Table of Content

10 September 2015, Volume 34 Issue 9

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Community type classification and species diversity of Pinus massoniana forest of Dayuan Creek.

TANG Min-zhong, ZHANG Chao, HAN Rui-yin, CHEN Jian

2015, 34(9):  2381-2389. 

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The community types of Masson pine forest of Dayuan Creek were classified by using flexible beta clustering, DCA and CCA. Meanwhile, the species diversity in the Masson pine forest was studied. The results showed that: (1) 27 sample plots containing Masson pine were classified into 8 community types and the classification showed explicit distribution boundaries in DCA by flexible beta clustering, so the dominant species of tree layer was an ideal basis of the classification to forest community. (2) Monte Carlo Permutation Test showed that the result of CCA ordination could not accept that the environmental factors explained the species distribution in plots, because the forest in the research area was seriously disturbed by human activities. However, combined with the eigenvalue of order axes, it was inferred that soil available nitrogen content was strongly correlated with species distribution. (3) The importance value of Masson pine had a marginally significant correlation with elevation, soil available nitrogen and available phosphorus contents, while it was negatively related to the diversity of the tree layer and herbaceous layer. (4) The analysis of variance showed that, compared with mixed broadleafconifer forest and evergreen broadleaf forest, the species diversity of tree layer in Masson pine forest was significantly lower while the differences were not obvious for the shrub and herb layers.

Responses of soil seed banks in tropical forests to an elevational gradient.

ZHANG Min1,2**, SONG Xiao-yang1,2

2015, 34(9):  2390-2400. 

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Knowledge about how soil seed banks in tropical forests respond to elevational gradients is crucial for predicting how tropical forests adapt to climate change. Soil seed banks of tropical forests in Xishuangbanna were investigated by setting transects and plots at four elevations (800, 1000, 1200, and 1400 m), in which soils were sampled and transported to a greenhouse for seed germination. The results showed that: (1) Seed density and species richness were the highest at 800 m; while the lowest seed density and species richness occurred at 1400 and 1200 m, respectively. NMDS analyses based on Bray-Curtis similarity indices showed great distinctions in species composition of soil seed banks among the 4 elevations. (2) The abundance of nonconstituent species in soil seed banks varied along the elevation gradient; nine species were found at 800 m, while only five at 1400 m. The number of individuals for nonconstituent species peaked at 1200 m. (3) The similarity in species composition between standing vegetation and soil seed banks was low at all elevations (<15%). All of these results suggested that forest soil seed banks respond significantly to the changes in elevation in Xishuangbanna.

Estimation on stock volume of  plantation forests using ALOS PALSAR images:  A case study of Larix principisrupprechtii plantations in Saihanba Forest Farm.

HUANG Li-yan1,2,3, YAN Qiao-ling1,2**, GAO Tian1,2, ZHU Jiao-jun1,2

2015, 34(9):  2401-2409. 

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Accurately estimating stock volume of plantation forests based on remote sensing images is important for regional forest management. In this study, stepwise multiple regression models were developed to describe the relationships between different remote sensing datasets \[Advanced Land Observing Satellite (ALOS) Phased Array Lband SAR (PALSAR) normalized backscatter data, Landsat-8 Operational Land Imager (OLI) data, Lband ALOS PALSAR data and Landsat-8 OLI data\] and fieldbased stock volume in a Larix principisrupprechtii plantation forest landscape (Saihanba Forest Farm) in North China, and an approach to estimating stock volume of plantation forests was provided in this study. The regression models were assessed based on the reserved samples and the optimal model was selected to estimate the distribution of stock volume of larch plantation. Our results showed that the exponential model regressed by HV normalized backscatter of PALSAR had the highest estimation accuracy (R²=0.67, the relative RMSE=26.78%, P<0.01), and the total stock volume was estimated to be 4.7×10⁶ m³ by using this model. A saturation effect of HV normalized backscatter was observed when the stock volume was greater than 250-300 m³·hm^-2. The stock volume of larch plantation forests increased with stand ages; the stock volumes were 78, 97, 136 and 127 m³·hm^-2 for <20, 20-30, 30-40 and >40 years old stands, respectively.

Effects of different epiphyllous species on the growth of Dendrobium nobile.

XIAO Yu1, YANG Zeng-jiang1**, LIN Guo-xiong2, XU Da-ping1, ZHANG Ning-nan1, LIU Xiao-jin1

2015, 34(9):  2410-2414. 

