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    10 December 2014, Volume 33 Issue 12
    Comparative pollination biology of Tamarix ramosissima in wild and managed populations.
    CHEN Min1,2**, ZHAO Xue-yong1
    2014, 33(12):  3169-3175. 
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    Tamarix ramosissima is an ecologically important species of vegetation in the arid regions of Northwest China. In order to understand its pollination biology of different populations, we investigated the following characteristics of the species: flowering dynamics, pollen viability, stigma receptivity, floral visitors, fruit set and breeding systems. We found that the species was characterized by four important reproductive characteristics. Firstly, the flowering peak and flower production period were different between wild and managed populations, being longer in the managed. Secondly, in the wild populations, Apis mellifera was the frequent pollinator, and the P/O rate was 337.2. In the managed populations, Megachile (Amegachile) kagiana was the most effective flower visitor, and the P/O rate was 356.1. Thirdly, fruit set appeared to be higher in the managed populations than in the wild. Finally, outcrossing indexes of both populations were 3, and facultative outcrossing was dominant and selfpollination just played an assistant role in the breeding system of both populations.
    Changes of antioxidant metabolism and organic solute accumulation of Pittosporum pentandrum and Koelreuteria elegans seedlings under salt stress.
    HUANG Yong-rong, LIN Wu-xing**, NIE Sen, ZHU Wei
    2014, 33(12):  3176-3183. 
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    Pittosporum pentandrum and Koelreuteria elegans, native to Taiwan Island, exhibit strong abilities of wind and salt tolerance. Although the field trials have proved their adaptation to the stressful environments of coastal zone, little information is available to understand their measures of salt tolerance. In the current study, the effects of salt stress on the growth and antioxidant metabolism of oneyear old seedlings of P. pentandrum and K. elegans were studied under NaCl concentrations of 6, 9, 12 and 15 g·kg-1. The results showed that, (1) The height and biomass of P. pentandrum and K. elegans seedlings decreased with the increase of NaCl concentration. Meanwhile, the root/shoot ratio increased for P. pentandrum, while decreased firstly and then increased for K. elegans. (2) The tolerance threshold values of P. pentandrum and K. elegans to NaCl concentration were 8.8 and 6.6 g·kg-1, respectively. (3) The MDA content in each of the two species increased under high salt stress, but was higher in K. elegans than in P. pentandrum. (4) SOD, APX and GR activities of P. pentandrum leaves under NaCl stress were higher than those of K. elegans leaves. (5) Proline and soluble protein contents of P. pentandrum leaves were higher than those of K. elegans leaves and they both increased significantly under NaCl stress. The above results indicated that the saltadaptation mechanisms of P. pentandrum and K. elegans were different, and P. pentandrum and K. elegans were saltresistance and saltavoidance species, respectively. The salttolerance ability of former was stronger than that of latter. The stronger salttolerance ability of P. pentandrum may be related to its stronger antioxidant enzyme system and higher capability to accumulate proline and soluble protein under salt stress.
    Effect of high ozone concentration on photosynthesis of Betula platyphylla and Populus alba × P. berolinensi.
    FU Wei1,2, GAO Jiang-yan1, XU Sheng1**, DENG Li-lan2, HE Xing-yuan1, CHEN Wei1, ZHAO Yi1, SU Li-li1
    2014, 33(12):  3184-3190. 
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    One-year-old seedlings of two main tree species (Betula platyphylla, Populus alba × P. berolinensi) in Shenyang were exposed to high O3 concentration (about 160 nmol·mol-1) in opentop chambers (OTCs) and its effect on photosynthesis in leaves of the two tree species was studied. The results showed that the foliage of both species showed necroses induced by the elevated O3. After 14 and 30 d exposures of elevated O3, the percentages of visible foliar injury per leaf in B. platyphylla were 72.0% and 91.6%, significantly higher than that in leaf of P. alba × P. berolinens, which were 21.5% and 26.2% (P<0.01). Chl-a and Car contents decreased significantly in B. platyphylla, but Chl-b content increased in P. alba × P. berolinensi (P<0.05). Electrolyte leakage and malondialdehyde (MDA) contents were significantly increased in leaves of the two tree species (P<0.05), while superoxide dismutase (SOD) and ascorbic acid peroxidase (APX) activities decreased significantly (P<0.05). The net photosynthetic rate (Pn) was decreased significantly and intercellular CO2 concentration (Ci) was significantly increased in the two tree species (P<0.05), but stomatal conductance (Gs) increased in P. alba × P. berolinensi and decreased slightly in B. platyphylla. We infer that the decrease in photosynthesis of the two tree species is related to nonstomatal factors. P. alba × P. berolinensi has higher tolerance to high O3 concentration than B. platyphylla, and B. platyphylla can be considered as an O3 indicator species.
    Carbon density and distribution in soft broad-leaved mixed forest of different age classes in Heilongjiang Province, Northeast China.
    TONG Jian1, JIN Guang-ze1**, LI Feng-ri2, JIA Wei-wei2, CUI Xiao-yang2
    2014, 33(12):  3191-3202. 
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    Accurate quantification of forest carbon (C) density and distribution is important for modeling C cycling in forest ecosystems. In this study, forest inventory and allometric approaches were used to measure and analyze C density and allocation in soft broad-leaved mixed forest of different stand age classes (young, halfmature, nearmature, mature and overmature forest) in Heilongjiang Province, Northeast China. The main results were: (1) The C sink function of soft broadleaved mixed forest was significant in Heilongjiang Province. The differences in C density were significant among the different stand age classes in terms of the forest ecosystem, vegetation, detritus, and soil C pool. However, there were no significant differences in distribution proportions of C densities among different stand age classes in the terms of the vegetation, detritus, and soil C pool. (2) The C densities of the ecosystem C pools increased with the stand age class. There were significant differences in the C densities of the overstory vegetation and the overstory components (except branches) among stand age classes. There were no significant differences in the distribution proportions of C densities in the overstory components among different stand age classes. The change of understory C densities was not significantly different among stand age classes. The C density of litter was significantly different among stand age classes, and the C density increased with stand age class in the detritus C pool. No significant differences were found for woody debris C density among stand age classes. (3) For the same stand age class, woodland characteristic differences in different areas have influence on C densities and the distribution proportions of ecosystem C pools in soft broad-leaved mixed forest in Heilongjiang Province. (4) Basal area could accurately reflect the dynamic variations of forest C density with the forest age.
    Physiological responses of three cool-season types of turfgrass to elevated O3 concentrations.
    ZHAO Yi1,2, XU Sheng1**, HE Xing-yuan1, CHEN Wei1, LI Mei1, 3, ZHANG Na1,2, FU Wei4
    2014, 33(12):  3203-3208. 
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    An experiment was conducted to study the variations of the physiological indexes in leaves of Trifolium repens, Poa pratensis and Festuca arundinacea exposed to elevated O3 concentrations (80 and 120 nmol·mol-1) in open top chambers (OTCS). The results showed that three turfgrass species showed different injury symptoms induced by O3 stress, while brown injury spots appeared on T. repens first. Elevated O3 significantly inhibited the growth of the three grass species and significantly increased the content of malondialdehyde (MDA) and the activities of superoxide dismutase (SOD) and peroxidase (POD) (P<0.05). Elevated O3 significantly increased the content of abscisic acid (ABA) in leaves of P. pratensis and F. arundinacea, while T. repens showed a decreasing trend after an initial increase. The results showed that T. repens is most sensitive to high concentrations of O3 while F. arundinacea least.
