Mold and Stain Resistance of Bamboo Treated with Pyraclostrobin Fungicide.

Bamboo is rich in starch and sugars and can be infected by mold and stain fungi, degrading its performance, shortening its service life, and reducing its utilization value. It is crucial to investigate how to protect bamboo against mold and stain fungi. The zone of inhibition test was used to evaluate the antifungal activity of azoxystrobin, kresoxim-methyl, pyraclostrobin and 3-iodo-2-propynyl-butylcarbamate (IPBC) against stain fungi (Botryodiplodia theobromae, Fusarium moniliforme, and Alternaria alternate) and mold fungi (Aspergillus niger, Penicillium citrinum, and Trichoderma viride) to develop new chemicals to protect bamboo against stain fungi and molds. The inhibitory activity of the composite pyraclostrobin and IPBC with different ratios was evaluated. Water-based formulations of the fungi were used to treat the bamboo, and the mold and stain resistance of the bamboo was investigated at different chemical retention rates. The results showed that the antifungal activity of pyraclostrobin was significantly higher than that of azoxystrobin and kresoxim-methyl. Different degrees of inhibitory activities against the stain and mold fungi were observed, and the inhibitory activity was higher against stain fungi than against molds. The three stain fungi were completely inhibited at a 7:3 ratio of pyraclostrobin to IPBC and 0.1% concentration. As the ratio increased, the inhibitory effect against mixed mold strains improved. The control efficacy of the pyraclostrobin formulations Str-1 and Str-2 at 0.1% concentration was 100% against Alternaria alternate and 70.8% against Fusarium moniliforme. The control efficacy of the composite formulations SI-1 and SI-2 at 0.1% concentration was 100% against all three stain fungi and greater than 91.8% against the mixed mold strains. This study provides new insights into the utilization of pyraclostrobin and its composite formulations as new bamboo antifungal agents.

Leachability and Anti-Mold Efficiency of Nanosilver on Poplar Wood Surface.

Water-based antimicrobial agents, used in environmentally friendly applications, are widely used in wood protection industries. Furthermore, nanomaterials as antimicrobial agents, because of their biocidal component, huge specific surface area, and unique nanoscale effect, have attracted attention in the field of biodurability. We employed aqueous dispersed nano-silver with a diameter of 10 nm~20 nm to treat poplar wood and evaluated its leaching resistance and anti-mold effect on the wood surface. The results revealed that the higher the retention of the nano-silver, the stronger the protection efficiency of the wood surface against three molds (Aspergillus niger V. Tiegh, Penicillium citrinum Thom, and Trichoderma viride Pers. ex Fr); and the leachability of the nano-silver presented a slowly growing trend with the increase in the retention. When the wood surface attained a silver retention of 0.324 g·m-2, its anti-mold efficiency against Aspergillus niger V. Tiegh, Penicillium citrinum Thom, and Trichoderma viride Pers. ex Fr reached 80, 75, and 80%, respectively, which achieved or even exceeded the required standard value of effective mold inhibition (75%). Notably, the nano-silver leaching rate at this retention attained merely 4.75 %. The nanoparticle, well distributed on a wood surface, may promote sufficient contact with fungi as well as strong interaction with wood cell wall components, which probably contributed to the effective anti-mold efficiency and the leaching resistance. This study provided positive evidence for the anti-mold effect of nano-silver on wood surface.

[Effects of Nitrogen Fertilizer and Straw Returning Methods on N2O Emissions in Wheat-Maize Rotational Soils].

In order to explore the impacts of nitrogen fertilizer and straw returning methods on N2O emissions, a two-factor split-zone design was adopted for experimentation under the winter wheat-summer maize rotation model in the Guanzhong area of Shanxi, China. The main areas of interest were conventional nitrogen (G) and reduced nitrogen (70% G); the sub-areas were straw no return (N), straw return (S), and straw return + biochar (SB); we analyzed their impacts on N2O emissions and crop yield, and the relationships with related impact factors. The results showed that the N2O emissions peaks appeared in the wheat season and maize season treatments within 5-16 days after fertilization, and also appeared after rainfall. The N2O flux was significantly and positively correlated with soil temperature and NH4+-N content. Regardless of the wheat season, maize season, or annual total N2O emissions, the 70% GSB treatment was the lowest and the GS treatment was the highest. At the same level of nitrogen application, S treatment increased N2O emissions, SB treatment could reduce N2O emissions, both S and SB treatments could significantly increase crop yields, and SB production increased more; 70%G-level annual N2O emissions, when compared with the G level, had been reduced by 40% to 48%, while the yield has not decreased significantly. Through comprehensive consideration, a reduction of nitrogen by 30% was achieved through the combination of straw + biochar on the basis of conventional nitrogen application, while ensuring high crop yields and the best N2O emissions reduction.

