Table of Content

10 July 2008, Volume 27 Issue 07

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Articles

Effects of elevated CO₂ and O₃ concentrations on quantitative characteristics of mature leaf stomata in Ginkgo biloba. 

XU Wen-duo¹;QI Shu-yan²;HE Xing-yuan¹;CHEN Wei¹-ZHAO Gui-ling³;ZHOU Yuan¹

2008, 27(07):  1059-1063 . 

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The changing patterns of the quantitative characteristics of mature leaves stomata of Ginko biloba treated with elevat CO₂ and O₃ concontration in open tap chamber (OTC) were Ohsered during 2005 and 2006 growing seasons. The results showed that under 700 μmol CO₂·mol^-1, the stomatal length, width, perimeter, and area were bigger than those of control group (P<0.05); while under 80 μmol O₃·mol^-1, they were smaller than those of control group (P<0.01). nder elevated CO₂, the stomatal density increased slightly (P>0.05), and there was a significant negative correlation between the stomatal index and elevated CO₂ concentration (P<0.05). The elevation of O₃ concentration did not have significant effect on stomatal density (P>0.05), but did on stomatal index. In other words, there was a negative correlation between the stomatal index and the elevation of O₃ concentration. Stomatal specific density was negatively correlated with stomatal length and width, and the correlations could be well expressed with unary quadratic curve equation.

Characteristics of vegetations and soil nutrients on subalpine degraded forestlands in Northwest Yunnan.

ZHANG Jin-feng^1,3;SONG Hong-tao²;GENG Yun-fen³;ZHOU Hong¹

2008, 27(07):  1064-1070 . 

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The subalpine degraded forestlands in Northwest Yunnan were categorized as five degradation stages, and the characteristics of the vegetations and soil nutrients on each type of the forestland were studied by the method of sampling plot. The results showed that on the degraded forestland with Quercus pannosa as the climax, the numbers of woody plant family, genera and species increased with the succession series from herb to shrub to tree communities, and shrub species had a particularly noticeable increase. As for the proportions of plant functional groups, annual herbs occupied larger in early stage but declined gradually along with perennial plants in middle and late stages, while shrubs and trees had an increasing trend through out all stages, being reached the greatest at needle and broadleaved mixed forest stage and then declined to some extent until steady. In different stages, soil pH had some decrease, soil organic matter, total N, hydrolysable N and available K had an increasing trend, while soil available P had no definite change pattern.

Diurnal variation of Hippophae rhamnoides L. subsp. sinensis Rousi stem sap flow in Huangfuchuan Basin and related environmental factors.

YU Hong-bo^1,2,3;YANG Jie^1,2;ZANG Chun-xin^1,2;XU Yan-da^1,2

2008, 27(07):  1071-1076 . 

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The sap flow rate of Hippophae rhamnoides L. subsp. sinensis Rousi in Huangfuchuan Basin was measured by using thermal dissipation probe method, and the related environmental factors such as incident solar radiation, air temperature, relative air humidity, wind speed, and soil temperature at the depth of 10 cm were recorded continuously by using automatic weather station. At the same time, the leaf transpiration rate during 6:00-18:00 was also measured by LI-6400. The results showed that in the period of no rainfall, the sap flow rate of H. rhamnoides varied regularly, with higher value in daytime than in nighttime and more apparent fluctuation in daytime than in nighttime. The sap flow rate increased significantly at the beginning of rainfall, but after then, it descended and became steady. Taking the incident solar radiation, air temperature, relative air humidity, wind speed, and soil temperature at the depth of 10 cm as independent variables and the sap flow flux per unit dry foliage mass as dependent variable, a multiple linear equation was established by stepwise regression, and the regression was significant.

Hyperspectral remote sensing estimation models for chlorophyll a concentration ofCalamagrostis angustifolia.

LI Feng-xiu^1,2;ZHANG-Bai¹;LIU Dian-wei¹;WANG Zong-ming¹; SONG Kai-shan¹;JIN Hua-an^1,2;LIU Huan-jun^1,2

2008, 27(07):  1077-1083 . 

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The canopy reflectance and Chl-a concentration of Calamagrostis angustifolia grown under the conditions of different vegetation coverage and water depth were measured with ASD spectroradiometer. Hyperspectral visible light-near infrared bands and their derivative spectral bands (350-1 050 mm) were adopted to construct the vegetation indices FNDVI, FRVI, FDVI, FDNDVI, FDRVI and FDDVI one by one, search after the best band for each vegetation index which had the best correlation with Chl-a, and establish the optimum estimation models for the Chl-a concentration of C. angustifolia. The comparison of the prediction precision between optimum estimation models and linear models showed that the prediction precision of the best forecasting models (FDNDVI, FDRVI and FDDVI) for derivative spectral vegetation indices and Chl-a was respectively 6.86%, 4.82% and 10.10% higher than that of the optimum reflectance vegetation index models (FNDVI, FRVI and FDVI). Vegetation indices (FNDVI, FDVI, FDNDVI, FDRVI) had a great linear relationship with Chl-a, and the prediction precision of the optimum estimation models were only increased by 0.60%, 1.40%, 1.02% and 0.93%, respectively than the linear models, suggesting that the simple linear models could be used to retrieve the Chl-a concentration of C. angustifolia in wetland.

