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101.
The review describes the history of pheromone research in Israel in 1975–2015. The research focused on sex pheromones of moths that were important agricultural pests. Identification, synthesis and field application of sex pheromones was performed. Synthetic procedures of several known sex pheromones were developed. Monitoring and control of key pest moths was evaluated. The interactions of pheromone components of closely related species were studied in field and laboratory experiments. The sex pheromones of three scale insects, two mealybug species and Matsucoccus josephi were studied. New syntheses were developed and the pheromones were implemented in pest management. Structure activity relationship of the pheromonal and kairomonal of the M. josephi pheromone was investigated. Different pherotypes of P. ficus were identified and evaluated. The aggregation pheromone of sap beetles in combination with food baits was evaluated. The aggregation pheromone of the almond bark beetle was identified and a stereospecific synthesis of its enantiomers was developed. Monitoring the pest in stone fruit orchards was implemented. The activity of the pheromone biosynthesis activating neuropeptide (PBAN) was studied in Helicoverpa armigera and Heliothis peltigera. The ligation technique was used to assess the effect of PBAN on the production of female and male pheromones. A structure-activity relationship study of PBAN indicated that shorter peptides display activity as the full length PBAN. A series of linear and cyclic peptide analogs was prepared, resulting in the discovery of a lead antagonist. The research and development activity facilitated the intensive integration of pheromones in the pest management regimes in Israeli agriculture.  相似文献   
102.
Bacterial blight disease of Persian walnut (Juglans regia, L.), caused by Xanthomonas arboricola pv. juglandis (Xaj), leads to significant nut losses in northern, central and western areas of Iran. To identify the natural sources of resistance to disease in the endemic walnut genotypes of Iran, sixteen walnut genotypes, collected from different areas of Hamedan province, were inoculated with Xaj in a randomized complete block design with five replicates for each genotype. Two-year old genotypes were gently sprayed with a suspension of bacteria adjusted to approximately 2 × 109 cfu ml−1 of distilled water in May. Infected leaves were rated for disease 28 and 42 days after inoculation, using a 0 to 5 severity scale, based on the number, size and distribution of lesions on the leaves. Data analyses showed that there were variations among genotypes in response to pathogen. Upon inoculation by bacterial suspension genotype 94 showed the highest resistance to both disease incidence and its progress after 4–6 weeks of infection. Genotype 65 showed high susceptibility to disease and genotype 69 showed high susceptibilities both to disease incidence and its progress after 4–6 weeks of infection.  相似文献   
103.
Studies were conducted in the laboratory and greenhouse to determine the distribution of Erwinia rhapontici in plants arising from naturally infected seeds of pea or artificially inoculated seeds of bean and wheat, and whether the pathogen is transmitted to the subsequent generation of seeds. Infected seeds were planted in pots of Cornell mix in the greenhouse, and sampled at specified intervals throughout the plant growth cycle (seedling stage, elongation stage, flowering stage, seed formation stage, and maturity). Plating of surface sterilized lateral roots, tap roots, basal stems, mid-stems, apical stems, petioles, pods, and seeds of pea and bean, and of lateral roots, sub-crown internodes, basal stems, mid-stems, apical stems, peduncles, glumes, and seeds of wheat revealed that the bacterial pathogen spread from infected seeds to the lower parts of the plant tissues, but failed to spread further to the seeds produced on these plants. The study concludes that E. rhapontici did not establish systemic infection throughout the plants. Possible mechanisms of infection of seeds are discussed.  相似文献   
104.

Context

Common indicators are needed to monitor biodiversity loss and the implications for the sustainable provision of ecosystem services (ES). A plethora of different sets of indicators may hinder the identification of major endpoints for large-scale assessments of biodiversity and ecosystem services (BES).

Objectives

We aim to describe the main challenges of indicators for BES assessment and provide suggestions for establishing a comprehensive indicator system.

Methods

An extensive literature review was conducted in this study. We review the main challenges of indicators for BES assessment and propose corresponding improvements from our perspectives of theory and practical applications.