     
    Relationship between leaf area index and leaf angle distribution based on single line, multi-angle measurement by TRAC.
    WANG Xu-peng1, FAN Wen-yi1**, QU Di1
    2014, 33(12):  3209-3215. 
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    A quantitative relationship exists between leaf area index (LAI) and leaf inclination angle distribution (LAD), two important parameters in study of vegetation canopy structure. In this study, the quantitative relationship between LAI and LAD of Betula platyphylla pure forest was analyzed based on the data of single line, multi-angle measurement by TRAC, with Norman and Campbell’s linear least-square inversion technique (NC technique) and Campbell model. The NC technique received a very good inversion result of leaf inclination angle distribution, and its interpretation capacity to the measured leaf angle distribution was up to 90%. The leaf inclination probability density calculated by the NC technique was slightly higher than the real density, while the fitting result of Campbell model was relatively lower, especially in the interval of \[0°, 10°\]. Considering the complementary relationship between the results of the two techniques, the correlation between the mean values of the results of the two techniques and the measured results was up to 96%. Besides, when using the NC technique, it is best that the number of the leaf angle interval is half of the number of the solar zenith angle during multiangle measurements. Our study provides an algorithm for LAI and LAD and a theoretical basis for parameter optimization of quantitative remote sensing. Meanwhile, the quantitative inversion of LAI can provide strong authentication in a wide range of LAI measurements.
    Response of reproductive characteristics of Saussurea macrota Franch. to elevation at eastern QinhaiTibetan Plateau.
    CHEN Ting, WANG Yi-feng**
    2014, 33(12):  3216-3221. 
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    The reproductive allocation of 12 Saussurea macrota Franch. populations at different elevations in eastern QinhaiTibetan Plateau was studied in this paper. The results showed that: (1) With the increase of elevation, the individual size of S. macrota decreased, and it invested more resource in reproductive organs to ensure sexual reproduction. (2) The floral traits of S. macrota changed with elevation, ensuring pollination effectively. (3) The seeds number of S. macrota decreased, while the 100seed weight increased with rising the elevation. Meanwhile, the numbers inflorescence and tubulous flower decreased but their weights increased with the increase of elevation. Therefore, the tradeoff is a common phenomenon in the organs of S. macrota.
    Photosynthetic characteristics of Cynodon dactylon in hydro-fluctuation belt of Three Gorges Reservoir at the end of flooding.
    PEI Shun-xiang1, HONG Ming2, GUO Quan-shui2**, QIN Ai-li2, ZHU Li2, ZHU Ni-ni2
    2014, 33(12):  3222-3229. 
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    Plant’s ability to synthesize and store carbohydrate in terrestrial environment and the tolerance mechanism to flooding are important theoretical basis for vegetation restoration and reconstruction of hydro-fluctuation belt. Cynodon dactylon is one of the adaptive plants of hydrofluctuation belt of Three Gorges Reservoir. In order to understand the photosynthetic physiology of C. dactylon after flooding, the photosynthetic physiology of C. dactylon was measured under deep water (22-27 m), shallow water (2-7 m) and nonflooded conditions along an elevation gradient in Three Gorges Reservoir region. The results showed that (1) the net photosynthetic rates (Pn) of C. dactylon growing in deep water and shallow water were higher than that in nonflooded area, and Pn of C. dactylon growing in shallow water was the highest. (2) The Pn, apparent light use efficiency and apparent CO2 use efficiency increased with the time extension of C. dactylon in terrestrial environment, indicating that the ability to synthesize and store carbohydrate of C. dactylon was enhanced after flooding. (3) The maximum photosynthetic rate and apparent quantum yield of C. dactylon growing in deep water and shallow water were higher than that growing in nonflooded area, while light compensation point significantly decreased, which suggested that the ability of C. dactylon to use low light improved. (4) Pn of C. dactylon was affected by the combination of both stomatal and nonstomatal factors and the flooding had a stimulating effect on C. dactylon photosynthetic potential. The positive selfadjustment ability and the photosynthetic compensation mechanism of C. dactylon after flooding and drought stress may be important reasons for its adaptation to floodingdrying habitat changes in hydrofluctuation belt of Three Gorges Reservoir.
    The ecological differentiation of dominant plants in phosphorus-enriched areas within the Dianchi Lake basin.
    CAO Jing-xiao, FU Deng-gao, YAN Kai, WANG Tian-tian, ZHANG Ya-jie, ZHANG Yan, ZHANG Long, DUAN Chang-qun**
    2014, 33(12):  3230-3237. 
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    In order to understand the ecological differentiation of plants within phosphorusenriched mountainous areas, four dominant species (Eupatorium adenophorumm, Rumex hastatus, Saccharum rufipilum, and Coriaria sinica) were selected from phosphorus-enriched mountainous areas that have various soil phosphorus contents in Dianchi watershed. The plants from six populations of each species were planted in a homogeneous garden. Single factor analysis of variance, coefficient of variation, and correlation analysis were applied to study the ecological differentiation among the populations of each of the four dominant species. The results showed that interpopulation variations in all morphological traits (plant height, leaf area, specific leaf area, leaf dry matter content) were significant for the four species. Interpopulation variations in E. adenophorumm, R. hastatus, S. rufipilum, and C. sinica were 16.80%, 4.58%, 24.01%, 9.42%, and the intrapopulations were 59.86%, 66.17%, 63.15%, 68.51%, respectively. The results suggested that the adaptation of dominant plants in phosphorus-enrich areas to local heterogeneous environments is not only characterized by the response in phenotype, but also by certain genetic differentiation.
    Species diversity along the succession series from bamboo forest to broad-leaved forest in a limestone mountain.
    FAN Yan1,2, LI Zu-yao1,2, FAN Cheng-fang3, FAN Fang-li3, SHI Jian-min1,2**, YANG Qing-pei1,2, YANG Guang-yao1,2, KE Guo-qing3
    2014, 33(12):  3238-3244. 
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    To clarify the species diversity change and its influential drivers along the succession of Phyllostachys glauca forest, bamboobroadleaved mixed forest and broadleaved forest in a limestone mountain in Ruichang City, Jiangxi Province, China, we analyzed the species composition, diversity index and environmental factors in fifteen plots from the three succession stages. The results showed that the numbers of species, genus and family increased from P. glauca forest to broadleaved forest. The woody plant diversity and herbaceous plant diversity increased from P. glauca forest to broadleaved forest, with the exception of the Simpson index and Pielou index of herbaceous plant, which were the highest at the middle succession stage of bamboobroadleaved mixed forest. On the contrary, the community similarity decreased along the succession series because of the accelerated species turnover rate. The species richness of community and herbaceous layer, and Shannon index of herbaceous plants were closely related to soil depth and rock coverage in the succession process of P. glauca forest. Our findings indicated that the soil formation and improvement may be the major driver of increased plant diversity during the succession from P. glauca forest to broadleaved forest in the limestone mountain.
    Spatial-temporal change of low temperature disaster of winter wheat in North China in last 50 years
    QIAN Yong-lan1**, WANG Jian-lin1, ZHENG Chang-ling1, YANG Fei-yun2, SONG Yan-ling3, SONG Ying-bo1
    2014, 33(12):  3245-3253. 
