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生化工程的新理念及其技术范例——生态生化工程的发展及其学科基础 被引量:6
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作者 陈洪章 李佐虎 《中国生物工程杂志》 CAS CSCD 2002年第3期74-77,共4页
生化工程在生物技术中占有重要地位 ,它是上游生物技术与生物技术产业化之间的纽带。根据多年对秸秆生物技术的研究 ,结合现代生物技术和工业生态学的新思维方式 ,对现有生化工程存在的问题进行思考 ,提出生态生化工程的新概念。
关键词 生态生化工程 技术范例 学科基础
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桃儿七生化生态适应的初步研究 被引量:10
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作者 马绍宾 胡志浩 李俊 《生态学杂志》 CAS CSCD 北大核心 1997年第3期67-70,共4页
桃儿七生化生态适应的初步研究马绍宾胡志浩李俊(云南大学生物系,昆明650091)(云南省香料中心,昆明650051)APriliminaryStudyoftheBiochemicalEcologicalAdapta... 桃儿七生化生态适应的初步研究马绍宾胡志浩李俊(云南大学生物系,昆明650091)(云南省香料中心,昆明650051)APriliminaryStudyoftheBiochemicalEcologicalAdaptationofSinopodophy... 展开更多
关键词 小檗科 桃儿七 生化生态适应
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生化生态组合湿地系统对农村生活污水的净化效果研究 被引量:7
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作者 许加星 徐力刚 +1 位作者 姜加虎 游海林 《农业环境科学学报》 CAS CSCD 北大核心 2012年第9期1815-1822,共8页
以江阴市陆桥湿地系统为例,采用生态-生化组合湿地工艺处理农村生活污水,研究生态-生化组合湿地的运行情况和对农村生活污水的净化效果。研究结果表明,采用生化-生态优化组合工艺达到了较好的处理效果,农村生活污水中氮、磷、化学需氧量... 以江阴市陆桥湿地系统为例,采用生态-生化组合湿地工艺处理农村生活污水,研究生态-生化组合湿地的运行情况和对农村生活污水的净化效果。研究结果表明,采用生化-生态优化组合工艺达到了较好的处理效果,农村生活污水中氮、磷、化学需氧量(COD)、五日生物需氧量(BOD5)、固体悬浮物(SS)、阴离子表面活性剂(LAS)的平均去除率分别为80.87%、80.70%、67.73%、77.24%、60.98%、92.64%。但该湿地系统对氮、磷和SS的净化能力仍有一定的波动性,在冬季尤为突出。研究结果为后期生态-生化组合湿地工艺和管理的改进提供了数据支撑和理论基础,为生态-生化组合人工湿地生态系统的推广和示范研究提供了直接的理论依据和实践经验。 展开更多
关键词 组合人工湿地 生化生态技术 去除率 农村生活污水
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基于生态内生化的旅游新业态的体系构建与规制研究 被引量:7
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作者 郭旸 沈涵 《生态经济》 北大核心 2011年第4期120-122,129,共4页
在旅游新型业态体系构建和政策规制的发展过程中,会产生某种生态内生化的趋势,它是伴随着旅游传统产业经营模式和增长方式的转变,以及旅游产业生命周期的可持续循环而实现的,因此从本质上说旅游新业态的发展是一种基于生态内生化的业态... 在旅游新型业态体系构建和政策规制的发展过程中,会产生某种生态内生化的趋势,它是伴随着旅游传统产业经营模式和增长方式的转变,以及旅游产业生命周期的可持续循环而实现的,因此从本质上说旅游新业态的发展是一种基于生态内生化的业态创新。 展开更多
关键词 生态生化 旅游新业态 政策规制
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海洋生化生态遗传学的研究——海洋生态学研究的新分支 被引量:5
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作者 王桂忠 李少菁 《生态学杂志》 CAS CSCD 北大核心 1991年第6期34-38,F004,共6页
生化生态遗传学是生态学、遗传学、分子生物学和生物化学等多学科的融合体。由于有现代生物学技术的渗入,使传统的生态遗传学研究发生了重大变革。尽管这支新学科起步较迟,但近年来发展却非常迅速。
关键词 生态遗传学 生化生态 海洋生态
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Interannual Variation in Terrestrial Ecosystem Carbon Fluxes in China from 1981 to 1998 被引量:33
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作者 曹明奎 陶波 +2 位作者 李克让 邵雪梅 Stephen D PRIENCE 《Acta Botanica Sinica》 CSCD 2003年第5期552-560,共9页
A dynamic biogeochemical model was used to estimate the responses of China's terrestrial net primary productivity (NPP), soil heterotrophic respiration (HR) and net ecosystem productivity (NEP) to changes in clima... A dynamic biogeochemical model was used to estimate the responses of China's terrestrial net primary productivity (NPP), soil heterotrophic respiration (HR) and net ecosystem productivity (NEP) to changes in climate and atmospheric CO2 from 1981 to 1998. Results show that China's total NPP varied between 2.89 and 3.37 Gt C/a and had an increasing trend by 0.32% per year, HR varied between 2.89 and 3.21 Gt C/a and grew by 0.40% per year, Annual NEP varied between -0.32 and 0.25 Gt C but had no statistically significant interannual trend. The positive mean NEP indicates that China's terrestrial ecosystems were taking up carbon with a total carbon sequestration of 1.22 Gt C during the analysis period. The terrestrial NEP in China related to climate and atmospheric CO2 increases accounted for about 10% of the world's total and was similar to the level of the United States in the same period. The mean annual NEP for the analysis period was near to zero for most of the regions in China, but significantly positive NEP occurred in Northeast China Plain, the southeastern Xizang (Tibet) and Huang-Huai-Hai Plain, and negative NEP occurred in the Da Hinggan Mountains, Xiao Hinggan Mountains, Loess Plateau and Yunnan-Guizhou Plateau. China's climate at the time was warm and dry relative to other periods, so the estimated NEP is probably lower than the average level. China's terrestrial NEP may increase if climate becomes wetter but is likely to continue to decrease if the present warming and drying trend sustains. 展开更多
关键词 China net primary productivity (NPP) soil heterotrophic respiration (HR) net ecosystem productivity (NEP) climate change
