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    10 August 2012, Volume 31 Issue 08
    Articles
    Effects of simulated rainfall on the soil respiration in tropical secondary forest and rubber plantation in Xishuangbanna of Yunnan, Southwest China.
    DONG Li-yuan1,3, WU Chuan-sheng1,2, GAO Jian-mei1,3, SHA Li-qing1,2**
    2012, 31(08):  1887-1892. 
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    Rainfall has important effects on soil respiration. To understand the relationship between rainfall and soil respiration is of significance in accurately estimating carbon flux. In this paper, an in situ observation was conducted in a tropical secondary forest and a rubber plantation in Xishuangbanna of Yunnan to measure the soil respiration rate and the soil temperature and moisture content at the depth 5 cm after a simulated rainfall, aimed to understand the responses of the soil respiration, soil temperature, and soil moisture content under the two main vegetation types to the simulated rainfall. Under the condition of one week norainfall in dry season, the soil respiration was rapidly stimulated 2 hours after the rainfall, with the maximum soil respiration rate in the secondary forest rubber plantation reached 11.15 and 15.88 μmol CO2·m-2·s-1, being 7 and 11 times greater than that of the control, respectively. This effect decreased through time, particularly in rubber plantation where the difference with the control was not significant 6 hours after the rainfall. Two days after the simulated rainfall, the soil moisture contents in the tropical secondary forest and rubber plantation were significantly higher than the control, but the soil temperature had less difference. This study supported the “Birch effect”, and showed that due to the rainfall event, the CO2 release from the two major tropical forest types in dry season was increased several folds.
    Effects of replacement control with forage species on the biomass allocation and photosynthetic characteristics of Flaveria bidentis.
    JIANG Na1, HUANGFU Chao-he1, WANG Nan-nan1, CHEN Dong-qing1, TU Chen-yang1, YANG Dian-lin1**, WANG Cai-ling2
    2012, 31(08):  1903-1910. 
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    Two native forage species (Sorghum bicolor × Sorghum sudanense and Astragalus adsurgens) were chosen to replace and control the exotic invasive plant Flaveria bidentis, and a field experiment was conducted to examine the effect of the replacement control with the two forage species on the growth and physiological characteristics of F. bidentis. The replacement control suppressed the growth and reproduction of F. bidentis effectively. Compared with that of monoculture F. bidentis, the total biomass of F. bidentis mixed cultured with A. adsurgens and S. bicolor × S. sudanense was decreased by 90.2% and 94.2%, respectively. Except for leaf biomass ratio, all the other biomass indices of F. bidentis in the replacement treatments decreased by more than 90%. The flower mass ratio of F. bidentis decreased significantly in A. adsurgens replacement treatment but increased in S. bicolor × S. sudanense replacement treatment. In the two replacement treatments, the net photosynthetic (Pn), stomatal conductance (Gs), transpiration rate (Tr), water use efficiency (WUE), and chlorophyll content of F. bidentis all had a significant decrease, and the Pn of F. bidentis in S. icolor × S. sudanense treatment was only 2.15 μmol CO2·m-2·s-1. The results revealed that under the replacement control with the forage species, insufficient light supply limited the carbon assimilation of F. bidentis. Plasticity analysis showed that F. bidentis had higher phenotypic plasticity, and the phenotypic index of flower mass ratio reached up to 0.91, indicating the high invasive potential of the invasive plant. It was suggested that field replacement control could realize a win-win situation of economic value and ecological benefits.
    Genetic diversity of different lifestage population of Glyptostrobus pensilis, an endangered plant in China: ISSR analysis.
    WU Ze-yan1,2, LIU Jin-fu2**, HONG Wei2, PAN Dong-ming3, ZHENG Shi-qun2, HE Zhong-sheny2
    2012, 31(08):  1911-1916. 
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    Glyptostrobus pensilis is a rare and endangered species in China, but few studies have been made on the conservation genetics of this species. In this study, the G. pensilis population in Pingnan of Fujian Province, East China was divided into 3 life stages, i.e., adult, juvenile, and seedling, according to the size class, and the genetic diversity and genetic differentiation of different life stage G. pensilis were investigated by using intersimple sequence repeat (ISSR) markers. Ten ISSR primers were used to amplify 72 individuals in the population, and 83 discernible DNA fragments were produced, of which, 32 were polymorphic loci (the percentage of polymorphic loci (P) = 38.55%), suggesting the low level genetic diversity of the population. The difference of the genetic diversity among the life stages was evident. Adult had the highest P, Nei’s gene index (He), and Shannon information index (I), followed by juvenile, and seedling, suggesting that the genetic diversity among the life stages presented a declining trend. The analysis of molecular variance (AMOVA) showed that the genetic diversity might exist within and among the life stages, mainly within the life stages. Moreover, the genetic differential index (Gst) among the life stages was 0.2872, while the gene flow (Nm) was 0.6203. The genetic identity between seedlings and juveniles was the highest. Based on the analysis of population genetic structure and the community investigation, it would be necessary to establish a conservation site in the optimal habitat of G. pensilis and to crosstransplant adult plants and seedlings mutually to enhance the gene flow. By this means, the genetic diversity resources of the species could be preserved to the greatest extent.
    Niche characteristics of main plant populations in natural Pinus tabulaeformis communities in Qinling Mountains, Northwest China.
    CHAI Zong-zheng, WANG De-xiang**, ZHANG Li-nan, ZHANG Yang, HUANG Qing-ping, WU Hao
    2012, 31(08):  1917-1923. 
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    By using Levins and Hurlbert formulae of niche breadth and Pianka formula of niche overlap, this paper analyzed the niche characteristics of 20 trees and 26 shrub populations in natural Pinus tabulaeformis communities in Qinling Mountains. In canopy layer, P. tabulaeformis, Quercus aliena var. acutiserrata, P. armandii, and Toxicodendron vernicifluum were the dominant populations; in shrub layer, the dominant populations were Corylus heterophylla, Euonymus alatus, Lonicera japonica, and Viburnum dilatatum. The dominant populations in canopy layer had the largest niche breadth, and were the main body of the communities; while the V. dilatatum, Elaeagnus pungens, E. alatus, and C. heterophylla in shrub layer had a larger niche breadth than the other populations. In canopy layer, there was a lower niche overlap between the dominant populations, but the Populus purdomiiDendrobenthamia anguwstata, Rhus chinensisPopulus davidiana, and Populus simoniiBetula platyphylla had a higher niche overlap. In shrub layer, more dominant populations appeared niche overlap, and E. alatus-E. schensianus, Spiraea salicifoliaLonicera japonica, Cotinus coggygria var. glaucophylla-Smilax scobinicaulis, and Rhododendron lapponicum-Salix cathayana showed a larger niche overlap. The dominant populations in the communities had a larger niche breadth and a higher niche overlap with other populations, but no positive correlation was observed between the niche breadth and niche overlap.
    Windbreak effect of Sonneratia apetala-S. caseolaris mangrove.
