Table of Content

15 November 2011, Volume 28 Issue 6 Previous Issue    Next Issue

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Relationships between UV Radiation and Meteorological Factors in the Tazhong Region of the Taklimakan Desert HE Qing, JIN Li-Li, YANG Xing-Hua, AI Li-?Mai-Mai-Ti-Ming 2011, 28 (6):  901-912.  Abstract ( 1763 )   PDF (6581KB) ( 1104 )   The Taklimakan Desert is the largest desert in China. It is particular and typical in all the deserts in China. It affects strongly the climate and entironment in northwest China. Solar ultraviolet radiation including its ecological effect and climatology was observed in recent decades, so it is very important to understand UV radiation in the Taklimakan Desert. Taklimakan Station for Desert Atmospheric Environment Observation and Experiment (39°01′ N, 83°40′ E) is located in the hinterland of the Taklimakan Desert. In this paper, the characteristics of solar ultraviolet radiation, affecting factors and their relationships with meteorological factors at the station were analyzed using the data of solar ultraviolet radiation, solar global radiation and some meteorological factors, observed in the hinterland of the Taklimakan Desert during the period from Jane to December 2007. The result shows that the global UV radiation was 305.64 MJ/（m2•a). The maximum and minimum values of total monthly UV radiation occurred in July and December respectively. The peak value of instantaneous radiant intensity of UV radiation was 67.11 W/m2 and occurred in June. There was a significant correlation between global radiation and UV radiation. The maximum (minimum) ratio of UV radiation to global radiation occurred in summer (winter). The effect of cloud cover and sand dust on UV radiation was significant. Compared with clear sky, UV radiation was reduced by 31.68% when the total cloud cover was ≥8, and it was reduced by 41.91% when a sandstorm occurred. Judged purely from the annual and daily variation, there were the significant correlations between UV radiation and air temperature and surface temperature, these correlations were stronger in summer than that in winter and stronger at noon than that in the morning or evening. Compared with temperature, there was a good correlation between UV radiation and surface temperature in summer. Water vapor did not directly absorb UV radiation, and there was no correlation between UV radiation and specific humidity except a weak correlation in winter. The factors affecting global radiation, including air temperature, surface temperature, visibility, cloud cover and specific humidity, were used to develop the prediction equations of estimating seasonal UV radiation. The factors used in the stepwise regression equation were different for different seasons. The test revealed that the stability and fitting results were good, and the equations can be used to estimate seasonal UV radiation. Related Articles | Metrics

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Climate Change in the Yuepuhu Oasis, Xinjiang in Recent 39 Years Gulbahar Zayit，Dilinuer Aji 2011, 28 (6):  913-920.  Abstract ( 2319 )   PDF (3395KB) ( 1161 )   his paper analyzes the annual and seasonal changes of some metrological factors in the Yuepuhu Oasis in recent 39 years using the methods of regression analysis, trend analysis and 5year moving average analysis using the data of temperature, precipitation, sunshine duration and wind speed observed by the meteorological stations in the oasis during the period from 1971 to 2009. The results show that the annual temperature in the oasis was in an increase trend with an increase rate of 0.21 ℃/10 a in recent 39 years. The change of seasonal temperature was different, that is, the temperature was increased in winter, autumn and spring but decreased in summer. Precipitation in the oasis was in a decrease trend with a decrease rate of -1.62 mm/10 a. Seasonal precipitation was increased in autumn and spring but decreased in summer and winter. Annual sunshine duration in the oasis was in an increase trend with an increase rate of 20.25 h/10 a in recent 39 years. In recent 39 years, wind speed over the oasis was in a decrease trend with a decrease rate of 0.4 m/(s•10 a). References | Related Articles | Metrics

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Study on Drought Disasters and Their Driving Forces in the Agricultural Regions of East Qinghai Province during the Period of 1421-1950 HU Jian, ZHAO Jing-Bo 2011, 28 (6):  921-927.  Abstract ( 1626 )   PDF (1760KB) ( 1050 )   In this paper, the characteristics of drought disasters and their driving forces in the agricultural regions of east Qinghai Province during the period from 1421 to 1950 were researched after collecting and analyzing the relevant historical documents. The results show that 152 drought disasters occurred in the agricultural regions of east Qinghai Province during the period from 1421 to 1950, including 64 slight drought disasters, 63 moderate drought disasters, 20 serious drought disasters and 5 extremely serious drought disasters, they accounted for 42.11%, 41.45%, 13.16% and 3.29% of the total respectively, and drought disaster occurred once every 3.5 years. There were 5 highfrequency periods of occurring drought disasters (1481-1499, 1711-1721, 1758-1780, 1861-1900 and 1921-1940), and drought disaster occurred once every 1.55 years; there were also 3 lowfrequency periods (1421-1480, 1781-1830 and 1541-1600), and drought disaster occurred once every 8.1years. Wavelet analysis shows that there were the 50-58, 25-32 and 10-15year longterm periods of drought grades in the agricultural regions of east Qinghai, and there was also a 3-5year shortterm period. Drought occurrence in the agricultural regions of east Qinghai was the joint result of climate change, uneven spatiotemporal distribution of precipitation and human activities, especially the effects of climatic factors, and then those of human factors, such as land reclamation and wars. References | Related Articles | Metrics

