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BACKGROUND: Leersia japonica (Makino) Honda is a perennial weed and currently identified as a new dominant weed species in rice fields in many countries, including China. Here, we studied the biological characteristics combined with nonchemical management of L. japonica to develop a proper control strategy of this weed. RESULTS: The results showed that 33/28 °C in a 12 h:12 h, light:dark photoperiod were the most suitable growth conditions for seedling regeneration. Salt (NaCl) inhibits the regeneration of seedlings totally at a concentration of 51.3 mm. Seedlings of L. japonica could regenerate in a wide range of pH environments (from 3.50 to 9.50), endowing L. japonica with strong pH adaptability. Osmotic stress also inhibits the regeneration of seedlings totally at −0.13 MPa. A long dehydration time inhibits the regeneration of seedlings; no seedlings could be regenerated for 15 h. With low soil moisture content (33.3% and 50%), the regeneration rate and aboveground fresh weight (FW) were significantly lower than these with high soil moisture content (66.7% and 100%). Stem segments buried in the surface (0 cm) of soil could produce seedlings with the highest regeneration rate (37.5%) and seedling aboveground FW (0.64 g). As the soil depth increased, the regeneration rate and aboveground FW decreased significantly and no seedlings could be regenerated beyond 6.9 cm. CONCLUSION: Based on these biological characteristics of L. japonica, creating an environment that is not conducive to regeneration combined with an appropriated tillage system could effectively reduce its occurrence. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

In this study, the aging process of a surface-functional titanium dioxide nanosheet (f-TNS) composited room-temperature-vulcanized silicone rubber (RTV) composite coating was simulated in a NO2 generation device, and then the electrochemical impedance spectroscopy (EIS) of the aged composite coating was tested in a 3.5% NaCl solution. The water permeation process was analyzed by the changes in the impedance modulus, porosity, and breakpoint frequency of the composite coating. The experimental results show that the water permeability of aged RTV decreases first and then increases with the increase in the composite proportion of f-TNS. When the composite proportion of TNS was 0.3 wt.%, the composite sample had the minimum water permeability and the best resistance to NO2 corrosion. The effect of TNS on the NO2 aging resistance of RTV composites and its mechanism were studied by SEM, FT-IR, and XPS. The impedance modulus and porosity of the aged 0.3% f-TNS/RTV, respectively, were 1.82 × 107 Ω cm2 and 0.91 × 10−4%, which increased by 2.23 times and decreased by 0.37 times, respectively, compared with the values of aged pure RTV sample. In addition, the breakpoint frequency of the aged 0.3% f-TNS/RTV also significantly reduced to 11.3 Hz, whereas it was 35 Hz in aged pure RTV. [ABSTRACT FROM AUTHOR]

Simple Summary: Ammannia arenaria and A. multifloras, the most common broad-leaved weeds in rice paddy fields in China, are morphologically similar at the seedling stage. However, their degree of damage to rice may vary. Furthermore, the sensitivity of two species to the constantly emerging new herbicides is also unknown. This study conducted field investigations, indoor biological experiments, and chloroplast genome construction and analysis to clarify the differences in biological characteristics, herbicide sensitivity, and chloroplast genetics between A. arenaria and A. multifloras. Our research results may provide theoretical basis for weed occurrence prediction, selection of herbicides, and Ammannia classification and distinction. Furthermore, the results provided valuable biological information on cp genomes of Ammannia that will be useful to identify and classify Ammannia, and study their phylogenetic relationships and evolution. Ammannia arenaria and A. multifloras, morphologically similar at the seedling stage, are the most common broad-leaved weeds in paddy fields. Our study showed that A. arenaria occupied more space than A. multifloras when competing with rice. However, A. multifloras germination has lower temperature adaptability. No difference in sensitivity to common herbicides between two Ammannia species was observed. Chloroplast (cp) genomes could be conducive to clarify their genetic relationship. The complete cp genome sequences of A. arenaria (158,401 bp) and A. multiflora (157,900 bp) were assembled for the first time. In A. arenaria, there were 91 simple sequence repeats, 115 long repeats, and 86 protein-encoding genes, one, sixteen, and thirty more than those in A. multiflora. Inverted repeats regions expansion and contraction and the phylogenetic tree based on cp genomes demonstrated the closely relationship between the two species. However, in A. arenaria, 20 single nucleotide polymorphisms in the CDS region were detected compared to A. multiflora, which can be used to distinguish the two species. Moreover, there was one unique gene, infA, only in A. arenaria. This study provides reliable molecular resources for future research focusing on the infrageneric taxa identification, phylogenetic resolution, population structure, and biodiversity of Ammannia species. [ABSTRACT FROM AUTHOR]