    YANG Huai1, CHEN Ren-li1, WANG Xu2,3,4**,ZHU Zheng2,ZHOU Guang-yi1, LIAO Bao-wen1
    2012, 31(08):  1924-1929. 
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    In order to understand the windbreak function of mangrove during tropical storm (typhoon), an observation with automatic weather station was conducted on the windbreak effect of Sonneratia apetalaS. caseolaris artificial mangrove in Dongzhaigang of Hainan Province, South China during the lashing period of tropical storm “Francisco” in 2007 (from 0:00 to 15:00, September 24, 2007). The mean value of the wind speed observed at various sites was lower at 1H (average tree height) distance of the forest back than at 1H distance of the forest front, and the wind speed behind the forest decreased significantly, indicating a noticeable windbreak service of the forest. The windbreak effect during the lashing period of tropical storm was 28%-68%, being less than that (65%-77%) under nontropical storm circumstances and decreased as wind speed increased. During the tropical storm, the prevailing wind direction was 45 degree. When the wind direction was nearly vertical to the forest, the damping effect on wind speed was much better. In sum, the windbreak performance of the S. apetala-S. caseolaris artificial mangrove was obvious during tropical storm.  
    Carbon storage of main tree species  plantations for water resources conservation in upper reaches of Huangpu River, Shanghai.
    WANG Zhe1, 4, HAN Yu-jie2, KANG Hong-zhang1,4, HUANG Dan2, XUE Chun-yan2, YIN Shan3,4, LIU Chun-jiang1,3,4**
    2012, 31(08):  1930-1935. 
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    To investigate the carbon storage and its distribution in forest ecosystem is essential for assessing the ecosystem services and managing carbonsink forest at local and regional scales. Elaeocarpus sylvestris, Cinnamomum camphora, Koelreuteria integrifolia, and Liriodendron chinense are the main tree species in the plantations for water resources conservation in upper reaches of Huangpu River, Shanghai. In this study, the biomass equations for these tree species were established, and the carbon storage of tree biomass, forest floor, and soil (0-40 cm) in these 9 year-old stands were estimated. There was a good relationship between the individual tree biomass and the diameter at breast height for these tree species, with the coefficient of determination (R2) >0.9. The total carbon storage in the four tree stands were 117.32, 127.38, 105.87, and 80.93 t·hm-2, among which, tree biomass carbon accounted for 35.1%, 44.6%, 352%, and 19.0%, forest floor carbon accounted for 1.2%, 1.9%, 1.2%, and 0.6%, and soil carbon accounted for 63.7%, 53.5%, 63.6%, and 80.4%, respectively, which indicated that these young plantations were at fast-growing stage, with a great potential of carbon sequestration.
    Structural diversity of Elaeagnus mollis communities.
    ZHANG Yin-bo1, ZHANG Feng2**
    2012, 31(08):  1936-1941. 
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    It is generally accepted that the research of structural diversity of communities can provide scientific basis for monitoring, conservation, and sustainable utilization of biodiversity in more efficient way. In this paper, both extended Shannon index and the structure index based on variance (STVI) were adopted to study the structural diversity of Elaeagnus mollis communities in Shanxi Province, China. The two indices showed a relatively consistent development trend, and thus, could comprehensively reflect the differences in the structural diversity of the communities. Community type, species composition, spatial structure, habitat condition, environmental feature, and human disturbance intensity were the main factors affecting the structural diversity. As compared to extended Shannon index, STVI index minimized the subjectivity in categorizing with diameter and height, and could better describe a wider array of structure, being more available in quantitatively analyzing the structural diversity of communities.
    Interspecific relationship of woody plants in Quercus wutaishanica community in Wulu Mountain Nature Reserve, Shanxi Province of China: A quantitative analysis.
    BAI Yu-hong, BI Rui-cheng**, ZHANG Qin-di
    2012, 31(08):  1942-1948. 
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    Based on 2 × 2 contingency table, and by using quantitative analysis methods, this paper studied the interspecific relationship among 351 species pairs of 27 dominant woody species in Quercus wutaishanica community in Wulu Mountain Nature Reserve. Variance analysis showed that the interspecific correlation of the 27 dominant populations was not significant, and the distribution of the species was relatively independent. The χ2 test showed that among the 351 species pairs, 154 pairs were positively while 188 pairs were negatively correlated, and the correlation ratio was 0.82. Pearson’s correlation coefficient test showed that 124 pairs were positively while 226 pairs were negatively correlated, and the correlation ratio was 0.55. Spearman’s rank correlation coefficient test showed that 151 pairs were positively while 200 pairs were negatively correlated, and the correlation ratio was 0.76. Compared with χ2 test, the Pearson’s correlation coefficient and Spearman’s rank correlation coefficient tests had higher sensitivity. For vast majority of the 351 species pairs, their interspecific relationship did not reach significant level, indicating that the Q. wutaishanica community in Wulu Mountain Nature Reserve was of obviously secondary succession. According to the adaptation to the environment and the leading ecological factors, and assisting with principal components analysis, the 27 dominant populations were divided into three ecological species groups.
    Effects of CO2 concentration on the quantum yield in the vicinity of plant light compensation point.
    YE Zi-piao1,2, KANG Hua-jing3,4
    2012, 31(08):  1949-1953. 
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    By using a modified model of lightresponse curve of plant photosynthesis, this paper studied the effects of different concentration CO2 (380 and 600 umol·mol-1) on the variations of quantum yield in the vicinity of light compensation point and the Kok effect of Koelreuteria paniculata  and Capsicum annuum L. The modified model fitted well the lightresponse curves of the photosynthesis of K. paniculata and C. annuum at 380 and 600 umol·mol-1 of CO2, and the photosynthetic parameters estimated by the modified model were in very close agreement with the measured data. The initial slope of the curve (φ0) was greater than the quantum yield in the light compensation point of K. paniculata and C. annuum, and the quantum yield in the vicinity of the light compensation point was not a constant, and did not relate with dark respiration rate. Moreover, C. annuum at 380 and 600 umol·mol-1 of CO2 did not exist Kok effect. CO2 concentration affected the Kok effect of K. paniculata but less affected the Kok effect of C. annuum. It was considered that the variation of the quantum yield in the vicinity of light compensation point of K. paniculata was come from the nonlinear response of the net photosynthesis rate to irradiance, but the Kok effect was not existed for C. annuum.
    Influence of long-term weak light on the growth and development of Vallisneria natans seedlings.
    XIE Yun-cheng1, LI Qiang1**, WANG Guo-xiang2
    2012, 31(08):  1954-1960. 