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    Low temperature disaster is one of the major disasters of winter wheat in North China, which could occur at its every growth stage. In this paper, low temperature disaster of winter wheat was identified based on daily minimum air temperature and injury threshold at different growth stages of winter wheat in North China in last 50 years, then the spatialtemporal change characteristics of the disaster were analyzed. The results showed that, in last 50 years, both the severity and frequency of the low temperature disaster of winter wheat in North China decreased along with decadalscale variation. The severity index of the disaster decreased from more than 0.6 in the 1960s to less than 0.4 in the 2000s, and the frequency of the disaster reduced from more than 50 days in the 1960s to less than 40 days in the 2000s. As to spatialtemporal change pattern of the disaster in North China, both the severity and frequency in the eastern region decreased faster than in the western region, and more rapidly in recent 20 years than in the former 30 years. At the different growth stages of winter wheat, the change tendency of the disaster frequency was obviously different. At the overwintering stage and turninggreen stage, the frequency of low temperature disaster was reduced rapidly at decadal scale, but it occurred unchangeably at high levels at the stages of tillering, jointing and head sprouting. The mean of daily minimum air temperatures when winter wheat suffered the low temperature disaster rose about 1-2 ℃ during the last 50 years in North China, but there was no clear trend of decrease in the extreme value of the disaster occurring in the same growth stage.
    Effect of elevated CO2 on physiological indexes of transgenic Bt rice.
    PENG Bo1, WANG Wen-jing1, ZHOU Ke-xin2, CHEN Fa-jun1**
    2014, 33(12):  3254-3261. 
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    The physiological responses in transgenic Bt rice expressing Cry1Ab (KMD) and in the isogenic non-transgenic rice (XSD) to elevated CO2 (750 μL·L-1) were studied after planting for 60 and 120 days in opentop chambers (OTC). The results showed that rice chlorophyll a, chlorophyll b, chlorophyll a+b, soluble protein content and glutamine synthetase activity increased from 60 to 120 days, while the content of free amino acids decreased significantly. The value of chlorophyll a/b significantly increased with the elevation of CO2 level. Elevated CO2 significantly reduced the contents of water, soluble protein, chlorophyll a and c in rice foliar tissue, and chlorophyll b content significantly increased at 60 days but significantly decreased at 120 days. The content of soluble protein decreased significantly and that of free amino acids increased significantly. Moreover, the glutamine synthetase activity wasn’t affected by elevated CO2 at 60 days, while it was significantly reduced at 120 days. There were significant differences in soluble protein content and glutamine synthetase activity but not in contents of chlorophyll and free amino acids between transgenic Bt rice and nontransgenic rice. Compared to nontransgenic rice, the glutamine synthetase activity of transgenic rice was significantly lower under the ambient or elevated CO2 treatments at 60 and 120 days.
    Application and comparison of three kinds of photo-thermal model to simulate the rice growth period.
    SONG Yang1, WANG Xue-lin1**, YIN Jian-min2, KONG Ping2, YANG Zai-qiang
    2014, 33(12):  3262-3267. 
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    In order to accurately simulate the rice growth process, based on the photothermal reaction of rice development, field experiments on different sowing dates were designed using double cropping early rice ‘Wuyou 157’ and double cropping late rice ‘Select 10’ in the Agrometeorological Experimental Station at Nanjing University of Information Science & Technology in 2012–2013. Meanwhile, the growth stage observational data as well as meteorological data for double cropping early rice ‘G98-202’ from Nanchang station of Jiangxi Province and double cropping late rice ‘Gold 207’ from Nankang station of Jiangxi Province were collected during 2002–2008. Three models (photothermal effective model, rice clock model and effective accumulative temperature model) were calibrated to obtain the model parameters, and then independent data were used to test the models. The results showed that the decision coefficients (R2) based on the 1:1 line between simulated and observed days of the photothermal effectiveness model for simulating rice were 0.994, 0.994, 0.988 and 0.989 at stages of sowing to jointing, jointing to heading, heading to filling, and filling to maturity, respectively, and the RMSE was less than four days. For the entire growth period, the simulation accuracy of photothermal effective model for ‘Wuyou 157’, ‘G98-202’, ‘Select 10’, ‘Gold 207’ increased by 2.42%, 4.55%, 8.74% and 4.55%, respectively, compared with the effective accumulative temperature model. Our results suggested that, in the simulation of Jiangxi early rice and late rice growth period, the precision of the photothermal effective model was slightly higher than that of the rice clock model, and the accuracy of effective accumulated temperature model performed the worst. The results can provide a reference for the selection of rice growth period prediction methods in Jiangxi Province.
    Spatial and temporal characteristics of water requirement and water deficit of winter wheat in Henan Province.
    JI Xing-jie1,2**, CHENG Lin3, ZHU Ye-yu1, SONG Ni4
    2014, 33(12):  3268-3277. 
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    Based on the meteorological data and the data of the growth period of winter wheat from 30 agrometeorological stations of Henan Province, the effective precipitation was calculated by using the U.S. Department of Agriculture Soil Conservation method. Meanwhile, the water requirement (ETc) of winter wheat in the whole growing period during 1981-2010 in Henan Province was estimated by using FAO PenmanMonteith equation and crop coefficient method recommended by Food and Agriculture Organization. The spatialtemporal distribution characteristics of ETc and water deficit (WD) and their major climatic impact factors were analyzed using the mathematical statistics. The results showed that the Penman-Monteith model well simulated the ET0 of winter wheat during the whole growing period in Henan Province in the past 30 years, with a correlation coefficient of 0.85 (P<0.01) between the modeled ET0 and the observed 20 cm pan evaporation during the same period in same stations. The mean precipitation and effective precipitation of the 30 years during the whole growing period of winter wheat were 244.0 and 114.9 mm, respectively. The mean ETc and WD for the study area were 408.0 and 293.1 mm for the whole growth period during the past 30 years, respectively. Spatially, precipitation and effective precipitation decreased gradually from south to north, which was opposite to the distribution characteristics of ETc and WD. The differences in precipitation and effective precipitation among different regions increased during 1981-2010, while the differences in ETc and WD among different regions decreased. Temporally, ETc and WD of Henan Province showed downward trends which were not significant. The variations of ETc and WD differed spatially. The ETc and WD increased in west and north of Henan Province, but reduced in the rest areas. Partial correlation analysis indicated that wind speed reduction during the past 30 years was the main cause of decreased ETc, however, the WD had the closest relationship with precipitation. Stepwise regression analysis suggested that the changes of ETc and WD had close relationships with meteorological factors and growth stages of winter wheat as a whole, and the contribution of each factor to ETc and WD differed, among them, the whole growing days and precipitation were the biggest one, respectively.
    Assessment and classified control of agricultural non-point source pollution in Nansihu Lake Basin, Shandong Province.
    LIN Xue-yuan1,2, JING Yan-de1,2**
    2014, 33(12):  3278-3285. 