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Trend of Sandstorm in the Manas River Basin Oasis and Its Correlation with Climatic Factors LING Hong-Bo, XU Hai-Liang, ZHANG Qing-Qing 2011, 28 (6):  928-935.  Abstract ( 1665 )   PDF (1672KB) ( 1026 )   he trends, periods and chaotic characteristics of sandstorm and the impacts of climatic factors on sandstorm variation were analyzed based on the meteorological data observed by 3 weather stations in the Manas River Bain oasis during the period of 1959-2007 and using the methods of wavelet analysis, chaotic theory, R/S analysis and nonparametric test. The results show that the sandstorm frequency was in a decrease trend, and sandstorm occurred mainly in spring and summer; there were the 4year and 17year periodic changes of sandstorm frequency in the Manas River Basin oasis; based on the R/S analysis, it is believable to predict that the decrease trend of sandstorm frequency will still maintained in next 15 years; there were the significant correlations between sandstorm and evaporation and gale, but the correlations between sandstorm and other climatic factors were not significant; the sandstorm is closely and significantly correlated with the NAO in summer. References | Related Articles | Metrics

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Risk Assessment on Climatic Factors Resulting in Sandstorm Disasters in the Xilingol Region WU Jian-Wei, LI Jin-Rong, SUN Tao, LI Feng, ZHOU Xiang-Shan 2011, 28 (6):  928-935.  Abstract ( 1540 )   PDF (1405KB) ( 905 )   The Xilingol region is one of the main typical steppes in China, it is located in an ecological fragile zone, and it is also an important ecological barrier around Beijing. In this paper, the correlations between sandstorm occurrence and climatic factors were analyzed, and the rating matrix of meteorological factors was used to calculate the composite scores so as to research the risk of meteorological factors resulting in sandstorm disasters. The result revealed that the frequency percentage of sandstorm occurred in spring was 77.28%, and the seasonal characteristics of occurring frequency of sandstorm were obvious. Moreover, the occurring frequency of sandstorm was in a decreasing trend in recent 30 years. Spatially, the occurring frequency of sandstorm was gradually decreased from the west to the east, and the areas with high occurring frequency were the desert steppes and the farmingpastoral ecotones. Formation and development of sandstorm are closely related to climatic factors, but the effects of climatic factors on sandstorm occurrence are temporally different. Holistically, the risk of climatic factors resulting in sandstorm disasters in the southwestern and northeastern parts of the study area was higher than that in the central part, and the risk distribution of climatic factors accorded basically with the occurring frequency of sandstorm. References | Related Articles | Metrics

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Temporal and Spatial Trends of Drought and Flood in the South and North of the Qinling Mountains in Shaanxi Province SONG Chun-Ying, YAN Jun-Ping, ZHANG Li-Wei 2011, 28 (6):  944-949.  Abstract ( 1674 )   PDF (1232KB) ( 992 )   Based on the monthly precipitation data observed by 57 meteorological stations in the Qinling Mountains during the period from 1961 to 2009, this paper analyzes the temporal and spatial trends of drought and flood in the north and south of the Qinling Mountains and the response of regional drought index and Z index to global climate change using mainly the MK mutation test, wavelet analysis and Kriging interpolation. The conclusions are as follow: (1) Climate trend rate of average annual temperature in Guanzhong was higher than that in south Shaanxi Province, and the abrupt change of average annual temperature occurred in 1996 in these two areas; (2) In recent 49 years, the warmingdrying trend, spring drought and summer flood in Guanzhong were more significant than that in south Shaanxi Province. The proportion of severe drought increased in both the north and south of the Qinling Mountains, but that of partial flood decreased after the abrupt change of average annual temperature. There were the 3-4year and 22-27year periodicities of drought and flood in Guanzhong, but 3-4year and 24-30year ones in south Shaanxi Province, and these periodicities corresponded to the occurrence of El Nino and solar activity; (3) Frequency of severe drought in south Shaanxi Province was higher than that in Guanzhong. The distribution regularity of annual severe flood frequency was not strong, and the centers were scattered. Frequency of drought and flood was distributed in a latitudinal way in winter but in a longitudinal way in other seasons. References | Related Articles | Metrics