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    By the method of shading, this paper studied the influence of weak light (5%, 1%, 0.5%, and 0.1% of full sunlight) on the growth and development of Vallisneria natans seedlings, with the biological variables and leaf chlorophyll fluorescence parameters measured. Under 0.1% of full sunlight, no new plants germinated; under 5%, 1%, and 0.5% of full sunlight, new plants germination was gradually inhibited with experimental time. With the increasing experimental time and the decreasing light intensity, the formation of new leaves of old plants was increasingly restrained. Meanwhile, the formation of new leaves of new plants was not restrained before the 20th day of the experiment but restrained significantly in the following days. The leaf width of both new and old plants under weak light was inhibited significantly. The leaf elongation of old plants under weak light was inhibited significantly, and the inhibition rate increased with decreasing light intensity. The leaf elongation of new plants was promoted before the 20th day of the experiment, but inhibited significantly with increasing experimental time. The leaf maximum quantum yield (Fv/Fm) of old plants decreased significantly with experimental time, and the relative electron transport rate (rETR) and nonphotochemical quenching (NPQ) decreased markedly on the 80th day of the experiment. The fresh weights of the roots, stems, and leaves of new plants and old plants under weak light were much lower than those under full light, and, with decreasing light intensity, the fresh weight ratio of stems to plants and that of roots to plants had an increasing trend, while the fresh weight ratio of leaves to plants decreased significantly. On the 80th day of the experiment, the plants still had photosynthetic capability, and the biomass of rhizome was higher than those of leaves and roots. This study showed that Vallisneria natans had stronger tolerance against ≤1% of full light.
    Effects of superabsorbent polymer composites on tree seedling’s growth.
    WANG Wen-jing, WANG Bai-tian**, LU Zhao, LI Zhen, CAO Xiao-yang, CHI Lu
    2012, 31(08):  1961-1967. 
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    To explore the effects of superabsorbent polymer composites (SAPCs) on tree seedling’s growth, a pot experiment with orthogonal design was conducted, using 2-year oldJuglans regia, Prunus armeniaca, Robinia pseudoacacia, and Populus sp. as test objects, and taking leaf area and new shoot height as the growth indicators. The SAPCs were composed of different proportions of superabsorbent polymer, polyaspartic acid, and compound fertilizer. All the test SAPCs promoted the seedling growth, and the promotion effect increased with increasing application dosage. The best proportions of the SAPCs for the seedlings were 20 g superabsorbent polymer, 1.5 g polyaspartic acid, and 15 g compound fertilizer (soil moisture content was 12%) for J. regia, 15 g superabsorbent polymer, 0.5 g polyaspartic acid, and 0 g compound fertilizer (soil moisture content was 12%) for P. armeniaca, 15 g superabsorbent polymer, 0 g polyaspartic acid, and 15 g compound fertilizer (soil water content was 7%) for R. pseudoacacia, and 20 g superabsorbent polymer, 1.0 g polyaspartic acid, and 0 g compound fertilizer (soil moisture content was 7%) for Populus. As compared with the control, the leaf area and new shoot height of the poplar seedlings under the application of the SAPC were increased by 48% and 21%, respectively.
    Responses of winter wheat antioxidant enzymes to the rhythmical and non-rhythmical changes of diurnal temperature in winter.
    ZHOU Rui-lian**, WANG Yan-jie, ZHU Lu-ying, WANG Ai-lan, ZUO Jing-cheng
    2012, 31(08):  1968-1976. 
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    After 30 days growing in greenhouse and field in winter, the winter wheat (Triticum aestivum) plants were exposed to naturally rhythmical change of diurnal temperature and to extremely high or low temperature, with the dynamic changes in the leaf antioxidant enzyme activities and osmoregulation substance contents analyzed, aimed to understand the physiological mechanisms of winter wheat to adapt freezethaw stress. The plants from the greenhouse (average temperature 11 ℃) at jointing stage and from the field (average temperature 1 ℃) at tillering stage all had the same patterns of leaf antioxidant enzyme activities and proline content in response to naturally rhythmical diurnal temperature change, i.e., increased with sunrise, peaked at 13:00, and decreased with sunset. When the plants from the field were exposed to high temperature (18 ℃) for 2 days, the leaf antioxidant enzyme activities and proline content increased, but it was in adverse when the plants were exposed to low temperature (-2.5 ℃). After freezethaw stress, the plants grew well. When the plants from the greenhouse were shortly exposed to -6 ℃, the leaves were frozen, their antioxidant enzyme activities and proline content decreased, but increased after exposure to 18 ℃. After short exposure to freezethaw stress, the plants from the greenhouse died. However, the plants from the field had lower net photosynthesis rate (Pn) but higher activities of antioxidant enzymes than those from the greenhouse. It was suggested that the rapid responses of the leaf antioxidant enzyme system and proline to the diurnal temperature and light intensity to scavenge oxygen freeradical and keep water balance in cell would play important role in the adaptation of winter wheat to diurnal freezethaw stress, and the higher Pn and lower antioxidant enzyme activities in the leaves of winter wheat growing in warming winter could be the reason why winter wheat died in late spring cold of next year.
    Effects of climate warming on the northern distribution boundary of brown planthopper (Nilaparvata lugens(Stl)) overwintering in China.
    LU Xiao-feng1,2, HUO Zhi-guo2**, SHEN Shuang-he1, HUANG Da-peng2, WANG Li2, XIAO Jing-jing3, YU Cai-xia2
    2012, 31(08):  1977-1983. 
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    Based on GIS technology, and by using the meteorological data from 289 meteorological stations as well as the historical overwintering data of brown planthopper (BPH) in southern China in 1951-2010, this paper chose the January isotherm of 10 ℃ as the optimal index to identify the northern distribution boundary of BPH overwintering in China. The optimal index was selected from the indices in previous researches by the verification of the actual overwintering data of BPH in typical years, and then, the interdecadal variation and inter30year variation of the northern distribution boundary in the past 60 years were analyzed. The results show that under the background of climate warming, due to the increase of the frequency of warm winter years, the average northern distribution boundary of BPH overwintering in southern China moved northward. Compared with that in cool winter years, the northern boundary in warm winter years moved northward by about 2-3 degrees in latitude. The average distribution boundary in the 1980s moved northward most obviously in decades, and that in 1981-2010 moved northward significantly, as compared with that in 1951-1980. The significant north-moving occurred in the central part of Yunnan Province and the southern part of Fujian Province, and the maximum distance of the north-moving in Yunnan Province in the past 60 years was about 90 km.
    Toxicological effect of paraquat and glyphosate on cladoceran Moina macrocopa.
    LIU Xiao-wei, XI Yi-long**
    2012, 31(08):  1984-1989. 