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    To clarify the spatial feature of agricultural non-point source pollution (ANPSP) and make reasonable pollutant control strategies in the Nansihu Lake Basin, Shandong Province, the pollution emission coefficient method was used to estimate the chemical oxygen demand (COD), total nitrogen (TN) and total phosphorus (TP) loads in the Nansihu Lake Basin. Equivalent standard pollution load method and GIS technology were used to analyze the pollution emission amount and emission intensity, sensitivity, and spatial characteristics. The cluster analysis was used to study the classification of the ANPSP. The results showed that the COD, TN and TP loads of Nansihu Lake Basin were 254574.06, 116976.87 and 15554.42 t in 2012, and the emission intensities of these pollutants were 88.18, 40.52 and 5.39 kg·hm-2, respectively. Livestock and poultry breeding were the most important pollution source, while TN was the most important pollutant. The highest emission intensity occurred in Yanzhou City, Liangshan County and Yutai County, while the lowest in Shanting District. The highly sensitive areas and priority control areas were Yanzhou City, Wenshang County, Liangshan County, Dingtao County and Tengzhou City for the whole Nansihu Lake Basin, and the livestock and poultry breeding were the key pollutant source of these regions. It is concluded that rural domestic pollution has the highest pollution contribution rate, while comprehensive pollution is hard to control.
    Regional eco-compensation standard in Gansu Province.
    PAN Jing-hu**
    2014, 33(12):  3286-3294. 
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    Standard of regional eco-compensation (REC) is one of the key issues to establish REC mechanism. Land use/cover data were acquired by using Landsat remote sensing images. From a geographical view of scale relevance and scale transition, this study put forward ecological compensation urgent index (ECUI) and the model of eco-compensation standard based on ecological value equivalents by taking both the ecosystem service value and the economic development level of different regions into consideration. The ecosystem service value, ECUI and REC standard of Gansu Province in 2011 were calculated and the spatial disparities were analyzed at three spatial scales: ecological zone scale, prefecture-level city scale and county scale. The results showed that Gannan Plateau, Hexi mountain and desert ecological zone should have priority to get compensation, and the urban ecological zone along the Yellow River should first provide compensation. The municipal districts and mining counties had the lowest priority level among all the counties of Gansu. Among all the 87 counties, Akesai, Subei, Maqu and Sunan were high in ecological output, which had the highest level of priority to get compensation. At the prefecture-level, REC values in Jiayuguan, Lanzhou and Pingliang were negative and they should pay REC while REC values in Jiuquan, Gannan and Zhangye are positive and they should receive REC.
    Effects of long-time chill acclimation on light use efficiency in photosynthesis of chewing cane Saccharum officinarum L. cv. Badila.
    ZHU Jun-jie1,2**, LI Yang-rui2
    2014, 33(12):  3295-3299. 
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    Saccharum officinarum L. cv. Badila seedlings were used to study the effect of longtime chill acclimation (12 ℃/8 ℃ for 28 days) on the light use efficiency in photosynthesis. The results showed that chill acclimation decreased the net photosynthetic rate but increased the dark respiration rate (Rd) and the ratio of PSII operating efficiency to CO2 assimilation efficiency (ΦPSII/ΦCO2) compared with the seedlings grown at 25 ℃/20 ℃ (control) regardless at ambient temperature (25 ℃) or at low temperature (12 ℃). The measurement under ambient temperature showed the chill acclimation decreased the declining rate of Fv′/Fm′ (changing reversely to NPQ) declining with ΦPSII while increased the declining rate of photochemical quenching (qP) declining with ΦPSII at different light intensities. The measurements at low temperature, however, showed no significant differences in the declining rates of Fv′/Fm′ and qP declining with ΦPSII compared with the control. It was indicated that the longtime chill acclimation treatment dissipated the excessive light energy through both nonphotochemical and photochemical quenching pathways, thus improved its photosynthetic sensitivity to chill. The present study provides important references for chillingresistant breeding and cultivation of chewing cane.
    Shorebird habitat changes in the East AsianAustralasian Flyway: A case study of the stopover site in Chongming Dongtan.
    ZOU Ye-ai1, NIU Jun-ying1, TANG Chen-dong2, PEI En-le3, TANG Si-xian1, LU Shan1, WANG Tian-hou1**
    2014, 33(12):  3300-3307. 
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    The Chongming Dongtan wetlands are an important stopover site for migratory shorebirds along the East AsianAustralasian Flyway. We used remote sensing images to map and assess migratory shorebird habitats and monitor temporal changes of these habitats during 2000-2010. In order to assess the quality of shorebird habitats, FRAGSTATS metrics were calculated. The results showed that the shorebird suitable habitats (Scirpus mariqueter grassland and mudflat) were the second largest habitats (followed by the deepwater habitats). The S. mariqueter grassland and mudflat habitats slightly increased from 10448.2 hm2 in 2000 to 10696.5 hm2 in 2006 and sharply decreased from 2006 to 2010 (9784.6 hm2). The S. mariqueter and mudflat habitats were mainly transferred from the deepwater habitats, while significantly transferred to the Spartina alterniflora and Phragmites australis habitats. The S. mariqueter and mudflat habitats became more fragmented and complex in 2010 compared with that in 2000. Specifically, such habitats first increased from 2000 to 2006 and then decreased from 2006 to 2010. The landscape patterns of all habitats became more heterogeneous and fragmented from 2000 to 2006 and less heterogeneous and fragmented from 2006 to 2010. This suggests that the quality of shorebird habitats decreased from 2000 to 2006 and increased after 2006 in terms of composition/configuration, complexity, connectivity, and heterogeneity. The findings of this study are expected to motivate the local community to develop wetland restoration or creation strategy to protect migratory shorebirds in the Yangtze estuary.
    Bird community structure and seasonal variation at Honghaizi Wetland Park in Yijinhuoluo, Inner Mongolia.
    LI Shi-wei, YANG Gui-sheng**, WANG Wei, LI Bo, LIANG Chen-xia, ZHANG Yu-wei
    2014, 33(12):  3308-3314. 
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    The community structure and seasonal dynamics of birds at four habitats in Honghaizi Wetland Park of Yijinhuoluo, Inner Mongolia were investigated from October 2012 to September 2013 utilizing line transects and the fixedradius points method. A total of 116 bird species were recorded, which belonged to 16 orders, 36 families. Among them, 49 were summer visitors, 9 winter visitors, 24 residents and 34 passage migrants. The diversity index of birds was highest in spring and lowest in winter. The similarity index of birds was highest between spring and summer, and lowest between summer and winter. The bird community structure of each habitat changed significantly with season and interacted with food, water source, shelter conditions, breeding conditions and other relevant factors. On April 12 of 2013, a total of 2340 Relict Gulls (Larus relictus, a first class national protected bird species in China) were spotted at Honghaizi Wetland Park. This finding indicated that this area was an important feeding site for Relict Gull in spring. This study provides fundamental data for protecting wetland bird resources and ecological environment of Honghaizi Wetland Park.
    Effects of different enrichments on behaviors of captive browneared pheasant (Crossoptilon mantchuricum). 
    HAO Ai-xia, DENG Wen-hong**
    2014, 33(12):  3315-3321. 
