RESUMO
Iron-based Fischer-Tropsch synthesis (FTS) catalyst is widely used for syngas conversion, but its iron carbide active phase is easily oxidized into Fe3O4 by the water produced during reaction, leading to the deterioration of catalytic performance. Here, we show an efficient strategy for protecting the iron carbide active phase of FTS catalyst by surface hydrophobization. The hydrophobic surface can reduce the water concentration in the core vicinity of catalyst during syngas conversion, and thus inhibit the oxidation of iron species by water, which enhances the C - C coupling ability of catalyst and promotes the formation of long-chain olefins. More significantly, it is unraveled that appropriate shell thickness plays a crucial role in stabilizing the iron carbide active phase without Fe3O4 formation and achieving good catalytic performance.
RESUMO
Peony (Paeonia suffruticosa Andr.), belonging to family Paeoniaceae, is an important medicinal and ornamental plant. During August of each year from 2016 to 2023, peony plants at Heze city were found to exhibit leaf yellows symptoms. The incidence rate of the symptomatic plant was recorded from 10% to 30% in four peony gardens with about 200 acres. Total DNA was extracted from 0.10 g fresh plant leaf tissues from 24 symptomatic and 8 asymptomatic samples using rapid plant genomic DNA isolation kit (Aidlab Biotechnology, Beijing, China). The extracted DNA was amplified by nested polymerase chain reaction using universal primers R16mF2/R16mR1 followed by R16F2/R16R2 (Lee et al., 1993; Gundersen and Lee, 1996) specific for the 16S rRNA gene and new designed tuf gene specific primers JWB-tuforfF1 (5'-ATGGCTGAAATATTTTCAAGAG-3') and JWB-tuforfR1 (5'-TTATTCTATGATTTTAATAACAG-3') followed by JWB-tuforfF2 (5'-ATGTAAACGTAGGAACTATTGG-3') and JWB-tuforfR2 (5'- TCCGATAGTTCTTCCACCTTCAC-3'). Amplicons of about 1.25 kb and 1.02 kb (16S rRNA gene and tuf gene, respectively) were obtained in 8 symptomatic samples from four peony gardens. However, no amplification was obtained in any of the asymptomatic samples. The representative amplicons of 16S rRNA and tuf genes of three positive samples (Heze-9, -18 and -27) were cloned into a zero background pLB-simple vector (Tiangen Biotechnology, Beijing, China) and sequenced by Taihe Biotechnology, Beijing, China. Sequences obtained in the study were deposited in NCBI GenBank with accession numbers PP504882, PP504883 and PP504884 for the 16S rRNA gene as well as PP530237, PP530238 and PP530239 for the tuf gene. The phytoplasma strain under the study was described as peony yellows (PeY) phytoplasma, PeY-Heze strain. Alignment analysis by DNAMAN software showed that three 16S rRNA gene sequences obtained in the study shared 99.36% to 99.60% sequence identity and three tuf gene sequences obtained in the study were identical. BLAST analysis of the 16S rRNA gene sequences of the PeY-Heze phytoplasma strains showed 99.60%-99.84% sequence identity with 'Candidatus Phytoplasma ziziphi' (GenBank accession: CP025121). And tuf sequences of the strains showed 100% similarity with 'Ca. P. ziziphi' (CP025121). Interestingly, the virtual RFLP patterns derived from three 16Sr RNA gene sequences obtained in the study by iPhyClassifier (Zhao et al., 2009) were different from the reference patterns of all previously established 16Sr groups/subgroups. The most similar are the reference pattern of the 16Sr group VII, subgroup E (AY741531), with a similarity coefficient of 0.72, which is less than 0.85. These phytoplasma strains may represent a new 16Sr group. Phylogenetic analysis based on 16S rRNA genes using MEGA 7.0 by neighbor-joining (NJ) method with 1000 bootstrap value indicated that PeY-Heze strains clustered into one clade with the phytoplasma strains of 'Ca. P. ziziphi' with 68% bootstrap value. Although there are several reports available on 'Ca. P. solani' infecting peony in Shandong Province, China (Gao et al., 2013). To our knowledge, this is the first report of 'Ca. P. ziziphi'-related strains infecting peony in China. The findings in this study will be beneficial to the detection, quarantine, and prevention of peony yellows phytoplasmas in China.
