Hongwen Cao,Liting Guo,Zhen Sun,Tifeng Jiao,Mingli Wang
Wheat leaves with natural microstructures as substrates were covered by the silver nanoislands by magnetron to prepare a low-cost, environment-friendly and mass production surface-enhanced fluorescence (SEF) substrate (Ag-WL substrate). The best SEF substrate was selected by repeatly certifying the fluorescence intensity of 10−5 M Rhodamine B (RB) and 10−5 M Rhodamine 6G (R6G) aqueous solutions. The abundant semi-spherical protrusions and flake-like structures on the surface of the Ag-WL substrate produce high-density hot spots, which provides a new and simple idea for the preparation of biomimetic materials. The results of 3D finite-different time-domain (FDTD) simulation show that the nanoisland gap of semi-spherical protrusions and flake-like structures has produced rich hotspots. By adjusting the time of magnetron sputtering, the enhancement factor (EF) was as high as 839 times, relative standard deviation (RSD) reached as low as 10.7%, and the substrate was very stable and repeatable, which shows that Ag-WL substrate is trustworthy. Moreover, semi-spherical protrusions provide stronger surface-enhanced Raman scattering (SERS) effects compared to flake-like structure. What is more surprising is that the detection limit of the substrate for toxic substance crystal violet (CV) is as low as 10−10 M.
Yanyan Zhang,Hao Zhang,Dongxian Li,Syed Muhammad Zaigham Abbas Naqvi,Mukhtar Iderawumi Abdulraheem,Rui Su,Shakeel Ahmed,Jiandong Hu
A rapid, accurate and novel detection method of plant hormones abscisic acid at ultra-low concentrations in wheat leaves was proposed in this study. This surface-enhanced Raman spectroscopy based method developed the substrate with the silver coated gold nanocomposites. This substrate exhibited excellent detection of rhodamine6G with an ultra-low concentration of 1 × 10−12 M. And resulted in high-performance, well homogeneity and reproducibility against abscisic acid hormone detection with a limit of detection of 1 × 10−9 M. This assay further measured abscisic acid hormones from the fresh leaves extract of wheat with the relative error of 3.72–10.66% compared with enzyme-linked immunosorbent assay bioassay.
Perfluoroether Carboxylic Acids (PFECAs), which are substitutes for perfluorooctanoic acid (PFOA), have been widely detected in various environmental matrices. PFECAs exhibit higher accumulation in plant leaves. Spatial heterogeneity of many contaminants in leaves can lead to varied ecological risks. However, the distribution patterns and metabolic impacts of PFECAs remain poorly understood in plants. In this study, an integrated approach employing desorption electrospray ionization mass spectrometry imaging (DESI-MSI), transcriptomics, metabolomics and molecular docking was used to investigate the spatially resolved distribution and metabolic effects of two PFECAs (HFPO-DA and HFPO-TA) in wheat. PFECAs, especially HFPO-DA, were observed to accumulate predominantly in the leaf margins. Significant spatial variations in gene expression and metabolite profiles were identified between the inner and outer regions of leaves. Notably, genes associated with photosynthesis were significantly downregulated in the leaf margins compared to the central tissue. Exposure to PFECAs also resulted in decreased chlorophyll content in leaves. Differentially expressed metabolites (DEMs) and genes (DEGs) associated with oxidative stress were observed to exhibit abnormal regulation at the leaf margins. Molecular docking simulations revealed that PFECAs preferentially bound to key proteins, such as ferredoxin-NADP+ reductase (FNR) in the photosynthetic electron transport chains and protoporphyrinogen oxidase (PPO) in chlorophyll biosynthesis. These interactions likely disrupted photosynthetic function and chlorophyll synthesis, ultimately contributing to leaf yellowing in the leaf margins. These findings provide important insights into the spatially explicit toxicological mechanisms of PFECAs in wheat and establish a foundation for future research on spatial toxicology of PFAS in plants.
危险品化学品经营许可证（带存储）