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Dendrobium nobile, an epiphyllous herb, has a high medicinal value. A growth experiment of D. nobile was conducted on 9 tree species in south China. The survival rate, height, diameter and biomass of the herb were determined to assess the growth behavior of the herb on different planting heights of different trees. Results showed that tree species and planting height had significant effects on the growth and biomass accumulation of the herb. Among the 9 trees, D. nobile grew best on Acacia mangium and worst on Araucaria cunninghamii. After 18 months’ growth, D. nobile on Acacia mangium accumulated 26.3% more biomass than on A. cunninghamii. A. confusa behaved similarly to A. mangium. A comprehensive index of growth behavior was computed to evaluate the suitability of D. nobile growth. A. mangium got the highest value of 0.77, compared to 0.44 for A. cunninghamii. Middle height (1.2-1.5 m above ground) was the best position, with more biomass than at the low height (0.6-0.9 m) and the high position (1.8-2.1 m) (4.7% and 9.8%, respectively). We concluded that the middle position of 
A. mangium tree was the ideal habitat for the growth of D. nobile in plantations of south China.

Spatial distribution of natural Haloxylon ammodendron forest in relation to topographic undulations in Tamushu.

LIU Hong-mei1, LYU Shi-jie2**, LIU Qing-quan1, CHAI Xiang-xian3, WANG Meng3, WANG De-hui4, NIE Yu-qian2

2015, 34(9):  2415-2423. 

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In order to study the spatial distribution of Tamushu natural sacsaoul (Haloxylon ammodendron (C. A. Meyer) Bunge) forest and its relationship with topographic undulation change (GPS altitude point), Tamushu wild Cistanche and H. ammodendron seed production base in Tamushu region at the eastern edge of the Badain Jaran Desert was chosen as test area and its H. ammodendron forest as study object. Line transect was used to survey plant height and crown diameter of H. ammodendron and H. ammodendron density was counted in combination with GPS points. Various analysis methods were then used to explore the relationship of spatial distribution of natural H. ammodendron forest with topographic undulations. It was found that quantitative features of H. ammodendron forest had highly significant correlation (P <0.01) with topographic undulation, and both were affected by structural factors within the autocorrelation scale, in which the spatial autocorrelation was to a high degree and spatial distribution pattern was simple. Furthermore, the complexities of density, height, crown diameter of H. ammodendron forest and topographic undulation decreased successively. The results also showed that H. ammodendron invaded the sand dune from its southern side and spread rapidly due to prevailing winds in this region. Hence, the dunes moved forward slowly, functioning as wind prevention and sand fixation. The results of this study provide a scientific reference for establishment of seed production base.

Correlations among leaf traits of typical shrubs and their responses to different light environments in shrubgrassland of southern China.

GAO Jing1,2, XU Bo1,2, WANG Jing-niu1,3**, ZHOU Hai-yan4, WANG Yan-xing1,2, WU Yan1**

2015, 34(9):  2424-2431. 

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It is widely accepted that light, one of the critical environmental factors, affects growth and distribution of plants. Leaf traits, which are of crucial importance to capture carbon, are generally consistent across environmental gradients. There are also similar patterns of correlations among different leaf traits, so it is essential to explore how leaf traits respond to and adapt to different light environments for a comprehensive understanding of ecosystem management. Our study aimed to investigate leaf traits and their correlations inside and outside the forests of three typical shrubs (i.e. Salix etosia, Rubus setchuenensis and Hydrangea aspera) in shrubgrassland of southern China. Field sampling survey was carried out to collect leaves under different light environments (inside and outside the forests) in Yunyang County. The results showed that the correlations among leaf traits of three shrubs vary one to another, i.e. speciesspecific. There was no significant difference in leaf traits of S. etosia under different light environments, while significant differences in leaf traits were found for R. setchuenensi and H. aspera. Both SLA and LNC of R. setchuenensi and H. aspera increased inside the forests for adapting to lower illuminance. In addition, LCC of H. aspera increased significantly inside the forests, which indicated a relatively strong carbon fixation capacity. Leaf traits of R. setchuenensis and H. aspera were mainly affected by soil temperature under different light environments. Our study demonstrated that there existed the phenotypic plasticity for plant leaf traits, and different plants had speciesspecific responses as well as strategies to adapt to different environments.

Effects of warming and clipping on vegetation species diversity and belowground biomass in an alpine meadow.