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Relationship between Profile Features of δ18O in Snow Pits over a Mountain Glacier and Local Climate—A Case Study on Glacier No.1 at the Headwaters  of the Urumqi River in the Tianshan Mountains LI Ya-Ju, ZHANG Ming-Jun, LI Zhong-Qin, WANG Sheng-Jie, WANG Fei-Teng 2011, 28 (6):  950-956.  Abstract ( 2001 )   PDF (1101KB) ( 937 )   During the period from October 2004 to September 2005, snow samples were collected from 16 snow pits at the accumulation zone of Glacier No. 1 at the headwaters of the Urumqi River in east Tianshan Mountains. According to the δ18O data of the snow samples, the relationship between  δ18O in the snow pits over the glacier in different seasons and local climate was discussed. The result indicated that an evident profile characteristic was displayed in different periods (dry season or wet season). In general, a significant variation occurred at the upper snow pits, and a high value was steadily maintained at the bottom (within 130 cm to superimposed ice layer). A snow stratigraphy was a record of temperature variation during accumulation period in dry season; in wet season, however, variation range of  δ18O was reduced, and the peak was dropped down. In dry season, isotope value was mainly affected by partial melting and refreezing process of surface snow, snow/firn texture transformation and exchange of atmospheric moisture, but most information of  δ18O variation in snow pits was kept. In wet season, distribution of δ18O  in snow pits was strongly affected by enrichment of melt water infiltration and homogenizing process, some typical values (e.g. peaks) were smoothed; so from the top to the button, the  δ18O value was homogenized more and more significantly. In conclusion, the δ18O  value in the snowpack at the accumulation zone of Glacier No. 1 at the headwaters of the Urumqi River reflects mainly the local temperature variation in dry season, but it was significantly affected by fractionation and homogenizing process. Due to the complex process of fractionation in wet season and the limited time density, a further investigation will be needed in the future, especially for the improvement in the sampling spatiotemporal interval and quantification of explanations. References | Related Articles | Metrics

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Desertification Process and Its Driving Forces in the Duneactivation Region between the Badain Juran and Tengger Deserts LIU Yu, WANG Xiu-Hong, ZHANG Xue-Qin, ZHANG Bai-Ping 2011, 28 (6):  957-966.  Abstract ( 1998 )   PDF (2896KB) ( 807 )   The Badain Juran and Tengger deserts are ones of the three main sources of sandstorm in China. With the increasing frequency and intensity of sandstorm occurrence in China, more and more attention has been paid to the merging status of deserts in the duneactivation region (DAR for short) between the Badain Juran and Tengger deserts. Based on Landsat TM/ETM+ images in 1989, 1999 and 2007 respectively, the desertification process in the DAR was investigated using the methods of dynamic change, transferred matrix and landscape pattern indexes. Its driving forces including natural factors and human activities were explored as well. The main conclusions are as follows: (1) During the period of 1989-2007, the areas of sandy land and cropland were expanded, while those of grasslands, saline land and wetland were shrunk. The dynamic change of grasslands, wetland, sandy land and saline land was higher than that of other land use types in the DAR. The transition among the land use types was remarkable, particularly between sandy land and grasslands. The landscape pattern indexes in the DAR demonstrated an obvious tendency of intensified fragmentation. The patch centroid of sandy land was moved northwestward, which could be regarded as a merging direction of deserts in the DAR from the northwest marginal zone of the Tengger Desert to the southeast marginal zone of the Badain Juran Desert. The analysis revealed that the land desertification, soil salinization, the degradation of grasslands and shrinkage of wetland were aggravated during the period of 1989-2007. Consequently, the Badain Juran Desert and the Tengger Desert tended to merge; (2) The expansion of sandy land, degradation of grasslands and the shrinkage of wetland were driven by both the natural factors and human activities, which resulted in the merging of deserts in the DAR between the Badain Juran and Tengger deserts. Thereinto, the warmingdrying trend was the precondition of desertification. Population growth and overgrazing sped up the desertification process. Although the related national policy and measures, e.g., the project of returning the grain plots to forests or grasslands, have been implemented to prevent land desertification and regenerate grasslands in the arid and semiarid regions of China, the desertification situation in the DAR between the Badain Juran and Tengger deserts is still serious. It is suggested to stabilize and sustain the policy support, ecological projects and longterm field observation and monitoring so as to guarantee the environmental protection and the ecological regeneration in the DAR between the Badain Juran and Tengger deserts. References | Related Articles | Metrics