Biological characteristics and physiological responses of Leymus chinensis seeded in soils with different pH.

HUANG Li-hua^1,2,3;LIANG Zheng-wei^1,4;MA Hong-yuan^1,3;YAN Chao^1,3

2008, 27(07):  1084-1084 . 

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Soils with different pH were artificially prepared by mixing various proportions of non-sodic and sodic soils, and pot experiment was conducted to investigate the biological characteristics and physiological responses of Leymus chinensis seeded in the prepared soils. The results showed that soil pH≤8.50 was beneficial to the growth of L. chinensis; when the pH was above >8.50, the tillering number and shoot dry mass had a decreasing trend; and when the pH was 9.78, the total plant number and shoot dry mass were decreased by 42.0% and 74.1%, respectively, compared with the control (pH=7.15). Under saline-alkali stress, the water content, soluble sugar content, chlorophyll content, and K⁺ concentration in shoot decreased, while the Na⁺ concentration and the conductivity of cytoplasmic membrane increased obviously. The K⁺/Na⁺ ratio in shoot decreased from 28.5 at pH 7.15 to 1.6 at pH 9.78. The higher concentration of K⁺ and higher ratio of K⁺/Na⁺ in shoot might be the main physiological mechanism of salinealkali tolerance of L. chinensis.

Chlorophyll fluorescence characteristics of Achyranthes bidentata under different planting densities.

ZHANG Yan-li¹;ZHANG Zhong-yi¹;LI You-jun²;LIU Hui³;LI Juan¹

2008, 27(07):  1089-1094 . 

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In order to supply the theoretical basis for the normalized planting of Achyranthes bidentata, a field determination on the leaf area, chlorophyll content of the 2nd leaf, and dynamic parameters of chlorophyll fluorescence, as well as the root yield and plant polysaccharide content of A. bidentata under different planting densities (A: 500 000 plants·hm^-1, B: 330 000 plants·hm^-1, C: 250 000 plants·hm^-1, D: 200 000 plants·hm^-1) was made. The results showed that under different planting densities, the maximum values of leaf area index and chlorophyll content were all appeared at the 45th day of post-emergence, with the order of A>B>C>D and B>C>A>D, respectively. The F_v/F_o,F_v/F_m,Ф_PSⅡ,qp, and ETR of photosystem Ⅱ increased first and decreased then, while the qN kept increasing. At the same growth period, treatment B had the highest F_v/F_o, F_v/F_m, Ф_PSⅡ, qN and ETR, and displayed the least restriction from high light and better performance of photosynthesis. The root yield and plantpolysaccharide content were correlated positively with F_v/F_o, and F_v/F_m, and negatively with qN. At the 55th day of spike bringing forth, the qN was correlated negatively with plant polysaccharide content. It was suggested that treatment B was the most suitable planting density.

Fine root biomass and its morphological characteristics of different vegetations along an elevation gradient of Wuyi Mountains in southeastern China.

QUAN Wei¹;XU Xia¹;WANG Feng¹;WANG Jia-she²;FANG Yan-hong²;RUAN Hong-hua¹;YU Shui-qiang¹

2008, 27(07):  1095-1103 . 

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With four plant communities along an elevation gradient of Wuyi Mountains as test objects, their fine roots in 0-10 cm and 10-25 cm soil layers were sampled to determine the root biomass and its configuration indices. The results showed that in 0-10 cm soil layer, the biomass, length density, surface area density, and volume density of living fine roots were all decreased in the order of evergreen broadleaf forest<dwarf forest<coniferous forest<alpine meadows, with significant differences (P<0.01) among the stands. For each stand, the biomass, length density, surface area density, and volume density of living and dead fine roots were all higher in 0-10 cm than in 10-25 cm soil layer, and the living and dead fine roots with a diameter of ≤2.0 mm had the greatest contribution to the total fine root length and total fine root surface area. The fine root biomass and its configuration indices decreased significantly along the elevation gradient, and soil moisture content was the main factor affecting the fine root biomass and its configuration.

Productivity potential of climate-soil for double cropping rice in Fujian Province based on GIS technology.

CHEN Hui;WANG Jia-yi;LIN Jin;PAN Wei-hua;LI Li-chun;CAI Wen-hua

2008, 27(07):  1104-1108 . 

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The spatiality and attribute database of double cropping rice in Fujian Province were established based on the GIS technology, and the productivity potentials of sunlight and temperature, climate, and climatesoil of double cropping rice in each county of Fujian Province were calculated by using modified Kassam-Wageningen method. In terms of grading statistics and mapping, the numerical distribution of the productivity potentials as well as the spatial distribution and potentially predominant development regions of double cropping rice in this province were analyzed. The results showed that the productivity potential of climate would be increased by 1 800 kg·hm^-2 when irrigation was appropriate, and that of climatesoil would be increased by 4 000 kg·hm^-2 when fertilization was at an optimal level. Therefore, there existed great productivity potential for double cropping rice. Moreover, the productivity potential of climatesoil for double cropping rice was greater in south Fujian than in north Fujian, and the greatest potential was in southwest Fujian. According to the variation characteristics of the productivity potentials and ensuring the directions of agricultural input, the countermeasures of keeping food security of Fujian were brought forward: (1) to strictly restrict nonagricultural land and to keep the planting area of double cropping rice in stable, (2) to adopt appropriate planting ratio of different double cropping rice cultivars and to use the agricultural and climatic resources adequately, (3) to construct stable yielding cropland regardless drought or flooding, (4) to improve soil fertility by increasing organic fertilizer application and planting green manure, and (5) to increase input to the potentially predominant regions of developing double cropping rice step by step.

