Melatonin-priming enhances maize seedling drought tolerance by regulating the antioxidant defense system.

Drought stress (DS) challenges sustainable agriculture production by limiting crop growth and development. The objective of the study was to evaluate the effect of melatonin-priming on enzymatic and non-enzymatic antioxidant defense mechanisms and its relation with leaf ultrastructure and stomatal traits in maize (Zea mays L) seedlings under DS (PEG-6000). DS drastically decreased seed germination, plant growth, and leaf chlorophyll content due to excessive reactive oxygen species (ROS) production. Melatonin-priming significantly (P < 0.05) increased seed germination, root length, shoot length, fresh seedling weight, proline content, total soluble protein content, sugar content, chlorophyll content, and stomatal aperture size by 101%, 30%, 133%, 51%, 22%, 59%, 54%, 20%, and 424%, compared to no priming (NP) under DS, respectively. Similarly, priming improved leaf ultrastructure and reduced the amount of chlorophyll loss and oxidative damage in maize seedlings. Melatonin seed priming with 500 µM melatonin (M2) greatly increased superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), glutathione, and ascorbate (AsA) activity, by 65%, 63%, 94%, 41%, and 55% compared to NP under DS and by 0.26%, 8%, 33%, 42%, and 15% under no-stress (NS), respectively. Melatonin-priming also reduced malondialdehyde content, electrolyte leakage, hydrogen peroxide (H2O2) content, and superoxide anion (O2-) content by 26%, 31%, 31%, and 33% compared to NP under DS and by 8%, 18%, 10%, and 11% under NS, respectively. In response to DS, melatonin-priming also stabilized the chloroplast structure, sustained cell expansion, protected cell walls, and greatly improved stomatal traits, including stomatal number, length, and width. Our results suggest that melatonin-priming improves drought tolerance in maize seedlings by alleviating the negative effect of ROS.

Low irrigation water minimizes the nitrate nitrogen losses without compromising the soil fertility, enzymatic activities and maize growth.

Nitrate nitrogen (NO3-_N) leaching increased with nitrogen (N) fertilization under high water supply to the field negatively affected the maize growth and performance. This study aimed to understand the mechanisms of NO3-_N leaching on a biochemical basis and its relationship with plant performance with 5 different doses (0, 200, 250, 300, 350 kg N ha- 1) of N fertilizers under low (60%; LW) and high (80%; HW) water holding capacity. Soil and plant enzymes were observed at different growth stages (V9, R1, R3, and R6) of the maize, whereas the leachates were collected at 10-days intervals from the sowing date. The LW had 10.15% lower NO3-_N leachate than HW, with correspondence increases in grain yield (25.57%), shoot (17.57%) and root (28.67%) dry matter. Irrespective of the irrigation water, RubisCo, glutamine synthase (GS), nitrate reductase (NR), nitrite reductase (NiR), and glutamate synthase (GOGAT) activities increased with increasing N fertilizer up to the V9 growth stage and decreased with approaching the maturity stage (R6) in maize. In HW irrigation, soil total N, GOGAT, soil nitrate (NO3-_N), leached nitrate (LNO3-_N), root N (RN), leaf N (LN) were positively correlated with N factors suggesting the higher losses of N through leaching (11.3%) compared to LW irrigation. However, the malondialdehyde (MDA), hydrogen peroxide (H2O2), superoxide (O2-), and proline were negatively correlated with the other enzymatic activities both under LW and HW irrigation. Thus, minimizing the NO3-_N leaching is possibly correlated with the LW and N300 combination without compromising the yield benefit and improving enzyme activities.

Selective extraction of fungicide carbendazim in fruits using ß-cyclodextrin based molecularly imprinted polymers.