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Shaanxi Province Key Laboratory of Disaster Survey & Mechanism Simulation, Department of Geographical Science and Environmental Engineering, Baoji University of Arts & Sciences, Baoji 721013, Shaanxi Province, China LI Jing-Yi 2011, 28 (6):  967-973.  Abstract ( 2009 )   PDF (1315KB) ( 1249 )   Environmental problems have become more and more serious and as the factors restricting the sustainable economic development in the Weihe River Basin in Shaanxi Province. After analyzing the historical statistical data and reviewing the research achievements, some conclusions were got. The main environmental problems in the drainage basin are the shortage of water resources, water pollution, water loss and soil erosion and frequent flood. It was recognized that the effective ways of solving the environmental problems are to regard the integrated management as the target, take the restructure as main line, and make scientific and technological progress as the power. Of course, all these are based on the research on environment and resources. In order to achieve the rational development and utilization of water resources, reduce flood disaster and improve ecological environment, the effective measures are to utilize floodwater, decrease the Tongguan elevation, control water pollution and strengthen soil and water conservation. References | Related Articles | Metrics

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Experimental Study on Effect of Urbanization on Service Functions of Ecosystems — A Case Study in Southern Suburbs of Xi’an City ZHOU Zhong-Xue, CHOU Li-Hui 2011, 28 (6):  974-979.  Abstract ( 1820 )   PDF (1533KB) ( 1548 )   The spatial pattern of urbanization controls the dynamic process of ecosystems. In this paper, the GIS and RS methods were used to carry out an experimental study on the effect of urbanization on the service functions of ecosystems after analyzing the spatial patterns of urbanization, service functions of ecosystems and interrelations among them in southern suburbs of  Xi’an  City. The conclusions are as follows: ① There was an obvious circular spatial pattern of urbanization in southern suburbs of  Xi’an City, that is the farther the regions away from the builtup area of the city were, the lower the urbanization level was; ② The farther the ecosystems away from the builtup area were, the stronger the service functions of ecosystems were, and the service value of ecosystem per hm2 was the lowest in the builtup area; ③ There was a strong negative correlation between the comprehensive urbanization level and the total value of service functions of ecosystems. There were also the quite remarkable negative impacts of urbanization on the service functions of ecosystems, but the impacts were different from different service functions of ecosystems. There were the significant negative impacts on waste treatment, food production, soil formation and conservation and climate regulation in the study area, but the impacts on biodiversity conservation, raw material production and entertainment were not remarkable. References | Related Articles | Metrics

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Study on Expansion of Land for Urban Construction and Its Driving Forces in Oases in the Northern Slope of the Tianshan Mountains, Xinjiang DONG Wen, YANG Yu, ZHANG Xiao-Lei, TAO Jiang, WANG Bin-Wu 2011, 28 (6):  980-985.  Abstract ( 1461 )   PDF (1195KB) ( 1002 )   Based on the TM/ETM images in the years of 1990 and 2007, this paper demonstrated the current land use maps in the northern slope of the Tianshan Mountains, Xinjiang using the mancomputer interactive interpretation. Expansion of land for urban construction and its driving forces in the study area were analyzed using the spatial analysis of GIS. Specifically, the land concentration, land expansion degree, land use intensity and relative change rate were computed using the principal component analysis. The results show that the expansion of land for urban construction, rural residential area construction and other construction purposes was much less than that of other land use types, but the change extent was the most obvious. Separated by the mountains in the south, the plains in the north were the main areas for the expansion of agricultural land and land for construction. With the rapid economic development, land use change was mainly affected by economic factors although population growth was the most direct driving force affecting land use change. The effect of industrial restructuring on land use change was significant. Moreover, the technological advance and the investment increase were the direct factors promoting the change of land for urban construction in the northern slope of the Tianshan Mountains. References | Related Articles | Metrics

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Influence of Crude Oil on Sorption of Dibromomethane in Soil Adsorbed Water SHEN Ya-Qin, SU Yu-Hong 2011, 28 (6):  986-989.  Abstract ( 1862 )   PDF (853KB) ( 1707 )   The sorption of dibromomethane in soil samples collected from crudeoil exploration area in Xinjiang was investigated to study the influence of crude oil on sorption mechanism. Results indicated that the sorption isotherms of dibromomethane in soil with or without contamination of crude oil accorded with the liner function, sorption mechanism was dominated by partition of organic phase (including organic matter in soil and crude oil phase). The sorption coefficients of dibromomethane in soil contaminated by crude oil with low concentration were lower than those in soil without concentration of crude oil. Sorption mechanism was dominated by partition of soil organic matter. However, the sorption coefficients of dibromomethane in soil contaminated by crude oil with high concentration were much higher than those in soil without concentration of crude oil, and there was a positive correlation between the sorption coefficient and the crude oil concentration in soil. The sorption mechanism was gradually dominated by partition of dibromomethane in crude oil phase in soil. The translocation of dibromomethane was decreased by high crude oil concentration in soil, but it was increased by low crude oil concentration. References | Related Articles | Metrics