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生化生态组合人工湿地系统对城镇污水处理厂尾水的净化效果研究 被引量:13
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作者 徐南军 李向阳 +1 位作者 祁琳琳 冯军 《环境工程》 CAS CSCD 北大核心 2015年第7期46-50,共5页
以江阴市新桥镇人工湿地系统为研究对象,采用生态生化组合湿地工艺处理污水处理厂尾水,研究生物-生态组合湿地的运行状况和小城镇污水处理厂尾水的进一步净化效果。研究结果表明:生物生态组合人工湿地系统对尾水中污染物具有较好的去除... 以江阴市新桥镇人工湿地系统为研究对象,采用生态生化组合湿地工艺处理污水处理厂尾水,研究生物-生态组合湿地的运行状况和小城镇污水处理厂尾水的进一步净化效果。研究结果表明:生物生态组合人工湿地系统对尾水中污染物具有较好的去除效果,对COD、氨氮、TN和TP的平均去除率分别为29%、31%、18%和8%,平均出水浓度分别为35.54,0.97,10.77,0.11 mg/L,完全符合GB 18918—2002《城镇污水处理厂污染物排放标准》一级A标准。研究结果能够为城镇污水处理厂尾水生态处理技术和管理的改进提供数据支撑和理论基础,为以后湿地生态系统的推广和示范研究提供直接的理论依据和实践经验。 展开更多
关键词 人工湿地 生态生化 组合工艺 去除率 尾水
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Research Progress of Heat-tolerance of Brassica campestris ssp. Chinensis 被引量:5
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作者 赵晓东 张景云 +1 位作者 范淑英 缪南生 《Agricultural Science & Technology》 CAS 2013年第2期248-253,共6页
Brassica campestris ssp. chinensis, also known as non-heading Chinese cabbage, is an important vegetable widely distributed in southern China. High temperature is the most common adversity factor in vegetable producti... Brassica campestris ssp. chinensis, also known as non-heading Chinese cabbage, is an important vegetable widely distributed in southern China. High temperature is the most common adversity factor in vegetable production, because Brassica campestris ssp. chinensis is a thermophilic vegetable, which can't well grow at high temperature. In summer and autumn, high temperature stress would prevent Brassica campestris ssp. chinensis from growing and result in poor quality of its seedlings, seriously influencing yield and quality of the vegetable in later period. In this paper, present situation and latest advances in heat resistance research of Brassica campestris ssp. chinensis in recent years were reviewed at home and abroad. The research tendency in Bassica campestris ssp. chinensis was also described, providing reference for breeding of heat-resistant Brassica campestris ssp. chinensis. 展开更多
关键词 Brassica campestris ssp. chinensis High temperature stress Morphological index Physiological and biochemical indexes Heat tolerance
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Effects of Probiotics on Growth Performance and Blood Biochemical Indexes of Cherry Valley Ducks 被引量:4
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作者 李小芬 杨晓志 +3 位作者 陶勇 张玲 顾文婕 袁旭红 《Agricultural Science & Technology》 CAS 2015年第8期1732-1734,1740,共4页
In order to investigate the effects of probiotics on growth performance, blood biochemical indexes and economic benefits of Cherry Valley ducks, different probiotics were added into the feed of Cherry Valley ducks. To... In order to investigate the effects of probiotics on growth performance, blood biochemical indexes and economic benefits of Cherry Valley ducks, different probiotics were added into the feed of Cherry Valley ducks. Total 240 1-d-old Cherry Valley ducks were selected, and they were randomly divided into 4 groups, including 1 control group and 3 treatment groups. There were 3 replicates for each group and there were 20 ducks for each replicate. The ducks in the control group were fed the basal diet, and the ducks in the 3 treatment groups were fed the basal diet added with Lactobacillus, Bacillus natto and florfenicol, respectively. The test lasted for 42 d. The results showed that the addition of Lactobacillus and Bacillus natto could improve the average daily weight gain and final average weight (P〈0.05) of Cherry Valley ducks, and reduce the glutamic-pyruvic transaminase ac- tivity, alkaline phosphatase activity and serum urinary nitrogen content in duck blood (P〈0.05) and reduce the creatinine content and total cholesterol content in Cherry Valley ducks (P〉0.05); at the same time, adding probiotics to feed could also in- crease the grass economic benefits of Cherry Valley ducks. In overall, the effects of adding probiotics were better than those of adding antibiotic. 展开更多
关键词 Cherry Valley duck Probiotic Growth performance Blood biochemicalindex Economic benefits
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Eco-environment Evolution and Its Sustainable Development Strategies in Western China 被引量:7