Considering the importance of developing a new analytical approach for pesticide residue detection for the sake of ensuring food safety, a ß-cyclodextrin based molecularly imprinted polymer was prepared for selective determination of carbendazim. The polymers consist of a porous and hollow structure demonstrating the selective abundant adsorption sites for carbendazim molecule. The selectivity and adsorption capacity of the imprinted polymers were analyzed with dispersive solid-phase extraction and analyzed with high performance liquid chromatography coupled with ultraviolet. The results of imprinted polymers were higher than non-imprinted polymers with the maximum adsorption capacity of 3.65 mg/g within 30 min of total adsorption time. The reusability of the imprinted polymers was determined to evaluate its effectiveness and stability, which proved that the polymers lost 10% efficiency within seven consecutive recycles. The developed method displayed good linearity over the concentration range of 0.05-2.0 mg/L. The recovery percentage of 81.33-97.23 with relative standard deviations of 1.49-4.66% was obtained from spiked apple, banana, orange, and peach samples with a limit of detection of 0.03 mg/L and a limit of quantification of 0.10 mg/L (signal to noise ratio = 3/10). The overall performance of the proposed method evident that this technique provided a desirable outcome and it can be used as a convenient approach, as it qualifies the analytical standards.

Etoxazole stereoselective determination, bioaccumulation, and resulting oxidative stress in Danio rerio (zebrafish).

An environmentally-friendly and fast analytical method for the stereoselective determination of etoxazole was developed and then applied to estimate stereoselective bioaccumulation and elimination in zebrafish using SFC-MS/MS. Optimal enantioseparation conditions were determined using a Chiralpak IG-3 column and CO2/MeOH mobile phase (80/20, v/v), at 3.0 mL/min within 1 min, 30°Me and 18 MPa. A modified QuEChERS method was developed for zebrafish sample pretreatment, and mean recoveries were 88.43-110.12% with relative standard deviations ranging from 0.32 to 5.34%. The enantioselectives of etoxazole enantiomers in zebrafish during uptake and depuration phases were evaluated. Significant enantioselective bioaccumulation was observed, with preferential accumulation of (-)-R-etoxazole compared to its antipode, during uptake at both low and high exposure concentrations. The toxic effects of etoxazole on zebrafish were further explored, and activities of antioxidant enzymes were determined in liver of zebrafish. Significant changes were observed in the SOD and GST activities and in the MDA levels, which indicated the occurrence of oxidative stress in liver of zebrafish. The toxic effects exhibited time- and dose-dependent properties. These results can facilitate the accurate risk evaluation of etoxazole and provide basic knowledge for further study of biotoxicity mechanisms.

Synthesis of core-shell magnetic molecularly imprinted polymer for the selective determination of imidacloprid in apple samples.

This work demonstrates the synthesis and characterization of core-shell magnetic molecularly imprinted polymers based on surface imprinting using methacryloyl chloride as a functional monomer for the selective extraction of imidacloprid (template) from apple fruit. The characterization analysis results ensured the successful synthesis of the magnetic molecularly imprinted polymers owing to their heterogeneous structure and good magnetic properties. An isothermal binding test was assessed with a pseudo-second-order kinetic model, and the kinetic results fit well to the Freundlich isothermal model. The polymers exhibited an adsorption capacity of 5.75 mg/g for the target analyte with a good selective extraction ability. In addition, the polymers can be reused several times without significant performance loss. The molecularly imprinted polymers showed good performance in the analysis of spiked apple sample with a linear range of 0.05-1.0 mg/L, a limit of detection of 0.048 mg/L and a limit of quantification of 0.146 mg/L (S/N = 3/10). The recoveries of the samples were 77.66-96.57% and their respective relative standard deviations were 3.36-0.45%. All the results indicated that the proposed method provided good selective extraction, as qualifying the analytical standards.

Geographical origin of Chinese apples based on multiple element analysis.

BACKGROUND: Apples from different regions of China show different qualities and internal characteristics, and appeal to different customers. However, these aspects have not been studied in depth. We characterized the profiles of 14 elements in 317 apple samples collected from five regions of China. Principal component analysis (PCA), linear discriminant analysis (LDA), and back-propagation artificial neural networks analysis (BP-ANN) were used to build models for apple authentication. RESULTS: Fourteen elements were successfully identified in apple samples by performing graphite furnace atomic absorption spectrometry (GFAAS) and inductively coupled plasma atomic emission spectroscopy (ICP-AES) analyses. Comparative analysis showed significantly different element profiles in samples from different regions. The first five principal components obtained by PCA accounted for 71.8% of the total variance. The LDA obtained 70.0% classification rates. The BP-ANN obtained 82.7% classification rates. CONCLUSION: This study indicated the possibility that apples could be authenticated based on differences in their element profiles, and provided a basis for further geographical origin studies. © 2019 Society of Chemical Industry.