Canopy- and leaf hyperspectral reflectance of spring wheat under different planting densities in Loess Plateau.

WANG Xiao-ping¹;GUO Ni¹;ZHANG Kai¹;YANG Jia²;ZHANG Rong³; DONG Long-li³

2008, 27(07):  1109-1114 . 

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The canopy and leaf hyperspectral reflectance of three spring wheat cultivars at their different growth stages and with seven planting densities were measured in field during April and August 2006. It was found that at booting stage, the canopy and leaf reflectance of spring wheat under the 7 planting densities was distinctly different, though the wave shapes were similar. Meanwhile, the canopy spectral reflectance decreased with increasing planting density in visible (VIS) region but increased in near infrared (NIR) region at booting stage, while this change was not evident and the difference in VIS region was less than that in NIR region at ripening stage. The change of leaf reflectance under different planting densities showed coherence in VIS and NIR regions at different growth stages, but the change with planting density was not clear. The canopy reflectance was higher at ripening than at booting stage; while the leaf reflectance in NIR region was higher at booting than at ripening stage. There were some differences for different spring wheat cultivars at canopy and leaf level. At booting stage, the difference of canopy spectral reflectance among different cultivars was less in VIS region but obvious in NIR and shortwave infrared regions, while the difference at ripening stage was less. The difference of leaf spectral reflectance among different cultivars was obvious in NIR region. There existed “double peak” phenomena for the spring wheat at vegetative growth stage. Additionally, there existed a ‘blue shift’ phenomenon for the position of red edge (λ_red), and the slope of red edge (D_λred) and the area of red edge (S_red) at canopy- and leaf level were decreased from booting to ripening stage, suggesting that the λ_red change could be used to estimate wheat yield, and S_red could be the indicator of wheat growth stage.

Soil readily oxidizable carbon along an elevation gradient of Wuyi Mountains in southeastern China.

XU Xia¹；WANG Feng¹；LUAN Yi-ling¹;WANG Jia-she²;FANG Yan-hong²;LUAN Hong-hua¹

2008, 27(07):  1115-1121 . 

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The shortterm fluctuation of soil organic matter mainly takes place in its labile fraction, and readily oxidizable carbon (ROC), a sensitive factor of soil active organic carbon, is always considered as one of the indices in predicting the early change of soil organic matter. By using potassium permanganate oxidation, the change characteristics of soil ROC in evergreen broadleaf forest (200-1 000 m above sea level), coniferous forest (1 350-1 750 m above sea level), dwarf forest (1 750-1 900 m above sea level), and alpine meadow (1 700-2 158 m above sea level) in Wuyi Mountains Natural Reserve in Fujian of China was studied, with the relationships of soil ROC with soil microbial biomass carbon (MBC), total organic carbon (TOC), total nitrogen (TN), and moisture content analyzed. The results showed that the content of soil ROC increased with elevation, but decreased with soil depth. Soil ROC had positive correlations with soil MBC, TOC, TN, and moisture content, and the percentage of soil ROC to soil TOC (8.69%-14.73%) was 3.32-11.41 times higher than that of soil MBC to soil TOC. The soil ROC along the elevation gradient was significantly affected by soil TOC, moisture, and temperature.

Effects of greenbelt plant communities’ litterfalls in Shanghai Outer Ring on soil water physical properties.

ZHENG Si-jun¹;ZHANG Qing-fei¹;WU Hai-ping²;XIA Lei¹

2008, 27(07):  1122-1126 . 

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Taking eight artificial plant communities in the greenbelts of Shanghai Outer Ring as test objects and with bare land as the control, this paper studied the amount of litter falls and the characteristics of soil porosity and water-holding, aimed to approach the effects of the litter falls of urban greenbelt plant communities on soil water physical properties. The results showed that in upper soil layer (0-10 cm), soil maximal water-holding capacity, capillary waterholding capacity, minimal water-holding capacity, mass water content, volume water content, capillary porosity, non-capillary porosity, total porosity, and aeration were significantly higher (P<0.05) in greenbelts than in bare land, while soil bulk density was in adverse; but in lower soil layer (10-20 cm), there were no significant differences in these parameters between greenbelts and bare land. The capillary porosity in upper soil layer had significant negative correlation but waterholding characters had less correlation with annual litterfall, and the total porosity and aeration had significant positive correlations but bulk density had significant negative correlation with litter stock. No significant correlations were observed between the water physical properties in lower soil layer and the annual litterfall and litterfall standing stock. It was suggested that the litterfall stock of greenbelt plant communities could effectively improve soil water physical properties, especially the porosity of upper soil layer, and thus, should be reserved during urban greenbelt management.