In this work, a series of iso-structural eulyite-type Ba3Yb(PO4)3:Tb3+ solid solution phosphors were synthesized via high-temperature solid-phase method. The corresponding unit cell structure, luminescence properties, thermal stability, and chromaticity coordinates of the as-obtained phosphors were systematically investigated. The crystal structure of Ba3Yb(PO4)3:Tb3+ was refined by GSAS program, which indicates the oxygen ions in Ba3Yb(PO4)3 are disordered at one C3 site, and the oxygen atoms are distributed at two sites. Under 378 nm ultraviolet excitation, the emission peak of Ba3Yb(PO4)3:Tb3+ appears in the range of 450–650 nm, and a characteristic green emission peak appears at 542 nm. Moreover, the luminous intensity of the Ba3Yb(PO4)3:14 at.% Tb3+ sample at 160 °C is 87.7% at room temperature, and the quantum yield is 55.8%, which reveals good thermal stability. Our results suggest that the Ba3Yb(PO4)3:Tb3+ phosphors are promising high-efficiency green light conversion materials for UV-LED applications. [ABSTRACT FROM AUTHOR]

In this study, silicone rubber (SiR) with 0, 90, and 180 parts of aluminum hydroxide (Al(OH)3, ATH) contents prepared in the laboratory was treated in a certain concentration of NO2 for 0, 12, 24, and 36 h. Fourier transform-infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), and thermogravimetry (TG) were used to study the changes in the surface structure and thermal stability of SiR, as well as the influence of Al(OH)3 on the properties of SiR. According to AFM, the root-mean-square roughness of ATH-90 SiR was 192 nm, which was 2.7 times of ATH-0 SiR. With the incorporation of ATH, the surface of SiR became more susceptible to corrosion by NO2. According to FT-IR and XPS, with the increase in aging time, the side chain Si-CH3 of polydimethylsiloxane (PDMS) was oxidized gradually and a few of nitroso -NO2 groups were formed. According to TG, the incorporation of ATH caused the maximum decomposition rate temperature of PDMS to advance from 458.65 °C to 449.37 and 449.26 °C, which shows that the thermal stability of SiR degraded by adding ATH. After NO2 aging, a new decomposition stage appeared between 75 and 220 °C (stage Ⅰ), and this decomposition trend was similar to aluminum nitrate, which was proven to reduce the thermal stability of PDMS. The effects of NO2 on the surface structure and thermal stability of different ATH contents of silicone rubber were preliminarily clarified by a variety of characterization methods, which provided ideas for the development of silicone rubber resistant to NO2 aging. [ABSTRACT FROM AUTHOR]

In this study, functional graphene oxide (f-GO) nanosheets were prepared to enhance the NO2 resistibility of room-temperature-vulcanized (RTV) silicone rubber. A nitrogen dioxide (NO2) accelerated aging experiment was designed to simulate the aging process of nitrogen oxide produced by corona discharge on a silicone rubber composite coating, and then electrochemical impedance spectroscopy (EIS) was used to test the process of conductive medium penetration into silicone rubber. After exposure to the same concentration (115 mg·L−1) of NO2 for 24 h, at an optimal filler content of 0.3 wt.%, the impedance modulus of the composite silicone rubber sample was 1.8 × 107 Ω·cm2, which is an order of magnitude higher than that of pure RTV. In addition, with an increase in filler content, the porosity of the coating decreases. When the content of the nanosheet increases to 0.3 wt.%; the porosity reaches a minimum value 0.97 × 10−4%, which is 1/4 of the porosity of the pure RTV coating, indicating that this composite silicone rubber sample has the best resistance to NO2 aging. [ABSTRACT FROM AUTHOR]