Molecularly imprinted polymers' application in pesticide residue detection.

Molecularly imprinted polymers (MIPs) are produced using molecular imprinting technology (MIT) and have specific analyte-binding abilities and unique properties, including chemical and thermal stability, reusability, high selectivity, and high sensitivity. The application of MIPs in the detection of pesticides represents an advance and a superior scientific approach owing to their detection and characterization of trace levels in comparison with other methods. In this review, we have summarized the pre-treatment extraction of pesticides with different types of molecularly imprinted polymer for the detection of single and multiple pesticides by elaborating upon their specific extraction efficiency. The importance of different polymerization methods, functional monomers and cross-linkers is highlighted. The aim of this study is to investigate the importance of the application of MIPs in the detection of pesticides and recent advances in the last few years to overcome the limitations of previously developed methods. Existing restrictions and required future aspects are discussed.

Method development, validation, and risk assessment of multiple pesticide residues of fruits in China.

In this study, a muti-residue analysis method of 40 pesticides in five different categories of fruits in China was developed based on ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). Five hundred real samples were analyzed and assessed for the dietary exposure risk. The sample treatment method was optimized by comparing four clean-up methods. The matrix effects of different fruits were evaluated. The analytical method was validated in terms of linearity, limit of detection (LOD), limit of quantification (LOQ), accuracy, and precision. The results showed that the optimal method was the treatment by clean up with ODS (octadecylsilane) and MgSO4. The matrix effect was the strongest in orange and weakest in apple. The LOD and LOQ of pesticides were 0.04-5.9 µg kg-1 and 0.13-19.5 µg kg-1, respectively. The recoveries at three spiked levels were ranged from 71.2 to 115.2% with the RSDs from 0.1 to 19.6%. Twenty-two pesticides were detected in 500 fruit samples from the major production regions of China, with concentrations ranging from 0.1 to 1930 µg kg-1. A total of 13, 10, 9, 8, and 4 pesticides were detected in peach, orange, grape, apple, and strawberry. Both the acceptable daily intake (ADI) and acute reference dose (ARfD) for all the detected pesticides were lower than 100%, indicating that the dietary intake risks are acceptable and would not pose potential health risks.

Assessing the greenification potential of cyclodextrin-based molecularly imprinted polymers for pesticides detection.

Cyclodextrins, with their unparalleled attributes of eco-friendliness, natural abundance, versatile utility, and facile functionalization, make a paramount contribution to the field of molecular imprinting. Leveraging the unique properties of cyclodextrins in molecularly imprinted polymers synthesis has revolutionized the performance of molecularly imprinted polymers, resulting in enhanced adsorption selectivity, capacity, and rapid extraction of pesticides, while also circumventing conventional limitations. As the concern for food quality and safety continues to grow, the need for standard analytical methods to detect pesticides in food and environmental samples has become paramount. Cyclodextrins, being non-toxic and biodegradable, present an attractive option for greener reagents in imprinting polymers that can also ensure environmental safety post-application. This review provides a comprehensive summary of the significance of cyclodextrins in molecular imprinting for pesticide detection in food and environmental samples. The recent advancements in the synthesis and application of molecularly imprinted polymers using cyclodextrins have been critically analyzed. Furthermore, the current limitations have been meticulously examined, and potential opportunities for greenification with cyclodextrin applications in this field have been discussed. By harnessing the advantages of cyclodextrins in molecular imprinting, it is possible to develop highly selective and efficient methods for detecting pesticides in food and environmental samples while also addressing the challenges of sustainability and environmental impact.

Comprehensive review on patulin and Alternaria toxins in fruit and derived products.