Effects of leaf litter from dominant tree species during forest succession on the composition of soil microbial communities.

LIANG Jian;WANG Xiao-an;TAO Shu-xing;HE Wen-ying;WANG Hui-min

2008, 27(07):  1127-1133 . 

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In order to further understand the mechanisms of forest succession, the composition of soil microbes under forests at different succession stages in the Malan forest region of Loess Plateau and the effects of leaf litter from dominant tree species on the composition of soil microbial communities were investigated. The extracts of leaf litter were imposed to different types of soil samples. The number of soil microbes was determined by using solid medium added with the extracts of soil, and cluster and principal component analyses were applied to process the obtained data. The results showed that the total number of soil microbes and the number of bacteria increased in the order of Betula platyphylla forest→Pinus tabulaeformis forest→Quercus liaotungensis forest. From the pioneer community to the climax community, Shannon-Wiener index, a comprehensive indicator used to describe the microbial composition, showed a downward trend. Of three soil microbial groups, the group with a smaller number played a more important role in the changes of Shannon-Wiener index. According to the composition of culturable soil microbes, the test eight soil samples were divided into three groups. Compared with that from P. tabulaeformis, the leaf litter from Q. liaotungensis played a greater role on the composition of soil microbial communities. It was suggested that the composition of soil microbes in Malan forest region was closely related to the forest vegetation type and its succession stage. Through its specific dominance, the leaf litter from the dominant tree species at advanced succession stage could change the soil microbial composition gradually, and thereby, promote the occurrence of vegetation succession.

Effects of different vegetation coverage on microbial functional diversity in black soil.

MENG Qing-jie^1,2;XU Yan-li¹;LI Chun-jie¹; HAN Xiao-zeng¹;PEI Xi-chao^1,2

2008, 27(07):  1134-1140 . 

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In order to approach the microbial metabolic activity and functional diversity in black soil before and after reclamation, the cropland, grassland, and bare land with 21 years utilization or unreclaimed in the Hailun Agroecological Experimental Station were selected, and Biolog method was adopted to study the seasonal variations of the metabolic activity and functional diversity. The results showed that in spring and summer, the average well color development (AWCD) and the Shannon diversity index of soil microbes were the highest in grassland, followed by in cropland, and in bare land. In cropland and grassland, soil microbial metabolic activity and functional diversity exhibited a trend of high in summer and low in autumn; while in bare land, these two indices raised gradually with seasonal change. In the three lands, the carbon sources with higher utilization efficiency or utilization intensity by soil microbes were carbohydrates, amino acids, and carboxylic acids.

Gradient analysis of urban green space landscape pattern in Shenyang City based on QuickBird image.

TAN Li^1,2;HE Xing-yuan¹;CHEN Wei¹;LI Xiao-yu¹;XU Wen-duo¹;TANG Ling^1,2

2008, 27(07):  1141-1148 . 

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Based on the urban green space distribution map interpreted by 2006 QuickBird image of Shenyang and under the support of GIS, 5 km was taken as the appropriate spatial extent for urban landscape pattern analysis based on the effects of spatial extent, and the gradient analysis in combination with landscape metrics was made to study the landscape structure and its spatial characters along the transect of urban green space in Shenyang City. The results showed that at class level, different types of urban green space across this transect had obvious gradient characters. The dominant landscape type in urban center was public park, while that in rural region was agricultural land. The urban green space had high fragmentation, and patch shape was complex. At landscape level, the landscape metrics along this transect had different variation patterns. It was suggested that urbanization induced landscape fragmentation and heterogeneity. The patch density, landscape shape index, and landscape aggregation index had significant gradient characteristics, while the largest patch index and Shannon’s diversity index were in adverse. It was also suggested that gradient analysis in combination with landscape metrics would be a robust tool to study the spatial pattern of urban green space.

Landscape change and its spatial heterogeneity in Yellow River Delta based on boundary characteristics.

YANG Min;LIU Shi-liang;SUN Tao;CUI Bao-shan;ZHAO Xin-sheng

2008, 27(07):  1149-1155 . 

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Taking Yellow River Delta as study area, the landscape element information of August 24, 1992 and August 9, 2001 were extracted by supervised classification, and the boundary characteristics of various elements were acquired by using 2×2pixel boxes skimming over the landscape map. The landscape indices such as diversity, evenness, heterogeneity, and spatial complexity were calculated based on boundary number and cumulative length, and, considering of the spatial distribution and gradient change of various landscape elements, the landscape components heterogeneity of farmland and Tamarix chinensis-Phragmites communis were analyzed by using information entropy and lacunarity index methods. The results indicated that in study period, the boundary characteristics were more complicated, reflecting the transformation from farmland to T. chinensis-P. communis as a result of town expansion, oil exploitation, and water break off in the Yellow River. Compared with those based on element area proportions, the landscape indices based on boundary characteristics could give more detailed information on landscape structure. In 1992-2001, the spatial distribution of farmland and T. chinensis-P. communis in study area showed macroscopic heterogeneity, while partly microscopic heterogeneity at smaller scales. The heterogeneity scale of T. chinensis-P. communis was 50-pixel smaller than that of farmland, and the scale gap between them enlarged with time. Information entropy and lacunarity index methods, especially used together, could well indicate the landscape heterogeneity.