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    We conducted an experiment of environmental enrichment and feeding enrichment on the captive browneared pheasant (Crossoptilon mantchuricum) in Pangquangou National Nature Reserve, Shanxi Province from April to May, 2010 and from December, 2010 to August, 2011. In order to test the effects of different enrichments on the captive browneared pheasant, scan sampling, focal sampling and all occurrence sampling methods were used to observe the behaviors of these pheasants. The results showed that the exploring behaviors of both environmental enrichment and feeding enrichment groups were significantly lower than that of the control group. Foragingrelated behavior had no obvious pattern at different enrichment stages. The performance intensities of the abnormal behavior in the two enrichment groups were lower than that of the control group. Taking the whole enrichment stage into account, the timeallocation percentages of foraging, locomotive and breeding behaviors in the environmental enrichment group were significantly higher than those of the control group. However, the timeallocation percentages of vigilant behavior and abnormal behavior were significantly lower than those of the control group. The timeallocation percentages of foraging behavior and resting behavior in the feeding enrichment group were extremely significantly higher than those of the control group, while the percentages of vigilant and abnormal behaviors were significantly lower than those of the control group. With the progress of the enrichment program, the behavior diversity increased gradually in the environmental enrichment group, and initially increased and then reduced in the feeding enrichment group, while reduced gradually in the control group.
    Spatial patterns of agricultural and forest pests in China and the impact factors.
    LIU Dong1, SHEN Wei-shou1, ZHU Si-xi2, ZOU Chang-xin1, XIE Hao-jing3, OUYANG Yan1**, LIN Nai-feng1
    2014, 33(12):  3322-3331. 
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    Agricultural and forest pests have increasingly caused ecological environment damage and economic losses in China. Based on filed investigation and data from related references, we obtained the number, density and spatial distribution of pests in 34 provinces of China. We used principal component analysis, correlation analysis and multiple forward regression to determine the relative importance of climate factors and anthropological variables on the number and density of agricultural and forest pests in different provinces of China. The results showed that the number and density of agricultural and forest pest species decreased from the east to the west in China. Agricultural and economic factors were the main factors, while climate factors were secondary factors affecting the spatial pattern of agricultural and forest pests. The regions with higher values in cropland area, forest coverage, GDP, temperature, hmidity, and transport length had higher risks for the occurrence of agricultural and forest pests. Our study suggested the important implications for pest management in China.
     
    Explanation of elevational patterns of amphibian and reptile species richness in the Baishuijiang Nature Reserve: Waterenergy dynamic hypothesis and habitat heterogeneity hypothesis.
    ZHENG Zhi1, GONG Da-jie1**, ZHANG Qian2
    2014, 33(12):  3332-3338. 
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    Water-energy dynamic hypothesis and habitat heterogeneity hypothesis were used to explain elevational patterns of amphibian and reptile species richness in the Baishuijiang Natural Reserve by employing the methods of linear regression models and variation partitioning analysis. The results showed that the explanatory power of water-energy dynamic hypothesis was stronger for shaping the patterns of amphibian and reptile species richness in the Baishuijiang Natural Reserve, and there existed a stronger collinearity between water-energy dynamic hypothesis and habitat heterogeneity hypothesis. The variable mean annual rainfall (PAN) was included in the final linear regression model of amphibian species richness elevational pattern, but not in that of reptile species richness elevational pattern. However, the variables, potential evapotranspiration (PET) and PET2, were included in the final linear regression model of reptile species elevational pattern. These results suggested that water and temperature played an important role in shaping the elevational patterns of amphibians and reptiles, respectively. The consequence of variation partitioning analysis showed that the independent exploratory power for shaping the elevational pattern of amphibian and reptile richness was weak, while that of waterenergy dynamic hypothesis was powerful for the pattern. For the largerange species, the exploratory powers of two hypotheses were weak because of the boundary constraint effect.
    Spatiotemporal variation of the cold island effect and its relationship with NDVI and LUCC in Golmud oasis in the last 27 years.
    WANG Lin-lin, LIU Pu-xing**, YAO Yu-long, GAO Yuan
    2014, 33(12):  3339-3348. 
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    Four remote sensing images from Landsat TM/ETM+/TIRS in 1987, 2000, 2006 and 2013 were used to invert the land surface temperature (LST) of Golmud oasis. The LST values were normalized and the grade figures of LST were obtained. Then the transition matrix of the grade figures of LST from two adjacent dates was constructed. Furthermore, the normalized vegetation index (NDVI) and land use/land coverage change (LUCC) were used to analyze the spatiotemporal variation and the causes of cold island effect in Golmud oasis. Overall, in the last 27 years, the LST in the oasis presented a spatial pattern of lower temperature center in high vegetation coverage and it ascended from the center to surrounding areas. Oasis cold island effect was significant, and had a strongweakstrong variation. There was a remarkable negative correlation between normalized surface temperature (NLST) and NDVI that coincided with the changes of the cold island effect, indicating that the vegetation played an important role in the cold island effect. The area increased for farmland and woodland in 2000, decreased for farmland and water bodies in 2006, and increased for farmland, woodland and urban greening in 2013. Woodland, farmland, grassland and water bodies had the priority position in the lowest three grades of LST, and their temperature reduction roles were of significance in maintaining the stability of oasis cold island effect.
    Landscape pattern evolution of typical karst plateau in Puding, Guizhou during last 40 years.
    QIN Luo-yi1,3, BAI Xiao-yong2,3, WANG Shi-jie2,3**, ZHOU De-quan1, LUO Guang-jie2, ZHANG Si-yu2, LI Pan-long1,2, LI Yue2,4
    2014, 33(12):  3349-3357. 
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    Based on 1973 MSS and 1990, 2002, 2009 TM remote sensing images, the evolution process and driving force of landscape pattern in Puding County, a typical karst region during past 40 years were analyzed by using GIS, RS technology and landscape ecology research methods. The results showed that the main structure changes of landscape were the mutual conversion between woodland, grassland and farmland. Before 1990, about 43.97% of the woodland and grassland transferred to the farmland; after 1990, 50.09% of the farmland transferred to the woodland and grassland. At the class level, before 1990, the farmland landscape showed a trend of increase in area and of integration in space, while the woodland decreased in area and fragmented in space; after 1990, an opposite trend was found for the woodland and farmland. At the landscape level, before 1990, fragmentation index increased, and the diversity and evenness decreased, indicating that the landscape became simplified. From 1990 to 2002, the landscape shape became complicated, and the diversity and evenness increased. After 2002, the fragmentation decreased, and the discrete and separation degree increased, leading to unstable spatial distribution. All together, in the region with extremely fragile karst ecological environment in Southwest China, ecological restoration project construction and industrial structure adjustment were the main and effective means for ecological restoration in the future.
    The contribution of climate change to economic output of Wuniuzao spring tea in Shaoxing.
    LOU Wei-ping1**, WU Li-hong2, JI Zong-wei3
    2014, 33(12):  3358-3367. 
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    Taking Shaoxing City as the study area, tea tree phenological data and tea production data were collected to establish Wuniuzao tea phenological model, tea leaf picking amount model and economic output model by adopting the accumulated temperature method. A sequence of historical data was established by combining meteorological data, and the influences of climate change on the phenology of Wuniuzao tea tree, frost disaster and economic output were analyzed. The results showed that the increase in February’s average temperature over the past four decades led to the early arrival of Wuniuzao tea production period in Shaoxing City, with 1.34-2.48 d·10 a-1 in advance, but the MannKendall tests failed to get a level of significance of 5% except in Shaoxing County. The significant increase in March’s average temperature shortened the picking period of Wuniuzao tea 1.03-1.29 d·10 a-1, reduced economic output of 272.86-347.66 RMB Yuan·person-1·10 a-1, and the MannKendall tests of all counties achieved a level of significance of 5%. The influence of rainfall in March on the economic loss of Wuniuzao tea was not significantly associated with time. Spring frost was one of the main disasters affecting the economic output of Wuniuzao tea. Frost risk did not have a significant trend in the context of climate change, but the tea economic loss resulting from frost disaster showed a trend of decrease.
