Study on change in value of ecosystem service function of Tarim River

The characteristic of change in value of Tarim River ecosystem service function and its causes are discussed by combining the remote-sensing images with social statistical data related to the change in land utilization of Tarim River Main stream area during 1973–2005 and applying correlation analysis, regressional analysis and principal component analysis methods. The results show a right ascension state in the value of Tarim River ecosystem service function over the past 30 years. Of which, the Cropland ecosystem service function is of the largest increment in the economic value, which is far in excess of other ecosystem systems; the capacity of forest, grassland and wetland in service supply and value attribution show a downward tendency relatively; the area of Cropland and unused land ecosystems increase while that of forest, grassland and wetland ecosystems decrease, which indicates that the integral capacity and balance of the ecosystem in the region investigated has been affected severely and the ecosystem deteriorated; the economic activity of human is the key factor to regulate the change in economic value of Tarim River ecosystem service function and its trend in development.     

Forest ecosystem services of changbai mountain in china

The forest ecosystem of the Changbai Mountain is the most typical upland temperate forest ecosystem in eastern Asia. It is also of the most primitive vegetation type that came into being through the natural succession of soil and vegetation following volcanic eruption. The forest ecosystem has great importance for maintaining the structures and functions of the watershed ecosystems of the Songhua River, the Yalu River and the Tumen River. We combined physical assessment method (RAM) with the value assessment method (VAM) to evaluate the forest ecosystem services of the northern slope of the Changbai Mountain, including eco-tourism, forest by-products, timber, soil and water conservation, air purification, and the recycling of nutritive elements. We also assessed the integrated forest ecosystem service and analyzed its dynamics. The service value provided by the Changbai Mountain forest ecosystem amounts up to RMB 3.38×1012 yuan, of which, water conservation is 66%, water conservation and air purificatio     

Effects of permafrost degradation on ecosystems

Permafrost, covering approximately 25% of the land area in the Northern Hemisphere, is one of the key components of terrestrial ecosystem in cold regions. As a product of cold climate, permafrost is extremely sensitive to climate change. Climate warming over past decades has caused degradation in permafrost widely and quickly. Permafrost degradation has the potential to significantly change soil moisture content, alter soil nutrients availability and influence on species composition. In lowland ecosystems the loss of ice-rich permafrost has caused the conversion of terrestrial ecosystem to aquatic ecosystem or wetland. In upland ecosystems permafrost thaw has resulted in replacement of hygrophilous community by xeromorphic community or shrub. Permafrost degradation resulting from climate warming may dramatically change the productivity and carbon dynamics of alpine ecosystems. This paper reviewed the effects of permafrost degradation on ecosystem structure and function. At the same time, we put forward critical questions about the effects of permafrost degradation on ecosystems on Qinghai–Tibetan Plateau, included: (1) carry out research about the effects of permafrost degradation on grassland ecosystem and the response of alpine ecosystem to global change; (2) construct long-term and located field observations and research system, based on which predict ecosystem dynamic in permafrost degradation; (3) pay extensive attention to the dynamic of greenhouse gas in permafrost region on Qinghai–Tibetan Plateau and the feedback of greenhouse gas to climate change; (4) quantitative study on the change of water-heat transport in permafrost degradation and the effects of soil moisture and heat change on vegetation growth.     

Effects of permafrost degradation on ecosystems

Permafrost, covering approximately 25% of the land area in the Northern Hemisphere, is one of the key components of terrestrial ecosystem in cold regions. As a product of cold climate, permafrost is extremely sensitive to climate change. Climate warming over past decades has caused degradation in permafrost widely and quickly. Permafrost degradation has the potential to significantly change soil moisture content, alter soil nutrients availability and influence on species composition. In lowland ecosystems the loss of ice-rich permafrost has caused the conversion of terrestrial ecosystem to aquatic ecosystem or wetland. In upland ecosystems permafrost thaw has resulted in replacement of hygrophilous community by xeromorphic community or shrub. Permafrost degradation resulting from climate warming may dramatically change the productivity and carbon dynamics of alpine ecosystems. This paper reviewed the effects of permafrost degradation on ecosystem structure and function. At the same time, we put forward critical questions about the effects of permafrost degradation on ecosystems on Qinghai–Tibetan Plateau, included: (1) carry out research about the effects of permafrost degradation on grassland ecosystem and the response of alpine ecosystem to global change; (2) construct long-term and located field observations and research system, based on which predict ecosystem dynamic in permafrost degradation; (3) pay extensive attention to the dynamic of greenhouse gas in permafrost region on Qinghai–Tibetan Plateau and the feedback of greenhouse gas to climate change; (4) quantitative study on the change of water-heat transport in permafrost degradation and the effects of soil moisture and heat change on vegetation growth.     