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Advances in Study on Eco-environmental Carrying Capacity in the Drainage Basins with Shortage of Water Resources ZHU Yong-Hua, REN Li-Liang, XIA Jun, LV Hai-Shen , YU Zhong-Bo, FANG Xiu-Qin 2011, 28 (6):  990-997.  Abstract ( 1898 )   PDF (815KB) ( 1047 )   In the drainage basins with shortage of water resources, water resources is the main factor affecting ecoenvironmental quality and social and economic development. Therefore, it is necessary to study the eco-environmental carrying capacity related to water resources in these basins so as to provide the references for realizing sustainable development. Shortage of water resources in the drainage basins is caused by low mean annual precipitation. Eco-environmental carrying capacity is defined as the largest population and economic scale (usually expressed as gross domestic product, GDP) that can be sustained in a particular region or drainage basin over a specified time and under a certain environmental protection standard and social welfare level, when the ecoenvironment, society and economy of the region are reached a critical acceptable level by using local (or diverted) water and other resources available. After analyzing the documental data since the 1980s, firstly, the significance of study on ecoenvironmental carrying capacity and the current status of the study are described, on which the future challenges are proposed as follows: ① The theory needs to be improved from developing a measuring system so as to apply it in drainage basins. The measuring system includes the concept of ecoenvironmental carrying capacity is given based on the concept, a measuring index system and a measuring model is developed, and an application case of the abovementioned measuring model is given. ② In the measuring system, social and economic sustainable development in the drainage basins with shortage of water resources needs to be considered so as to serve national needs. In this respect, the serving value and dynamic change of ecoenvironmental carrying capacity is emphasized. Because the carrying capacity is the threshold of social and economic sustainable development in the drainage basins, the development of the drainage basins will be reasonable and feasible under the limitation of the eco-environment carrying capacity. The carrying capacity is variable with the change of social and economic development, therefore, time series should be considered in the future. ③ Eco-environmental problems need to be considered as complete as possible. In a drainage basin with shortage of water resources, there are many ecoenvironmental problems related to water resources, such as excessive groundwater pump, water pollution, river channel shortening or river water drying, decrease of the volume of water reaching sea, water loss and soil erosion and polluted water discharge. In the hilly area and plain of a drainage basin, the eco-environmental problems are different. Therefore, in the future study on eco-environmental carrying capacity in the drainage basins or areas with shortage of water resources, the eco-environmental problems should be considered. In the future, water resources could not be considered as an invariable value when eco-environmental carrying capacity in the drainage basins with shortage of water resources is studied, because of its change with the change of precipitation, especially in recent years under climate change and increase of human activities. References | Related Articles | Metrics

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Analysis on the Long-term Evolution of Runoff Volume and Its Affecting Factors in the Luanhe River Basin WANG Gang, YAN Deng-Hua, HUANG Zhan-Feng, JIN Xin, Piao Shu-Ming 2011, 28 (6):  998-1004.  Abstract ( 1822 )   PDF (1808KB) ( 1034 )   Based on the data of runoff volume in the Luanhe River Basin during the period of 1956-2008, the M-K test and power spectrum analysis were used to analyze the evolution of runoff volume in the Luanhe River Basin. Meteorological data observed by 9 meteorological stations during the period of 1957-2008 and the land use data during the period of 1985-2000 were used to identify the factors affecting the change of runoff volume. The results show that the runoff volume was holistically in a decrease trend, especially in the upper reaches. The decrease trend was more significant during the low-flow periods, which indicates that drought and flood may occur more frequently．The results also show that the runoff volume was sharply decreased in 1959 and 1996, increased in the late-1980s, and decreased again after 1998. There was a 16-year periodicity of runoff volume change in the Luanhe River Basin and a 64-year one in the upper reaches, and there were also the 9-10-year 2-3-year periodicities in the middle and lower reaches. The most important climate factors affecting runoff volume were precipitation and evaporation, and then land use cover change. References | Related Articles | Metrics

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Dynamic Life Table and Analysis on Survival of Quercus liaotungensis Seedlings in Mt. Ziwuling of the Loess Plateau GUO Hua, WANG Xiao-An, WANG Shi-Xiong, FAN Wei-Yi 2011, 28 (6):  1005-1010.  Abstract ( 1725 )   PDF (1329KB) ( 1053 )   In the Malan forest region of the Mt. Ziwuling on the Loess Plateau, three kinds of communities, i.e. the Pinus tabulaeformis forests,Quercus liaotungensis forests and shrub grasslands, were selected as the experimental plots. The seeds of Q. liaotungensis were sowed to build the seedling cohorts in three habitats. According to the growth data gathered continuously in three years, the dynamic life tables, curves of cumulative survival rate, cumulative mortality rate and hazard rate are drawn in this paper. The results show that the survival curve of Q. liaotungensis trended to the DeeveyⅡ and fluctuated clearly at different stages. There was no significant difference in survival rate of Q. liaotungensis seedlings in P. tabulaeformis and Q. liaotungensis forests, but the survival rate was significantly higher than that in shrub grasslands. In dense forests, the survival rate of Q. liaotungensis seedlings was higher in the first year, and the highest mortality rate occurred in the third spring. In the shrub grasslands, the mortality rate of seedlings was high in the first two months, and the highest mortality rate of seedlings occurred in the third spring. Drought in the third spring is the key factor affecting the survival of Q. liaotungensis seedlings. References | Related Articles | Metrics