Mycotoxins are toxic secondary metabolites produced by certain fungi, which can contaminate various food commodities, including fruits and their derived products. Patulin and Alternaria toxins are among the most commonly encountered mycotoxins in fruit and their derived products. In this review, the sources, toxicity, and regulations related to these mycotoxins, as well as their detection and mitigation strategies are widely discussed. Patulin is a mycotoxin produced mainly by the fungal genera Penicillium, Aspergillus, and Byssochlamys. Alternaria toxins, produced by fungi in the Alternaria genus, are another common group of mycotoxins found in fruits and fruit products. The most prevalent Alternaria toxins are alternariol (AOH) and alternariol monomethyl ether (AME). These mycotoxins are of concern due to their potential negative effects on human health. Ingesting fruits contaminated with these mycotoxins can cause acute and chronic health problems. Detection of patulin and Alternaria toxins in fruit and their derived products can be challenging due to their low concentrations and the complexity of the food matrices. Common analytical methods, good agricultural practices, and contamination monitoring of these mycotoxins are important for safe consumption of fruits and derived products. And Future research will continue to explore new methods for detecting and managing these mycotoxins, with the ultimate goal of ensuring the safety and quality of fruits and derived product supply.

Transcriptome and anatomical studies reveal alterations in leaf thickness under long-term drought stress in tobacco.

Drought is one of the foremost environmental factors that limit the growth of plants. Leaf thickness (LT) is an important quantitative trait in plant physiology. The experiment was carried out in a growth room and the plants were divided into two groups such as well-watered and drought-stressed. This work investigated leaf growth in terms of leaf surface growth and expansion rate, leaf stomata traits, LT, anticlinal growth, and leaf cell layers. The results showed that the leaf area and leaf surface expansion rate were decreased by drought stress (DS). Similarly, LT, anticlinal expansion rate, palisade and spongy tissue thickness, and their related expansion rates were also decreased at different days' time points (DTP) of DS. However, a steady increase was observed in the aforementioned parameters after 12 DTP of DS. The stomatal density increased while stomata size decreased at 3 DTP and 12 DTP (low leaf water potential and relative leaf water content at these time points) and vice versa at 24 DTP compared with the well-watered plants indicating adaptations in these traits in response to DS, and thus the leaf water status played a role in the regulation of leaf stomata traits. The cell length decreased in the upper epidermis, palisade and spongy tissues by DS up to 12 DTP led to lower LT while an increase was observed after 12 DTP that resulted in higher LT. The increase in the LT was supported by the upregulation of starch and sucrose metabolism, glycerolipid metabolism, protein processing in endoplasmic reticulum pathways at 18 DTP along with the differentially expressed genes induced that were related to cell wall remodeling (cellulose, expansin, xyloglucans) and cell expansion (auxin response factors and aquaporin). The results explain the response of leaf thickness to drought stress and show alterations in LT and leaf stomatal traits. This study might serve as a valuable source of gene information for functional studies and provide a theoretical basis to understand leaf growth in terms of leaf anatomy and leaf stomatal traits under drought stress.

Regulation of Soil Microbial Community Structure and Biomass to Mitigate Soil Greenhouse Gas Emission.

Sustainable reduction of fertilization with technology acquisition for improving soil quality and realizing green food production is a major strategic demand for global agricultural production. Introducing legume (LCCs) and/or non-legume cover crops (NLCCs) during the fallow period before planting main crops such as wheat and corn increases surface coverage, retains soil moisture content, and absorbs excess mineral nutrients, thus reducing pollution. In addition, the cover crops (CCs) supplement the soil nutrients upon decomposition and have a green manure effect. Compared to the traditional bare land, the introduction of CCs systems has multiple ecological benefits, such as improving soil structure, promoting nutrient cycling, improving soil fertility and microbial activity, controlling soil erosion, and inhibiting weed growth, pests, and diseases. The residual decomposition process of cultivated crops after being pressed into the soil will directly change the soil carbon (C) and nitrogen (N) cycle and greenhouse gas emissions (GHGs), and thus affect the soil microbial activities. This key ecological process determines the realization of various ecological and environmental benefits of the cultivated system. Understanding the mechanism of these ecological environmental benefits provides a scientific basis for the restoration and promotion of cultivated crops in dry farming areas of the world. These findings provide an important contribution for understanding the mutual interrelationships and the research in this area, as well as increasing the use of CCs in the soil for better soil fertility, GHGs mitigation, and improving soil microbial community structure. This literature review studies the effects of crop biomass and quality on soil GHGs emissions, microbial biomass, and community structure of the crop cultivation system, aiming to clarify crop cultivation in theory.

