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21.
The objectives were to determine the content and composition of lipophilic extractives, particularly fatty and resin acids, in three Scots pine trees from each of two stands in northern Sweden, one that was due for thinning and one due for final cutting. Extractives content of branches, needles, barks, stem discs from branch whorls, and sapwood and heartwood samples from various heights was measured. Fractions had very different concentrations and distributions of extractives due to differences in the composition of tissues. The needles had the highest total extractive concentration (around 150?kg/ton d.w.), followed by the branches, bark, timber from the final cut stand, and then the pulpwood and timber from the thinning stand. The final cut stand generally provided higher yields of extractives in assortments per hectare than the thinning stand; the difference was five-fold for timber, three-fold for whole trees, two-fold for branches, needles and bark and similar for pulpwood. This information on the content and composition of extractives in different tissues, and the dependence of these quantities on tree age could be used together with information on conventional stand data such as tree numbers and dimensions to guide the selection and management of feedstocks for biorefineries.  相似文献   
22.

One of the basic requirements for sustainable forest management in mixed broadleaved stands is to provide suitable conditions for natural regeneration of trees. These conditions include, but are not limited to, the frequency, quality and the composition of seedling species. Compacted soil layers caused by forest machinery traffic are the most common problem affecting seedling establishment and growth after skidding operations. In this study, we evaluated the frequency, quality, diversity of seedling species and physicochemical properties of soil on 10-, 20- and 30-year-old abandoned skid trails. Further comparison to the values of the mentioned above parameters in control areas allowed for the evaluation in terms of natural recovery processes, under varying traffic intensity and the longitudinal slope of the skid trails in a mixed broadleaved forest. Results showed that there is a significant positive trend of recovery for soil physicochemical properties and ecological characteristics (density and quality) of seedling growing on the skid trails. The time required to recover soil properties and ecological attributes of seedlings increased with increasing traffic intensity and slope of the skid trail. Our results showed that it takes 20 and 30 years to fully recover the chemical and physical properties of the soil, respectively. On the 30-year-old skid trails, density and species diversity indices were fully recovered, but the quality of the seedlings was not restored to the control conditions. The results suggest the importance of a proper planning of the skid trail network, avoiding in particular skid trails with a slope gradient higher than 20%.

  相似文献   
23.
Experiments were conducted in 2009–2010 at the Agricultural and Natural Resources Research Center of Yazd, Iran, to study the effect of nitrogen levels and plant growth-promoting rhizobacteria (PGPR) containing Azotobacter sp. and Azospirillum sp. on seed yield, its components and quality traits of sesame cultivars. Treatments were arranged in a factorial experiment based on randomized complete block design with nitrogen rates (0 (control), 25 and 50 kg N ha?1), cultivars (Darab-14, GL-13 and local) and N-fixing bacteria levels (non-inoculation and inoculation) were applied with three replications. Nitrogen fertilizer significantly increased yield and yield components, but reduced oil content in 2010. Inoculating seeds with PGPR increased yield and yield components of sesame cultivars compared to the control treatment. Seed yield in PGPR inoculation with half a rate of N fertilizer treatment was more than seed yield in the full rate of N fertilizer without a PGPR inoculation treatment. N fertilizer and PGPR application significantly decreased saturated fatty acids (palmitic and stearic acid) while it significantly increased unsaturated fatty acids (oleic and linoleic acid). Oleic acid had a significant negative correlation with linoleic acid (r = ?0.79). The result showed that an application of PGPR could be usefully applied to reduce use of chemical fertilizer.  相似文献   
24.
The growth, yield and fruit quality of 7-year-old trees of “Sahahmiveh” pear grafted on six rootstocks, including four quinces (QA, QB, QC, and PQBA29) and an Iranian native pear “Konjoni,” and a wild-type European pear (Pyrus communis L.), were evaluated in a completely randomized design trial with three replications at the Agricultural Research Center of Kabutarabad, Isfahan, Iran in 2 years (2013 and 2014). Yield and fruit weight of all rootstocks were markedly enhanced in the second year of the experiment. Considering both fruit yield and quality, “Sahahmiveh” scions on PQBA29 had the most suitable performance in both years. “Sahahmiveh”-PQBA29 combination exhibited the largest leaf dimensions (5.03?cm width and 7.27?cm length), fruit size values (6.3?cm width and 9.3?cm length), fruit weight (205?g per fruit) the highest yield (41.3?kg per tree), and acceptable fruit internal quality (0.4% titratable acidity and 17.4°brix total soluble solid) in 2014. The highest yield followed by QA (39.6?kg per tree) without significant differences compared to PQBA29. However, “Sahahmiveh”-QA fruit weight (189?g per fruit) and width (5.9?cm) values were markedly less than that of “Sahahmiveh”-PQBA29 in 2014. In conclusion, “Shahmiveh” pear cultivar grafted on PQBA29 exhibited more suitable fruit yield and quality values compared to the other rootstocks and, thus, would be the best rootstock for “Sahahmiveh” pear in Isfahan.  相似文献   
25.