Analysis of the environmental behavior of farmers for non-point source pollution control and management: An integration of the theory of planned behavior and the protection motivation theory.

Agricultural non-point source (NPS) pollution in water source protection areas poses serious challenges for governments in developing countries. It is important to consider the environmental behavior of farmers when exploring the causes of NPS pollution as well as when establishing scientific controls and management measures. However, the poor understanding of factors influencing the environmental behavior of farmers and the lack of a suitable environmental socio-psychological model limit the application of the environmental behavior of farmers in NPS pollution management. In this study, we therefore integrated the theory of planned behavior (TPB) and the protection motivation theory (PMT) to identify the main determinants of the NPS pollution-related environmental behavior and intention of farmers in the Water Source Area of the Middle Route of the South-to-North Water Diversion Project in China. Results indicated that the integrated model provided a better understanding of the environmental behavior and intention of farmers than that provided by each component when used individually, and revealed that farmers perceived that the susceptibility and severity of threats caused by water deterioration influenced environmental intention through the mediating effects of subjective norm and attitude toward adopting pro-environmental behavior. At the same time, the perceived vulnerability of farmers was relatively high and their perceived severity was relatively low. Furthermore, the subjective norm, attitude, self-efficacy (i.e., the perceived behavioral control), and response efficacy positively and significantly influenced intention. However, response cost had a significantly negative effect on intention. Among them, subjective norm had the largest effect on intention. Intention was the key determinant for the actual environmental behavior of farmers, while self-efficacy also had a significantly positive effect on behavior. Managing and controlling agricultural NPS pollution requires a multi-disciplinary and comprehensive approach. Therefore, an integrated theoretical framework was developed in this study by integrating TPB and PMT to gain insight into the environmental behaviors and intention of farmers. The results provided a theoretical basis for NPS pollution control.

Correlation study between molecular structure of sesquiterpene lactones and the selective adsorption performance of molecularly imprinted polymers.

We preliminarily report that the structure of template molecules and target components correlates with the selective adsorption performance of molecularly imprinted polymer (MIPs) in sesquiterpene lactones. Template molecules involved three categories of sesquiterpene lactones with distinct ring systems: 5-mem lactone ring atractylenolide III, 7-mem lactone ring dehydrocostus lactone, and 10-mem lactone ring costunolide lactone, of which the conformations were verified by variable-temperature (1)H NMR spectroscopy. Reciprocal MIPs were prepared by precipitation polymerization and employed as selective sorbents in the columns of solid phase extraction (SPE). These columns were further used for enriching the mixed adsorption solution of sesquiterpene lactone ingredients and reference components. Finally, the extract of Radix Aucklandiae, a Chinese medicine herb, was used to verify the efficiency of this method. Our results demonstrate that the steric conformational stability of molecules is associated with the selective adsorption of their corresponding MIPs. We have further observed that the maximum adsorption capacity occurs when the target molecule conformation is consistent with that of the template molecule. The addition of more hydrophilic groups correlates with weaker adsorption of MIPs. Our findings provide important information to help guide the selection of appropriate template molecules for synthesis of MIPs with specific adsorption.

Physcion, a natural anthraquinone derivative, enhances the gene expression of leaf-specific thionin of barley against Blumeria graminis.

BACKGROUND: Physcion is a key active ingredient of the ethanol extract from roots of Chinese rhubarb (Rheum officinale Baill.) that has been commercialised in China for controlling powdery mildews. The biological mechanism of action of physcion against the barley powdery mildew pathogen was studied using bioassay and microarray methods. RESULTS: Bioassay indicated that physcion did not directly affect conidial germination of Blumeria graminis Speer f. sp. hordei Marchal, but significantly inhibited conidial germination in vivo. Challenge inoculation indicated that physcion induced localised resistance rather than systemic resistance against powdery mildew. Gene expression profiling of physcion-treated barley leaves detected four upregulated and five downregulated genes (ratio >or= 2.0 and P-value < 0.05) by using an Affymetrix Barley GeneChip. The five upregulated probe sequences blasted to the same barley leaf-specific thionin gene, with significant changes varying from 4.26 to 19.91-fold. All downregulated genes were defence-related, linked to peroxidase, oxalate oxidase, bsi1 protein and a pathogenesis-related protein. These changes varied from - 2.34 to - 2.96. Quantitative real-time PCR data confirmed that physcion enhanced the gene expression of leaf-specific thionin of barley. CONCLUSION: Results indicated that physcion controls powdery mildew mainly through changing the expression of defence-related genes, and especially enhancing expression of leaf-specific thionin in barley leaves.