The effects of Micro/Nano-plastics exposure on plants and their toxic mechanisms: A review from multi-omics perspectives.

In recent years, plastic pollution has become a global environmental problem, posing a potential threat to agricultural ecosystems and human health, and may further exacerbate global food security problems. Studies have revealed that exposure to micro/nano-plastics (MPs/NPs) might cause various aspects of physiological toxicities, including plant biomass reduction, intracellular oxidative stress burst, photosynthesis inhibition, water and nutrient absorption reduction, cellular and genotoxicity, seed germination retardation, and that the effects were closely related to MP/NP properties (type, particle size, functional groups), exposure concentration, exposure duration and plant characteristics (species, tissue, growth stage). Based on a brief review of the physiological toxicity of MPs/NPs to plant growth, this paper comprehensively reviews the potential molecular mechanism of MPs/NPs on plant growth from perspectives of multi-omics, including transcriptome, metabolome, proteome and microbiome, thus to reveal the role of MPs/NPs in plant transcriptional regulation, metabolic pathway reprogramming, protein translational and post-translational modification, as well as rhizosphere microbial remodeling at multiple levels. Meanwhile, this paper also provides prospects for future research, and clarifies the future research directions and the technologies adopted.

Development of a Purity Certified Reference Material for Vinyl Acetate.

Vinyl acetate is a restricted substance in food products. The quantification of the organic impurities in vinyl acetate is a major problem due to its activity, instability, and volatility. In this paper, while using the mass balance method to determine the purity of vinyl acetate, an improved method was established for the determination of the content of three impurities in vinyl acetate reference material, and the GC-FID peak area normalization for vinyl acetate was calibrated. The three trace organic impurities were identified by gas chromatography tandem high-resolution mass spectrometry to be methyl acetate, ethyl acetate, and vinyl propionate. The content and relative correction factors for the three organic impurities were measured. The purity of vinyl acetate determined by the mass balance method was 99.90% with an expanded uncertainty of 0.30%, and the total content of organic impurities was 0.08% with a relative correction factor of 1.23%. The vinyl acetate reference material has been approved as a national certified reference material in China as GBW (E) 062710.

Critical review on modified floating photocatalysts for emerging contaminants removal from landscape water: problems, methods and mechanism.

Due to the disorderly discharge in modern production and daily life of people, emerging contaminants(ECs) began to appear in landscape water, and have become a key public concern. Because of the unique characteristics of landscape water, it is difficult to efficiently remove ECs either by natural purification or by traditional large-scale sewage treatment facilities. The ideal purification method is to remove them while maintaining a beautiful environment. Possessing the feature of low-density, floating photocatalysts could harvest sufficient light on the surface of the water for photocatalytic degradation, which may be an important supplement for ECs treatment in landscape water. This paper gave a review related to floating photocatalysts and proposed an idea of combining floating photocatalysts to construct bionic photocatalytic materials for contaminative landscape water treatment. Six types of common floating substrates and corresponding applications for floating photocatalysts were concluded in this paper, and the main problem leading to the low efficiency of photocatalysts and three corresponding three improvement strategies were discussed. Besides, the modification mechanisms of photocatalysts were discussed thoroughly. On this basis, the engineering application prospects of bionic photocatalytic materials were proposed to remove ECs in landscape water.

A Query-Based Network for Rural Homestead Extraction from VHR Remote Sensing Images.

It is very significant for rural planning to accurately count the number and area of rural homesteads by means of automation. The development of deep learning makes it possible to achieve this goal. At present, many effective works have been conducted to extract building objects from VHR images using semantic segmentation technology, but they do not extract instance objects and do not work for densely distributed and overlapping rural homesteads. Most of the existing mainstream instance segmentation frameworks are based on the top-down structure. The model is complex and requires a large number of manually set thresholds. In order to solve the above difficult problems, we designed a simple query-based instance segmentation framework, QueryFormer, which includes an encoder and a decoder. A multi-scale deformable attention mechanism is incorporated into the encoder, resulting in significant computational savings, while also achieving effective results. In the decoder, we designed multiple groups, and used a Many-to-One label assignment method to make the image feature region be queried faster. Experiments show that our method achieves better performance (52.8AP) than the other most advanced models (+0.8AP) in the task of extracting rural homesteads in dense regions. This study shows that query-based instance segmentation framework has strong application potential in remote sensing images.

Synthesis of environmental-friendly ion-imprinted magnetic nanocomposite bentonite for selective recovery of aqueous Sc(III).