XU Man-hou1**, LIU Min1, XUE Xian2, ZHAI Da-tong1, PENG Fei2, YOU Quan-gang2, LIU Zhong-quan3

2015, 34(9):  2432-2439. 

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Alpine meadow in China is degrading, seriously influencing species diversity and biomass production of vegetation. In this study, we chose a typical alpine meadow in QinghaiTibetan Plateau as a model system by establishing four treatments, including control (CK), 3-year warming (W), 2-year clipping (C), and 3-year warming + 2-year clipping (WC). The experiment followed a randomized block design consisting of five replications. We measured  species diversity (Margalef index, Shannon index, Simpson index and Pielou index) and belowground biomass of the vegetation in all treatments during the growing season of 2012 and 2013. The aim of this study was to assess the effects of warming and clipping on plant species diversity and  belowground biomass. The results showed that: (1) Species diversity was significantly higher in the middle growing season (from June to August) than in the early (May) and late (September) growing season. (2) The response of species diversity was not sensitive to 3-year warming and 2-year clipping, and species diversity was slightly increased in the W and C treatments while slightly decreased in the WC treatment. (3) Warming and clipping tended to increase vegetation belowground biomass and caused the variation of allocation pattern of belowground biomass across different soil layers. Clipping had significant effects on biomass in the 0-30 cm soil layer, whereas warming had significant effects on biomass in the 30-50 cm soil layer.

Effects of magnesium levels on seedling growth and photosynthetic characteristics of Tung tree.

LI Ze, TAN Xiao-feng**, LU Kun, ZHANG Lin, LONG Hong-xu, LU Jia-bin, LIN Qing

2015, 34(9):  2440-2447. 

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This study focused on the effects of magnesium (Mg²⁺) on growth, photosynthetic characteristics and chlorophyll fluorescence parameters of Tung tree leaves under sandy culture conditions. The results showed that the optimal concentrations of Mg²⁺ for Tung tree growth and photosynthesis were 2-4 mmol·L^-1. Under low Mg concentration (Mg²⁺ <2 mmol·L^-1), the growth of Tung tree was inhibited. This low level of Mg²⁺ resulted in significant decreases of leaf chlorophyll content, RuBP carboxylase and PEPC activities, net photosynthetic rate (P_n), stomatal conductance (G_s), transpiration rate (T_r), stomatal limitation value (L_s), water use efficiency (WUE), maximum photochemical efficiency (F_v/F_m), Φ_PSII,F_v/F_o and q_P, but increases of intercellular CO₂ concentration (C_i), F_o and NPQ. Under high Mg stress (Mg²⁺ >4 mmol·L^-1), the growth of Tung tree was also inhibited. The chlorophyll content, RuBP carboxylase activity, P_n, G_s, F_v/F_m, F_v/F_o and q_P were reduced (P<0.05). With the increasing Mg supply, the growth, chlorophyll content, RuBP carboxylase and PEPC activities, P_n and Φ_PSII all exhibited a trend of increasing initially and decreasing later. The decrease of net photosynthetic rate in Tung tree seedlings under Mgdeficient stress was probably due to nonstomatal factors.

Species composition of bryophyte crusts and microhabitat formation under artificial vegetations in Huangfuchuan Watershed, Inner Mongolia, China.

TIAN Gui-quan1**, ZHAO Dong-ping2

2015, 34(9):  2448-2456. 

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Based on the investigation of bryophyte communities in four artificial vegetations including Caragana intermedia scrub, Populus simonii forest, Platycladus orientalis forest and Pinus tabuliformis forest in Huangfuchuan Watershed (Inner Mongolia), the species composition, mosses patches in microhabitats of the same vegetation, as well as the formation and development mechanism of bryophyte crusts were studied. A total of 23 species in 15 genera and 8 families of bryophytes were found. The sum of relative coverage of Bryum argenteum, B. dichotomum and Didymodon vinealis in four vegetations was above 95%. In the thinnest moss crust of microhabitats, the heights of B. argenteum, B. dichotomum and Didymodon vinealis were 0-(0.93±0.04), (0.72±0.03)-(1.82±0.04) and 0-(2.82±0.08) mm with the densities of 0-(11.08±0.28), (2.30±0.23)-(20.08±0.55) and 0-(29.56±1.07) plants·cm^-2, respectively. In the thickest moss crust of the microhabitat, the heights of B. argenteum, B. dichotomum and D. vinealis were (3.23±0.09)-(6.55±0.12), (5.99±0.08)-(11.64±0.11) and (7.71±0.11)-(22.05±0.23) mm with the densities of (64.34±1.54)-(400.12±2.87), (216.23±3.23)-(356.27±2.19) and (32.27±0.99)-(236.03±2.48) plants·cm^-2, respectively. Thickness of moss crusts, height of subterraneous section and aboveground section of plants of three kinds of dominant species were also obviously different among the four vegetations. Finally, some measures of artificially promoting formation of moss crusts were put forward based on the analysis of distribution of species, succession of moss crusts and correlations of all indexes of moss crusts in microhabitats.