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    This paper examined the acute toxicities of glyphosate and paraquat to Moina macrocopa, and studied the effects of the sub-lethal concentrations of paraquat (0, 0.01, and 0.04 mg·L-1) and glyphosate (0, 0.4, and 1.6 mg·L-1) on the lifetable demography of this cladoceran. The 48 h LC50 values of glyphosate and paraquat to M. macrocopa were 0.626 mg·L-1 and 26.287 mg·L-1, respectively. Paraquat concentration had significant effects on the life expectancy at birth, generation time, net reproductive rate, and intrinsic rate of population increase (P<0.01), and glyphosate concentration affected the life expectancy at birth, generation time, and intrinsic rate of population increase significantly (P<0.01). The interaction between the two herbicides had significant effects on the generation time and intrinsic rate of population increase of M. macrocopa (P<0.01). Multiple comparisons indicated that regardless of the effect of glyphosate, the paraquat at 0.01 mg·L-1 had significant effect on the increase of the life expectancy at birth, but the reverse was also true for the paraquat at 0.04 mg·L-1. The paraquat at 0.04 mg·L-1 decreased the net reproductive rate of M. macrocopa significantly. Regardless of the effect of paraquat,
     the glyphosate at 0.4 and 1.6 mg·L-1 decreased the life expectancy at birth significantly. Compared with the blank control, the mixture of paraquat at 0.01 mg·L-1 and glyphosate at 1.6 mg·L-1 increased the generation time significantly, but the mixture of paraquat at 0.04 mg·L-1 and glyphosate at 0, 0.4, and 1.6 mg·L-1 decreased the generation time and the intrinsic rate of population increase. With the increase of glyphosate concentration, the toxicity of paraquat at 0.04 mg·L-1 to M. macrocopa decreased significantly, suggesting a significant antagonism existed between paraquat and glyphosate.
    Spatiotemporal variation of zoobenthos community and bio-assessment of water quality in Gehu Lake.
    WANG Li-qing1, WU Liang1, ZHANG Rui-lei1**, ZHANG Yi-min2
    2012, 31(08):  1990-1996. 
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    From May 2009 to February 2010, an investigation was conducted on the zoobenthos community in Gehu Lake, and the water quality of the Lake was assessed based on the structure of the zoobenthos community. A total of 35 zoobenthos species belonging to 3 phyla and 25 genera were identified, among which, Tanypus chinensis, Limnodrilus hoffmeisteri, Branchiura sowerbyi, L. claparedeianus, and Rhyacodrilus sinicus were dominated. The annual density of the zoobenthos averaged 374.1 ind·m-2, and oligochaeta contributed most, occupying 77.4% of the total. The annual biomass averaged 17.78 g·m-2, and molluscs had the most contribution (97.4%). The density and biomass of the zoobenthos were the highest in summer, but the lowest in spring and in winter, respectively. Among the observation stations, St14 had relatively higher zoobenthos density and biomass. The zoobenthos density and biomass varied greatly with season. The highest density occurred in summer, followed by in autumn, spring, and winter; the highest biomass occurred in summer, followed by in spring, winter, and autumn. The values of ShannonWiener diversity index, Margalef species richness index, Pielou index, and BI index suggested that the Gehu Lake was of moderate to serious pollution.
    Variations of behavior and haemolymph physiology of female parent Chinese crab (Eriocheir sinensis) under different water salinities.
    ZHUANG Ping1,2**, JIA Xiao-yan1,2, FENG Guang-peng1, ZHANG Long-zhen1, WANG Rui-fang1,3, ZHAO Feng1
    2012, 31(08):  1997-2003. 
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    Four treatments of water salinity (fresh water, CK; salinity 18, group A; salinity rapidly varied from 18 to 30, group B; and salinity rapidly varied from 18 to 0, group C) were installed to monitor eight behavior indicators of female parent Chinese crab (Eriocheir sinensis) by the method of video recording analysis and to measure the haemolymph osmolality, haemolymph ion concentration, and hemocyanin concentration of the female parent E. sinensis under different water salinities. The closure reaction behavior of the E. sinensis only occurred in groups A and B, and the duration of this reaction was significantly longer in group B than in group A (P<0.05). The abdomen extension behavior was only found in group C. The duration of antennule retraction in groups A and B was significantly higher than that in CK (P<0.05). The reaction frequency of other five behaviors was significantly higher in group C than in other 3 groups. The haemolymph osmolality and haemolymph ion concentration of the E. sinensis were higher in groups A, B, and C than that in the CK, and the haemolymph osmolality and haemolymph Na+ and Cl- concentrations increased with increasing water salinity. On the contrary, the hemocyanin concentration increased with decreasing water salinity, being significantly higher in group C than in group B (P<0.05). It was considered that the female parent E. sinensis was in hyper osmoregulation when the water salinity was varied from 0 to 30. Abdomen extension could bring the hindgut into direct contact with the water, functioning as an additional means of ion uptake in low water salinity. Closure reaction could help the reduction of water absorption and salt loss in high salinity environment.
    Nutritional components and utilization values of golden apple snails (Pomacea canaliculata) in different habitats.
    LUO Du-1, MU Xi-dong1, SONG Hong-mei1, GU Dang-en1, YANG Ye-xin1, WANG Xue-jie1, LUO Jian-ren1, HU Yin-chang1**, ZHANG Jia-en2
    2012, 31(08):  2004-2010. 
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    This paper analyzed the nutritional components and amino acids composition of black and white fleshcolored golden apple snails (Pomacea canaliculata) collected from different habitats (fish pond, ditch, and paddy field), aimed to compare the differences in the nutritional components of these snails and explore the potential utilization values of the snails during the process of integrated control. The snails in fish pond had the highest contents of water and crude fat, those in ditch had the highest ash content, while those in paddy field had the lowest contents of water, crude fat, and crude protein. The crude protein content of the snails in ditch and pond was higher than 13%, and the snails in pond had the highest contents of total amino acids, essential amino acids, and flavor amino acids and the highest index of essential amino acids, but the proportion of essential amino acids was the lowest. The snails in paddy field had higher contents of essential amino acids and flavor amino acids than the snails in ditch, and the index of the essential amino acids of the snails in different habitats was in the order of fish pond > paddy field > ditch. Overall, white flesh snails had higher nutritional values than black flesh ones, and the nutritional composition of the snails essential amino acids was similar to that of fish meal (CP 53.5%). It was suggested that in the utilization of golden apple snails, their flesh color and origin should be fully considered.
    Breeding behavior of sympatric silky starlings and white-cheeked starlings.
    JIANG Xue-lei1, WANG Rong-rong1, LI Zhong-qiu2**, ZHANG Zhi-yuan2
    2012, 31(08):  2011-2015. 
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    Silky starling (Sturnus sericeus) is endemic in East Asia, but little is known about its breeding behavior. From March to June 2011, an experiment with artificial nest box was conducted to study the breeding ecology of silky starlings and that of sympatric whitecheeked starlings (S. cineraceus) at the old and new campus of Nanjing University. A total of 40 nest boxes were installed, of which, 33 boxes (84.6%) were occupied by the starlings, and 17 broods (51.5%) were successfully hatched. We videotaped the reproductive behavior at three nests of silky starlings and three nests of whitecheeked starlings. The clutch size of silky starlings ranged from 6 to 7 eggs while that of whitecheeked starlings varied from 5 to 7 eggs, and the eggs of whitecheeked starlings were significantly larger than those of silky starlings. Silky starlings had a longer nestling period than whitecheeked starlings (with a mean of 20 days vs. 16 days), and also, an obviously higher feeding rate. Compared with whitecheeked starlings, silky starlings were more vigilant and aggressive during their nestling period, and thus, could have more constructive parental care mechanism than whitecheeked starlings. In addition, this paper first reported the occurrence of silky starlings intraspecific nest parasitism.