RESUMO
Sugarcane, a vital cash crop, contributes significantly to the world's sugar supply and raw materials for biofuel production, playing a significant role in the global sugar industry. However, sustainable productivity is severely hampered by biotic and abiotic stressors. Genetic engineering has been used to transfer useful genes into sugarcane plants to improve desirable traits and has emerged as a basic and applied research method to maintain growth and productivity under different adverse environmental conditions. However, the use of transgenic approaches remains contentious and requires rigorous experimental methods to address biosafety challenges. Clustered regularly interspaced short palindromic repeat (CRISPR) mediated genome editing technology is growing rapidly and may revolutionize sugarcane production. This review aims to explore innovative genetic engineering techniques and their successful application in developing sugarcane cultivars with enhanced resistance to biotic and abiotic stresses to produce superior sugarcane cultivars.
RESUMO
Plants significantly shape root-associated microbiota, making rhizosphere microbes useful environmental indicator organisms for safety assessment. Here, we report the pyrosequencing of the bacterial 16S ribosomal RNA in rhizosphere soil samples collected from transgenic cry1Ab/cry1Ac Bt rice Huahui No. 1 (GM crop) and its parental counterpart, Minghui63. We identified a total of 2579 quantifiable bacterial operational taxonomic units (OTUs). Many treatment-enriched microbial OTUs were identified, including 14 NonGM-enriched OTUs and 10 GM-enriched OTUs. OTUs belonging to the phyla Proteobacteria, Actinobacteria, Acidobacteria, Firmicutes, Nitrospirae, Chlorobi and GN04 were identified as statistically different in abundance between GM and the other two treatments. Compared with the different impacts of different rice varieties on microbiota, the impact of rice planting on microbiota is more obvious. Furthermore, Huahui No. 1 transgenic Bt rice had a greater impact on the rhizosphere bacterial communities than Minghui63. Early developmental stages of the transgenic Bt rice had a significant impact on many Bacillaceae communities. Soil chemical properties were not significantly altered by the presence of transgenic Bt rice. The peak concentration level of Bt protein products was detected during the seedling stage of transgenic Bt rice, which may be an intriguing factor for bacterial diversity variations. Based on these findings, we conclude that transgenic Bt rice has a significant impact on root-associated bacteria. This information may be leveraged in future environmental safety assessments of transgenic Bt rice varieties.
RESUMO
An efficient synthetic method for constructing 2,3- and 2,4-disubstituted pyrimidio[1,2-b]indazole skeletons through I2-DMSO-mediated and substrate-controlled regioselective [4 + 2] cyclization is reported. The reaction conditions are mild, its operation is simple, and the substrate scope is wide. More than 60 pyrimidio[1,2-b]indazole derivatives have been synthesized, providing a new methodology for constructing related molecules and potentially enriching bioactive-molecule libraries.