Ecosystems patterns and dynamics in Haihe river basin

Research on ecosystems patterns and dynamics is critical for understanding the regional problems of resources and environment. In this study, based on the technology of RS and GIS, the composition, patterns and dynamics of the ecosystems in Haihe river basin during 1990–2005 were analyzed using landscape indices including the area of average patches, aggregation index and Shannon–Weaver diversity index. According to the development situation of economy and society in Haihe river basin, some driving factors for dynamics of ecosystems patterns were concluded based on correlation analysis. Results showed that the ecosystems patterns in Haihe river basin changed greatly from 1990 to 2005. The area of urban and grassland increased, but farmland, forest and wetland decreased. As for landscape indices, the area of average patches, value of aggregation index, clump index and diversity index all increased, indicating the trend of evenness for the whole ecosystems. Growth of population, economy growth together with urbanization and policy were the main driving factors for dynamics of ecosystem pattern in this basin.     

Ecosystems patterns and dynamics in Haihe river basin

Research on ecosystems patterns and dynamics is critical for understanding the regional problems of resources and environment. In this study, based on the technology of RS and GIS, the composition, patterns and dynamics of the ecosystems in Haihe river basin during 1990–2005 were analyzed using landscape indices including the area of average patches, aggregation index and Shannon–Weaver diversity index. According to the development situation of economy and society in Haihe river basin, some driving factors for dynamics of ecosystems patterns were concluded based on correlation analysis. Results showed that the ecosystems patterns in Haihe river basin changed greatly from 1990 to 2005. The area of urban and grassland increased, but farmland, forest and wetland decreased. As for landscape indices, the area of average patches, value of aggregation index, clump index and diversity index all increased, indicating the trend of evenness for the whole ecosystems. Growth of population, economy growth together with urbanization and policy were the main driving factors for dynamics of ecosystem pattern in this basin.     

Ecosystem service values and land use change in the opium poppy cultivation region in Northern Part of Lao PDR

Land use change and land-cover impacts ecosystem services and functions. In this paper according to the study area’s land use characteristic and ecosystem type, the Land use category of the study area was divided into seven categories, including Forest, Grassland, Farmland, Water, Wetlands, Urban land and Barren land. The dynamic information of the forest Land use change during 10 years was calculated by the map algebra in ArcGIS 9.2. Both in 1992 and in 2002, Forest and Grassland were two largest Land use category in the study area. Forest took up 44.7% and 39.4% of the total area, and Grassland was 50.13% and 50.72% of the total area in 1992 and 2002. Finally, we valued change in ecosystem services delivered by each land use category using coefficients published by Costanza et al. [5]. Ecosystem services value of study area, the total ecosystem services value of 10.6 million hectares of this study area decreased by 11.74%. From the coefficient of sensitivity (CS) was less than unity in all case, it indicated that the total ecosystem services values was relatively inelastic and the results suggest that we have to pay attention more on land use change and finally, policy for driving forces of land use change were developed.     

Ecosystem service values and land use change in the opium poppy cultivation region in Northern Part of Lao PDR

Land use change and land-cover impacts ecosystem services and functions. In this paper according to the study area’s land use characteristic and ecosystem type, the Land use category of the study area was divided into seven categories, including Forest, Grassland, Farmland, Water, Wetlands, Urban land and Barren land. The dynamic information of the forest Land use change during 10 years was calculated by the map algebra in ArcGIS 9.2. Both in 1992 and in 2002, Forest and Grassland were two largest Land use category in the study area. Forest took up 44.7% and 39.4% of the total area, and Grassland was 50.13% and 50.72% of the total area in 1992 and 2002. Finally, we valued change in ecosystem services delivered by each land use category using coefficients published by Costanza et al. [5]. Ecosystem services value of study area, the total ecosystem services value of 10.6 million hectares of this study area decreased by 11.74%. From the coefficient of sensitivity (CS) was less than unity in all case, it indicated that the total ecosystem services values was relatively inelastic and the results suggest that we have to pay attention more on land use change and finally, policy for driving forces of land use change were developed.     