Heterogeneity of landscape pattern with elevation in karst area.

ZHANG Ming-yang^1,2，3;WANG Ke-lin^1，3; LIU Hui-yu⁴;CHEN Hong-song^1，3

2008, 27(07):  1156-1160 . 

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Karst area is a typical ecologically fragile region where the economy development is restricted by ecoenvironmental problems. In this paper, based on the remote images and elevation data, the heterogeneity of landscape pattern with elevation in karst area in Huanjiang of Guangxi Province in 2000 was studied by using Erdas, ArcGIS and Fragstats programs. The results showed that in Huanjiang County, foothill and hill were the main geomorphic types, and woodland and shrub land were the main landscape types. Anthropogenic landscape types mainly lied in lowaltitude zones, while natural landscape types mainly distributed in highaltitude zones. Landscape patterns were evidently affected by elevation and human activities. In low-attitude zones with frequent human activities, landscape was highly fragmented, diverse, and complex; while in highattitude zones with less human activities, landscape was lowly fragmented, simplex, and simple. Because foothill was the ecotone among upland, woodland, shrub land and rural residence, its landscape pattern was complex and fugitive, being the most complex elevation zone.

Characteristics of soil scarab communities in central region of Inner Mongolia.

LIU Xin-min

2008, 27(07):  1161-1166 . 

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By the methods of soil sampling and bait trap, the characteristics of soil scarab communities in seven different habitats in central region of Inner Mongolia were studied in 2003-2004. Community coefficient, Euclidean distance, percent similarity index, and factor analysis were used to analyze the similarity of the communities. A total of 101788 soil scarabs belonging to 7 families, 22 genus and 59 species were captured, among which, shytophagous scarabs were of 3 families, 12 genus and 18 species and dominated by Melolonthidae and Rutelidae, and coprophagous and saprophagous scarabs were of 4 families, 10 genus and 41 species and dominated by Scarabidae, Aphodiidae and Geotrupidae. Clustering analysis on the community similarity showed that the result from factor analysis was reasonable. The soil scarab communities in the seven habitats could be divided into two groups by the ordering result of factor analysis, one was composed by the communities of typical steppe, meadow steppe, desert steppe, and sandy land, and the other was composed by those of farmland, abandoned farmland, and artificial woodland.

Behavior and activity rhythm of flower-visiting insects on Chrysanthemum morifolium in Nanjing suburb.

WANG Wei^1，2;LIU Yong¹;CHEN Fa-di²;DAI Hua-guo¹

2008, 27(07):  1167-1172 . 

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The species and visiting behavior of flowervisiting insects on Chrysanthemum morifolium- were investigated during flowering period in Chrysanthemum Germplasm Resource Preserving Center of China. There were 32 flowering-visiting species of C. morifolium, belonging to Hymenoptera, Lepidoptera, Diptera, and Hemiptera. The species of flowervisiting insects differed-among- different months, and the morphology, flower-visiting motive, and flower-visiting behavior of the insects also differed with their species. Apis mellifera was the main pollinator, which had a large population and an average visiting frequency of 16 flowers per minute. On sunny days, the visiting frequency of A. melliferaand Vanessa indica was significantly positively correlated with temperature (r=0.876 and 0.887, respectively); while temperature sudden dropping, cloud, and rain had definite effects on the species number and individual quantity of flowervisiting insects. Field observation further showed that at different time in the same day, the visiting frequency of flowervisiting insects to C. morifolium inflorescences was different, with the highest from 11:00 to 13:00.

Effects of cadmium stress on expression of mismatch repair gene in Arabidopsis thaliana seedlings.

ZHANG Qiao-li;LIU Wan;LI Pei-jun;HAN Yan-ping

2008, 27(07):  1173-1180 . 

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Using semiquantitative reverse transcriptionpolymerase chain reaction (RT-PCR), the effects of cadmium (Cd) stress on the mismatch repair and proliferating cell nuclear antigen gene expression of Arabidopsis thalianaseedlings were studied and linked to the morphological and physiological indices of A. thaliana seedlings, aimed to choose the biomarkers sensitive to Cd stress. The results indicated that under Cd stress, no significant changes were observed in leaf number and shoot fresh mass of A. thaliana eedlings. The total soluble protein content of the shoots increased significantly when exposed to 0.25 mg Cd·L^-1 (P<0.05) but decreased significantly at 0.5 and 1.0 mg Cd·L^-1 (P<0.05), while the chlorophyll content had a slight increase with increasing Cd concentration (P>0.05). Using 18S rRNA as the internal standard, the expression of PCNA1, PCNA2, MSH2, MSH3, MSH6 and MSH7 genes in shoots was significantly induced at 0.25 mg Cd·L^-1. When the Cd concentration increased to 1.0 mg·L^-1, the expression of the genes was still induced, except that MSH6 was persistently induced and MSH3 was repressed compared with the control, but the expression was lower than that at 0.5 mg·L^-1of Cd. The above results suggested that specific gene expression could serve as the potential and useful biomarker for the detection of genotoxic effects of Cd pollution on plants.