Development of Molecularly Imprinted Polymers for Fenthion Detection in Food and Soil Samples.

Modern agricultural production is greatly dependent on pesticide usage, which results in severe environmental pollution, health risks and degraded food quality and safety. Molecularly imprinted polymers are one of the most prominent approaches for the detection of pesticide residues in food and environmental samples. In this research, we prepared molecularly imprinted polymers for fenthion detection by using beta-cyclodextrin as a functional monomer and a room-temperature ionic liquid as a cosolvent. The characterization of the developed polymers was carried out. The polymers synthesized by using the room-temperature ionic liquid as the cosolvent had a good adsorption efficiency of 26.85 mg g-1, with a short adsorption equilibrium time of 20 min, and the results fitted well with the Langmuir isotherm model and pseudo-second-order kinetic model. The polymer showed cross-selectivity for methyl-parathion, but it had a higher selectivity as compared to acetamiprid and abamectin. A recovery of 87.44-101.25% with a limit of detection of 0.04 mg L-1 and a relative standard deviation of below 3% was achieved from soil, lettuce and grape samples, within the linear range of 0.02-3.0 mg L-1, using high-performance liquid chromatography with an ultraviolet detector. Based on the results, we propose a new, convenient and practical analytical method for fenthion detection in real samples using improved imprinted polymers with room-temperature ionic liquid.

Room-Temperature, Ionic-Liquid-Enhanced, Beta-Cyclodextrin-Based, Molecularly Imprinted Polymers for the Selective Extraction of Abamectin.

To ensure environmental protection and food quality and safety, the trace level detection of pesticide residues with molecularly imprinted polymers using a more economic, reliable, and greener approach is always demanded. Herein, novel, enhanced, imprinted polymers based on beta-cyclodextrin, using room-temperature, ionic liquid as a solvent for abamectin were developed with a simple polymerization process. The successful synthesis of the polymers was verified, with morphological and structural characterization performed via scanning electron microscope analysis, nitrogen adsorption experiments, and thermogravimetric analysis. The imprinted polymers showed good adsorption ability, which was confirmed with a pseudo-second-order kinetic model and a Langmuir isotherm model, as they exhibit a theoretical adsorption of 15.08 mg g-1 for abamectin. The polymers showed high selectivity for abamectin and significant reusability without significant performance loss. The MIPs were used to analyze abamectin in spiked apple, banana, orange, and grape samples, and as a result, a good recovery of 81.67-101.47%, with 1.26-4.36% relative standard deviation, and limits of detection and quantitation of 0.02 µg g-1 and 0.05 µg g-1, respectively, was achieved within a linear range of 0.03-1.50 µg g-1. Thus, room-temperature, ionic-liquid-enhanced, beta-cyclodextrin-based, molecularly imprinted polymers for the selective detection of abamectin proved to be a convenient and practical platform.

Application, advancement and green aspects of magnetic molecularly imprinted polymers in pesticide residue detection.

Molecularly imprinted polymers (MIPs) have added a vital contribution to food quality and safety with the effective extraction of pesticide residues due to their unique properties. Magnetic molecularly imprinted polymers (MMIPs) are a superior approach to overcome stereotypical limitations due to their unique core-shell and novel composite structure, including high chemothermal stability, rapid extraction, and high selectivity. Over the past two decades, different MMIPs have been developed for pesticide extraction in actual food samples with a complex matrix. Nevertheless, such developments are desirable, yet the synthesis and mode of application of MMIP have great potential as a green chemistry approach that can significantly reduce environmental pollution and minimize resource utilization. In this review, the MMIP application for single or multipesticide detection has been summarized by critiquing each method's uniqueness and efficiency in real sample analysis and providing a possible green chemistry exploration procedure for MMIP synthesis and application for escalated food and environmental safety.

Irrigation and Nitrogen Fertilization Alter Soil Bacterial Communities, Soil Enzyme Activities, and Nutrient Availability in Maize Crop.