    Comparisons of different camera trap placement patterns in monitoring mammal resources in Gutianshan National Nature Reserve.
    ZHANG Shu-sheng, BAO Yi-xin**, WANG Yan-ni, FANG Ping-fu, YE Bin
    2012, 31(08):  2016-2022. 
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    From June 2010 to August 2011, four different camera trap placement patterns, i.e., line pattern, cross pattern, random pattern, and same elevation pattern, were adopted to monitor the mammal resources in the Gutianshan National Nature Reserve. A total of 2551 mammals independent photographs (IP) were taken, among which, 1240 were of recognized mammal IP, accounting for 48.6% of the total, 1167 were of unrecognized mammal IP, accounting for 458%, and 144 were of invalid IP, accounting for 5.6%. Fourteen mammal species were identified, belonging to 9 families of 4 orders. The mammals included black muntjac (Muntiacus crinifrons), the national I class protective animal in China, and serow (Naemorhedus sumatraensis) and black bear (Selenarctos thibetanus), the national I class protective animals in China. According to the curve of speciesmonitoring day, it was found that the number of the mammal species tended to be stable after six months monitoring, and thus, it could be more appropriate to monitor the mammal resources with six months as a cycle. As for the four different camera trap placement patterns, there were no significant differences in trapping mammals species number and trapping rate among the line pattern, cross pattern, and random pattern (P>0.05), but the three patterns had significant difference (P<0.01) with same elevation pattern. Due to its grid model, welldistributed camera, and arrangement specifications, same elevation pattern operated better than the other three patterns.
    Changes of soil microbial activity during the mineralization of organic carbon in typical soils in Karst region of Northwest Guangxi, South China.
    HU Le-ning1,2,3, SU Yi-rong1,2**, HE Xun-yang1,2, LI Yang1,2, LI Lei1,2
    2012, 31(08):  2023-2028. 
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    In order to understand the accumulation and transformation of organic carbon in typical Karst soils, soil samples were collected from terra fusca and rendzina, and a 100day incubation experiment was conducted to study the accumulation and transformation of soil organic carbon under no exogenous substance addition (CK), 14Clabeled rice straw addition (T1), calcium carbonate addition (T2), and 14Clabeled rice straw + calcium carbonate addition (T3), taking soil microbial biomass carbon (MBC), basic respiration (BR), BR/MBC ratio (qCO2), and MBC/SOC ratio as the indicators and with red soil as the contrast soil. During the mineralization of the organic carbon in test soils, both the BR and the qCO2 followed the order of rendzina > terra fusca > red soil (P<0.05). Treatment T3 had the greatest effect in enhancing the stability of soil MBC. The changes of the soil microbial indicators differed significantly with test soils, and thus, using these indicators to measure the stability of soil organic carbon would be more credible.
    Impacts of linear project construction on soil eco-environment: A meta analysis.
    SHI Peng1,2, WANG Ya-feng1, CHEN Li-ding1**
    2012, 31(08):  2029-2037. 
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    Because of the unavoidable impacts of linear project construction on regional ecology, it is of significance to quantitatively research the impacts of this project construction on the soil ecological environment along the related regions and to select the potential countermeasures. In this paper, meta analysis was adopted to analyze the impacts of three kinds of linear project construction, i.e., pipeline, highway, and railway constructions on the peripheral soil ecological environment. These three project constructions had definite impacts on the soil physical and chemical properties. Their impact sizes for the soil nutrients and moisture contents were less than 1. Pipeline construction had significant impacts on soil organic matter, total and available nitrogen, and total phosphorus contents and pH value (P<0.05); highway construction decreased soil total phosphorus and moisture contents and CEC but increased soil bulk density and pH value significantly (P<0.05), and gave rise to the severe soil pollution by heavy metals Cu, Zn, Pb, Ni, Cd, Cr, and As (P<0.05); railway construction decreased soil organic matter and total nitrogen contents significantly (P<0.05) and increased the soil pollution by Cu, Zn, Pb, and Cd (P<0.05).
    Changes of surface soil organic carbon components and its quality in the wetlands with different duration of recovery from farmlands in Caizi Lake of Anhui Province, East China.
    WANG Qing**, ZHANG Ping-jiu, MENG Xiang-dong
    2012, 31(08):  2038-2043. 
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    To assess the changes of soil organic carbon components and its quality in the wetlands  recovered from farmlands is of importance in the study of wetland ecological restoration. In this paper, surface soil samples were collected from the wetlands having been recovered from farmlands for different durations (2, 5, 8, 10, and 20 years) in the Caizi Lake of Anhui, with the total organic carbon (TOC), particulate organic carbon (POC), and mineralbound organic carbon (MOC) concentrations and the organic carbon quality studied. The TOC, POC, and MOC concentrations all increased significantly with recovery duration, and the increase of active organic carbon exemplified by POC took the priority while that of stable organic carbon exemplified by MOC was relatively lagged behind. With increasing recovery duration, the POC/MOC and the stratification ratio (SR) of TOC and POC increased, reflecting the obvious enhancement of organic carbon activity. The increased organic carbon during the recovery duration was mainly the labile POC which was easily degradable, and thus, having less contribution to the stability of surface soil organic carbon pool. The carbon pool management index (CPMI) analysis showed that the soil quality increased with the recovery duration, and it would take 13 years to recover the soil quality to original level. In the ecological restoration of the wetland recovered from farmland, the soil organic carbon content (carbon pool index, CPI) recovered more quickly, while the soil organic carbon quality (carbon pool activity index, AI) recovered more slowly, which would take 7.6 and 22.7 years, respectively.
    Effects of vegetation type on the spatial variation of soil NO3--N  and NH4+-N concentrations in a small watershed.
    YAN Jia-liang1,2, FAN Zhi-ping1,3, SUN Xue-kai1, WANG Qiong1, LI Sheng-nan1,2, WANG Ye-hong4
    2012, 31(08):  2044-2049. 
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    As the key factors affecting the inorganic nitrogen sources and eutrophication of downstream aquatic system, the vegetation type and topographical feature in a watershed play an important role in soil nitrogen cycle. In this study, a comparison was made on the soil NO3--N and NH4+-N concentrations in Changbai larch plantation, Chinese pine plantation, broad-leaved forest, and maize land in a small watershed, aimed to approach the relations between the vegetation types and the characteristics of soil inorganic nitrogen within the watershed. Our results showed that the soil NO3--N and NH4+-N concentrations varied significantly with the vegetation types (P<0.05). From downslope to upslope, the soil NO3--N and NH4+-N concentrations decreased significantly from upper layer to lower layer, and the soil NO3--N concentration in maize land was the highest (11.86 mg·kg-1), with a higher risk of nitrogen leaching.
    Effects of sulfur-coating residual degradation of controlled-release fertilizers on the soil properties of fertilized microsite.
    SUI Chang-ling1,2, ZHANG Min1**
    2012, 31(08):  2050-2058. 