The resistance of weeds to herbicides poses a major threat to agricultural production, and non-target-site resistance (NTSR) is often a serious problem as its mechanisms can in some cases confer resistance to herbicides with different modes of action. In this study, we hypothesized that bZIP transcription factors (TFs), which regulate abiotic stress responses in many plants, play a regulatory role in NTSR. Whole-plant assays indicated that the wild grasses Echinochloa crus-galli and E. glabrescens are resistant to the herbicides penoxsulam, cyhalofop-butyl, and quintrione. Transcriptome sequencing then identified 101 and 49 bZIP TFs with differential expression following penoxsulam treatment in E. crus-galli and E. glabrescens , respectively. Twelve of these genes had >60% homology with rice genes. The expression of bZIP88 was considerably up-regulated 6 h after treatment with the three different herbicides, and it was similar between resistant and susceptible populations; however, the relative expression levels before herbicide treatment and 24 h after were the same. We used rice (Oryza sativa ssp. japonica cv Nipponbare) as a model system for functional validation and found that CRISPR-Cas9-knockout of the rice bZIP88 ortholog increased the sensitivity to herbicide, whereas overexpression reduced it. The OsbZIP88 protein was localized to the nucleus. Using ChIP coupled with high-throughput sequencing, OsbZIP88 was found to form a network regulatory center with other TFs such as bZIP20/52/59 to regulate OsKS1 , OsCOE1 , and OsIM1 , which are related to auxin, abscisic acid, brassinosteroids, and gibberellic acid. Based on these results, we have established a database of bZIP TFs corresponding to herbicide stress, and resolved the mechanisms of the positive regulation of herbicide resistance by bZIP88, thereby providing new insights for NTSR. [ABSTRACT FROM AUTHOR]

BACKGROUND: Barnyardgrass (Echinochloa crus‐galli (L.) P. Beauv) has evolved resistance to the acetolactate synthase (ALS) inhibitor penoxsulam which is used to control weeds in rice fields in China. The present study is conducted to identify the target‐site resistance (TSR) mechanisms conferring resistance in a penoxsulam‐resistant population. RESULTS: The ALS sensitivity in vitro of the resistant population was sixfold lower to penoxsulam than that of the sensitive population. ALS sequencing revealed that no known mutation conferring ALS herbicide resistance was detected. However, a novel mutation Phe‐206‐Leu was identified in the ALS gene. Additionally, ALS gene expression level of the resistant population was lower than that of the sensitive population. Therefore, the penoxsulam resistance was not due to the overexpression of ALS gene. Molecular docking revealed that this mutation may change the interaction of the penoxsulam‐ALS binding and weaken its mutual affinity by approximately 10%. Arabidopsis thaliana transformed with mutant ALS had fourfold greater resistance to penoxsulam and varied cross‐resistance to other ALS herbicides than those transformed with sensitive ALS. Mutant and sensitive ALS proteins expressed by the baculovirus system exhibited different in vitro penoxsulam sensitivity levels. Mutant ALS had eightfold lower sensitivity to penoxsulam than sensitive ALS. CONCLUSION: This report provides clear evidence that the ALS mutation at position 206 (Phe‐206‐Leu) confers penoxsulam resistance in barnyardgrass. Phe‐206 was confirmed to be the ninth amino acid residue related to ALS herbicide resistance in weeds. © 2022 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Background: Salinization is a primary abiotic stress constraining global plant growth and production. Weedy rice, though highly homologous to cultivated rice, is more salt tolerant during seed germination and seedling growth; we hypothesize that this is owing to ionic homeostasis and changes in the expression of genes encoding ion transport regulators. Results: The four different genotypes of weedy (JYGY-1 and JYFN-4) and cultivated (Nipponbare and 9311) rice have different salt-tolerance during seed germination and seedling vegetative growth under salt stress. In this study, Na+ and Ca2+content increased in weedy and cultivated rice genotypes under salt stress while K+ and Mg2+decreased; however, JYGY-1 had the lowest Na+/K+ ratio of assessed genotypes. Genes in the high-affinity K+ transporter (HKT) and tonoplast sodium-hydrogen exchanger (NHX) families, and salt overly sensitive 1 (OsSOS1) have more than 98% homology in amino acid sequences between weedy and cultivated rice genotypes. Under salt stress, the HKT family members were differentially expressed in the roots and shoots of four different genotypes. However, the NHX family transcripts were markedly up-regulated in all genotypes, but there are significant differences between different genotypes. OsSOS1 was significantly up-regulated in roots, especially in JYGY-1genotype. Conclusions: The results showed that different genotypes had different germination and nutrient survival under salt stress, which was related to the difference of ion content and the difference of a series of ion transport gene expression. At the same time this study will provide new insight into the similarities and differences in ion homeostasis and gene regulatory mechanisms between weedy and cultivated rice under salt stress, which can aid in novel rice breeding and growth strategies. [ABSTRACT FROM AUTHOR]