A novel reusable ion imprinted nanocomposite magnetic bentonite(IIPNMB) was prepared for selective recovery of aqueous scandium. Based on the fact that oxyphosphorus functional groups in sodium tripolyphosphate have good affinity to Sc(III) and chitosan is rich in hydroxy and amino active sites, they were chosen to build ion imprinted layers. Mesoporous IIPNMB showed good adsorption performance. The pseudo second-order kinetic model and Langmuir model fit the experimental data. According to XPS features, the amino, hydroxyl, PO and PO bonds of the adsorbents had electrostatic interaction and complexation with Sc(III), leading to the good selectivity of IIPNMB for Sc(III). In addition, the material atomic structure was proposed based on the chemical structure of IIPNMB for DFT calculation of ion imprinting adsorption, which clearly proved that the adsorption process of Sc(III) was stable, and it gave another proof for the mechanism of the selective extraction.

Non-Destructive Detection of Moldy Walnuts Based on Hyperspectral Imaging Technology.

Walnuts with their shells are a popular agricultural product in China. However, mildew from growth can sometimes be processed into foods. It is difficult to visually determine which walnuts have mildew without breaking the shells. A non-destructive method for detecting walnuts with mildew was studied by combining spectral data with image information. A total of 120 "Lüling" walnuts with shells were used for the mildew experiment. The characteristics of the spectral data from six surfaces of all samples were collected in the range of 370-1042 nm on days 0, 15, and 30. The spectrum was pretreated using SNV, and the feature bands were extracted using PCA and modeled using a support vector machine (SVM). The results show that the overall classification accuracy was 93%, with an of accuracy of 100% for INEN walnuts (normal internally and externally). The accuracy for IMEM walnuts (mildew internally and externally) reached 87.29%. There was an accuracy of 78.6% for IMEN walnuts (mildew internally and normal externally). The non-destructive detection of mildewed walnuts can be undertaken using hyperspectral imaging technology, which provides a new technique for exploring the mechanisms of walnuts with mildew.

Significant Impacts of Both Total Amount and Availability of Heavy Metals on the Functions and Assembly of Soil Microbial Communities in Different Land Use Patterns.

Land use change alters the accumulation of heavy metals (HMs) in soils and might have significant influence on the assembly and functions of soil microbial community. Although numerous studies have discussed the impacts of either total amounts or availability of metals on soil microbes in land change, there is still limited understanding on which one is more critical. In the present study, soils from three land use types (forest, mining field, and operating factory) located in Shaoguan city (Guangdong Province, China) were collected to investigate the impacts of soil HMs on soil enzyme activities and bacterial community structures. Mining activities remarkably increased the concentrations of HMs in soils, and land use patterns changed soil properties and nutrition level. Soil pH, total and available HMs (Cu, Pb, Zn, and Cd) and organic matters (SOM) were identified as the key influential factors shaping soil ecological functions (soil enzyme activities) and community assembly (bacterial community composition), explained by HMs accumulation and soil acidification caused by human activities. In addition, total amount and availability of some metals (Zn, Pb, Cu, and Cd) showed similar and significant effects on soil bacterial communities. Our findings provide new clues for reassessing the environmental risks of HMs in soils with different land use.

The mechanism underlying fast germination of tomato cultivar LA2711.

Seed germination is important for early plant morphogenesis as well as abiotic stress tolerance, and is mainly controlled by the phytohormones abscisic acid (ABA) and gibberellic acid (GA). Our previous studies identified a salt-tolerant tomato cultivar, LA2711, which is also a fast-germinating genotype, compared to its salt-sensitive counterpart, ZS-5. In an effort to further clarify the mechanism underlying this phenomenon, we compared the dynamic levels of ABA and GA4, the transcript abundance of genes involved in their biosynthesis and catabolism as well as signal transduction between the two cultivars. In addition, we tested seed germination sensitivity to ABA and GAs. Our results revealed that insensitivity of seed germination to exogenous ABA and low ABA content in seeds are the physiological mechanisms conferring faster germination rates of LA2711 seeds. SlCYP707A2, which encodes an ABA catabolic enzyme, may play a decisive role in the fast germination rate of LA2711, as it showed a significantly higher level of expression in LA2711 than ZS-5 at most time points tested during germination. The current results will enable us to gain insight into the mechanism(s) regarding seed germination of tomato and the role of fast germination in stress tolerance.

Melatonin promotes seed germination under high salinity by regulating antioxidant systems, ABA and GA4 interaction in cucumber (Cucumis sativus L.).