RESUMO
Introduction: This study investigated the effects of maggot antimicrobial peptides on growth performance, blood parameters, immune organ index, and cecum microbial diversity in yellow broilers. Methods: The addition of 100-300 mg/kg maggots antimicrobial peptides to the corn-soybean meal basal diet was evaluated. Two hundred and forty one-day-old yellow-feathered broilers were randomly divided into four groups (60 chickens in each group): basal diet group (BC group), basal diet group + 100, 200, 300 mg/kg maggots antimicrobial peptides (MDAL group, MDAM group, and MDAH group). Results: The result showed that the average daily feed intake (ADFI) of the BC group, MDAM group, and MDAH group was higher than that of the MDAL group (P > 0.05), the average daily gain of MDAM group and MDAH group was significantly higher than that of BC group and MDAL group (P < 0.05), but the feed-weight ratio (F/G) was significantly lower than that of BC group (P < 0.05). The total protein (TP) content in the MDAM group and MDAH group was significantly higher than that in the BC group (P < 0.05), and the albumin (ALB) content in the MDAH group was higher than that in the BC group (P > 0.05). The contents of IgA and IgG in the MDAH group were significantly higher than those in the BC group (P < 0.05). In contrast, the content of alanine aminotransferase (ALT) in the MDAH group was significantly lower than that in the BC group (P < 0.05). The thymus and spleen indexes of the MDAH group were significantly higher than those of the BC group (P < 0.05). 16S rDNA sequencing results showed that Bacteroidota and Bacteroides were the dominant phylum and genus of cecal microorganisms at the phylum and genus levels, respectively. Cecum microorganisms are mainly involved in biological processes such as energy production and conversion, amino acid transport and metabolism, and carbohydrate transport and metabolism. Discussion: It was concluded that adding different doses of maggot antimicrobial peptide to the basal diet could improve yellow-feathered broilers' growth and immune performance and change the cecum flora. The appropriate dose of antimicrobial peptide addition was 300 mg/kg.
RESUMO
Although considerable efforts towards directly converting syngas to liquid fuels through Fischer-Tropsch synthesis have been made, developing catalysts with low CO2 selectivity for the synthesis of high-quality gasoline remains a big challenge. Herein, we designed a bifunctional catalyst composed of hydrophobic FeNa@Si-c and HZSM-5 zeolite, which exhibited a low CO2 selectivity of 14.3 % at 49.8 % CO conversion, with a high selectivity of 62.5 % for gasoline in total products. Molecular dynamic simulations and model experiments revealed that the diffusion of water molecules through hydrophilic catalyst was bidirectional, while the diffusion through hydrophobic catalyst was unidirectional, which were crucial to tune the water-gas shift reaction and control CO2 formation. This work provides a new fundamental understanding about the function of hydrophobic modification of catalysts in syngas conversion.
RESUMO
In this study, we characterized a WRKY family member gene, SsWRKY1, which is located in the nucleus and contains multiple stress-related cis-acting elements. In addition, constructed SsWRKY1-overexpressing Arabidopsis thaliana had higher antioxidant enzyme activity and proline content under drought stress conditions, with lower malondialdehyde content and reactive oxygen species (ROS) accumulation, and the expression levels of six stress-related genes were significantly upregulated. This indicates that the overexpression of SsWRKY1 in Arabidopsis thaliana improves resistance to drought stress. SsWRKY1 does not have transcriptional autoactivation activity in yeast cells. The yeast two-hybrid (Y2H) system and the S. spontaneum cDNA library were used to screen 21 potential proteins that interact with SsWRKY1, and the interaction between SsWRKY1 and ATAF2 was verified by GST pull-down assay. In summary, our results indicate that SsWRKY1 plays an important role in the response to drought stress and provide initial insights into the molecular mechanism of SsWRKY1 in response to drought stress.
Assuntos
Proteínas de Arabidopsis , Arabidopsis , Saccharum , Arabidopsis/genética , Arabidopsis/metabolismo , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Saccharum/genética , Resistência à Seca , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Saccharomyces cerevisiae/metabolismo , Plantas Geneticamente Modificadas/genética , Regulação da Expressão Gênica de Plantas , Secas , Antioxidantes/metabolismo , Estresse Fisiológico/genéticaRESUMO
Composition analysis in wine is gaining increasing attention because it can provide information about the wine quality, source, and nutrition. In this work, in situ liquid secondary ion mass spectrometry (SIMS) was applied to 14 representative wines, including six wines manufactured by a manufacturer in Washington State, United States, four Cabernet Sauvignon wines, and four Chardonnay wines from other different manufacturers and locations. In situ liquid SIMS has the unique advantage of simultaneously examining both organic and inorganic compositions from liquid samples. Principal component analysis (PCA) of SIMS spectra showed that red and white wines can be clearly differentiated according to their aromatic and oxygen-contained organic species. Furthermore, the identities of different wines, especially the same variety of wines, can be enforced with a combination of both organic and inorganic species. Meanwhile, in situ liquid SIMS is sample-friendly, so liquid samples can be directly analyzed without any prior sample dilution or separation. Taken together, we demonstrate the great potential of in situ liquid SIMS in applications related to the molecular investigation of various liquid samples in food science.