Results

The main theoretical challenges of existing indicators include inconsistent definitions and classifications of ES, misunderstanding of linkages among biodiversity, ecosystem structure, functions and services, and practical problems relate to such issues as indicator representativeness, data availability, and uncertainty. Our suggested improvements include clarifying the main terms, concepts and classification of indicators, establishing a robust conceptual framework with clear interactions among different components and indicators, selecting indicators based on ecosystem properties, streaming existing data into one platform, and strengthening validation of proxies. The steps for constructing a comprehensive indicator system for BES assessment are summarized.

Conclusions

Clear definitions of key terms are indispensable to classify indicators and construct a conceptual framework. Improved understanding of the relations among indicators of biodiversity, ecosystem functions, and ES across multiple scales can guide the development of the indicator system. The integrated indicator system is an important tool for BES assessment to support decision making for sustainable development.
  相似文献   
105.
Previously, we have reported a method for producing photochromic wool fabric by applying a thin layer of hybrid silica-photochromic dye onto the wool surface. While the photochromic coating showed a very fast optical response and had little influence on the fabric handle, its durability was poor. In this study, the durability of the photochromic coating layer was improved by introducing epoxy groups into the silica matrix via co-hydrolysis and co-condensation of an alkyl trialkoxysilane compound (ATAS) and 3-glycidoxypropyltrimethoxysilane (GPTMS). The presence of epoxy groups in the silica enhanced both washing and abrasion durability or fastness. In addition, the optical response speed was slightly increased as well. Effects of the type of alkyl silane and the GPTMS/alkyl silane ratio on the coating durability, fabric handle and optical response were examined.  相似文献   
106.
Innovations in precision agriculture (PA) have created opportunities to achieve a greater understanding of within-field variability. However, PA adoption has been hindered by uncertainty about field-specific performance and return on investment. Uncertainty could be better addressed by using innovative analyses that provide insights into variability among fields and across a region. The objectives of this research were to: (1) generate a within-field soil clay-content variability index (VIc), (2) create a regional-scale growing-season precipitation variability index (VIp), and (3) integrate the soil and weather indices with the USDA NRCS soil erosion vulnerability index (SVI) to produce a final index that incorporated both variability and vulnerability (VVI). The interpretation of the outcomes represented by each objective supports unique decisions that land managers may consider for reducing uncertainty about implementing PA. All indices were derived using publically available information for Missouri, USA. The VIc was the ratio between the maximum and minimum clay content within fields. The VIp was calculated as the standard deviation of the total growing-season precipitation from 2006 to 2015. Significant clustering of VIc and VIp were observed along the Missouri River corridor, northeast and northwest Missouri. Fields with high VVI were mostly in the claypan soil region of northeast Missouri, and along a portion of the Missouri River dominated by loess soils on steep slopes. Southeast Missouri displayed the greatest diversity in soil and weather variability, but had low vulnerability. This research could be used as a decision-support tool to aid producers and PA service and product providers in determining where PA opportunities exist.  相似文献   
107.
Total antioxidant activity of six non-cultivated but traditionally collected fruits from the south of Europe was assessed by measuring their ability to reduce the hydroxyl radical ( OH· ) \left( {{\hbox{O}}{{\hbox{H}}^\bullet }} \right) and hydrogen peroxide (H2O2), and their Trolox equivalent antioxidant capacity (TEAC). This antioxidant activity was compared with that shown by the synthetic antioxidants BHA (E-320), BHT (E-321) and propyl gallate (E-310). Total phenolics, ascorbic acid and the carotenoid content of the fruits were also analyzed. All fruits showed a high ability to scavenge the OH· {\hbox{O}}{{\hbox{H}}^\bullet } radical, ranging from 60.61% to 81.04% inhibition for Rosa canina and Crataegus monogyna, respectively. The H2O2 scavenging capacity and the TEAC value varied widely, ranging between 3.63% and 87.26% inhibition of H2O2 and between 0.47 and 416.64 mM trolox g−1 FW for Sorbus domestica and Rosa canina, respectively. The antioxidant activity of fruits was higher than that of the synthetic additives analyzed, except in the TEAC assay. The phenolic and carotenoid content of R. canina was much higher than that of the other fruits analyzed and its ascorbic acid concentration was also high, reflecting its higher efficacy towards ABTS ·- {\hbox{ABT}}{{\hbox{S}}^{ \bullet - }} (TEAC assay) and H2O2 species. In spite of these associations, the correlation coefficients between total antioxidant activity and the antioxidant compounds analyzed were not very significant; only phenolics and carotenoids showed a marginal correlation with the TEAC assay. The results support the possible use of R. canina as natural antioxidant to replace the synthetic additives, as well as their use in the production of functional foods with a high antioxidant activity.  相似文献   
108.
In this work, a novel hybrid fibrous vehicle was developed for the release and real-time detection of nitric oxide (NO). The vehicle consisted of poly(L-lactide)/chitosan (PLLACS), cadmium tellurium quantum dots (CdTe QDs), and conjugating S-nitrosothiols. CdTe QDs were placed on the surface of PLLACS fibers as NO fluorescent probes through coaxial electrospinning; in this method, the PLLACS was used as filament material. Water-dispersible CdTe QDs were synthesized using mercaptoacetic acid as a stabilizer. The amino groups of chitosan served as reactive sites where chitosanbased S-nitrosothiols were formed. The fibrous PLLACS-QDs-NO composite was found to release NO under UV. The released NO could be detected in real time on the basis of the fluorescence quenching mechanism of QDs. These PLLACSQDs-NO nanofibers provide insights into novel designs of biocompatible NO delivery systems.  相似文献   
109.
The successful isolation and characterization of water hyacinth fiber (Eichornia crassipes) (WHF) nanocellulose is presented in this study. The novelty was in exploring a wider range of properties of highly purified samples of WHF after each stage of production in more depth. The isolation was accomplished by pulping in a digester and sonication. Morphological changes before and after treatment were demonstrated by scanning electron microscopy (SEM). The lignin and hemicellulose content decreased during chemical treatment. Transmission electron microscopy (TEM) and particle size analyzer (PSA) were used to determine the morphology of WHF after sonication for 1 h. TEM shows that the diameter and length of nanocellulose WHF were 15.61 and 147.4 nm, respectively. The crystallinity index and crystalline domain area significantly increased after chemical treatment. The highest crystallinity index was 84.87 % after an acid hydrolysis process. The increase in crystallinity leads to good thermal stability. Moisture absorption tests of WHF were carried out before and after treatment. The lowest moisture absorption was in the cellulose fiber after sonication (nanocellulose).  相似文献   
110.

