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建设森林城市 提高沈阳生态环境的可持续发展能力   总被引:4,自引:0,他引:4  
孙丽娜  孙铁珩 《水土保持研究》2004,11(3):181-183,219
从城市森林与森林城市的概念出发,论述了森林城市的特征和城市森林的结构、功能及其与城市可持续发展能力之间的关系。分析了沈阳市生态环境的现状、绿地景观存在的问题和建设森林城市的必要性,提出了建设沈阳森林城市的原则和对策。  相似文献   

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Urban forest mainly refers to urban green space and suburban forest. Urban forest is quite significant in reducing negative effects of civilization and preserving the ecological balance of city ecological system. This paper applied remote sensing method in the study of urban forest in Jinan City. Results show that there are various kinds of greenbelts in Jinan City, including public greenbelt, residential greenbelt, greenbelt attached to branches, protective greenbelt in production, landscape forest and road greenbelt. The urban greenbelt area is limited, the layout is irrational, and development of the scenery forest is slow.  相似文献   

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Ethnobotanical survey was conducted in 101 randomly selected home gardens of Phong My commune, central Vietnam, situated in the buffer-zone of Natural Reserve. Data were collected through semi-structured questionnaires and direct observation. Sixty-seven species belonging to 35 families were identified to be used for various purposes. For each species the botanical and vernacular names, plant parts used and main purposes of use are given. The major use categories reported for plant species were food (86%), medicine (32%) and firewood (32%), however, seventy-seven percent of all inventoried plants have multiple uses. The species Artocarpus heterophyllus Lam., Citrus grandis Osbeck, Citrus reticulata Blanco, Ipomoea batatas (L.) Lam. and Musa spp. were identified as the main sources of plant foods consumed within the households. Statistical analyses indicated by Shannon-Wiener and Margalef indices have shown that local species diversity and richness is affected by home garden size. On the contrary, no relationship between diversity and home garden age was found. On the basis of a cluster analysis of plant species diversity, five home garden types were differentiated. In comparison to previously reported studies on tropical home gardens, the diversity in Phong My is lower, probably due to market-oriented strategy. Nevertheless, based on the results achieved, we can conclude that useful plants cultivated in local home gardens provide valuable foods complementing daily diet and subsequently contributing to socioeconomic status of the households.  相似文献   

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用网状内皮组织增生病病毒(REV)感染SPF鸡造成免疫抑制状态,用双抗体夹心ELISA对鸡脾淋巴细胞IFN-γ的分泌量进行了测定。结果显示,SPF雏鸡接种REV后,除呈现生长缓慢症状外,并且出现了中枢免疫器官严重萎缩等免疫抑制状态的典型表现。IFN-γELISA显示,REV感染后7 d (7 dpi),脾淋巴细胞IFN-γ的分泌量显著升高,与对照组相比差异极显著。至15 dpi,IFN-γ水平最高,以后逐渐下降,但至50 dpi仍显著高于对照鸡。这是REV感染鸡后对IFN-γ影响的首次直接定量研究。  相似文献   

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This paper presents an overview of a long-term study on sediment pollution in the city canals of Delft, the Netherlands. This pollution was most evident for the inner city canal system, with copper, lead, zinc, and polycyclic aromatic hydrocarbons (PAHs) as main pollutants. Sediments of the outer city canals generally had a much better quality. Pollution levels, mutual correlations, and spatial variations were investigated for the various sediment parameters. Also, heavy metal binding forms onto Delft sediments were assessed with the help of sequential extraction techniques; results were found to be in line with expected preferential physicochemical binding processes. Input of sediments into the Delft inner city canals was shown to be largely driven by busy shipping traffic on the main canal surrounding the inner city. Mass balances for the inner city were used to quantify internal and external pollution sources; 65?C85?% of the heavy metal pollution can be attributed to sources outside the Delft area. As shown by factor and cluster analyses, it is highly probable that these external sources derive from the river Rhine. A gradual improvement of the sediment quality has set in; it is expected that, due to further pollution abatement measures, this improvement will continue over the years to come. With respect to the ship-induced sediment input into the inner city canals, it was estimated that a reduction of ship velocities to <1.5?m/s will bring down the sediment input mentioned above to about 85?%.  相似文献   

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稻作农业在保障粮食安全方面贡献巨大,但因经济利益驱动,化肥农药被过量施用,造成了氮、磷等营养物质流失,对水环境产生严重影响。本文基于全国第一次污染普查数据,结合各类污染物的产排污系数计算了稻作农业COD、TN和TP入河量,通过污染足迹模型计算了稻作农业COD、TN和TP的污染足迹,通过污染压力模型计算了稻作农业COD、TN和TP的污染压力指数,并对其进行评估。结果表明:(1)常州市、宜兴市稻作农业生产过程中向水环境排放的污染物中以COD和TN为主,其入河量分别为792.96 t·a-1和605.28 t·a-1,TP入河量为27.16 t·a-1;(2)常州市、宜兴市稻作农业TN污染足迹最大(3 944.50 hm2),其次为TP污染足迹(2 578.95 hm2),最小的是COD污染足迹(523.52 hm2);(3)常州市、宜兴市稻作农业对水环境的污染压力指数为2.10,处于中度污染压力状况,表明常州市、宜兴市稻作农业生产活动超出了当地水域的承载能力,对当地水环境产生了压力。  相似文献   