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Study on Types and Features of Urban Vegetation in Urumqi YIN Lin-Ke, NAN Wei-Jiang , YAN Cheng, WANG Lei, JIANG Feng-Qing, ZAN Qin 2011, 28 (6):  1011-1019.  Abstract ( 4027 )   PDF (807KB) ( 1399 )   According to the degree of human disturbance, community functions and advantages of the dominant and constructive species, in this paper, urban vegetation in Urumqi was divided into three parts, i.e. the natural vegetation, seminatural vegetation and artificial vegetation, including 3 vegetation races, 13 vegetation groups and 125 vegetation types. Natural vegetation race is classified into 7 vegetation groups, i.e. the coniferous forest vegetation group, broadleaf forest vegetation group, shrub vegetation group, desert vegetation group, meadow vegetation group, steppe vegetation group and alpine vegetation group with 82 vegetation types; semi-natural vegetation race is divided into 4 vegetation groups, i.e. the broadleaf forest vegetation group, shrub vegetation group, herbaceous vegetation group and partner person vegetation group with 33 vegetation types; artificial vegetation race is classified into 2 vegetation groups, i.e. the green space and agricultural vegetation group with 10 vegetation types. Urumqi has a full spectrum of natural vegetation race and rich type diversity. Affected by inland desert climate, the zonal desert vegetation types develop well, and there are the obvious advantages in xerophyte shrubs, superxerophyte shrubs, semi-shrubs and perennial herbaceous vegetation. The number of plant community species of semi-natural vegetation race is increased significantly due to human disturbance, and the proportions of trees and shrubs are increased compared with those of natural vegetation. In the community, the majorities of the upper species of trees and shrubs are the cultivated species, while the most endemic herb groups are composed of the wild and exotic species. All these make the species diversity index of the semi-natural vegetation be relatively high. Green space of artificial vegetation race has a high fragmentation, showing a spatial distribution of points, blocks, slabs and other forms with a low vegetation coverage and low correlation between communities and populations in the central area of the city. Among them, the protection green space is dominated by a high proportion of the introduced exotic species and naturalized species. Affected by market economy, agricultural vegetation group is composed of three main vegetation types, i.e. the food, vegetable and oilseed plants. References | Related Articles | Metrics

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Analysis on Plant Species Composition and Structure in the Testudo horsfieldi Nature Reserve in Ili, Xinjiang JIA Feng-Qin, LI Zi-Wei, JIN Xi-Tang, ZHANG Wei 2011, 28 (6):  1020-1024.  Abstract ( 1878 )   PDF (1107KB) ( 940 )   In this study, vegetation in 40 sample plots in the Testudo horsfieldi Nature Reserve, Ili, Xinjiang was investigated in April and September 2009. The results reveal that there were 65 plant species in 56 genera and 22 families in the nature reserve. In which the proportion of Brassicaceae species was the highest and for 16.9%, than that of Compositae species and for 15.4%, and the proportions of Leguminosae and Chenopodiaceae species were all 10.8%. There were 5 plant growth forms, 4 root growth forms, 5 life forms and 3 water ecological forms in the nature reserve, and there were also 4 food forms of T. horsfieldi. In the plant growth form spectrum, the proportion of erect species was the highest and for 52.3%, the proportions of branch species and the tuft species were 24.6% and 9.2% respectively. In the root growth form spectrum, the proportion of taproot species was the highest and for 76.9%, and that of rhizome species was 13.9%. In the life form spectrum, the proportion of therophytes was the highest and for 50.8%, and that of hemicryptophytes was 26.1%. In the water ecological form structure, the proportion of mesophytes was the highest and for 55.4% of total. The food structure types were consisted of 21.5% faworite food. Climate in the Testudo horsfieldi Nature Reserve is the temperatedesert therophytes, and there are a few favorite food plants for T. horsfieldi. References | Related Articles | Metrics