Irrigation and nitrogen (N) fertilization rates are widely used to increase crop growth and yield and promote the sustainable production of the maize crop. However, our understanding of irrigation and N fertilization in the soil microenvironment is still evolving, and further research on soil bacterial communities under maize crop with irrigation and N management in subtropical regions of China is needed. Therefore, we evaluated the responses of two irrigation levels (low and high irrigation water with 60 and 80% field capacity, respectively) and five N fertilization rates [i.e., control (N0), N200 (200 kg N ha-1), N250 (250 kg N ha-1), N300 (300 kg N ha-1), and N350 (350 kg N ha-1)] on soil bacterial communities, richness, and diversity. We found that both irrigation and N fertilization significantly affected bacterial richness, diversity index, and number of sequences. Low irrigation with N300 treatment has significantly higher soil enzymes activities, soil nutrient content, and bacterial alpha and beta diversity than high irrigation. In addition, the Proteobacteria, Actinobacteriota, Chloroflexi, and Firmicutes were the dominant bacterial phyla under both irrigation regimes. The acidic phosphates, acidic invertase, ß-glucosidase, catalase, cellulase, and urease were positively correlated with the Shannon index under both low and high irrigation. Therefore, low irrigation improves soil nutrient utilization by boosting soil enzyme activity, directly affecting soil bacterial communities. It was concluded that greater soil nutrients, enzyme activities with higher bacterial diversity are the main indicators of soil reactivity to low irrigation water and N300 for maintaining soil fertility and soil microbial community balance.

Transcription Factors Interact with ABA through Gene Expression and Signaling Pathways to Mitigate Drought and Salinity Stress.

Among abiotic stressors, drought and salinity seriously affect crop growth worldwide. In plants, research has aimed to increase stress-responsive protein synthesis upstream or downstream of the various transcription factors (TFs) that alleviate drought and salinity stress. TFs play diverse roles in controlling gene expression in plants, which is necessary to regulate biological processes, such as development and environmental stress responses. In general, plant responses to different stress conditions may be either abscisic acid (ABA)-dependent or ABA-independent. A detailed understanding of how TF pathways and ABA interact to cause stress responses is essential to improve tolerance to drought and salinity stress. Despite previous progress, more active approaches based on TFs are the current focus. Therefore, the present review emphasizes the recent advancements in complex cascades of gene expression during drought and salinity responses, especially identifying the specificity and crosstalk in ABA-dependent and -independent signaling pathways. This review also highlights the transcriptional regulation of gene expression governed by various key TF pathways, including AP2/ERF, bHLH, bZIP, DREB, GATA, HD-Zip, Homeo-box, MADS-box, MYB, NAC, Tri-helix, WHIRLY, WOX, WRKY, YABBY, and zinc finger, operating in ABA-dependent and -independent signaling pathways.

Systemic Stereoselectivity Study of Etoxazole: Stereoselective Bioactivity, Acute Toxicity, and Environmental Behavior in Fruits and Soils.

This is the first systemic assessment of the stereoselectivity of etoxazole enantiomers. Etoxazole's stereoselective bioactivity was assessed against target organisms ( Tetranychus urticae eggs and Tetranychus cinnabarinus eggs), and its acute toxicity was assessed toward nontarget aquatic organisms ( Daphnia magna and Danio rerio). Additionally, stereoselective elimination was investigated in three species of fruits (grape and strawberry grown in a greenhouse and apple grown in an open field) and in field soil. The ovicidal activity of (+)-( S)-etoxazole against Tetranychus urticae and Tetranychus cinnabarinus eggs was about 16 and 24 times higher, respectively, than that of (-)-( R)-etoxazole. Inconsistent order of etoxazole isomer toxicity was found toward different aquatic organisms: (+)-( S)-etoxazole showed nearly 8.7 times higher acute toxicity than (-)-( R)-etoxazole toward Daphnia magna, whereas (-)-( R)-etoxazole was ∼4.5 times more toxic to Danio rerio than (+)-( S)-etoxazole. Stereoselective degradation of etoxazole enantiomers showed significant variation in various fruits and field soil. The (+)-( S)-etoxazole was preferentially dissipated in grape and strawberry fruits grown under greenhouse condition, whereas (-)-( R)-etoxazole degraded faster than its antipode in apple fruits and soils under open-field condition. Overall, the stereoselectivity of etoxazole enantiomers should be fully considered in comprehensive environmental health risk in future work.