RESUMO
Molecular structure conversion concomitant with mass transfer processes at the electrode-electrolyte interfaces plays a central role in energy electrochemistry. Mass spectrometry, as one of the most intuitive, sensitive techniques, provides the capability to collect transient intermediates and products and uncover reaction mechanisms and kinetics. In situ time-of-flight secondary ion electrochemical mass spectrometry with inherent high mass and spatiotemporal resolution has emerged as a promising strategy for investigating electrochemical processes at the electrode surface. This review illustrates the recent advancements in coupling time-of-flight secondary ion mass spectrometry and electrochemistry to visualize and quantify local dynamic electrochemical processes, identify solvated species distribution, and disclose hidden reaction pathways at the molecular level. Moreover, the key challenges in this field are further discussed to promote new applications and discoveries in operando studying the dynamic electrochemical interfaces of advanced energy systems.
RESUMO
Cesium lead triiodide (CsPbI3 ) is a promising light-absorbing material for constructing perovskite solar cells (PSCs) owing to its favorable bandgap and thermal tolerance. However, the high density of defects in the CsPbI3 film not only act as recombination centers, but also facilitate ion migration, leading to lower PCE and inferior stability compared with the state-of-the-art organic-inorganic hybrid PSC counterpart. Theoretical analyses suggest that the effective suppression of defects in CsPbI3 film is helpful for improving the device performance. Herein, the stable and efficient γ -CsPbI3 PSCs are demonstrated by developing an acyloin ligand (1,2-di(thiophen-2-yl)ethane-1,2-dione (DED)) as a phase stabilizer and defect passivator. The experiment and calculation results confirm that carbonyl and thienyl in DED can synergistically interact with CsPbI3 by forming a chelate to effectively passivate Pb-related defects and further suppress ion migration. Consequently, DED-treated CsPbI3 PSCs yield a champion PCE of 21.15%, which is one of the highest PCE among all the reported CsPbI3 PSCs to date. In addition, the unencapsulated DED-CsPbI3 PSC can retain 94.9% of itsinitial PCE when stored under ambient conditions for 1000 h and 92.8% of its initial PCE under constant illumination for 250 h.
RESUMO
All-inorganic CsPbI3 perovskite solar cells (PSCs) have been extensively studied due to their high thermal stability and unprecedented rise in power conversion efficiency (PCE). Recently, the champion PCE of CsPbI3 PSCs has reached up to 21%; however, it is still much lower than that of organic-inorganic hybrid PSCs. Interface modification to passivate surface defects and minimize charge recombination and trapping is important to further improve the efficiency of CsPbI3 PSCs. Herein, a new zwitterion ion is deposited at the interface between electron transporting layer (ETL) and perovskite layer to passivate the defects therein. The zwitterion ions can not only passivate oxygen vacancy (VO ) and iodine vacancy (VI ) defects, but also improve the band alignment at the ETL-perovskite interface. After the interface treatment, the PCE of CsPbI3 device reaches up to 20.67%, which is among the highest values of CsPbI3 PSCs so far. Due to the defect passivation and hydrophobicity improvement, the PCE of optimized device remains 94% of its original value after 800 h storing under ambient condition. These results provide an efficient way to improve the quality of ETL-perovskite interface by zwitterion ions for achieving high performance inorganic CsPbI3 PSCs.