Although previous studies have found that melatonin can promote seed germination, the mechanisms involved in perceiving and signaling melatonin remain poorly understood. In this study, it was found that melatonin was synthesized during cucumber seed germination with a peak in melatonin levels occurring 14 hr into germination. This is indicative of a correlation between melatonin synthesis and seed germination. Meanwhile, seeds pretreated with exogenous melatonin (1 µM) showed enhanced germination rates under 150 mM NaCl stress compared to water-pretreated seeds under salinity stress. There are two apparent mechanisms by which melatonin alleviated salinity-induced inhibition of seed germination. Exogenous melatonin decreased oxidative damage induced by NaCl stress by enhancing gene expression of antioxidants. Under NaCl stress, compared to untreated control, the activities of antioxidant enzymes including superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD) were significantly increased by approximately 1.3-5.0-fold, with a concomitant 1.4-2.0-fold increase of CsCu-ZnSOD, CsFe-ZnSOD, CsCAT, and CsPOD in melatonin-pretreated seeds. Melatonin also alleviated salinity stress by affecting abscisic acid (ABA) and gibberellin acid (GA) biosynthesis and catabolism during seed germination. Compared to NaCl treatment, melatonin significantly up-regulated ABA catabolism genes (e.g., CsCYP707A1 and CsCYP707A2, 3.5 and 105-fold higher than NaCl treatment at 16 hr, respectively) and down-regulated ABA biosynthesis genes (e.g., CsNECD2, 0.29-fold of CK2 at 16 hr), resulting in a rapid decrease of ABA content during the early stage of germination. At the same time, melatonin positively up-regulated GA biosynthesis genes (e.g., GA20ox and GA3ox, 2.3 and 3.9-fold higher than NaCl treatment at 0 and 12 hr, respectively), contributing to a significant increase of GA (especially GA4) content. In this study, we provide new evidence suggesting that melatonin alleviates the inhibitory effects of NaCl stress on germination mainly by regulating the biosynthesis and catabolism of ABA and GA4.

Hormone profiling and transcription analysis reveal a major role of ABA in tomato salt tolerance.

The response and adaptation of plants to different environmental stresses are of great interest as they provide the key to understanding the mechanisms underlying stress tolerance. In this study, the changing patterns of four endogenous hormones and various physiological and biochemical parameters of both a salt-tolerant (LA2711) and a salt-sensitive (ZS-5) tomato cultivar were examined under salt stress and non-stress conditions. Additionally, the transcription of key genes in the abscisic acid (ABA) biosynthesis and metabolism were analyzed at different time points. The results indicated that gene expression responsible for ABA biosynthesis and metabolism coincided with the hormone level, and SlNCED1 and SlCYP707A3 may play major roles in the process. LA2711 performed superior to ZS-5 on various parameters, including seed germination, Na(+) compartmentation, selective absorption of K(+), and antioxidant enzymes activity. The difference in salt tolerance between the two genotypes could be attributed to the different levels of ABA due to differences in gene expression of key genes in ABA biosynthesis and metabolism. Although gibberellin, cytokinin and auxin were involved, our results indicated that ABA signaling plays a major role in tomato salt tolerance. As compared to ZS-5, LA2711 had a higher capability to selectively absorb and redistribute K(+) and a higher tolerance to Na(+) in young leaves, which may be the main physiological mechanisms of salt tolerance.

Molecular analysis of two salt-responsive NAC-family genes and their expression analysis in tomato.

The NAC family transcription factor has demonstrated its importance in plant development and environmental stress response. Based on the microarray results under salt stress and EST information, the full-length cDNAs of two salt-inducible NAC-family genes (SlNAC1, SlNAM1) were isolated from a salt tolerant tomato cultivar, Edkawi, using Rapid Amplification of cDNA Ends (RACE). SlNAC1 and SlNAM1 encoded 301 and 296 amino acids, respectively, and the deduced protein sequences contained the typical domain of NAC-family transcription factors. Tissue expression profile analysis using semi-quantitative RT-PCR showed that SlNAC1 was expressed mainly in root, flower and green fruit; transcripts of SlNAM1 were detected in all tested tissues except for root, and high-level expression was detected in flower and matured tomato fruit. Both SlNAC1 and SlNAM1 were induced by salt stress in Edkawi, while the expression pattern was different in a salt-sensitive cultivar, ZS-5. Phylogenetic analysis for putative NAC-family peptides available in the tomato genome indicated a wide diversity of this gene family. Results obtained in the present study suggest that both SlNAC1 and SlNAM1 might play important roles in tomato stress tolerance.