Waste disposal has become one of the greatest global concerns, which has high operational costs and might cause environmental pollution. Due to the lack of the organic matter in most of the Iranian agro-ecosystem, recycling organic waste materials favors the environment by reducing chemical fertilizers as well as improving soil structure and fertility. A vermicomposting system using cow manure (CM), pomegranate meal (PM) + sawdust (S), CM + potato waste (PW), PM + PW, CM + PM, and CM + PM + PW was set up to find a viable alternative raw material for improving physico-chemical properties of vermicompost after 60 days. The amended vermicompost of PM + S and PM + PW markedly improved the electrical conductivity (EC), which were below the EC limit (by 1.01 and 2.27 dS m?1, respectively), pH (by 7.04 and 6.60, respectively), and water holding capacity (respectively 1.9 and 1.2 times higher than CM). Vermicompost amendment led to significant reduction of organic carbon (OC), but nonetheless, PM + S and PM + PW showed higher OC content in the final product probably due to the higher initial carbon to nitrogen (C:N) ratio, raw material origin, and lower decomposition rate. In regard to nutrient value, the total phosphorus content in the end-product of PM + S and PM + PW was, respectively, 19.3 and 7.9 times higher compared with the final product of CM. Additionally, the amended vermicompost of PM + PW markedly improved total nitrogen content as compared with CM. The findings suggested that the additional amounts of nitrogen and potassium to PM + S and also potassium to PM + PW would improve the physico-chemical properties and fertilization of the final vermicompost considerably higher than CM vermicompost. This amendment has the potential to mitigate the adverse effects of vermicompost of CM, for example, salinity and alkalinity; and chemical fertilizers, for example, soil pollution with heavy metals in phosphate fertilizers, as well as the potential for soil rehabilitation.  相似文献   
26.
The chemokines CCL21 and CXCL13 are immune factors that dictate homing and motility of lymphocytes and dendritic cells in lymphoid tissues. However, the means by which these chemokines are regulated and how they influence cell trafficking during immune responses remain unclear. We show that CCL21 and CXCL13 are transiently down-regulated within lymphoid tissues during immune responses by a mechanism controlled by the cytokine interferon-gamma. This modulation was found to alter the localization of lymphocytes and dendritic cells within responding lymphoid tissues. As a consequence, priming of T cell responses to a second distinct pathogen after chemokine modulation became impaired. We propose that this transient chemokine modulation may help orchestrate local cellularity, thus minimizing competition for space and resources in activated lymphoid tissues.  相似文献   
27.
This work examines the effects of two deficit irrigation strategies, conventional deficit irrigation (DI) and partial root-zone drying (PRD), on mature navel orange trees. The study carried out during two consecutive years (2008 and 2009) in a semi-arid climate on a silty–clay–loam soil in the north of Iran. Both DI and PRD trees were irrigated at two levels, 75 and 50% (DI75, PRD75, DI50 and PRD50) of the full irrigation (FI). In DI, irrigation water was applied to both sides of the tree rows, similar to FI. In PRD, irrigation water was applied alternately to only one side, at each irrigation event. Results showed that DI treatments reduced fruit yield by ~30% compared with FI, but PRD treatments caused no reduction in fruit yield. No negative impact was detected in fruit quality after applying DI and PRD treatments. Shoot growth decreased in all DI and PRD treatments in both years. In DI, stomatal resistance was higher (50%) than in FI, but it was not significantly affected in PRD. The irrigation water use efficiency of PRD trees increased to nearly twice that of FI. According to these two years' results, we recommend PRD as an acceptable deficit irrigation strategy in the region.  相似文献   
28.
A Western blot immunoassay (WBI) was developed as a confirmatory test for 2 commercial Mycoplasma hyopneumoniae (Mhyo) ELISAs. The WBI detected at least 5 antigen bands (150, 130, 74, 70, and 30 kDa) from Mhyo whole membrane proteins that were not present in the antigens prepared from M. hyorhinis and M. hyosynoviae. Among discrepant sera from vaccinated pigs (n = 17) and field samples (n = 91) assayed by WBI: 1) 2 of the ELISA-positive samples reacted with all 5 antigens bands; 2) all blocking ELISA-positive samples (n = 53) bound 150-, 130-, 74-, and 70-kD antigen bands; and 3) all indirect ELISA-positive samples (n = 55) bound 150-, 130-, and 30-kD antigens. We conclude that the WBI targeting the top 4 antigen bands is a useful confirmatory test for samples initially screened using the commercial Mhyo ELISAs.  相似文献   
29.
Chemical industry project management involves complex decision making situations that require discerning abilities and methods to make sound decisions. Chemical engineers as project managers are faced with decision environments and problems in chemical industry projects that are complex. Multiple-criteria decision making (MCDM) approaches are major parts of decision theory and analysis. This paper presents all of MCDM approaches for use in chemical engineering management decisions. In this work, case study is Research and Development (R&D) project selection in chemical industry. The ability to make sound decisions is very important to success of R&D projects. It is hoped that this work will provide a ready reference on MCDM and this will encourage the application of the MCDM in chemical engineering management.  相似文献   
30.
The present study was designed to investigate the effects of dietary apple cider vinegar (ACV) on digestive enzyme activity and growth performance as well as immune responses and antibacterial activity of skin mucus in green terror (Andinoacara rivulatus). Fish were fed diets supplemented with 0%, 1%, 2% and 4% of ACV (40.830 ppm acetic acid concentration) for 63 days. The final weight and weight gain values were observed to be significantly higher in fish fed with 2% of ACV compared to the control group (p < .05). ACV inclusion in the diets had significant effects on SGR (%) and FCR values (p > .05). ACV treatment resulted in a significant increase in the intestinal protease, α‐amylase, lipase and alkaline phosphatase activities compared to control (p < .05). The activities of digestive enzymes in fish fed with 2% and 4% of ACV diets were significantly higher than the other groups (p < .05). The total protein content, alternative haemolytic complement, alkaline phosphatase, total immunoglobulins and lysozyme activities of skin mucus increased significantly in fish fed with ACV diets (p < .05). In conclusion, administration of ACV enhanced digestive enzyme activity, growth performance, immune responses and the immune properties of skin mucus, and it can be used as a natural growth promoter and immunostimulant in green terror culture.  相似文献   
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