RESUMO
OBJECTIVE: To investigate the clinical characteristics and treatment outcomes of Nocardia infection after ocular surface surgery. METHODS: This is a retrospective study. Eight cases of culture-proven Nocardia infection, which developed within 1 month after ocular surface surgery were included. Demographics and clinical history of patients were investigated. RESULTS: There were 8 eyes (2 left and 6 right) of 8 patients (5 males and 3 females), aged 27-65, with a median age of 52.9 years. Three cases underwent pterygium excision, three were subjected to conjunctival flap covering, and two were treated with lamellar corneal transplantation. The time interval between previous surgery and the onset of symptoms varied from 7 to 28 days (mean = 20.5 ± 7.13 days). All the cases presented grey-white infiltrates at the surgical incision site while appearing with six corneal ulcers and two conjunctival ulcers. Filaments of Nocardia were founded by confocal microscopy in two of the five cases. All responded poorly to medical therapy. Seven of the eight cases were treated with reoperation. Nocardia infection recurred in three cases after reoperation, and one was eviscerated. CONCLUSIONS: Surgical trauma is a risk factor for ocular Nocardia infection. Nocardia infection should be suspected when secondary infection occurs in a surgical incision with an atypical clinical presentation. The use of corticosteroids may influence the efficacy of drugs. Complete removal of lesions may lower the recurrence of Nocardia infection with poor drug treatment effects.
Assuntos
Olho , Nocardiose , Ferida Cirúrgica , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Nocardia , Nocardiose/diagnóstico , Nocardiose/tratamento farmacológico , Estudos Retrospectivos , Ferida Cirúrgica/microbiologia , Úlcera , Olho/microbiologia , OftalmologiaRESUMO
Scirpus planiculmis, an important weed in rice and cotton fields, stresses crop growth and development, leading to yield loss. However, it is unclear how stressed plants respond to this weed. In this study, we analysed the stress effect of S. planiculmis on cotton under different weed densities, competition periods, and distribution conditions from the perspective of morphogenesis, physiological metabolism and crop yield. The effect of a low dose of herbicide on the relationship between cotton and S. planiculmis was also explored. The results showed that plant height, stem diameter, fresh weight, root length, boll number, single boll weight and yield of cotton all decreased with increasing S. planiculmis density and damage. The spatial distribution of S. planiculmis had no significant effect on plant height, stem diameter, fresh weight or root length of cotton, but crop yield loss decreased with increasing distance. S. planiculmis stress altered cotton chlorophyll, soluble protein and malondialdehyde (MDA) content, and protective enzyme activities. Compared with superoxide dismutase (SOD) and peroxidase (POD) activities, catalase (CAT) activity was increased under different S. planiculmis stress conditions. Therefore, we concluded that CAT plays a key role in protecting enzymes involved in defence responses. Under low-dose herbicide action, the activities of protective enzymes were increased, which helped cotton plants to resist S. planiculmis stress. The results revealed that regulating protective enzyme activities is important in cotton responses to S. planiculmis stress.
