Spirotetramat is a pesticide with bidirectional systemicity and can effectively control pests by inhibiting the biosynthesis of fatty acids. In this study, adsorption and desorption behaviors of spirotetramat in six soils and its interaction mechanism were studied using the batch equilibrium method and infrared radiation. The results showed that the adsorption and desorption behaviors of spirotetramat conformed to the Freundlich isotherm model. The values of adsorption capacities K F‑ads ranged from 2.11 to 12.40, and the values of desorption capacities K F‑des varied from 2.97 to 32.90. From the hysteresis coefficient, spirotetramat was easily desorbed from the test soils. The adsorption capacity of the soil to spirotetramat enhanced with an increasing temperature. Moreover, the changes in pH values and exogenous addition of humic acid and surfactant could also affect soil adsorption capacity, but for desorption, there was no correlation.

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As a diamide insecticide, ubendiamide is widely used and has many adverse effects on environmental organisms. In this study, bioaccumulation and toxicity effects of ubendiamide in zebra sh (Danio rerio) were studied. Speci cally, the results showed that the concentrations of ubendiamide increased in the early stage and achieved steady stages at 14 days and the bioconcentration factors (BCFs) of ubendiamide in zebra sh were 1.125 -2.011. Furthermore, ubendiamide had no signi cant effects on the growth phenotypes of zebra sh. However, zebra sh hepatic somatic index (HSI) of zebra sh had changed signi cantly with exposure. Histopathological analysis showed that exposure to ubendiamide could cause structural damage to liver tissue of zebra sh. Further physiological and biochemical analysis showed that ubendiamide could signi cantly change the activity of CAT and the contents of MDA and GSH in liver of zebra sh. In particular, exposure to ubendiamide could also cause signi cant changes in the mRNA expression levels of cell apoptosis-related genes involving p53, puma, caspase-3, caspase-9, apaf-1 and bax in liver of zebra sh. In general, these results indicated that exposure to ubendiamide could induce liver damage by inducing oxidative stress and apoptosis in liver of zebra sh.The results of this study will help to further comprehensively evaluate the safety of ubendiamide to aquatic organisms.

Spirotetramat is a pesticide with bidirectional systemicity in both xylem and phloem. Currently, researches show that spirotetramat has definite toxicity to aquatic organism. This paper aims to study the environmental behaviors of spirotetramat in water, in the hope of providing guidance for security evaluation of spirotetramat. The researches in this paper showed that under lighting condition, the half-life period of spirotetramat in water was 13.59 days. In water, spirotetramat could be degraded into B-enol and B-keto. As seen from the residual concentrations of two products, B-enol was the dominant degradation product. Under different temperatures, the hydrolysis products of spirotetramat remain B-enol and B-keto. The temperature has little effect on the residual concentration of spirotetramat in water. The residual concentration of B-enol in water gradually increased with the extension of time but B-keto had no significant change. In the buffer solution of different pH values, the degradation rate of spirotetramat was significantly enhanced with the increase of solution pH value. The hydrolysis products of spirotetramat in buffer solution of different pH values were still B-enol and B-keto, and pH exerted certain influence on the residual concentration of B-enol in water. The hydrolysis conversion of spirotetramat has theoretical and practical significance for the safe and reasonable usage of it, as well as for the further evaluation of spirotetramat's ecological risk in water.

A regulator of chromosome condensation 1 (RCC1) family protein has been functionally characterized to be involved in various cellular processes. In this study, one RCC1 gene named SaRCC1 was cloned from the full-length cDNA library of Spartinaalterniflora. The open reading frame (ORF) of SaRCC1 was 1440 bp, and it encoded 479 amino acids with a calculated molecular mass of 51.65 kDa. Multiple amino acid sequence alignments showed that SaRCC1 had high identity with other plant RCC1s, and the phylogenetic analysis indicated that SaRCC1 had a closer affinity to Zea mays RCC1 family protein (ZmRCC1). SaRCC1 gene was induced under salt stress conditions, and its encoded protein was located in peroxisome. In order to further investigate the function of SaRCC1, transgenic Arabidopsis plants ectopically both sense-overexpressing and antisense-overexpressing SaRCC1 were generated. SaRCC1-overexpressing lines exhibited an increased salt and ABA hypersensitivity and reduced resistance to salinity stress. On the other hand, the transcripts of some stress-responsive genes in the SaRCC1 transgenic plants were affected in response to salinity stress. Our results provide evidence for the involvement of SaRCC1, negatively regulating salt stress responses by affecting stress-related gene expression in Arabidopsis.

With the purpose of guaranteeing the safe use of spirotetramat and preventing its potential health threats to consumers, a QuEChERS extraction method coupled with LC triple-quadrupole tandem MS was applied in this study to determine residual spirotetramat metabolites in different tissues of amaranth (Amaranthus tricolor) and in soil. The results indicate that the spirotetramat degraded into different types of metabolites that were located in different tissues of amaranth and in soil. B-keto, B-glu, and B-enol were the three most representative degradation products in the leaf of amaranth, and B-glu and B-enol were the two major degradation products found in the stem of amaranth; however, only B-enol was detected in the root of amaranth. B-keto and B-mono were the two products detected in the soil in which the amaranth grew. The cytotoxicity results demonstrate that spirotetramat and its metabolite B-enol inhibited cellular growth, and the toxicity of spirotetramat and its metabolite B-enol exceeded than that of the metabolites B-keto, B-mono, and B-glu. This investigation is of great significance to the safe use of spirotetramat in agriculture.

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Ethofenprox, pyraclostrobine, trifloxystrobin and enestroburin are strobilurin fungicides that can effectively control fungal diseases caused by ascomycetes, zygomycetes, imperfect fungi, etc. With the purpose of guaranteeing the safe use of strobilurin fungicides in the prevention and treatment of citrus diseases, toxicity and control effects of the fungicides on citrus storage diseases and GC-MS (gas chromatography-mass spectrometry) were applied in this study to determine its residual safety. The results indicated that ethofenprox, trifloxystrobin, pyraclostrobine, and enestroburin had excellent inhibitory effects on citrus storage diseases at concentration of 200-400 μg/mL. Degradation dynamics of 4 fungicides during the storage period of citrus could be expressed as the first-order kinetics equation. The fungicides could penetrate into flesh through peels slowly. Therefore, the residue content of the fungicide on peels was higher than that in the flesh of the same citrus. After citrus fruits were treated for 90 d, the residues were lower than the maximum residue limits in all the countries, so the citrus were safe. This investigation provided the theoretical guidance and technical support for the quality evaluation of citrus products.