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作者 张巧显 柯兵 +2 位作者 刘昕 刘国华 吴钢 《Agricultural Science & Technology》 CAS 2010年第1期176-181,共6页
Natural condition in Western China is relatively poor and regional economy level is low. The ecological environment has been seriously damaged by population growth and over-exploitation of natural resources. It is ver... Natural condition in Western China is relatively poor and regional economy level is low. The ecological environment has been seriously damaged by population growth and over-exploitation of natural resources. It is very important for coordinating the regional development and safeguarding ecological security to discuss the eco-environment evolution trend and its sustainable development strategies in Western China. Based on analyzing documents and relative research,the changes of main ecological and environmental problems in the western region,such as degradation of forest and grassland ecosystems,shrinkage of wetland,desertification,water and soil erosion,etc. were synthetically discussed. Then,according to the development trend,some countermeasures for eco-environment protection and rehabilitation and sustainable development were proposed. 展开更多
关键词 Eco-environment evolution Ecological degradation Sustainable development Western China
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RELATIONSHIP BETWEEN GROWTH AND MORPHOLOGY OF METARRHIZIUM ANISOPLIAE IN BIOTRANSFORMATION OF STEROID 被引量:2
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作者 阳葵 李晓静 +2 位作者 王积分 段世铎 张鎏 《Transactions of Tianjin University》 EI CAS 2001年第1期1-6,共6页
The fermentation with mold metarrhizium anisopliae has been carried out to determine the relationship between mycelial morphology and growth.Like the biomass concentration,the mycelial morphology seems to be coupled t... The fermentation with mold metarrhizium anisopliae has been carried out to determine the relationship between mycelial morphology and growth.Like the biomass concentration,the mycelial morphology seems to be coupled to growth phases:the fractal dimension,a feature calculated from the morphological images,increases during the late lag phase and the early exponential phase,and culminates at a value near 2.4 at half of the exponential phase.This can be attributed to the marked change of rough and smooth pellet proportions during growth and the change can be well expressed by the fractal analysis of mycelial morphology.The mycelial morphology is also strongly related to the biotransformation activity:a mycelial sample was withdrawn from the culture to use for fractal analysis before the steroid substrate (16α,17α epoxy 4 pregnene 3,20 dione) was added;the higher fractal dimension corresponds to the higher conversion rate of steroid biotransformation.And the maximum of fractal dimension appeared prior to the maximum of biomass concentration.It is therefore possible to utilize the fractal dimension curve to supervise the fermentation process more timely and availably than to use the conventional biomass curve to do. 展开更多
关键词 metarrhizium anisopliae MORPHOLOGY GROWTH fractal dimension BIOTRANSFORMATION STEROID
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Assessment of Climate for Agricultural Suitability and Optimal Allocation of Agricultural Production in the Guanzhong Region, Shaanxi Province 被引量:2
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作者 杨忍 刘彦随 任志远 《Agricultural Science & Technology》 CAS 2012年第11期2379-2384,2448,共7页
Based on spatial climatic data of agriculture and the experiment data, the models of agro-ecological assessment of climate for agricultural suitability in this study were developed using the fuzzy mathematical method.... Based on spatial climatic data of agriculture and the experiment data, the models of agro-ecological assessment of climate for agricultural suitability in this study were developed using the fuzzy mathematical method. Three coefficients, in- cluding the resource coefficient (Cr), the efficiency coefficient (Ce), and the utility co- efficient (K), were used in the models, which were calculated based on temperature, moisture, and sunshine duration data of Guanzhong region, Shaanxi Province. The results indicated that resource coefficient was higher in west of the region than that in east, and higher in south (especially in the