Effects of applying organic acids on Cd and Cu accumulation and physiological characteristics of Iris pseudacorus L.

HUANG Su-zhen;YUAN Hai-yan;SUN Yan-dong;HAN Yu-lin

2008, 27(07):  1181-1186 . 

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Applying organic acids to improve the efficiency of phytoremediation becomes an effective approach for the remedy of heavy metals contaminated soils and waters. By the method of hydroponic culture, this paper studied the effects of EDTA and citric acid on the Cd and Cu accumulation and physiological characteristics of Iris pseudacorus L. under Cd and Cu stresses. The results showed that EDTA and citric acid promoted the absorption of Cd and Cu by I. pseudacorus, and enhanced the translocation of these two heavy metals from plant root to shoot. Citric acid had a higher promotion effect on the Cd absorption than EDTA, while EDTA promoted more Cu adsorption than citric acid. Different concentrations of EDTA and citric acid had different effects on the growth and physiological characteristics of I. pseudacorus, e.g., 5 mmol·L^-1 of EDTA and 0.5 and 5 mmol·L^-1 of citric acid decreased the dry mass of I. pseudacorus to a certain extent and increased the malondialdehyde (MDA) content significantly, while 0.5 mmol·L^-1 of EDTA not only increased the Cd and Cu accumulation and decreased the lipid peroxidation of I. pseudacorus, but also played an active role in the plant growth.

Dynamic evaluation on ecosystem service value of Chongqing City.

DU Jia-qiang^1,2;WANG Jin-sheng^1,2;TENG Yan-guo^1,2;ZHANG Tong³

2008, 27(07):  1187-1192 . 

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To study the dynamic change of ecosystem service value is of significance in regional ecoenvironmental protection and restoration. In this paper, Costanza’s and Xie’s methods were adopted to evaluate the ecosystem service value (ESV) of Chongqing City from 1997 to 2005. Two price systems, i.e., 2000 constant price and current price, were adopted in the coefficient computations of Chinese terrestrial ecosystem service value per unit area. According to our results, the ESV of Chongqing had an increasing trend, while the ESV/GDP ratio was in adverse. A gray system model was built to predict the ESV and GDP from 2006 to 2010, and the prediction showed that in these 5 years, the ESV would continue increasing while the ESV/GDP would continue decreasing. There were significant differences among the results calculated from Costanza’s method and from Xie’s method with 2000 constant price and current price, indicating the low comparability of the three methods, which was due to the different aspects emphasized in each situation. By adopting Costanza’s method, the influence of land use change on ESV was mainly reflected; by adopting Xie’s 2000 constant price method, the influence of biomass variation on ESV was reflected as well; while adopting Xie’s current price method, besides the influences of land use change and biomass variation on ESV, the people’s willingness to pay for ESV was also partially reflected.

Spatiotemporal characteristics and diffusion flux of partial pressure of dissolved carbon dioxide (pCO₂) in Hongjiadu reservoir.

YU Yuan-xiu^1,3;LIU Cong-qiang¹;WANG Fu-shun²;WANG Bao-li¹;WANG Shi-lu¹;LIU Fang¹

2008, 27(07):  1193-1199 . 

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In order to understand the characteristics of greenhouse gases emission from artificial reservoirs, the distribution characteristics of partial pressure of dissolved carbon dioxide (pCO₂) in inflow waters, outflow waters, and the waters in Hongjiadu reservoir, a newly-built reservoir located in Guizhou Province of Southwest China, were analyzed in April, July and October 2006 and January 2007. The results showed that the pCO₂ value in inflow waters was spring <summer<autumn<winter, and the annual average pCO₂ in the inflow waters from Liuchong river and Washui river was 488 and 624 μatm, respectively. The pCO₂ in reservoir epilimnion reached to the highest value (925 μatm) in winter and the lowest (279 μatm) in spring, with the annual average of 598 μatm. The pCO₂ in water column increased with water depth. In the outflow waters, pCO₂ was the highest (8 417 μatm) in summer and the lowest in winter (382 μatm), with the annual average value of 3 260 μatm. The annual average pCO₂ in inflow waters, reservoir epilimnion, and outflow waters was higher than that of air (380 μatm pCO₂), and the diffusion flux of CO₂ at waterair interface was 3.93-6.29, 4.87-7.79 and 64.29-102.86 mmol·m^-2·d^-1, respectively, showing that the reservoir should be a CO₂ source of the atmosphere. Through the action of the reservoir, the diffusion flux of CO₂ was enhanced, with the pCO₂ in outflow waters being 16 and 13 folds of that in inflow waters and reservoir epilimnion, respectively. Accordingly, much attention should be paid on the CO₂ emission from the outflow waters of the reservoir.

Ecological sanitation development in China: Potential, challenges and strategies.

WANG Ru-song;ZHOU Chuan-bin

2008, 27(07):  1200-1206 . 