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Study on Rootshoot Ratios of Natural Grasslands and Their Relationships with Climatic Factors in the Northern Slopes of the Qilian Mountains HUANG De-Qing, YU Lan, ZHANG Yao-Sheng, ZHAO Xin-Quan 2011, 28 (6):  1025-1030.  Abstract ( 2382 )   PDF (1208KB) ( 1264 )   In this paper, the relationships between the rootshoot ratios and meteorological factors were analyzed using the data of aboveground and underground biomasses of five types of natural grasslands and the synchronous meteorological data in northern slope of the Qilian Mountains. The results indicated that the biomass of five types of natural grasslands was in an order of mountain meadow > mountain steppe > mountain meadow steppe > alpine steppe > mountaindesert grasslands; difference of the biomass among the five types of natural grasslands was significantly except that among alpine steppe, mountain meadow steppe and mountain steppe (P＜0.05); rootshoot ratios of alpine steppe, mountain meadow, mountain meadow steppe, mountain steppe and mountaindesert grasslands were 9.3, 8.7, 5.1, 7.0 and 7.1 respectively; there was a reverseparabolashaped seasonal variation in curves of rootshoot ratios of the five types of natural grasslands, but the seasonal variation of their rootshoot ratios was different; rootshoot ratio of alpine steppe was significantly decreased with the increase of soil moisture content in previous month, the rootshoot ratios of mountain meadow steppe and mountain steppe were significantly decreased with the increase of potential evapotranspiration in previous month, but there was no significant correlation between the rootshoot ratios of mountain meadow and mountaindesert grasslands and the hydrological and sunshine factors in previous month. References | Related Articles | Metrics

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Effects of Desulphurization Magnesium Slag from Flue Gas on Seed Germination and Seedling Growth of Ammopiptanthus mongolicus WANG Ling, LI Yan, YIN Lin-Ke, CHEN Chang-He, WANG Lei-Tao, LIU Yan-Li 2011, 28 (6):  1031-1037.  Abstract ( 1837 )   PDF (1209KB) ( 947 )   In this paper, the effects of applied desulphurization magnesium slag from flue gas to sand on seed germination and seedling growth of [WTBX]Ammopiptanthus mongolicus[WTBZ] were researched using the indoor illuminating incubator. Five different fertilizer rates (i.e. 0, 5, 10, 15, 20 grams of desulphurization magnesium slag per 1 kilogram sand) were designed to observe the effects of applied desulphurization magnesium slag on germination energy, seeding index, germination rate, emergence percentage, emergence fresh or dry weight per plant, total biomass and growth of seedling stems and roots of A. mongolicus. The results show that desulphurization magnesium slag application had the effects on seed germination and seedling growth. Desulphurization magnesium slag restricted significantly the seed germination, seedling emergence and seedling root growth, and the restriction increased with increasing the application rates. Application of desulphurization magnesium slag promoted significantly the seedling fresh or dry weight per plant, total biomass and seedling stem growth, and this effect was increased with increasing the application rate. In the whole process from seed germination to seedling growth, seed germination and seedling emergence were significantly decreased when the application rate ranged from 5 to 15 g/kg compared with the control, but seedling biomass was significantly increased. When the application rate was lower than 5 g/kg, there was no significant effect on seed germination and seedling growth. When the application rate was higher than 15 g/kg, seed germination and seedling emergence were decreased very significantly, while seedling fresh or dry weight per plant, total biomass and seedling stem growth were increased very significantly. References | Related Articles | Metrics

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Response of Seedling Emergence of Three Dominant Plant Species to Soil Type and Sand Burial Depth in the Southern Marginal Zone of the Tengger Desert FAN Bao-Li, MA Quan-Lin, ZHANG De-Kui, AN Jing-Rong 2011, 28 (6):  1038-1044.  Abstract ( 2055 )   PDF (1934KB) ( 1137 )   Agriophyllum squarrosum, Artemisia sphaerocephala and Artemisia ordosica are the dominant plant species at different stages of vegetation succession in the southern Tengger Desert. A fieldpot experiment was conducted at Wuwei Station for Desert Control Research in summer 2009. Response of the seedling emergence rates of the 3 species to two soil types (sand and sandy loam) and seven sand burial depths (0, 1, 2, 3, 4, 6 cm and 8 cm) was measured. Seedling emergence rate of A. squarrosum seeds buried at 0 cm in sand was the lowest, that of the 3 species seeds buried at 1 and 2 cm in sand was the highest, and that of the 3 species seeds buried in sandy loam was lower than that in sand. The optimal burial depth for seedling emergence of A. squarrosum and A. ordosica was decreased from 2 cm in sand to 1 cm in sandy loam. In sand, A. squarrosum seeds at all sand burial depths emerged, the seedling emergence rate was high, and the seedling mortality rate was low; thus, A. squarrosum could be the dominant species for sand dunes. In sandy loam, however, the emergence speed of A. squarrosum seeds at sand burial depths of 0-4 cm was slow, and the seedling mortality rate was higher than that of other two species. Thus, A. sphaerocephala and A. squarrosum replaced A. squarrosum on fixed and semifixed dunes at the seeding stage. References | Related Articles | Metrics