RESUMO
BACKGROUND: 2-methyl-4-chlorophenoxy acetic acid-Na (MPCA-Na) is a phenoxy carboxylic acid selective hormone herbicide that is widely used in the crop fields. However, drift of MPCA-Na during application is highly damaging to cotton (Gossypium hirsutum) and other crop plants. This study was carried out from 2019 to 2020 to determine the effects of different concentrations of MPCA-Na on physiological and metabolic activities besides growth and yield of cotton plants at seedling, budding, flowering and boll stages. Moreover, we evaluated the different combinations of 24-epibrassinolide, gibberellin (GA3), phthalanilic acid and seaweed fertilizer to ameliorate herbicide damage. RESULTS: 2-methyl-4-chlorophenoxy acetic acid-Na (MPCA-Na) exposure caused a decrease in the chlorophyll content, and an increase in the soluble protein content, Malondialdehyde (MDA) content and protective enzyme activity. It also caused significant reductions in plant height, boll number and the single boll weight at the seedling and budding stages, but had little effects on plant height and the single boll weight at flowering and boll stage. Under the maximum recommended dose of MPCA-Na (130 g/L), the number of cotton bolls at seedling and budding stages decreased by 75.33 and 79.50%, respectively, and the single boll weight decreased by 46.42 and 36.31%, respectively. Nevertheless, the number of G. hirsutum bolls and single boll weight at flowering and boll stage decreased by 48.15 and 5.38%, respectively. Application of plant growth regulators decreased the MDA content, and increased chlorophyll, soluble protein content and protective enzyme activity, and alleviated MCPA-Na toxicity. Positive effects in case of growth regulators treated plants were also observed in terms of G. hirsutum yield. Phthalanilic acid + seaweed fertilizer, 24-epibrassinolide + seaweed fertilizer, and GA3 + seaweed fertilizer should be used at the seedling, budding, and flowering and boll stages, respectively. CONCLUSIONS: The results of current study suggest that certain plant growth regulators could be used to alleviate MPCA-Na damage and maintain G. hirsutum yield. When the cotton exposed to MCPA-Na at the seedling stage, it should be treated with phthalanilic acid + seaweed fertilizer, while plants exposed at the budding stage should be treated with 24-epibrassinolide + seaweed fertilizer, and those exposed at the flowering and boll stages should be treated with GA3 + seaweed fertilizer to mitigate stress.
Assuntos
Ácido 2-Metil-4-clorofenoxiacético , Herbicidas , Gossypium/metabolismo , Reguladores de Crescimento de Plantas/farmacologia , Fertilizantes , Clorofila/metabolismoRESUMO
In this paper, an SVIR epidemic model with temporary immunities and general incidence rates is constructed and analyzed. By utilizing Lyapunov functions, we prove the existence and uniqueness of the positive global solution of the constructed model, as well as the sufficient conditions of extinction and persistence of disease, are provided. Due to the difficulty of obtaining the analytical solution to our model, we construct two numerical schemes to generate an approximate solution to the model. The first one is called the split-step θ-Milstein (SSTM) method, and the second one is called the stochastic split-step θ-nonstandard finite difference (SSSNSFD) method, which is designed by merging split-step θ method with stochastic nonstandard finite difference method for the first time in this paper. Further, we prove the positivity, boundedness, and stability of the SSSTNSFD method. By employing the two mentioned methods, we support the validity of the studied theoretical results, as well, the effect of the length of immunity periods, parameters values of the incidence rates, and noise on the dynamics of the model are discussed and simulated. The increase in the size of time step size plays a vital role in revealing the method that preserves positivity, boundedness, and stability. To this end, a comparison between the proposed numerical methods is carried out graphically.
RESUMO
A new flavonoid (bunge A) (1), a new sesquiterpene (bunge B) (8), a new furan derivative (bunge C) (12) and a new alkenoic acid (bunge D) (14), together with ten known ones [four flavonoids (2, 3, 4, 5), two phenylpropanoids (6, 7), three sesquiterpenes (9, 10, 11) and one lactone (13)] were isolated from the fruits of Prunus humilis Bunge [Cerasus humilis (Bunge) Sokolov]. Their structures were elucidated based on extensive spectroscopic analysis (including HR-ESI-MS and NMR) and comparison with previously published data. All compounds were evaluated for cytotoxic activity against three human tumour cell lines. Compound 3 and 4 showed weak antiproliferative activities against hepatocarcinoma cell HepG-2 at the concentration of 100 µM, which the inhibition rates were 55.34 ± 0.29 and 45.52 ± 0.37, respectively. And other compounds had almost no cytotoxic activity against the three tumour cell lines in vitro.