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对鸡脂肪性状候选基因进行连锁不平衡(linkage disequilibrium,LD)分析可以为理解鸡体脂沉积的遗传学机制提供重要信息,并且可以提高脂肪性状相关分子遗传标记的检出效率.本研究以东北农业大学肉鸡高、低脂双向选择品系第8世代肉仔鸡为实验材料,通过直接测序、高效液相色谱(DHPLC)、单链构象多态性(PCR-sscv)、限制性片段长度多态性(PCR-RFLP)、长度多态性(PCR-LP)等方法对过氧化物酶增殖体激活受体(PPAR-γ)、载脂蛋白B(ApoB)、解耦联蛋白(UCD)以及其他10个鸡脂肪性状重要候选基因进行多态性检测,计算候选基因标记间LD参数∣D'∣与r2,分析这些候选基因标记间的LD模式并探讨其规律.初步发现了以下特征:1、在各候选基因内,标记间的∣D'∣与r2值并不匹配,取值区间差异很大,∣D'∣值普遍大于r2;另外,在有些基因内的相同标记间,∣D'∣、r2值相差很大,甚至在∣D'∣=1时,r2接近于0.2、在不同基因甚至在同一基因内不同区域LD水平差异很大且物理距离与LD关系并不成线性关系.3、在有些基因内,如ApoB基因,相间位点间的∣D'∣和r2值大于相邻位点间的值.4、有些基因,如PPAR4-γ,相同标记间LD水平在高、低脂系间存在很大差异.本研究结果提示,在群体遗传学研究中进行候选基因LD分析时,LD参数r2的应用价值比∣D'∣更大.  相似文献   

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用网状内皮组织增生病病毒(Reticuloendotheliosis virus,REV)感染SPF鸡造成免疫抑制状态,用双抗体夹心ELISA对鸡脾淋巴细胞γ-干扰素(IFN-γ)的分泌量进行了测定。结果显示,SPF雏鸡接种REV后,除呈现生长缓慢症状外,并出现了中枢免疫器官严重萎缩等免疫抑制状态的典型表现。IFN-γELISA显示,REV感染后7d(7dpi),脾淋巴细胞IFN-γ的分泌量显著升高,与对照组相比差异极显著,至15dpi,IFN-γ水平最高,以后逐渐下降,但至50dpi仍显著高于对照鸡。这是REV感染鸡后对IFN-γ影响的首次直接定量研究。  相似文献   

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In 1986, the then Nigerian Military Governmentpromulgated a decree stipulating that all small-scaleindustries be moved out of the city centres to designatedlocations in the more remote areas or villages. In linewith that decree, the then Edo State Government decidedto create the Small-scale Industrial village at Ogbesan,near Benin City, Nigeria. This article summarises thesituation leading to the establishment of a typicalsmall-scale industrial site (Ogbesan), its failure andthe current state of the abandoned site. To test thephytotoxic effect of soils taken from the impacted areain the abandoned site at Ogbesan, seeds of Arachishypogaea were used for experiments. Growth of test plantwas generally depressed by soils from the impacted area.One hundred percent germination inhibition was observedin sub-soil obtained from the centrally located plot (D3)in the study area. Twenty eight days after sowing, plantheight, root elongation and leaf area values wereconsistently lower in plants from almost all theexperimental plots than the control and this effect wasmore in the subsoil samples. In the most affected plots,plant height, root elongation and leaf area were 83, 100 and 87% (B5) and 94, 67 and 71% (C1),respectively, lower than the control. The resultsindicate clearly that the activities and wastes dumped atthe sites adversely affect the ability of soils from thesite to support plant growth.  相似文献   

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有机氯农药(Organochlorine Pesticides,OCPs)是一类由人工合成的杀虫广谱、毒性较低、残效期长的化学杀虫剂。本文以汕头市为研究区域,探讨了土壤OCPs的残留现状和特征,并对该区的土壤进行了环境质量评价和初步的生态风险评价。结果表明:(1)汕头地区土壤中OCPs的检出率高达99.13%,OCPs残留量的平均值是113.37ng·g-1,主要的OCPs污染物为DDTs和硫丹类;南澳县OCPs残留量平均值最高(174.68 ng·g-1),其次为龙湖区,濠江区含量平均值最低(69.24 ng·g-1);(2)与国内外一些地区土壤中OCPs的残留量对比,本研究区域土壤中的OCPs处于中等污染残留水平;与美国马里兰州标准、纽约州可容许的土壤浓度标准和我国的土壤环境质量标准相比较,OCPs基本没有超标;(3)本研究地区土壤存在较高的生态风险,OCPs可能对环境造成一定的危害,其中生态风险最高的是DDTs,BHCs的生态风险较低。  相似文献   

