanomaterials and their expanding use raises concerns about their impacts on soil ecosystems and functioning. The present study evaluates the potential impacts of TiO NPs applied at low doses (0, 1.0, 2.5, 5.0, 10.0 and 20.0 mg L) on soil chemical properties including the macro and micronutrient contents, microbial population and enzyme activities in rhizosphere soil of mung bean crop at different time intervals (7, 14, 28 and 56 days). A quantitative RT-PCR study was also performed to study the relative change in the gene expression of ammonia oxidizer and nitrogen fixers upon TiO NP supplementation. An increase in soil nutrient content viz., available N, P, Cu, Fe, Mn, nitrate-N and ammonical-N was observed with NP application except available K and Zn content. The TiO NPs stimulated the growth of soil microflora at low concentrations while an inhibitory effect was recorded at high concentrations. The soil fungi and actinobacteria emerged as the most sensitive groups of soil microbes towards TiO NP exposure exhibiting detrimental impacts on their growth at all concentrations. Similarly, the soil enzyme activities enhanced till TiO NPs (10.0 mg L) which was followed by decrease at higher concentrations. The qRT-PCR study showed that the ammonia oxidizers were more affected by TiO NPs application than nitrogen fixers. These findings suggest that TiO NPs can be used as stimulators of soil nutrients and soil microbial dynamics at low concentrations.
二氧化钛 (TiO) 纳米颗粒 (NPs) 是应用最广泛的纳米材料，其使用范围的不断扩大引起了人们对其对土壤生态系统和功能影响的关注。本研究评估了低剂量 (0、1.0、2.5、5.0、10.0 和 20.0 mg L) TiO NPs 对绿豆根际土壤化学性质的潜在影响，包括宏量和微量营养素含量、微生物种群和酶活性，在不同时间间隔 (7、14、28 和 56 天)。还进行了定量 RT-PCR 研究，以研究在 TiO NP 补充后氨氧化菌和固氮菌的基因表达相对变化。除了有效钾和有效锌含量外，施用 NP 可增加土壤养分含量，即有效氮、磷、铜、铁、锰、硝酸盐氮和氨氮。TiO NPs 在低浓度下刺激土壤微生物群的生长，而在高浓度下则表现出抑制作用。土壤真菌和放线菌是对 TiO NP 暴露最敏感的土壤微生物群，在所有浓度下对其生长都有不利影响。同样，土壤酶活性在 TiO NPs (10.0 mg L) 之前增强，然后在更高浓度下降低。qRT-PCR 研究表明，氨氧化菌比固氮菌更容易受到 TiO NPs 应用的影响。这些发现表明，TiO NPs 可低浓度作为土壤养分和土壤微生物动态的刺激物。