     
    Spatial variations in soil properties of cropland in North Canal basin in Beijing.
    ZHANG Rui, DAI Wei**, PANG Huan, ZOU Jian-mei
    2014, 33(12):  3368-3373. 
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    Spatial variations in soil fertility parameters of the soil (0-50 cm) of cropland in the North Canal basin of Beijing were analyzed using geo-statistics and geographical information system (GIS). Soil fertility parameters included pH, bulk density, organic matter, total nitrogen and available phosphorus. The results revealed a significant spatial variation in the five soil fertility parameters. Available soil phosphorus had the largest coefficient of variation (68%). The coefficient of variation ranged from 6% to 22% for soil pH, bulk density, organic matter, and total nitrogen. The semi-variograms of the five soil fertility parameters were best described by the Gaussian model. Soil pH and bulk density had a relatively strong spatial correlation, which was caused by structural factor. In contrast, soil organic matter, total nitrogen and available phosphorus had moderate spatial correlations, which were related to both structural and random factors. Using a Kriging method, spatial distribution maps of the soil fertility parameters were made and the areas of graded lands were counted. Meanwhile, the spatial variations of soil fertility parameters were analyzed. We argue that the analysis of spatial patterns of soil fertility parameters in the North Canal basin is essential for precision agriculture.
    Concentrations of different nitrogen forms in gaps of natural Pinus koraiensis mixed forest in Xiao Xing’anling Mountains.
    JIANG Yi1, CHEN Li-xin1**, DUAN Wen-biao1, BU Fan1, SUN Shuang-hong1, LI Fan-fan1, XU Yi-fan2
    2014, 33(12):  3374-3380. 
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    The concentrations of different nitrogen (N) forms in soil (ammonium N (NH4+-N), nitrate N (NO3--N), total soluble N (TSN), soluble organic nitrogen N (SON), microbial biomass N (MBN) and total N (TN)) were investigated under gaps with different sizes in three Korean pine (Pinus koraiensis) mixed forests (i.e., TiliaKorean pine mixed forest, sprucefirKorean pine mixed forest, and birchKorean pine mixed forest) in Xiao Xing’anling Mountains. The results showed that organic N was the dominant form of TN, accounting for more than 98% of TN. Concentration of NO3--N was higher than that of NH4+-N, and SON concentration were higher than NH4+-N and NO3--N. Concentrations of NH4+-N, NO3--N, SON and MBN showed significant differences between large and small forest gaps and between forest gaps and closed forests. Especially, MBN was in the order of closed forests > small gap > medium gap > large gap, showing a significant negative correlation with gap size. NO3--N/TN and MBN/TN decreased with the increase of gap size in the three forests. NH4+-N/TN, TSN/TN and SON/TN decreased with the increase of gap size in the TiliaKorean pine mixed forest gaps and sprucefirKorean pine mixed forest gaps, but increased with the increase of gap size in the birchKorean pine mixed forest gaps. Significant correlations were observed between TSN and SON in forest gaps and closed forests. NH4+-N was significantly correlated with NO3--N and MBN in forest gaps, but such relationships were not found in the closed forests.
    Changes of soil microbial biomass carbon and nitrogen along the altitude gradient and its influence factors in Shennongjia Natural Reserve, China.
    CONG Jing1,2, LIU Xiao2, LU Hui2, XUE Ya-dong2, LIU Xue-duan1, YIN Hua-qun1, LI Di-qiang2, ZHANG Yu-guang2**
    2014, 33(12):  3381-3387. 
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    In order to explore the variation trend of soil microbial biomass carbon (MBC) and nitrogen (MBN) along an elevation gradient and their main controlling factors in a mountain forest region in Shennongjia Natural Reserve, China, MBC and MBN at 0-10 cm soil layer were measured and their relationships with environmental factors were analyzed in four typical forest types in late August of 2011. The results showed that the values of MBC and MBN were in order of alpine shrub > subalpine coniferous forest > coniferous and broadleaf mixed forest > deciduous broadleaved forest. MBC and MBN significantly increased with the elevation (P<0.05), in consistent with the trend of soil organic carbon and total nitrogen. However, soil microbial quotient (qMB) decreased first and then increased with the elevation. Pearson’s correlation analysis showed that MBC and MBN were significantly positively correlated (P<0.05) with soil organic carbon and total nitrogen, but negatively with soil moisture, soil temperature and soil pH (P<0.05). Therefore, soil moisture, soil temperature, soil pH, soil organic carbon and soil total nitrogen might be the important factors influencing the variations of soil microbial biomass along the elevation gradient in Shennongjia Mountain.
     
    Effects of acetone chromatography extracts of parsley root materials on the cell wall degrading enzymes activities and fusaric acid contents of Fusarium oxysporum f. sp. cucumerinum.
    GAO Xiao-min, MA Li-guo, HAO Jing, PAN Jing, LI Jie, YUN Xing-fu**
    2014, 33(12):  3388-3394. 
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    The acetone extracts of parsley root materials obtained by four times column chromatography were used for exploring the effects of allelochemicals in the parsley root materials on physiological and biochemical aspects of Fusarium oxysporum f. sp. cucumebrium. Best column fractions were screened by the allelopathic inhibition effect and the activities of three cell wall degrading enzymes and fusaric acid content after 144 h of coculture with F. oxysporum f. sp. cucumebrium in the liquid medium. The results indicated that the best column fractions obtained from the acetone extracts of fresh parsley root and rhizosphere soil inhibited the growth of F. oxysporum f. sp. cucumebrium. In comparison to CK, the cell wall degrading enzymes activities and fusaric acid contents decreased significantly with increased numbers of chromatography. The correlation analysis indicated that allelopathic inhibition effect had significant negative correlations with the activities of pectinase and β-glycosidase enzymes, but no significant correlation with the fusaric acid content.
    Effects of arbuscular mycorrhizal fungus on the growth and physiological salt tolerance parameters of Carthamus tinctorius seedlings under salt stress.
    XU Yao, FAN Yan, YU Yun-he, XU Cai-yun, GE Ying**
    2014, 33(12):  3395-3402. 
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    A pot experiment was conducted to investigate the impact of arbuscular mycorrhizal fungus (AMF) Glomus mosseae inoculation on the growth and physiological indicators of safflower (Carthamus tinctorius) under NaCl stress. The results showed that AMF inoculation significantly increased the root dry weight and chlorophyll content and reduced the accumulation of MDA of safflower under the salt stress. Compared with noninoculation, the AMF inoculation significantly enhanced the production of proline and soluble sugar while improved the total antioxidant capacity (T-AOC) in the leaves under salt stress. In addition, inoculating AMF promoted the uptake of mineral nutrients such as P and Mg. Under the treatment with the high salt level (3‰ NaCl), the uptake of Na+ was significantly reduced and leaf K+ concentration was increased in the AMFcolonized safflower. Therefore, G. mosseae reduced salt interferences on the chlorophyll synthesis and increased chlorophyll content; meanwhile it alleviated the salt stress on safflower plants by raising the content of osmotic adjustment matter, boosting mineral elements uptake, decreasing the MDA content, and lowering Na+ absorption under high salinity.