Establishment of trophic continuum in the food web of the Yellow Sea and East China Sea ecosystem: Insight from carbon and nitrogen stable isotopes

The determination of trophic level for the biology in a marine ecosystem is very important as alteration of its structure and function may be reflected in the tro-phic level of component species. A change in trophic level indicates variation in an organism’s feeding bi-ology or in the pathway of energy flow from primary producers to the consumer. The gut content analysis is a traditional method for studying trophodynamics of food web in marine ecosystems. Species composition and amounts in al…     

Carbon storage and its distribution of forest ecosystems in Zhejiang Province,China北大核心CSCD

Aims The concentration of CO2 and other greenhouse gases in the atmosphere has considerably increased over last century and is set to rise further. Forest ecosystems play a key role in reducing CO2 concentration in the atmosphere and mitigating global climate change. Our objective is to understand carbon storage and its distribution in forest ecosystems in Zhejiang Province, China. Methods By using the 8th forest resource inventory data and 2011 2012 field investigation data, we estimated carbon storage, density and its distribution in forest ecosystems of Zhejiang Province. Important findings The carbon storage of forest ecosystems in Zhejiang Province was 602.73 Tg, of which 122.88 Tg in tree layer, 16.73 Tg in shrub-herb layer, 11.36 Tg in litter layer and 451.76 Tg in soil layer accounting for 20.39%, 2.78%, 1.88% and 74.95% of the total carbon storage, respectively. The carbon storage of mixed broadleaved forests was 138.03 Tg which ranked the largest (22.90%) among all forest types. The young and middle aged forests which accounted for 70.66% of the total carbon storage were the main body of carbon storage in Zhejiang Province. The carbon density of forest ecosystems in Zhejiang Province was 120.80 t•hm2 and that in tree layer, shrub-herb layer, litter layer and soil layer were 24.65 t•hm2, 3.36 t•hm2, 2.28 t•hm2 and 90.51 t•hm2, respectively. The significant relationship between soil organic carbon storage and forest ecosystem carbon storage indicated that soil carbon played an important role in shaping forest ecosystem carbon density. Carbon density of tree layer increased with age in natural forests, but decreased in the order over-mature > near-mature > mature > middle-aged > young forest in plantations. The proportions of young and middle aged forests were larger than any other age classes. Thereby, the carbon storage of forest ecosystems in Zhejiang Province could be increased through a proper forest management.     

六种藓类植物茎的比较解剖学研究

通过对6种藓类植物,即褶叶青藓(Brachythecium salebrosum(Web.et Mohr.)B.S.G.)、湿地匐灯藓(Plagiomnium acutum(Lindb.)Kop.)、侧枝匐灯藓(Plagiomnium maximoviczii(Lindb.)Kop.)、大凤尾藓(Fissidensnobilis Griff.)、大羽藓(Thuidium cymbifolium(Doz.et Molk.)B.S.G.)和大灰藓(Hypnum plumaeforme Wils.)嫩茎和老茎的石蜡切片和显微观察发现,同一藓类植株的嫩茎和老茎,茎结构稳定,不同种藓类植物茎横切面具有不同特征.植物体茎横切面形状、表层细胞的层数、细胞大小和细胞壁厚薄、皮层细胞大小和形状、中轴的有无以及比例等特征可以作为藓类植物的分科分类依据之一.     

Photoregulation of seed germination of wild-type and of an aurea-mutant of tomato

Seed germination of an aurea mutant of tomato ( Lycopersicon esculentum Mill.) is promoted by continuous irradiation with red, far-red or long-wavelength far-red (758 nm) light as well as by cyclic irradiations (5 min red or 5 min far-red/25 min darkness). Far-red light applied immediately after each red does not change the germination behaviour. Seed germination of the isogenic wild-type, cv. UC-105, is promoted by continuous and cyclic red light while it is inhibited by continuous and cyclic far-red light and by continious 758 nm irradiation. Far-red irradiation reverses almost completely the promoting effect of red light. The promoting effect (in the aurea mutant) and the inhibitory effect (in the wild-type) of continuous far-red light do not show photon fluence rate dependency above 20 nmol m⁻² s⁻¹. It is concluded that phytochrome controls tomato seed germination throgh low energy responses in both the wild type and the au mutant. The promoting effect of continuous and cyclic far-red light in the au mutant can be attributed to a greater sensitivity to P_fr.     

真菌类遗传学分析的知识结构教学

本文以认知结构理论为指导,讨论了真菌类遗传分析与高等动植物遗传分析的内在联系,认为利用这种内在联系进行教学可收到好的效果并说明了作者的具体教学过程。 Abstract:In the paper, the relationship between genetic analysis of Fungi and genetic analysis of high animal and plant was discussed.A good results were obtained when we adopted this method in the teaching.     