Central Shaanxi Plain) than that in the Weibei plateau. The value of Cr changed from 6.5 to 9.2 from north to plain area. Spatial change of efficiency coefficient was obvious, lower in the northeast than in the central plain, and the value of Ce changed from 2.3 to 6.5 from the northeast to the central plain. As for utility coefficient, it was lower in northeastern part of the Weibei plateau and in southern mountain areas than that in the central plain, showing significant latitudinal zonality. Furthermore, the value of K increased from 0.35 to 0.78 from northeast to the central plain, and decreased from 0.78 to 0.53 from the central plain to southern mountain areas. These indicated that climate resource in the central plain region was more abundant and potential, compared with other regions. GuanZhong region was classified into three larger agricultural zones and three small independent zones, according to agro-ecological assessment. Light, heat and water resources should be made use of in an efficient way in spatial allo- cation of agricultural production. For example, water facilities should also be im- proved in Weibei plateau region where highly-qualified fruit should be enhanced and fruit processing industrial chain should be shaped. Large-scale production area of wheat should be increased in central irrigation region and more vegetable bases should be developed around large and medium-scale cities. Thanks for outstanding water conservation function, the three-dimensional agriculture including medicine and other sideline production should be developed in Qinling Mountains and the special- ized commercial agriculture should be accelerated in independent small zones, ac- cording to local conditions. In the research, different crop varieties were developed in corresponding regions as per current eco-climatic conditions. 展开更多
关键词 Assessment of climate for agricultural suitability Optimal allocation ofagricultural production Guanzhong region
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Appropriate Garden Design of Primitive Ecology Based on the Indigenization of Environmental Ethics 被引量:1
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作者 章晓岗 王长富 《Journal of Landscape Research》 2010年第2期29-32,95,共5页
The accelerating urbanization process leads to aggravated environmental problems, thus garden design which is a creative activity connecting human and nature has attracted much attention, and also garden designers hav... The accelerating urbanization process leads to aggravated environmental problems, thus garden design which is a creative activity connecting human and nature has attracted much attention, and also garden designers have had to rethink about environmental ethics and morals. This study, from the perspective of environmental ethics, duly proposed the brand-new concept of 'appropriate garden of primitive ecology', proceeded from the orientation, form, value, theoretical basis, realistic significance, culture and consumption psychology of 'garden of primitive ecology', fully developed outstanding ecological wisdoms and morals in traditional Chinese garden culture, boosted garden designs to the environmental ethics level of eco-justice, to seek for the approach to 'garden of primitive ecology' with indigenous Chinese environmental ethic characteristics. 展开更多
关键词 Environmental ethics Garden of primitive ecology Appropriate design INDIGENIZATION Eco-justice
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Dynamic Change Laws of Chlorophyll Fluorescence Parameters in Different Parts of Leaves of Ginkgo biloba
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作者 王秀珍 段爱国 +1 位作者 保尔江 张建国 《Agricultural Science & Technology》 CAS 2011年第4期530-532,536,共4页