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Based on the framework of the structure and function of socialeconomicnatural complex ecosystem, and with the focus on the rural sanitation system of China, the current status of China rural sanitation was analyzed. Six districts for developing ecological sanitation (ecosan) in this country were divided, with the consideration of geographic distribution and socialeconomic status, and four categories of rural sanitation system of the six districts and their population distribution were studied. The districts with the highest potential of developing ecosan were those without basic sanitation and lacking of investment capacity, which carried a population of 468.2 million, and 67.8% of the population was mainly in the middlewest and southwest of China. If the ecosan would be developed there, new industries could be promoted and 50-100 thousands of employing opportunities could be created, incidence rate of diseases could be reduced, 560 thousand cubic meters of methane could be recycled, investment of sanitary toilet could be reduced to an acceptable price, i.e., 600-750 RMB yuan per house, ecological agriculture could be developed, and pollutants discharge could be reduced while ecological security could be guaranteed. The strategy of developing ecosan in each district and the system bottlenecks were also discussed in this paper.

Models of mass exchange in terrestrial ecosystem: A review.

LI Zhi-heng^1,2;ZHANG Yi-ping¹

2008, 27(07):  1207-1215 . 

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Modeling the mass exchange in terrestrial ecosystem is an important aspect and a very promising and irreplaceable instrument in studying the cycles of water, carbon, and nutrients in ecosystems. Numerous models about the mass exchange in terrestrial ecosystem were developed in recent years, and in this paper, they were categorized into: 1) empirical, process, and hybrid models based on the differences in modeling idea; 2) biophysical and biogeochemical models in terms of the mechanisms of mass transfer; 3) single, dual, and multiple models complying with the distinction of vegetation structure; 4) diagnostic and prognostic models according to the differences in application; 5) bottomup and top-down models in the light of logical structure of modeling; 6) ecosystem, landscape, and regional scale models based on the dissimilarity of scale; and 7) photosynthesis and transpiration models depending on plant physiological processes. The merits and shortcomings of the models were analyzed, and the directions in further research were proposed.

Utilization potential of Spartina alterniflora Loisel as a bio-energy source.

QING Hua;YAO Yi-han;LI Hong-li;AN Shu-qing

2008, 27(07):  1216-1220 . 

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As an exotic invasive species, Spartina alterniflora Loisel strongly disturbs the structure and function of native ecosystems, but at the same time, it is also a potential bio-energy source due to its high standing biomass. To develop this bioenergy source is an efficient and useful way in fully utilizing the resource of S. alterniflora while control its crazy expansion, being of both ecological and economic significances. In this paper, the utilization potential of S. alterniflora as a bio-energy source, including the superiority of its biomass resources at both temporal and spatial scales, its highefficient photosynthetic mechanisms and high productivity, its high energy storage and higher contents of carbohydrate, protein and fat, and the unoccupying of crop land, etc., was summarized, and the present situations about the exploitation and utilization of S. alterniflorawere introduced. It was pointed out that the exploitation and utilization of S. alternifloral as a bio-energy source would have a promising prospect.

Measurement methods of soil heterotrophic respiration and key factors affecting the temperature sensitivity of the soil heterotrophic respiration.

FAN Zhi-ping¹;WANG Hong^1,2;DENG Dong-zhou^1,2;SUN Xue-kai¹;GAO Jun-gang^1,2;ZENG De-hui¹

2008, 27(07):  1221-1226 . 

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Soil heterotrophic respiration can indicate the CO₂ efflux from the decomposition of soil organic matter, the major pathway of soil carbon into atmosphere. The difference between soil heterotrophic respiration and ecosystem net primary productivity is crucial to determine whether the ecosystem is a carbon source or sink. In this paper, the operations, merits, and drawbacks of the methods used to measure soil heterotrophic respiration, including those of laboratory incubation (incubation with rootremoval soil or soil core) and in situ investigation (root-exclusive method, stand girdling method, and isotopic method), were introduced. The dependence of soil heterotrophic respiration to temperature has received considerable interest in studying the carbon cycle and its potential feedbacks to climate change. Temperature, soil moisture, and the availability of soil organic carbon are the major factors affecting the temperature sensitivity of soil heterotrophic respiration (Q₁₀). Under normal condition, the Q₁₀ value decreases with the increase of temperature. When the desiccation stress happens or the soil water content is far above the field capacity, the dependence of soil heterotrophic respiration to temperature will be weakened. The availability of soil organic carbon also affects the sensitivity of soil heterotrophic respiration to temperature change. The Q₁₀ decreases with decreasing availability of soil organic carbon. The temperature sensitivity of soil heterotrophic respiration differs when soil organic carbon has different turnover rate, and this respiration has a lower sensitivity to labile organic carbon than to inert organic carbon.

Research progress and prospect on chemical ecology of Monochamus alternatus.

HAO De-jun¹;YANG Jian-xia²;DAI Hua-guo²

2008, 27(07):  1227-1233 . 