Decomposition, carbon and nitrogen stable isotopes and chemical composition of dead leaves clinging in a Chinese fir (Cunninghamia lanceolata) plantation.

GAO Shi-lei1,2, HE Zong-ming1,2**, HUANG Zhi-qun3, LIN Si-zu1,2, LIU Zhuo-ming1,2

2015, 34(9):  2457-2463. 

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The decomposition and nutrition release of the dead canopy leaves and branches are critical for the nutrient cycling in Chinese fir (Cunninghamia lanceolata) because they can cling to stems for several years and are of large biomass. In this paper, we estimated the decomposition degree of these dead leaves in the canopy of different heights in a 17yearold C. lanceolata plantation by determining the leaf mass per area. We also measured carbon (C)/nitrogen (N) ratio, C and N isotope compositions and chemical compositions of the dead leaves. The results showed that the leaf mass per area of the dead leaves at the lower canopy was lower. The leaf mass per area of the dead leaves in 8-10 m (26.02 mg·cm^-2) was much higher than the leaves that just died (23.12 mg·cm^-2) and the leaves in 6-8 m (15.39 mg·cm^-2). However, there was no significant difference in the leaf mass per area of dead leaves at 0-2, 2-4, or 4-6 m. C and N concentrations in the recently dead leaves were significantly lower than in the dead leaves clinging to branches of different heights. No significant differences in C and N concentrations and in C/N ratio were found between the dead leaves clinging at different heights of canopy. The C/N ratio (67.58) in the recently dead leaves was significantly higher than that in the dead leaves clinging to the branches of different heights. When the C/N ratio in the dead leaves clinging to the branches reached 45.91±0.45, the nitrogen started to release. The values of δ¹⁵N of the recently dead leaves and the dead leaves clinging at canopy of 8-10 m height were greater than in that of the dead leaves clinging at canopy of other heights. However, no difference was found for the dead leaves clinging at the canopy of 0-2, 2-4, 4-6, and 6-8 m. The values of δ¹³C in dead leaves clinging at the canopy of different heights were not significantly different. Moreover, we demonstrated that polysaccharide C and aldehyde acetal C in the dead leaves clinging at the canopy decomposed firstly and then followed by alkyl C, aromatic C, phenol and carboxyl C.

Long-term pattern and driving factors of cladoceran community changes in Lake Xingyun, Yunnan.

SHI Hai-bin, CHEN Guang-jie**, LIU Yuan-yuan, LU Hui-bin, CHEN Xiao-lin, DUAN Li-zeng, ZHANG Hu-cai

2015, 34(9):  2464-2473. 

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Xingyun Lake, a large and hypereutrophic lake in Southwest China, has experienced deterioration of water quality and degradation of ecosystem functioning during the past few decades. Despite the fact that this lake has suffered from multiple environmental stressors (i.e. eutrophication, fish invasion and hydrological regulation), few studies have examined their interactive roles in driving lake communities. Therefore, it is urgently needed to identify the pattern of multiple stressors in driving longterm ecosystem changes in Xingyun Lake. In combination with lake survey and historical data, we conducted multiproxy analyses of sediment records for Xingyun Lake with a focus on cladoceran community. We identified 10 genera and 16 species of cladocerans from sediments, with taxa such as Chydorus and Bosmina generally dominating through the sediment cores. The concentration of Chla pigments remained consistently low before 1890, but thereafter rose slowly and was concurrent with the increased proportion of sand particles (>63 μm). From 1980, the Chl-a level began to rise rapidly with increasing abundance of C. sphaericus which is known to tolerate high nutrient levels. Further analysis showed that total cladoceran production increased significantly with increased lake productivity (R²=0.753, P <0.001, n=33), and primary production was also a significant driver of cladoceran community change (R²=0.953, P<0.001, n=33). In addition, changes in predation pressure associated with fish introduction have led to an obvious reduction of Bosmina production. The gradual loss of macrophytes due to eutrophication and water level fluctuation may have caused the decline or even decimation of benthic cladocerans. In all, cladoceran community in Xingyun Lake has experienced longterm changes over the past century with nutrient enrichment identified as the key environmental driver. Furthermore, we found evidence for the impacts from fish introduction, hydrological fluctuation and change in macrophytes. Our sediment evidence of longterm ecological changes in Xingyun Lake can provide supplemental information for catchment management and lake restoration.