     
     
    pH affects antioxidant property of Phaeoporus obliquus H011 strain in submerged culture.
    LIU Cheng-rong**
    2014, 33(12):  3403-3408. 
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    The effects of pH value (4.0 to 7.0) on antioxidant ability, free radical scavenging ability and production of antioxidants of methanolic extracts from mycelia and filtrates of Phaeoporus obliquus H011 strain in submerged culture were studied. We found that, pH significantly affected antioxidant activity, scavenging free radical activities, yields of total phenolics and polysaccharide in methanol extracts of the mycelia and the filtrates of P. obliquus in submerged culture. The antioxidant ability and the scavenging free radical activities of methanol extracts of the filtrates were strongest when pH was 6.0, being significantly higher than in other pH treatments (P<0.05). Also, the yields of total phenolics and polysaccharide at pH 6 reached the peak, being 189.9 mg·g-1 and 47.2 mg·g-1 respectively, significantly higher (P<0.05) than in other pH treatments. The total phenolics and polysaccharide in methanol extracts might be responsible for the antioxidant activities and free radical scavenging ability of the mycelia and the filtrates of P. obliquus in submerged culture. Higher yields of antioxidants were obtained in the submerged culture as compared with sporophores. Therefore, an alternative approach for producing antioxidants of P. obliquus in a submerged culture could be used in place of solid culture.
     
    Effect of Cdtolerance bacterium inoculation on Cd uptake in soil by Celosia argentea.
    WU Bing-qi1, LIU Shu-jie1**, ZHANG Miao1,2, CHEN Fu-ming1, LIU Li-hua1, YANG Xiao-long1, JIN Wen-biao2
    2014, 33(12):  3409-3415. 
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    A superior cadmium (Cd)tolerance plant Celosia argentea was screened from a mining area in Dabao Mountain, Guangdong Province. The Cd absorption capacity of the plant was studied by cultivating its seedlings in soil with different concentrations of Cd. The results showed that the C. argentea was able to tolerate Cd at the concentrations higher than 40 mg·kg-1 in soil. Moreover, the content of Cd in the C. argentea was positively correlated with the Cd concentration in a certain range in soil. With different concentrations of Cd (CdCl2·2.5H2O) added into the mediums, a strain of endophytic bacteria DE5 capable of tolerating Cd at a high concentration of 200 mg·kg-1 was sifted from the leaves of Solanum nigrum, a kind of Cd hyperaccumulator, which was identified as Variovorax paradox (Genebank accession number: KF051781) by physiological and biochemical experiments and 16S rDNA sequence analysis. The C. argentea rootirrigated by DE5 fermentation broth was cultivated in the soil with a higher concentration (100 mg·kg-1) of Cd in a pot experiment, and the plant height, biomass and Cd absorption capability were analyzed. The results showed that the dry weight of C. argentea treated with DE5 increased by 125.0% compared with the control, and noticeably, the total Cd absorbed by the aerial part and whole plant increased by 81.7% and 81.1%, respectively. Our study indicated that the C. argentea was a superior botanic resource conducive to the remediation of Cdpolluted soil. It is feasible and potentially applicable to inoculate DE5 into the rhizosphere of C. argentea, whose effect showed advantages over that of pouring the chelating agent EDTA.
    Spectrum characteristics and spatial distribution of dissolved organic matter in sediment porewater from northern Dianchi Lake.
    WANG Li-ying1, ZHANG Run-yu1**, WU Feng-chang2
    2014, 33(12):  3416-3422. 
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    Concentration, composition and vertical distribution of dissolved organic matter (DOM) were investigated in sediment porewater from the north part of Dianchi Lake by UVvisible and fluorescence spectroscopy, and its main source and potential environmental effect were also revealed. DOC concentration was highest in the uppermost layer, with a sharp decrease within the sediment depth of 4-10 cm, and then increased. The ratios of α253/α203 and E3/E4 ranged from 0.03 to 0.22 and 5.3 to 8.8 respectively, which implied that the DOM in sediment porewater had relatively low humification and aromaticity with the predominance of small molecular weight fulvic acid. Humiclike peaks A and C were two dominant fluorophores in threedimensional fluorescence spectroscopy, whereas proteinlike fluorescence peaks B and D were observed only in the overlying water and top 2 cm porewater. Fluorescenee index (f450/f500) of DOM in sediment porewater varied from 1.8 to 2.0, indicating the majority nature of endogenous aquatic organisms. The results suggested that the geochemical characteristics of DOM in sediment porewater were related to lake eutrophication and regional cyanobacterial blooms in Dianchi Lake, and more attention should be paid to its potential effect on water environment.
    Spatial distribution characteristics of air pollutants in major cities in China during the period of wide range haze pollution.
    PAN Jing-hu**, ZHANG Wen, LI Jun-feng, WEN Yan, WANG Chun-juan
    2014, 33(12):  3423-3431. 
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    Based on the air pollutants monitoring data obtained from 667 meteorological stations of 118 major cities in China in the period from November to December in 2013, the spatial distribution maps of air pollutant concentrations every five days were obtained by selecting optimal spatial interpolation method. Kernel density and trend surface analysis were used to study the spatiotemporal distribution characteristics of pollutant concentrations during the period of wide range haze pollution, and the spatial heterogeneities of pollutant concentrations were explored by using global autocorrelation and local autocorrelation analysis methods. The results indicated that the variation trend of air pollutants was large at different time. The concentrations of air pollutants such as nitrogen dioxide (NO2), inhalable particles (PM10 and PM2.5), and sulfur dioxide (SO2) showed an apparent tendency of the eastern region > the western region and the northern region > the southern region. PM10 and PM2.5 were the main contributors to the widespread haze weather. There were significant positive spatial autocorrelations in mean concentrations of all the air pollutants. The hot spots of mean concentrations of NO2 were concentrated in the central regions of Shandong Province, south regions of Heibei Province and the urban agglomerations of the Pearl River Delta. The hot spots of mean concentrations of PM10 were distributed in the south regions of Hebei Province, Huaihai and GuanzhongTianshui economic zones. The hot spots of mean concentrations of PM2.5 were concentrated mostly in BeijingTianjinHebei urban agglomerations, the Yangtze River Delta and the coast region of South China, and the hot spots of mean concentrations of SO2 mainly distributed in the central regions of Hebei Province and the northeastern region of Shandong Province.
    The correlation between dynamic change of phytoplankton community structure and environmental factors in Sanbanxi Reservoir of Guizhou Plateau.
    OU Teng, LI Qiu-hua**, WANG An-ping, ZHANG Lei, HUANG Guo-jia, JIAO Shu-lin, GAO Ting-jin
    2014, 33(12):  3432-3439. 