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Japanese pine sawyer Monochamus alternatus Hope is a dangerous insect of conifer trees in Asia, and a main vector of pine wood nematode Bursaphelenchus xylophilus, the causal agent of destructive pine wilt disease. In this paper, the research progress on the chemical ecology of M. alternatus was reviewed, aimed to provide a brief overview on the interactions between M. alternatus and host plants, intraspecific interactions of M. alternatus, and interactions between M. alternatus and B. xylophilus. In the interactions between M. alternatus and host plants, the volatile terpenes of host plants play an important role in regulating the feeding and ovipositing ofM. alternatus adults. The compositions of the terpenes and their relative contents have large variations between healthy and damaged host plants, and M. alternatus has a significant sexual bias response to some of the volatiles. In addition to the volatiles, the carbohydrate, amino acid, phytosterol, phospholipids, and flavone in host plants can act as stimulants or repellents to regulate the feeding and ovipositing behaviors of M. alternatus. Sex pheromone is hypothesized in the forms of contact pheromone and short or longrange sex pheromones that initiate the reproductive behaviors such as attraction, courtship, mounting, and copulation, etc. The ovipositiondeterring pheromone originated from female reproductive gland or hindgut can deter gravid females ovipositing on oviposition scars occupied by eggs or larvae, which is confirmed to be helpful in spacing eggs and reducing the mortality in early larval stages due to conspecific competition. Chemicals such as monoterpenoids, CO₂, and unsaturated fatty acid produced by host plants, sawyer beetle, and pine wood nematode could be the basis of chemoecological relationship between pine wood nematodes and their vector insects. These chemicals control the behaviors of nematode’s assembly to pupae chamber, and its entering in or divorced from insect body. Future research directions on the chemical ecology of the M. alternatus were also discussed.

Allelopathic potential of invasive alien weed Sorghum halepense (L.) Pers.

HUANG Hong-juan;ZHANG Chao-xian;MENG Qing-hui;WEI Shou-hui;LIU Yan; CUI Hai-lan

2008, 27(07):  1234-1237 . 

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The allelopathic potential of invasive alien weed Sorghum halepense（L.） Pers. (Johnsongrass) to wheat, maize and cotton was investigated by the laboratory tests of seed germination and seedling growth. The results demonstrated that S. halepensecould inhibit the seed germination and seedling growth of the three crops. The allelopathic potential of S. halepense increased with its concentration, but decreased with time. At 0.1 g·ml^-1 of S. halepense, the seed germination rate of wheat was decreased from 404% on the 3rd day to zero on the 20th day, and the seedling growth of the three crops was inhibited on the 3rd or 10th day but not affected on the 20th day. The allelopathic potential of S. halepense could be one of the reasons of its successful invasion.

Theoretical model of Ochotona curzoniae control via contraception.

LIU Han-wu^1,2;ZHOU Li¹;LIU Wei¹;ZHOU Hua-kun¹

2008, 27(07):  1238-1243 . 

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The proliferation of plateau pika (Ochotona curzonia) aggravates the degradation of alpine meadow, and rodenticides are commonly used to annihilate plateau pika. However, the poisoning program can only transitorily reduce the abundance of plateau pika, and the remnant population can recover rapidly. Therefore, to control plateau pika via contraception is considered. This paper discussed in theory how contraception control affects the population of plateau pika. Mathematical models of plateau pika with sexual structure were formulated to assess the effects of two sexes’ contraception rates on the dynamics of plateau pika population, and to clarify the difference between contraception control and lethal control. It was indicated that contraception control would have better effects than lethal control on eliminating or depressing plateau pika population. In contraception control, the contraception rate of female is more important, and thus, more attention should be paid to it.

Health-oriented optimal selection method for ecological restoration scenarios of urban water system.

ZHAO Yan-wei¹;ZENG Yong²;YANG Zhi-feng¹;LIU Jing-ling¹

2008, 27(07):  1244-1248 . 

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Ecosystem health is one of the objectives of water body’s ecological restoration, while the current health idea based on river reach scale cannot provide clear guidance for the ecological restoration of urban water system, and the shortage of optimal selection method for restoration scenarios is very serious. In this paper, the connotation of urban water system health was identified as embracing water quantity, water quality, and aquatic health with spatial and temporal homogeneity. Based on this health idea, the technical procedure of the optimal selection for the ecological restoration scenarios of urban water system was put forward, and the related indicator system was established, covering the average satisfying degree and the temporal and spatial standard deviations of ecological water demand, water quality, and aquatic ecosystem. The flexible and quick optimal selection of restoration scenarios could be realized by using the technique for order preference by similarity to ideal solution (TOPSIS).

Assessment of urban ecological security based on entropy-weighted gray correlation analysis.

ZHANG Feng-tai¹;SU Wei-ci^1,2;ZHOU Ji-xia¹

2008, 27(07):  1249-1254 . 

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An assessment indicator system of regional ecological security was set up based on Pressure-State-Response Model. Entropy was used to determine the weights of assessment indicators, which avoided the uncertainty in estimating the weights subjectively. The standards of security assessment indictors were established, the correlation degree of ecological security in Chongqing was calculated by gray correlation analysis, and then, an assessment of Chongqing urban ecological security was made. The assessment result of the urban ecological security by the method of entropy-weighted gray correlation analysis was identical with actual situation, suggesting that this method offered a new means to quantitatively assess regional ecological security and had certain practical value and popularization meaning.