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Trophic Niche Width and Overlap of Equus przewalskii，E. hemionus and Gazella subgutturosa in Autumn HUANG Yan, CHU Hong-Jun, LAN Wen-Xu, SHI Kun, TAO Yong-Shan, SHAO Chang-Liang 2011, 28 (6):  1045-1050.  Abstract ( 2141 )   PDF (732KB) ( 1027 )   In this study, the fresh excrements of Equus przewalskii，E. hemionus and Gazella subgutturosa were systematically collected from the Qiaomuxibai of Karamori Natue Reserve in Xinjiang in autumn 2009. Fecal microscopic means were used to analyze the habitats of the abovementioned three species and their food niche. The results show that the 3 species have similar diet in terms of types, but different in terms of proportion, where Stipa spp. are the main food sources of these species, and their diet percentages are 43.63%, 49% and 44.65% respectively. The nutritional niche breadths of E. przewalskii, E. hemionus and G. subgutturosa are 0.634, 0.619 and 0.539 respectively. The nutritional niche overlap values of E. przewalskii and E. hemionus, E. przewalskii and G. subgutturosa, E. hemionus and G. subgutturosa are 0.98, 0.986 and 0.962 respectively, and the extent of nutritional niche overlap between the three species is 0.477. The three species are very similar in terms of consuming food resources. References | Related Articles | Metrics

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Progress in Studies on Genetic Diversity of Equus przewalskii LIU Gang, HU De-Fu, ZHAO Sha-Sha 2011, 28 (6):  1051-1056.  Abstract ( 2183 )   PDF (637KB) ( 972 )   The progress in studies on genetic diversity of Equus przewalskii is reviewed from the aspect of genetic markers, such as the chromosome, blood group and allozyme, mitochondrial DNA, microsatellite DNA and MHC. After analyzing systematically the achievements in researching the genetic diversity of E. przewalskii at home and abroad, it can be found that there is still an inbreeding depression, which threatens the EPR population and genetic diversity of E. przewalskii, and the taxonomic issue between E. przewalskii and Equus caballus is still in debate. As the historical bottleneck effect and inbreeding have impacted severely the viability of E. przewalskii, it is necessary to document the genetic diversity of E. przewalskii in China so as to benefit the international gene flow and offer a theoretical basis for further conservation of E. przewalskii in China.   References | Related Articles | Metrics

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Characteristics of Soil Nematode Communities under the Canopy of Tamarix spp. in Different Habitats WANG Xue-Feng, SU Yong-Zhong, LIU Wen-Jie, YANG Rong, YANG Xiao 2011, 28 (6):  1057-1063.  Abstract ( 1947 )   PDF (1542KB) ( 1360 )   In this paper, an investigation on the soil nematode communities under the canopy of Tamarix spp. at different habitats including sand dune, riverside wetland and saline wetland was conducted in Linze town, Gansu Province. In the study 1 245 soil nematode individuals in 20 genera were captured. The results show that the total number of nematodes was significantly higher in the soil under the canopy of Tamarix spp. than that in the soil out of the canopy at all the habitats; the total number of nematodes under the canopy ofTamarix spp. was higher than that out of the canopy at all the habitats, and that under and out of the canopy was in an order of fixed dune > riverside wetland > saline wetland. The bacterivores of  cp-2 guild (Ba2) were dominant in bacterivores over fixed dune, whereas the herbivores of cp-3 guild (H3) were dominant in plant parasites and prevalent in the both wetland soils. There was a significant restriction of soil salinity to the Ba2 guild, but a few effect on the H3 guild. It was found that the analysis on soil nematode communities is a useful method for interpreting the soil ecological process under the canopy of Tamarix spp. in arid area. References | Related Articles | Metrics

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Gain of the KatB Genetic Tobacco and Analysis on Stress Resistance of Transgenic Tobacco YU Na, CHENG Chen, SUN Hui, XU Deng-Xian, ZHU Jian-Bo 2011, 28 (6):  1064-1070.  Abstract ( 1422 )   PDF (3293KB) ( 958 )   NC 89 tobacco plants were transformed via Agrobacterium tumefaciens. PCR and RT-CR indicate that the foreign gene KatB of Pseudomonas aeruginosa has been integrated into the genome of tobacco. Stress resistance tests were carried out under water stress, 300 mmol/L NaCl stress and 0.3 mmol/L H2O2 stress. The results proved that the physiological indexes including leaf relative water content, MDA activity, relative conductivity and maximum photochemical yield of PSII of KatB tobacco were evidently higher than those of wild tobacco on the 13th day of water stress, 20th day of 300 mmol/L NaCl stress and the 33rd day of 0.3 mmol/L H2O2 stress. The stress resistance of transgenic plants was high, which testified that there is a good application prospect of KatB gene in stress resistance of genetic engineering. References | Related Articles | Metrics