Purpose

With the increase of surfactant usages, more and more concerns were paid on their effects on the physicochemical characteristics of soils. Up to now, only few researches have examined the effects of ionic surfactants on the stability of soil structure and soil water repellency.

Materials and methods

Cetyltrimethyl ammonium bromide (CTAB) as cationic surfactant and sodium dodecyl sulfate (SDS) as anionic surfactant were adopted to investigate their effects on the aggregate stability and water repellency of a silt loam soil which was sampled in Corn High-Tech Park, Huang-Huai-Hai region, China. (1) Aggregate stability: 50 g soil was mixture with 100 mL surfactant solution in a beaker. The concentrations of surfactant solutions were 0 (the blank), 200, 400, 600, 800, 1000, and 2000 mg L?1, respectively. After 30 min, the soil was sieved and divided into four fraction aggregates. (2) Soil water repellency: the concentrations of surfactant solutions were the same as experiment 1. Forty grams of soil was blended with 80 mL surfactant solution in an aluminum specimen. Drying the water by oven of 40 °C firstly and then by air, the whole period was about 1 week. After that, soil water infiltration and sorptivity were measured.

Results and discussion

Compared to the blank, surfactants increased the amounts of 2–0.25 and <0.053 mm aggregates of the soil and decreased the amounts of 0.25–0.053 mm aggregates of the soil. Surfactants also increased the mean weight diameter (MWD) of the soil. Except the 200 mg L?1 treatment, CTAB promoted the soil water infiltration. All SDS treatments impeded the soil water infiltration. The soil repellency factor (R) value of the blank was 1.22, lower than the critical value of 1.95, which implied that the soil of blank treatment was free of soil water repellency. For CTAB, only 200 and 400 mg L?1 treatment’s R were higher than 1.95 while for SDS, all the treatment’s R were higher than 1.95.

Conclusions

Surfactants improved the stability of soil aggregates. Soil treated with CTAB did not show the repellency, whereas SDS treatment resulted in intense water repellency compared with the wettable blank soil. Findings of this study can be used to explain the role of ionic surfactants on soil structure stability as well as on the development of water repellency in lower soil depths.
  相似文献   
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