RESUMO
Low-temperature solution processing of thin-film semiconductors is more cost-effective than traditional vacuum processing; however, it leads to more defects during fast bulk crystallization and residual tensile stress. Herein, a new strategy of dynamic liquid-crystal transition (DLCT) is developed to solve these problems in one step. The design principle is used to suggest that the DLCT molecule should firstly interact with the perovskite grains in the bulk and meanwhile go through a dynamic transition to spontaneously heal the interface. A thermotropic LC molecule (CBO6SS6OCB) is then designed to demonstrate the strategy. The LC interacting with perovskite colloid forms an intermediate adduct to retard the crystallization. The annealing processes stimulate the concentrated LC solid, causing it to flow to the electron transport layer to release the residual stress to attain improved electron extraction. Consequently, the device efficiency is increased to 24.38%, where its VOC of 1.184 V is among the best for the formamidine-based perovskite solar cells. Furthermore, the ambient stability (93.0% of initial efficiency after 2000 h of aging) and light stability (96.3% of initial efficiency after 500 h of aging) are much improved. This work conceives a new engineering of additive phase transition for high-performance perovskite solar cells.
RESUMO
Powdery mildew, caused by Sphaerotheca fuliginea (Schlecht.) Poll., and melon aphids (Aphis gossypii Glover) are a typical disease and insect pest, respectively, that affect cucumber production. Powdery mildew and melon aphid often occur together in greenhouse production, resulting in a reduction in cucumber yield. At present there are no reports on the physiological and biochemical effects of the combined disease and pest infection/infestation on cucumber. This study explored how cucumbers can regulate photosynthesis, protective enzyme activity, and basic metabolism to resist the fungal disease and aphids. After powdery mildew infection, the chlorophyll and free proline contents in cucumber leaves decreased, while the activities of POD (peroxidase) and SOD (superoxide dismutase) and the soluble protein and MDA (malondialdehyde) contents increased. Cucumber plants resist aphid attack by increasing the rates of photosynthesis and basal metabolism, and also by increasing the activities of protective enzymes. The combination of powdery mildew infection and aphid infestation reduced photosynthesis and basal metabolism in cucumber plants, although the activities of several protective enzymes increased. Aphid attack after powdery mildew infection or powdery mildew infection after aphid attack had the opposite effect on photosynthesis, protective enzyme activity, and basal metabolism regulation. Azoxystrobin and imidacloprid increased the contents of chlorophyll, free proline, and soluble protein, increased SOD activity, and decreased the MDA content in cucumber leaves. However, these compounds had the opposite effect on the soluble sugar content and POD and CAT (catalase) activities. The mixed ratio of the two single agents could improve the resistance of cucumber to the combined infection of powdery mildew and aphids. These results show that cucumber can enhance its pest/pathogen resistance by changing physiological metabolism when exposed to a complex infection system of pathogenic microorganisms and insect pests.
RESUMO
The Asian longhorned beetle, Anoplophora glabripennis, is a forestry pest found worldwide. A. glabripennis causes serious harm because of the lack of natural enemies in the invaded areas. Dastarcus helophoroides and Dendrocopos major are important natural enemies of A. glabripennis. MaxEnt was used to simulate the distribution of D. helophoroides and D. major in China, and their suitable areas were superimposed to pinpoint which regions are potentially appropriate to release or establish natural enemy populations under current and future conditions. The results showed that, with climate change, the suitable areas of D. helophoroides and D. major migrated northward; the centroid shift of A. glabripennis was greater than those of D. helophoroides and D. major. From current conditions to 2090, the suitable area of A. glabripennis, D. helophoroides, and D. major will increase by 1.44 × 104, 20.10 × 104, and 31.64 × 104 km2, respectively. Northern China (e.g., Xinjiang, Gansu, and Inner Mongolia), where A. glabripennis causes more serious damage, is also a potentially suitable area for D. helophoroides and D. major, and this provides a potential strategy for the management of A. glabripennis. Therefore, we suggest that natural enemies should be included in the model used for predicting suitable areas for invasive pests.