Effects of DCPTA on root growth, osmotic adjustment and cell membrane permeability of maize seedlings under salt stress.

ZHANG He1,2, GU Wan-rong1,2, WANG Yong-chao1, LI Li-jie1, ZENG Fan-xing1, YANG Zhen-fang1, YANG De-guang1,2, WEI Shi1,2**

2015, 34(9):  2474-2481. 

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The salinealkali land area is about 667000 hm² in the western Heilongjiang Province, and the salinealkali soil restricts the further enhancement of food production level in the province. The diethylaminoethyl3,4dichlorophrylether (DCPTA) is one of tertiary amines active substances, playing an important role in improving crop resistance. The objective of this study was to investigate the mechanism of maize salt tolerance enhanced by DCPTA. A hydroponic experiment was performed with ‘Xianyu 335’ (salttolerant) and ‘Fenghe No. 1’ (saltsensitive) to investigate the effects of DCPTA (15 mg·L^-1) on root growth, osmotic adjustment and cell membrane permeability of maize seedlings under salt stress (150 mmol·L^-1). The results showed that exogenous DCPTA application led to a marked increase in root length, root surface, root volume, root fresh weight and root dry weight of seedlings, alleviating growth inhibition under salt stress. In comparison with salt stress, DCPTA could maintain the water balance of roots and improved the relative water contents of ‘Xianyu 335’ and ‘Fenghe No. 1’ seedlings by 3.6% and 6.4%, respectively. DCPTA enhanced the osmotic adjustment ability of maize seedling roots by increasing soluble sugar and soluble protein and decreasing proline content. The exogenous DCPTA may play an important role in stabilizing root plasma membrane structure and function. The malondialdehyde (MDA) content and relative conductivity of ‘Xianyu 335’ and ‘Fenghe No. 1’ under DCPTA pretreatment were decreased by 21.6% and 24.2%, and 28.1% and 30.4%, respectively. The mitigating effects of DCPTA on root damage by salt stress of ‘Fenghe No. 1’ were greater than those of ‘Xianyu 335’.

Simulating the impact of drought on spring maize biomass and yield.

WU Rong-sheng1, WU Rui-fen1**, SUN Xiao-long1, TIAN Lei2, HOU Qiong1, ZHANG Chao1, SUN Lin-li3

2015, 34(9):  2482-2488. 

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Based on WOFOST crop growth model, we simulated the impacts of different drought intensities during jointing to tasseling and tasseling to milkripe stages on spring maize biomass and yield in Inner Mongolia. The results showed that the rates of grain-filling intensity, yield, biomass increment and biomass decreased with the increase of drought degree. After rewatering, the grain-filling intensity and biomass increment were rapidly restored to the level without drought. Grainfilling intensities under light drought, moderate drought and serious drought were reduced by 14.8%-15.4%, 40.9%-42.9% and 52.4%-60.8% respectively. Meanwhile, the yields were reduced by 1.9%-6.1%, 9.5%-15.4% and 18.6%-25.8%, the biomass increments were reduced by 12.6%-12.8%, 31.0%-35.5% and 50.4%-50.8%, and the biomasses were reduced by 2.9%-6.1%, 6.9%-19.4% and 12.0%-32.1% accordingly. The grain-filling period was differently affected by droughts from jointing to tasseling and from tasseling to milkripe stage. The yield loss was higher when the drought occurred from tasseling to milkripe stage because the grain-filling intensity at peak and decline phases was both influenced at this developmental stage. The droughts from jointing to tasseling stage and from tasseling to milkripe stage affected the peak and decline phases of assimilate accumulation, respectively. The duration of the impact by drought from jointing to tasseling stage was longer; therefore, the descent rate of biomass affected by drought was more obvious in this period than that from tasseling to milkripe stage.

Dynamic early warning of occurrence degree for wheat powdery mildew in Hebei.