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    In order to investigate the relationship between phytoplankton community structure and environmental factors in Sanbanxi Reservoir, a nitrogenlimited deep reservoir of Guizhou Plateau, phytoplankton and water were sampled in December (wet season) 2012, and in April (normal season) and August (dry season) 2013. There existed 87 genera and 6 phyla phytoplankton in the samples, which were mainly composed of the Chlorophyta, Bacillariophyta and Cyanobacteria. In wet, normal and dry seasons, the phytoplankton abundance ranged from 0.064×104 to 1.17×104 cells·L-1, from 8.21×104 to 422.47×104 cells·L-1, and from 9.08×104 to 2903.33×104 cells·L-1 respectively. The phytoplankton abundance of dry and wet seasons peaked in Jiachi and was minimized in Nanjia, and that of normal season peaked in Daba and was minimized in Nanjia. The dominant species were Melosira granulata, Fragilaria capucina and Microcystis marginata in dry, normal and wet seasons, respectively. The phytoplankton mainly distributed at the surface of 0 to 10 m, and its abundance decreased with water depth. The concentrations of total phosphorus averaged at 0.403 mg·L-1 in Sanbanxi Reservoir, ranging from 0.281 to 1.139 mg·L-1 in dry season, from 0.394 to 0.639 mg·L-1 in normal season, and from 0.054 to 0.736 mg·L-1 in wet season. The mean concentration of total nitrogen was 1.38 mg·L-1. The N/P ratio (3.7:1) was lower than the most appropriate ratio 7:1 of phytoplankton, indicating that nitrogen is the limiting factor in Sanbanxi Reservoir. RDA analysis and Pearson analysis showed that water temperature was the key environmental factor, and N/P ratio was the important factor, regulating the phytoplankton community composition in the Sanbanxi Reservoir. Nutritive salt can affect phytoplankton community composition via improving the growth of Bacillariophyta and limiting the growth of Cyanobacteria.
    Inhibitory effects of aqueous extracts of thirty aromatic plants on urea hydrolysis and nitrification.
    SHI Yun-feng1,2, ZHANG Fan1, XU Xiao-xiong1, ZHANG Li-li2, ZHAO Mu-qiu1**
    2014, 33(12):  3440-3446. 
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    An incubation experiment was carried out to investigate the effects of aqueous extracts of 30 aromatic plant species from 17 families on urea hydrolysis and nitrification in 3 soils. The results indicated that the aqueous extracts from 22 of the aromatic plants could inhibit urea hydrolysis, and 5 of the extracts showed better effects than urease inhibitor hydroquinone (HQ). The aqueous extracts from 30 of the aromatic plants could inhibit nitrification of NH4+, and 11 of the extracts showed better effects than nitrification inhibitor dicyandiamide (DCD). Chamomila recutita belonging to Asteraceae and Citrus reticulate belonging to Rutaceae could effectively inhibit both urea hydrolysis and nitrification, and hence may be applied as synergist of urea. The results also indicated that the best inhibitory effects of C. recutita and C. reticulate on urea hydrolysis and nitrification appeared during 24-36 h and during 7-14 d of incubation, respectively, and their inhibitory effects increased with increasing their dosages.
     
    Research progress of mineral weathering by ectomycorrhizal fungi.
    WEI Song-po, JIA Li-ming**
    2014, 33(12):  3447-3454. 
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    As an important part of ecosystems, ectomycorrhizal fungi play a significant role in many microbiological and biogeochemical processes, influencing cycling of minerals, boosting soil fertility, and improving plant nutrition. Research advances on mineral weathering by ectomycorrhizal fungi in recent years are reviewed and a brief perspective is provided in this paper. Recent research suggests that ectomycorrhizal fungi may accelerate mineral (apatite, biotite and vermiculite) weathering processes through pressurization, soil acidification of the mycorrhizosphere, and complexation of metal cations with organic acids. Ectomycorrhizal fungi may actively release phosphorus, potassium, magnesium, and other nutrients from apatite, phlogopite, biotite, vermiculite, and certain rock particles. The mineral weathering of ectomycorrhizal fungi is influenced by a number of factors, such as the presence of different types of minerals and fungi, soil nutrient conditions, various forms of nitrogen in different concentrations, growth conditions (pure or symbiotic growth) of fungi, and the presence of other rhizosphere microbes. The processes and mechanisms of ectomycorrhizal weathering can be understood through weathering budgets, analysis of microbial exudates, observations of the mineralfungal interface, and observations of the distribution of carbon. However, quantification of the effects of ectomycorrhizal weathering and the relative contribution of ectomycorrhizal inorganic nutrient mobilization to nutrient cycling has to be further studied.
    Research progress on the methods of cyanobacterial toxin removal.
    JIANG Min1,2**, WANG Jing1, XU Hui1
    2014, 33(12):  3455-3462. 
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    Cyanobacterial toxin is the secondary metabolite produced by cyanobacteria. It has serious toxicity and carcinogenicity to human or terrestrial animals, and it may damage the structure and function of water ecosystems. Environmental and health issues caused by the frequent occurrence of toxic algal blooms have become research hotspots in the field of environmental science. Available water treatment facilities being used nowadays to remove cyanobacterial toxin from drinking water are unsatisfying, so searching an efficient method for removing algal toxin is an urgent issue to be solved. This paper described the production and release mechanism of cyanobacterial toxin firstly, divides the removal methods of cyanobacterial toxin into two categories, as algae removal and the removal of dissolved toxin in water. In addition, current degradation pathways of cyanobacterial toxin were reviewed based on a large number of research results. The details of activated carbon adsorption, advanced oxidation degradation, microbial degradation and other removal methods that have practical application prospects were introduced. Finally, this paper summarized the limitations of current cyanobacterial toxin removal methods, and points out that the future methods should be highly efficient, with low energy consumption, pollution free and practicable.
     
    Formation process and characteristics of “Fertile island” and “Arthropod island” in desertified shrub land and their relations to ecosystem succession.
    LIU Ren-tao1,2**
    2014, 33(12):  3463-3469. 
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    Shrubcovered “Fertile island” and “Arthropod island” in desertified land have special ecological implications, and their interactions contribute much to the succession of ecosystems. There is a close relationship between “Fertile island” and grazing management, and between “Arthropod island” and shrub age. Both kinds of islands are usually combined together. “Arthropod island” facilitates the formation of “Fertile island” in feedback, which could improve the succession process of ecosystems. Future studies should be focused on the following fields: (1) The formation mechanism of “Arthropod island” and their feedback to the microhabitats. (2) The relationship between “Arthropod island” and grazing management in light of shrub species identity and stand age. (3) Controlled microcosm experiments with consideration of soil, vegetation, arthropod, microhabitat, and microbe influenced by shrub canopy and identity. (4) “Arthropod island” formation and bioindicators, and their relations to ecosystem succession, which are essential for the management of artificial shrub land.
    Modification of similarity method and its application in optimization design of river quality monitoring section in the mainstream of Hun River. 
    WANG Hui1, SUN Jia-jun2, SUN Li-na1**, LIU Zhe3
    2014, 33(12):  3470-3474. 
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    As a fuzzy evaluation method, the similarity method has been widely applied in evaluation on pollution level of heavy metals in soil and water environment. Due to lack of quantitative approach to point selection after optimization, this study improved the similarity method by integrating the method of the distance to the center of gravity in order to enhance the accuracy and rationality of results. The improved similarity method was applied to optimize 7 monitoring sections of the main stream of the Hun River. Then, the results were validated by Ttest and Ftest after optimization. The number of the water monitoring sections was reduced to 5 after optimization, and the water quality after optimization had no significant difference compared to that before optimization, which indicated that the improved similarity method has the advantage practical application the optimization of monitoring sections of water quality.