Interconnection of parameters of regulation system of lipid peroxidation and of morphophysiological parameters of mouse liver

A complex analysis of seasonal fluctuations of the mean group parameters of the system of regulation of lipid peroxidation has been performed in liver of Balb/c mice. Association of lipid characteristics and morphophysiological parameters is studied in the Balb/c mouse liver. An inter-connection is revealed between the liver index and the amount of lysoforms of phospholipids, the scale and character of the interconnection differing essentially depending on proportion of phos-phatidylcholine in mouse liver phospholipids.     

龙胆科药用植物化学成分的研究现状

龙胆科植物在我国的分布范围很广,且多数为药用植物,其多数种属的药用植物,至今其化学成分尚未被系统研究。综述了目前龙胆科药用植物的化学成分的研究现状及一般提取方法,对近年来发现的环烯醚萜及裂环烯醚萜类化合物进行了总结,为本科药用植物的更深入研究提供了参考。     

History of the discovery of the mode of transmission of yellow fever virus

This essay documents and examines the historical circumstances and events surrounding the discovery of the mode of transmission of yellow fever virus in Cuba. Close scrutiny of the articles published by Walter Reed and his colleagues in 1900, 1901 and 1902 reveals their limitations as historic documents. Fortunately, other sources of information from that period survive in letters and documents written by individuals involved in the quest for the mode of transmission. Examination and comparison of those sources of information unveiled a fascinating story which reveals that misunderstandings engendered by published articles accorded merit where it was not fully due.     

Physiological characteristics of various species of strains of carboxydobacteria

Seven strains of aerobic carbon monoxide-oxidizing bacteria (carboxydebacteria) when growing on CO as sole source of carbon and energy had doubling times which ranged from 12–42 h. The activity profiles obtained after discontinuous sucrose density gradient centrifugation indicated that the CO-oxidizing enzymes are soluble and the hydrogenases are membrane-bound in all strains examined. The CO-oxidizing enzymes of Pseudomonas carboxydohydrogena, Pseudomonas carboxydoflava, Comamonas compransoris, and the so far unidentified strains OM2, OM3, and OM4 had a molecular weight of 230,000; that of Achromobacter carboxydus amounted to 170,000. The molecular weights of the CO-oxidizing and H₂-oxidizing enzymes turned out to be identical. The cell sonicates were shown to catalyze the oxidation of both CO and H₂ with methylene blue, thionine, phenazine methosulfate, toluylene blue, dichlorophenolindophenol, cytochrome c or ferricyanide as electron acceptors. Methyl viologen, benzyl viologen, FAD⁺, FMN⁺, and NAD(P)⁺ were not reduced. The spectrum of electron acceptors was identical for all strains tested. Neither free formate, hydrogen nor oxygen gas were involved in the CO-oxidation reaction. Methylene blue was reduced by CO at a 1:1 molar ratio. The results indicate that CO-oxidation by carboxydobacteria is catalyzed by identical or similar enzymes and that the reaction obeys the equation CO+H₂OCO₂+2H⁺+2e^- as previously shown for Pseudomonas carboxydovorans.Dedicated to Otto Kandler remembering almost three decades of enjoyable cooperation     

Modulation of allostery of pyruvate kinase by shifting of an ensemble of microstates

Since the introduction of the concepts of allostery about four decades ago, much advancement has been made in elucidating the structure-function correlation in allostery. However, there are still a number of issues that remain unresolved. In this review we used mammalian pyruvate kinase (PK) as a model system to understand the role of protein dynamics in modulating cooperativity. PK has a triosephosphate isomerase (TIM)(α/β)₈ barrel structural motif. PK is an ideal system to address basic questions regarding regulatory mechanisms about this common (α/β)₈ structural motif. The simplest model accounting for all of the solution thermodynamic and kinetic data on ligand-enzyme interactions involves two conformational states, inactive E^T and active E^R. These conformational states are represented by domain movements. Further studies provide the first evidence for a differential effect of ligand binding on the dynamics of the structural elements, not major secondary structural changes. These data are consistent with our model that allosteric regulation of PK is the consequence of perturbation of the distribution of an ensemble of states in which the inactive E^T and active E^R represent the two extreme end states. Sequence differences and ligands can modulate the distribution of states leading to alterations of functions. The future work includes: defining the network of functionally connected residues; elucidating the chemical principles governing the sequence differences which affect functions; and probing the nature of mutations on the stability of the secondary structural elements, which in turn modulate allostery.