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日本北海道农村生态系统中N循环研究   总被引:2,自引:0,他引:2  
L. LIANG  T. NAGUMO  R. HATANO 《土壤圈》2006,16(2):264-272
This study of Mikasa City in 2001, which analyzed N flow between N production and N load in seven agricultural and settlement subsystems, i.e., paddy, onion, wheat, vegetable, dairy, chicken, and citizen subsystems, aimed to compare N flow in each subsystem, to determine the main sources of the N load, and to evaluate the influence of agricultural production and food consumption on N cycling in a rural area. The results showed that in Mikasa city, 38.5% of the N load came from point sources and the remainder from non-point sources with intensive vegetable farming imparting a serious N load. Because of the internal N cycling in the dairy subsystem, chemical fertilizer application was reduced by 70.2%, and 23.72 Mg manure N was recycled to the field; therefore, the N utilization efficiency was raised from 18.1% to 35.1%. If all the manure N in the chicken subsystem was recycled, chemical fertilizer application would be reduced by 8.1% from the present level, and the point sources of N pollution would be reduced by 20.8%.  相似文献   

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Polycyclic aromatic hydrocarbons (PAHs) were studied in street dust (SD) samples collected in the center of Niterói, a tropical city located in the State of Rio de Janeiro, Brazil, at the margins of Guanabara Bay. Sampling was carried out monthly during the year of 2002 in order to evaluate seasonal variation of PAH concentrations. Samples were extracted by ultrasonic treatment with dichloromethane, cleaned up by solid phase extraction and analyzed by gas chromatography-mass spectrometry. The concentrations of the twenty one analyzed PAHs ranged from 3.2 to 132 ng/g. Of all PAHs, pyrene, fluoranthene and naphthalene showed the highest geometric means. Total PAH concentration (σPAH) ranged from 434 to 1247 ng/g with levels of carcinogenic PAHs (σCARC) representing 29 to 45% of σPAHs. The highest value of σPAH occurred in July 2002, when the lowest temperatures were measured in the Central Area of Niterói City. σPAH and σCARC showed significant correlations with daily mean and minimum temperature, as well as with temperature during sampling, indicating that both are influenced by these parameters. The obtained results suggest that a seasonal variation of total PAH levels in SD may occur in the studied area.  相似文献   

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MxA是由Ⅰ型干扰素诱导宿主细胞所产生的抗病毒蛋白家族的成员之一。采用RT-PCR方法从鸡胚成纤维细胞(CEF)中扩增MxA,将其克隆至载体pMD-T18中,筛选阳性克隆后回收目的片段,将其克隆入原核表达质粒pGEX-6p-1,构建其重组表达质粒pGEX-MxA,以IPTG诱导表达,经SDS-PAGE、鸡胚新城疫病毒增殖干扰实验和VSV-CEF微量细胞抑制实验进行分析、鉴定。结果表明,经RT-PCR扩增获得的MxA序列与GenBank报道的序列一致,SDS-PAGE和干扰实验证实重组质粒可以表达出相应分子量为45kD的蛋白,与GST-MxA融合蛋白分子量一致,影像分析系统分析显示表达的融合蛋白约占菌体蛋白的30%。  相似文献   

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In vivo experiments were conducted to verify whether arabinoxylooligosaccharides (AXOS) obtained as low molecular mass compounds by enzymic hydrolysis from wheat bran arabinoxylan (AX) can exert nutritional effects. Two feeding trials were performed on chickens fed diets with either wheat or maize as the main component. Supplementation of bran AXOS at either 0.5% (w/w) to the wheat‐based diet or at 0.25% (w/w) to the maize‐based diet diets significantly (P < 0.05) improved the feed conversion rate without increasing the body weight of the animals, thus pointing to improved nutrient utilization efficiency. The positive effect of bran AXOS supplementation on feed utilization efficiency was similar to that obtained by adding an AX‐degrading xylanase directly to the wheat‐based diet. No significant effect on feed utilization efficiency was obtained with another type of nondigestible oligosaccharide such as fructooligosaccharides (FOS) derived from chicory roots. Bran AXOS significantly increased the level of bifidobacteria but not total bacteria in the caeca of the chickens, an effect not observed with either xylanase or FOS addition. These data suggest that bran AXOS have beneficial nutritional effects and may act as prebiotics.  相似文献   

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Journal of Soils and Sediments - Microplastics have been widely reported to contaminate aquatic environments, particularly impacting marine organisms, but little is known of microplastic...  相似文献   

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湿地指的是一类既不同于水体,又不同于陆地的特殊过渡类型的生态系统,为水生、陆生生态系统界面相互延伸扩展的重叠空间区域。黄河湿地生态系统是维持黄河健康生命的重要基础。通过对临猗县黄河湿地的现状分析,提出了加强宣传、开展湿地动植物资源调查、退田退耕还湿、加大资金投入、加强管理等湿地保护对策。  相似文献   

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