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    With the application of sulfur-coated controlled-release fertilizers (CRFs) in agriculture, much attention has been paid to the effects of the degraded CRFs sulfur coatings on soil environment. In this study, two types of representative agricultural soils in Shandong Province, i.e., Argosols and Cambosols, and three types of CRFs sulfurcoating residuals including polymersulfur residual, sulfur residual, and sulphur slice were selected to study the effects of the residuals on the soil properties of fertilized microsite and non-microsite separated by nylon net. In Agrosols, the residuals had significant effects on the fertilized microsite soil pH. In Cambosols, the residuals had little effects on the soil pH of fertilized microsite, but the soil pH of the microsite had more obvious decrease than that of the non-microsite. Sulfurcoating residuals had definite activation effects on soil microelements, especially on the available Fe in Cambosols, with the available Fe content being 6.58 times of the control for polymer-sulfur residual by the end of the experiment. Applying sulfurcoated CRFs in the Cambosols could activate soil nutrients, and increase the available sulfur and phosphorus contents. The prominent effect of the residuals on soil properties was observed within the microsite 5 mm around the sulfurcoatings.
    Dynamic changes of landscape pattern of soil erosion intensity in hilly area of centralsouth Shandong Province, China.
    SHI Yun-fei, ZHANG Ling-ling**
    2012, 31(08):  2059-2065. 
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    By using Landsat TM images and topographic maps as the data sources, and with the supports of GIS and RS techniques, the data of soil erosion intensity in hilly area of central-south Shandong Province in 1986, 1995, and 2004 were collected, and the recent 20 years dynamic changes of the landscape pattern of soil erosion intensity in this area were analyzed. In the study area, the areas with minute and slight soil erosion increased, while those with moderate to severe soil erosion had an obvious decreasing trend, in which, slight, intense, very intense, and severe soil erosion areas had significant changes. The transfer rate of lower level (minimal, slight, and moderate) soil erosion intensity was relatively low, but the higher level (intense, very intense, and severe) soil erosion intensity transferred greatly. At landscape level, the patch number and landscape shape index from 1986 to 1995 increased while the contagion index decreased, which indicated that in this period, the patch fragmentation was increased but the connection degree was decreased, and the shape became more complex. From 1995 to 2004, an opposite trend was observed.
    Spatiotemporal pattern of drought in Loess Plateau of Gansu Province, Northwest China in 1961-2010.
    ZHANG Tiao-feng1, ZHANG Bo1**, ZHANG Miao2, LIU Xiu-li1,3,SUN Li-wei1, AN Mei-ling1
    2012, 31(08):  2066-2074. 
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    Drought, one of the most severe hazards resulting in significant economic losses in agriculture and industry, is a natural phenomenon caused by the imbalance between the input of and the demand for water. As a major grain production zone in Gansu Province, the Loess Plateau of the Province shows great vulnerability in drought. In this paper, the characteristics of interannual and seasonal droughts in the Loess Plateau of Gansu Province were analyzed in terms of drought rate, drought intensity, and drought frequency, and by using the compound index of meteorological drought (CI) and the data of daily precipitation, air temperature, wind speed, relative humidity, and sunshine duration from 33 weather stations during the period from 1962 to 2010. Kriging interpolation was also applied to calculate the CI value for each station, so that all the CI values could be spatially and temporally comparable. In the Plateau of the Province, drought rate showed a significant increasing trend in spring and autumn but a slight increasing trend in summer and winter, and drought frequency was the most in summer, followed by in spring and autumn, and in winter. The 50-year average drought rate in spring, summer, autumn, and winter was 53.26%, 65.18%, 42.2%, and 44.16%, respectively. Over the past 50 years, the most serious inter-decadal drought in the Plateau of the Province occurred in spring and autumn since 2000, and in winter in the 1980s. In the 1970s and 1980s and since 2000, summer drought was more serious. There was a notable interannual fluctuation in the average annual lasting days and annual occurrence severity of meteorological droughts in the whole region, and their linear change tendency was obvious. Spatially, in spring, summer, and autumn, the droughtprone area was mainly located in the northwest of the region. Meanwhile, in the districts of “LintaoTongweiTianshui” and southeast of Qingyang, the change range was the largest. The droughtprone area in winter was mainly located in south of the region. In order to well prevent and mitigate the drought in the Loess Plateau of Gansu Province, government and agricultural managers should pay more attention to the droughts that occur from spring to autumn, especially in summer.
    Integrated spatial assessment of ecological security in Dongjiang River Basin based on gridding.
    DUAN Jin, KANG Mu-yi**, DAI Cheng, JIANG Yuan
    2012, 31(08):  2075-2081. 
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    Through the selection of the indicators highly frequently used in published literatures and by using pressure-state-response (P-S-R) model, an index system based on gridding for assessing the ecological security in Dongjiang River Basin was established. The selected indicators were weighted by entropy method, and then, integrated into the index system for the assessment. The results showed that the ecological security of Dongjiang River Basin was deteriorated from the relativelysecure level in 2000 to the less-secure level in 2004, and then, improved to the rather-secure level in 2008. The selected indicators that were applied to determine the index for assessing ecological security could largely overcome the lack of uniform standard in index system. The ecological security assessment based on gridding could remediate the impact of the changes in administrative boundary, and reflect the spatial differences within the region so as to improve the reliability of the assessment.
    GISbased division of ecological types and their characteristics of waterlevelfluctuating zone in the Three Gorges Reservoir of Yangtze River.
    LEI Bo, YANG Chun-hua, YANG San-ming**, ZHOU Yu, ZHANG Sheng, WANG Ye-chun
    2012, 31(08):  2082-2090. 
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    By using GIS technology, and taking water level change, bank slope of reservoir, and small scale geomorphology as the environmental evaluation indicators, the water level elevationslope and spatial geomorphological maps of the Three Gorges Reservoir were drawn, based on the digital topographic map, and, through overlay analysis, the ecological types of waterlevelfluctuating zone (WLFZ) in the Reservoir were classed. The ecological types of the WLFZ could be classified into 6 classes and 12 subclasses, including perennial submerged WLFZ (gentle slope and steep slope), periodic submerged WLFZ (gentle slope and steep slope), perennial nonsubmerged WLFZ (gentle slope and steep slope), island WLFZ (submerged and nonsubmerged), lake basinestuaryreservoir bayreservoir tail WLFZ (lake basin, estuary, bay, and reservoir tail), and valley WLFZ. The periodic submerged WLFZ, perennial nonsubmerged WLFZ, and lake basinestuaryreservoir bayreservoir tail WLFZ together accounted for 82.2% of the entire WLFZ area, indicating that the three main ecological types should be artificial ecological restorationbased and supplemented by natural recovery, while the perennial submerged WLFZ, island WLFZ, and valley WLFZ accounted for 17.8% of the entire WLFZ area, which should be natural recoverybased and supplemented by artificial ecological restoration.
    Range effect of the correlations among landscape metrics.