ZHANG Lei1,3, HUO Zhi-guo1,2**, WANG Li4, WU Li1, ZHANG Gui-xiang1

2015, 34(9):  2489-2497. 

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Based on disease index for winter wheat powdery mildew and meteorological data in Zhengding, Xinji, Guantao and Cixian in Hebei Province during 2001-2010, the key period and key factors were selected using correlation analysis, path analysis, Bayes criterion, Fuzzy math and generalized regression neural network. Bayes grade index model, Fuzzy model and GRNN model were constructed for dynamic early warning of occurrence degree of wheat powdery mildew. The results indicated that the key factors affecting occurrence degree of wheat powdery mildew were mean temperature from the previous three pentads to the current pentad, precipitation from the previous three pentads to the current pentad, rain coefficient from the previous three pentads to the current pentad, and the previous pentad occurrence degree of wheat powdery mildew. The three early warning models had progressively transformed relationships, and the prediction accuracy rates were all above 85%, which could be well applied in early warning of wheat powdery mildew at the pentad scale. Compared with Fuzzy model and Bayes grade index model, GRNN model had the highest prediction accuracy rate. The results can provide useful information that contributes to a better understanding of occurrence of wheat powdery mildew in Hebei and help make policy for disease risk management.

Dynamic variation of water deficit of spring wheat and sensitivity analysis of meteorological factors in eastern Qinghai.

ZHANG Tiao-feng1**, WANG Qing-chun1, HU Ai-jun2, WANG Zhi-jun1, SHEN Hong-yan1

2015, 34(9):  2498-2505. 

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Based on PenmanMonteith model and partial derivatives, this paper analyzed the meteorological and crop data during 1961-2013, to assess the spatial dynamic variation of water deficit of spring wheat at different growth stages in the plateau agricultural region of eastern Qinghai Province. Meanwhile, sensitivity coefficients of the mean temperature, relative humidity, wind speed, and sunshine duration were studied. The result identified an increasing trend of water deficit of spring wheat at each growth stage since 1988. Moreover, the drought degree of spring wheat showed more aggravation during the period between sowing and jointing stages along the line of GuideJianzhaXunhua; the drought degree of spring wheat showed an increasing trend in the period between jointing and heading stages in the regions of “TongrenHualongMinhe”, where the change range was the largest. However, a decreasing trend of water deficit was found in most parts of the whole region studied during the period between heading and maturing stages. The profit/loss amount of precipitation in the whole growth stage was the most sensitive variable to sunshine duration. The positively sensitive area to average air temperature was distributed in the valley of Huangshui River, while that to relative humidity, wind speed and sunshine duration was distributed in the northwestern part of eastern Qinghai. The findings from this study provide theoretical guidance on water resources management and regional irrigation scheduling.

Response of Avena nuda L. seedlings to salt stress and the modulation of hydrogen peroxide. 

LIU Jian-xin**, WANG Jin-cheng, WANG Rui-juan, JIA Hai-yan

2015, 34(9):  2506-2511. 

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To understand the regulative effect of exogenous H₂O₂ on the physiological and biochemical responses of oat (Avena nuda L.) seedlings under salt stress, a new cultivar, ‘Dingyou No. 6’ seedlings grown in Hoagland’s nutrient solution was used to investigate the effects of exogenous H₂O₂ on active oxygen metabolism, osmoticum accumulation and homeostasis of Na⁺, K⁺ in leaves of oat seedlings under NaCl stress. Exposure to NaCl at 50-100 mmol·L^-1 did not have significantly unfavorable effect on plant growth, however, exposure to 150 mmol·L^-1 and above of NaCl caused reductions in the plant dry weight and K⁺/Na⁺ ratio, and increases in the O₂^-_·  generation rate, contents of H₂O₂, malondialdehyde (MDA), soluble protein and praline, and activities of catalase (CAT) and plasma membrane H⁺ATPase in the seedling leaves, but no detectable changes in ascorbic acid (ASA) and glutathione (GSH) contents. The addition of 5 μmol·L^-1 H₂O₂ significantly alleviated the inhibitory effect of 150 mmol·L^-1 NaCl stress on the growth of oat seedlings by increasing the activities of superoxide dismutase (SOD), ascorbate peroxidase (APX) and CAT and the contents of GSH and H₂O₂, and decreased O₂^-_·  generation rate and MDA content in the seedling leaves. In addition, exogenous H₂O₂ supply also increased the contents of soluble protein, soluble sugar, organic acid and proline, plasma membrane H⁺ATPase activity and K⁺/Na⁺ ratio, while decreased free amino acid content in plant leaves under 150 mmol·L^-1 NaCl stress. These results indicated that exogenous H₂O₂ could enhance the tolerance of oat seedlings to salt stress by modulating antioxidative defense system and osmoticum accumulation, and maintaining K⁺/Na⁺ ratio in plant leaves.