[Objective] The aim was to explore the dynamic change laws of chlorophyll fluorescence parameters in different parts of leaves of Ginkgo biloba.[Method] The G.biloba cultivated in North China was used as materials in ... [Objective] The aim was to explore the dynamic change laws of chlorophyll fluorescence parameters in different parts of leaves of Ginkgo biloba.[Method] The G.biloba cultivated in North China was used as materials in this study to explore the law of daily change and ten-day change of the chlorophyll fluorescence parameters of leaves in different parts of leaves.[Result] The daily change of Fm(maximal fluorescence),Fv(variable fluorescence),Fv/Fm,Fm/Fo(electron transfer rate),Fv/Fo(potential activity of PSⅡ)in leaves of G.biloba obviously presented a descending-ascending trend,the lowest value was at 12:00 and the NPQ(non-photochemical quenching)of sunny leaves arrived at the maximum at noon.The values of Fm,Fv,Fv/Fm,Fm/Fo,Fv/Fo in shade leaves of G.biloba were obviously higher than those in sunny leaves,but the peak value of NPQ of shade leaves presented earlier and higher,suggesting that the shade leaves might have more sensitive hot dissipation mechanism.Comparing to sunny leaves,shade leaves had the higher PSⅡ potential activity and inner light energy translation efficiency.[Conclusion] This study had provided theoretical basis for the protection of G.biloba resources. 展开更多
关键词 Ginkgo biloba Chlorophyll fluorescence Sunny leaves Shade leaves Daily change Ten-day change
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Application Research of Restoration Materials on Degraded Land 被引量:3
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作者 胡慧慧 崔艳杰 +3 位作者 薛合伦 陈兰 孔秋婵 梁玉祥 《Agricultural Science & Technology》 CAS 2011年第9期1260-1264,1302,共6页
[Objective] The paper aimed at researching on the ecological remediation materials and related technologies in degraded land.[Method] Pointing at the specific reasons for degradation of soil moisture and fertility con... [Objective] The paper aimed at researching on the ecological remediation materials and related technologies in degraded land.[Method] Pointing at the specific reasons for degradation of soil moisture and fertility conditions,the ecological remediation materials and related technologies for soil moisture had been studied using layered silicates as substrate materials and using straw turnover as the method.The application research had been carried out in degraded cultivated land,compacted land,saline-alkali soil and laboratory of nine provinces and regions on 26 species and 48 varieties.[Result] The materials and related technologies are environment-friendly in formula,processing,application with no hidden trouble as secondary pollution,which can be used for the restoration of positive balance of soil moisture conditions(water,fertilizer,gas,and heat),establishment of the core of a stable circle and improving food production steadily.The materials are more suitable for plant growth than chemical fertilizers,applying of which helps plants obtain better adversity resistance.[Conclusion] The ecological remediation materials for soil moisture can reduce the application of chemical fertilizers effectively and improve the production and quality of crops remarkably. 展开更多
关键词 Land degradation Saline-alkali land Ecological restoration Ecological agriculture
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Change of Ecological Footprint and Analysis of Ecological Sustainability——Taking Zhangjiakou City as an Example 被引量:2
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作者 WANG Liyan LIU Yi CHEN Tian 《Chinese Geographical Science》 SCIE CSCD 2007年第1期40-46,共7页
This paper researches the ecological sustainability of Zhangjiakou City, Hebei Province, China, using the ecological footprint model. According to the study we find that Zhangjiakou City was in the situation of ecolog... This paper researches the ecological sustainability of Zhangjiakou City, Hebei Province, China, using the ecological footprint model. According to the study we find that Zhangjiakou City was in the situation of ecological deficit from 1990 to 2000 and the deficit had the enlarging tendency. In 1990 the per capita ecological footprint was 0.964 and the per capita ecological capacity was 0.5 l 8, thus it can be calculated that the per capita ecological deficit was 4).446. However in 2000, the per capita ecological footprint increased to 1.068, at the same time the per capita eco- logical capacity decreased to 0.471, then the per capita ecological deficit in 2000 was 4).597. Furthermore, this paper studies the ecological sustainability of the city from the changes of the ecological footprint of per 10,000 yuan GDP and the productivity of ecological system. Finally the authors point out the shortage of the model and the way to improve it. 展开更多