    WANG Yan-fang, SHEN Yong-ming**, CHEN Shou-jun, WU De-li
    2012, 31(08):  2091-2097. 
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    Taking Landsat TM image as the data source, an area with a size of 1764 km2 in the Dafeng District of Yancheng City, Jiangsu Province of East China was selected as the study area, and a landscape type map was generated with the help of GIS technology. At landscape level, 32 landscape metrics of 4 types were selected and calculated, and the range effect of the correlations among the landscape metrics was analyzed. With the range increased from 0.5 km to 14 km, the range effect of the correlations among the landscape metrics of the same types was most significant for area, perimeter, and density metrics, followed by contagion metrics, shape metrics, and diversity metrics. In the range effect of the correlations among the landscape metrics of different types, the area, perimeter, and density metrics had significant correlations with other metrics, while the shape metrics had a poor correlation with diversity metrics. An obvious qualitative change of the correlations among the landscape metrics  occurred when the range increased to 3 km × 3 km, and, with the further increase of the range, the majority of the metrics would be uncorrelated. This study provided reference for the selection of landscape metrics at different ranges.
    Single and joint toxicities of Cd2+ and SDS to Procambarus clarkii.
    TAN Shu-hua**, YUAN Zhi-dong, XIE Jing, HE Cheng-rong, XIAO Wei
    2012, 31(08):  2098-2102. 
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    By using static test method, this paper studied the single and joint toxicities of SDS and Cd2+ on adult Procambarus clarkii. For SDS, its 24, 48, 72, and 96 h 50% lethal concentration (LC50) and its safety concentration (SC) were 1365.60, 1171.72, 1128.43, 1120.43, and 258.79 mg·L-1, respectively. For Cd2+, the corresponding values were 1197.09, 142.06, 90.85, 82.64, and 0.6 mg·L-1, respectively. SDS had a lower toxicity while Cd2+ had a higher toxicity to P. clarkia. When the toxicity ratio of SDS and Cd2+ was 1:1 and the exposure time was 24, 48, 72, and 96 h, the additive index (AI) was 0.335, 0.017, 0.030, and 0.032, respectively, indicating that the joint toxicity of SDS and Cd2+ was synergistic.
    Surface soil mercury translocation in Wanshan mercury mining area of Southwest China.
    DAI Zhi-hui1,2, FENG Xin-bin1**, ZHANG Chao1,2, QIU Guang-le1, SHANG Li-hai1
    2012, 31(08):  2103-2111. 
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    Water and soil loss is the main cause of soil degradation, and one of the most serious ecological environmental problems. Many achievements have been obtained in the study of soil erosion in Karst region, but few studies are conducted on the mercury (Hg) translocation induced by soil erosion in seriously Hgpolluted areas of typical Karst regions. Selecting the Wanshan Hg mining area (167.4 km2) of Southwest China as study area and by using geographic information system (GIS) and a revised universal soil loss equation (RUSLE), this paper assessed the intensity of soil erosion and the surface soil Hg translocation via soil erosion. In the mining area, soil erosion modulus was in the range of 0-600884 t·km-2·a-1, and the areas with slight and severe erosion occupied 76.6% of the total, among which, the area with severe erosion made up 90.5%. On annual basis, the surface soil Hg loss was up to 505 kg·a-1, and the Hg loss rate was 3.02 kg·km-2·a-1. Land use type and slope gradient were the main factors affecting the Hg loss, and Hg loss easily occurred on the farmland and shrub land in steep zones, with an amount of 175 and 319 kg a-1, respectively. This study not only provided scientific basis for the control of water and soil erosion in the study area, but also supplied data support for the management of Hg pollution of local ecosystems.
    Spatial heterogeneity and controlling factors of autumn CH4 flux at waterair interface in Poyang Lake of Jiangxi Province, China.
    LIN Mao1, XU Ming2**, GENG Yu-qing1, LIU Li-xiang2,3, ZHANG Xin1
    2012, 31(08):  2112-2118. 
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    Limited observation stations and high spatial heterogeneity of CH4 flux are the challenges for the accurate estimation of CH4 flux at waterair interface. Poyang Lake is the largest freshwater lake in China. In order to understand the autumn CH4 flux at the waterair interface in the Lake, closed static chambers and gas chromatography were adopted to measure the CH4 fluxes at the waterair interfaces in 4 inner lakes of the Lake in October 2010. The environmental factors including meteorological variables and sediment and water properties were also measured. The mean CH4 flux in the Duchang inner lake was 0.26 mg·m-2·h-1, which was obviously higher than that in the inner lakes Xingzi (0.15 mg·m-2·h-1), Wucheng (0.13 mg·m-2·h-1), and Nanjishan (0.10 mg·m-2·h-1). The Lake had a mean CH4 flux of 0.17 mg·m-2·h-1, with the coefficient of variation being 58.6%. The CH4 flux was positively correlated with wind speed (P<0.01). After excluding the wind speed exceeding 5 m·s-1, the contents of sediment organic carbon and water body ammonium were significantly positively correlated with the CH4 flux. The dissolved organic carbon (DOC) content in water body was negatively correlated with the CH4 flux (P<0.05). The accurate estimation of the CH4 flux in the Lake would depend on more frequent measurements in larger areas.
    Mercury accumulation and distribution in Polygonum hydropiper: A hydroponic experiment.
    QIAN Jian-ping1**, JIANG Wen-ying2.3, ZHANG Li2
    2012, 31(08):  2119-2124. 
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    A hydroponic experiment was conducted to study the growth and tolerance performance of Polygonum hydropiper exposed to different concentration mercury (0, 0.5, 1, 10, 20, and 50 μg·L-1). In all treatments, the growth and physiological performances of P. hydropiper were not affected. The root tissue of P. hydropiper had the greatest accumulation of mercury, with the enrichment coefficient being 531.5%. The mercury accumulation in P. hydropiper stem, leaf, and root was significantly positively correlated with the mercury concentration in culture solution. Under a given mercury concentration, the mercury level in P. hydropiper plants increased with culture time. The subcellular mercury concentration in the stem, leaf, and root was in the order of cytoderm > cytoplasmic organelles > cytolymph. Due to the strong mercury-binding effect of cytoderm, the mercury translocation from cytoderm to cytoplasmic organelles and cytolymph was limited.  
    Effects of aged wastes from landfill on seed germination of Cucumis sativus L.
    LIU Bin, PENG Xu-ya, WU Gui-ju, ZHANG Qian, LIU Guo-tao
    2012, 31(08):  2125-2130. 
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    To properly utilize aged waste resources is an important issue in ecoenvironmental protection. In this study, 20%, 80%, and 100% of aged wastes from landfill were added to culture medium to investigate their ecotoxicity on the seed germination of Cucumis sativus, with distilled water and soil as the contrasts. The wastes could substantially improve the seed germination of C. sativus, and didn’t show any toxic effect. The optimal proportion of the wastes in the medium was 80%. In this case, the seed germination potential was increased by 12.8% and 7.6%, and the seed germination rate was increased by 11.3% and 7.2%, as compared with those in distilled water and soil substrate, respectively. The aged wastes could also promoted the growth of root and sprout markedly. In the medium with 80% of aged wastes, the root length, sprout length, and sprout fresh weight were increased by 177.6% and 49.0%, 44.9% and 28.4%, and 143.4% and 72.4%, as compared with those in distilled water and soil substrate, respectively. These results suggested that land application of the aged wastes from landfill could be a feasible approach for the recycling of the aged waste resources.
    Influence of different ecosystems on the rainfall and karst effect in Luota, west Hunan Province of China.
    SU Chun-tian**, TANG Jian-sheng, LIANG Bin
    2012, 31(08):  2131-2136. 
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    By using rain gauge, membrane filter, CO2 monitoring tube, and standard corrosion tablet, this paper measured the rainfall, suspended sediment content, soil CO2 concentration, and soil corrosion rate in forest ecosystem and shrub ecosystem in Luota of west Hunan Province. The rainfall in forest ecosystem was larger than that in shrub ecosystem, being 6.84 mm higher in the first observation year and 218.08 mm higher in the second year. There was a serious soil and water loss in shrub ecosystem, and the sediment content in the ecosystem was 1.53 times of that in forest ecosystem. The soil erosion was intensive in shrub ecosystem but slight in forest ecosystem. The CO2 concentration in different soil layers in forest ecosystem and shrub ecosystem had the same change trend, i.e., increased with the deepening of the soil layer in spring, autumn, and winter while increased after an initial decrease in summer. In forest ecosystem, the soil CO2 concentration in different layers and in different seasons was larger than that in shrub ecosystem. According to the comparison throughout the year, the soil CO2 concentration at the depths 10, 20, and 40 cm in forest ecosystem was 1.66, 1.59, and 1.90 times of that in shrub ecosystem, respectively. In different soil layers, the corrosion rate in forest ecosystem and shrub ecosystem had the same change trend, being larger at the depth 15 cm than on the soil surface. In the same soil layers, the corrosion rate was faster in forest ecosystem, being 1.11 and 2.57 times of that on the soil surface and at the depth 15 cm in shrub ecosystem, respectively. Our results suggested that there existed better karst effect in the forest ecosystem.
    Water driving mechanism of patched vegetation formation in arid areas: A review.
    DU Jian-hui1,2,3, YAN Ping1,2, DONG Yu-xiang1
    2012, 31(08):  2137-2144. 
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    Patched distribution of vegetation is the result of the longterm adaptation and selfadjusting of plants in waterlimited environment, and the vegetation succession process can be used as the indicator of the abrupt change of ecosystems affected by climate change and human activities. This paper reviewed the origin of patched vegetation, related ecohydrological processes, and their implications on the vegetation restoration in arid areas, and discussed the existing problems in the vegetation restoration in arid areas. It was considered that the origin of patched vegetation could be affected by the climate change, human activities, reproduction characteristics of plant species and their adaptation to the environmental stress, but the key for the formation and stabilization of patched vegetation in arid areas was the water redistribution in the patches with and without vegetation in different space scales. Bare land is the “source” of the runoff in the whole ecosystem, while patched vegetation is a highefficient water harvesting system, being the “sink” of the runoff in the whole ecosystem. Therefore, to protect vegetation patch while keeping a certain area of bare land is vital to the water redistribution and vegetation restoration in arid areas. Patched vegetation is also a very fragile ecosystem, both the extreme climate change and the excessive human activities can contribute to the loss of the function of patched vegetation ecosystem, leading to an irreversible consequence, and thus, a strict protection is needed for patched vegetation.
    Roost habitat selection by birds: A review.
    YUAN Bao-dong1,2, JIANG Ai-wu2, LI Xiao-dong2, LU Chang-hu1**
    2012, 31(08):  2145-2151. 
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    Roost habitat can provide safe, warm, and comfortable site for birds rest at night. Because of the poor night vision capability, daytimeactivity birds are difficult to perceive the potential threat of roosting environment, which make their roosting in a dangerous ambience. By choosing appropriate roosting sites, birds can take full advantage of roosting space resources. From the aspects of behavior adaptability in roost habitat selection and related affecting factors (temperature, food, and safety), this paper reviewed the researches on the roost habitat selection by birds, aimed to provide some useful ideas for the future study.
    Measurement of waters nitrate dual isotopes based on denitrifier method.
    YUE Fu-jun1,2, LI Si-liang1**, LIU Cong-qiang1, AN Ning1, CAI Hong-ming1,2
    2012, 31(08):  2152-2157. 
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    Denitrifier method is a novel method for nitrogen and oxygen isotopic analysis of nitrate, which has many advantages, e.g., low nitrate water sample, simple pretreatment, no crosscontamination, and small volume water, and obtained rapid popularization. In this study, the method was first developed in China for nitrate isotopic measurement in our laboratory. The denitrifier (Pseudomonas aureofaciens) was grown in an amended medium of Tryptic Soy Broth. After 5-10 days culture, the cells were harvested and concentrated 5 folds, and split into 3 mL aliquots in 20 mL headspace vials. The vials were sealed and then purged for at least 3 h with highpurity N2 to ensure anaerobic condition. A sample amount corresponding to 50 nmol of nitrate was added to the sample vials, and cultured overnight to allow the complete conversion of NO3- to N2O. On the following day, 0.1-0.2 mL of 10 mol·L-1 NaOH was injected into the vials to lyse the bacterium and to scrub any CO2 gas. Simultaneous δ15N and δ18O analysis of the produced N2O was carried out by using a Trace Gas Preconcentrator unit coupled to an IRMS instrument. The measured data showed good reproducibility and precision, in close with the similar international studies. The establishment of this method would promote our studies in nitrogen biogeochemical cycle in rivers and lakes (reservoirs) and in precipitation.
    Determination of Reaumuria soongorica leaf F3H and DFR activities under drought stress by using RP-HPLC-MS.
    LIU Mei-ling1,2, LIU Yu-bing1**, CAO Bo1,2
    2012, 31(08):  2158-2162. 
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    Flavanone 3-hydroxylase (F3H) and dihydroflavonol 4-reductase (DFR) are the key enzymes in flavonoids biosynthesis pathway, and to study their activities is a crucial step to explore the regulation of this pathway. In this paper, a RP-HPLC-MS determination method of F3H and DFR activities was established to investigate the effects of drought stress on the activities of F3H and DFR in Reaumuria soongorica leaves. The calibration range of F3H substrate naringenin and of DFR substrate dihydroquertin was 0.04-1.20 μg (r=0.998) and 0.08-2.40 μg (r=0.998), respectively, suggesting that this method was convenient and accurate to determine the activities of F3H and DFR. By using this method, the F3H and DFR activities in R. soongorica leaves were measured, and the results showed that under drought stress, the F3H activity increased first and then dropped to the same level as the control, while the DFR activity increased all along with increasing drought time, indicating that drought stress had induction effect on the F3H and DFR activities in R. soongorica leaves.