关键词 ecological footprint ecological productive land ecological deficit Zhangjiakou City
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Ecological control of forest pest: a new strategy for forest pest control 被引量:4
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作者 LIANG Jun ZHANG Xing-yao 《Journal of Forestry Research》 SCIE CAS CSCD 2005年第4期339-342,共4页
In comparison with integrated pest management and chemical control, the authors put forward a new strategy of forest pest control, named ecological control of forest pest (ECFP). This paper reviewed the development ... In comparison with integrated pest management and chemical control, the authors put forward a new strategy of forest pest control, named ecological control of forest pest (ECFP). This paper reviewed the development history, summarized the concept and principles of ECFP, discussed the technology and methods of ECFP, and evaluated the ECFP and its application conditions. 展开更多
关键词 Ecological control of forest pest (ECFP) Chemical control Integrated pest management Ecosystem management
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Telomeres:Linking stress and survival,ecology and evolution 被引量:2
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作者 Mark F.HAUSSMANN Nicole M.MARCHETTO 《Current Zoology》 SCIE CAS CSCD 北大核心 2010年第6期714-727,共14页
Telomeres are protective structures at the ends of eukaryotic chromosomes. The loss of telomeres through cell division and oxidative stress is related to cellular aging, organismal growth and disease. In this way, tel... Telomeres are protective structures at the ends of eukaryotic chromosomes. The loss of telomeres through cell division and oxidative stress is related to cellular aging, organismal growth and disease. In this way, telomeres link molecular and cellular mechanisms with organismal processes, and may explain variation in a number of important life-history traits. Here, we discuss how telomere biology relates to the study of physiological ecology and life history evolution. We emphasize current knowledge on how telomeres may relate to growth, survival and lifespan in natural populations. We finish by examining interest- ing new connections between telomeres and the glucocorticoid stress response. Glucocorticoids are often employed as indices of physiological condition, and there is evidence that the glucocorticoid stress response is adaptive. We suggest that one way that glucocorticoids impact organismal survival is through elevated oxidative stress and telomere loss. Future work needs to establish and explore the link between the glucocorticoid stress response and telomere shortening in natural populations. If a link is found, it provides an explanatory mechanism by which environmental perturbation impacts life history trajectories [Current Zoology 56 (6): 714-727, 2010]. 展开更多
关键词 CORTICOSTERONE STRESS SURVIVAL TELOMERES
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The forms of ecological logistics and its relationship under the globalization 被引量:3
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作者 Li Yanbo Liu Songxian 《Ecological Economy》 2008年第3期290-298,共9页
The logistics system is a complex ecosystem. Ecological logistics (EL) is development trend of modern logistics, and of important practical significance. Effective use of resources and environmental protection shoul... The logistics system is a complex ecosystem. Ecological logistics (EL) is development trend of modern logistics, and of important practical significance. Effective use of resources and environmental protection should be put in the top position of logistics development. To strengthen research on logistics ecologization and realize ecological and analyzes their relationship. 展开更多
关键词 Ecological logistics (EL) FORM ECOSYSTEM GLOBALIZATION
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Nitrogen Flow in the Rural Ecosystem of Mikasa City in Hokkaido, Japan 被引量:8
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作者 L. LIANG T. NAGUMO R. HATANO 《Pedosphere》 SCIE CAS CSCD 2006年第2期264-272,共9页
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, a... 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%. 展开更多
关键词 chemical fertilizers ECOSYSTEM environmental nitrogen load nitrogen flow nitrogen budget
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