 

Influence of environmental factors on hyporheic macroinvertebrate assemblage in the upper reaches of Heishuitan River.

ZHANG Yue-wei1,2,3, YUAN Xing-zhong1,2,3**, LIU Hong3, REN Hai-qing1,2,3, DENG Wei1,2,3, WANG Xiao-feng1,2,3

2015, 34(9):  2512-2520. 

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In order to study the influence of environmental factors on community structure and distribution of hyporheic macroinvertebrates at a microscale, we chose five sites to investigate hyporheic macroinvertebrates and habitat characteristics in the upper reaches of Heishuitan River. Our results indicated that a total of 29 species of macroinvertebrates were collected, and aquatic insects were the dominant group. The density, biomass and richness of macroinvertebrates decreased with the bed depth. The composition and distribution of the hyporheic macroinvertebrates were determined by median diameter (D₅₀) of sediments, vertical hydrological gradient (VHG) and vertical hydraulic conductivity (K_v), and D₅₀ was the most important factor. Besides, the food sources and the interactions of macroinvertebrates may also play important roles in affecting community structure of hyporheic macroinvertebrates. All of these factors formed a complex natural filter to control the composition and distribution of the hyporheic macroinvertebrates.

Influence of Fokienia hodginsii forest environment on the spontaneous behaviors of mice.

WANG Qian1,2, WANG Cheng1,2**, DONG Jian-wen3

2015, 34(9):  2521-2529. 

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The effects of ecological health care factors on spontaneous behaviors of mice were studied through 6-day continuous observation in an open field. The results showed that: 1) The total movement distance of the experimental group was significantly longer than the control, indicating that the excitability of mice in Fokienia hodginsii forest was increased. 2) The traveling distance in the center for the experimental group was longer than that of the control except for the first day, indicating that the excitability and cognitive ability of mice after treated with the forest environment were improved. 3) With respect to the frequency of traveling in the center, the experimental group was lower than the control in the first day and the sixth day, but was higher in the other 4 days. In addition, the experimental group had longer residence time in the central grid than the control in the 6 consecutive days, suggesting that after treatment in the forest environment, the anxiety of the mice was positively remedied, and the exploring capability was enhanced to some extent. 4) In the 6-day experiment, the weight of experimental group was always higher than that of the control, but the waste grain number of the experimental group was less than the control, indicating that the appetite of the mice treated with the forest environment was improved dramatically, and the sense of tension was relatively decreased on the other hand. 5) From the typical trajectory, the frequency of the experimental group entering the central grid was higher than that of the control, and the total distance was longer, which indicated that the amount of mice exercise after treatment in the forest environment increased and the mental status was improved. 6) Comparing between indoor and outdoor health factors, we found a large gap between them, i.e. the Fokienia hodginsii forest was superior to indoor environment, and was suitable for development and exploration of human health functions.

Embryonic development of wild Phoxinus lagowskii Dybowskii collected from Suifen River in Heilong River Valley.

GUO Wen-xue1, ZHANG Yong-quan1, TONG Guang-xiang1, CHEN Zi-wen2, QI Peng2, YIN Jia-sheng1**

2015, 34(9):  2530-2536. 

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The features of embryonic and early larvae development of Phoxinus lagowskii Dybowskii were studied by live body observing and fixed samples observing methods. The results showed that the mature oocyte eggs of wild P. lagowskii are spherical in shape, slightly transparent with light yellow in color, sinkadhesive with moderate and elastic egg envelopes. At water temperature of 15.0-17.1 ℃, the development of fertilized eggs from fertilization to hatching took 170 h with an accumulative temperatures of 2612.8 ℃·h. The whole embryonic development processes of P. lagowskii were divided into 6 stages, including fertilization stage, cell division stage, blastula stage, gastrula stage, neurula stage and organogenesis stage, and the accumulative temperatures of each stage were 17.0, 119.0, 145.0, 132.0, 164.0, and 2035.8 ℃·h, respectively. The organs differentiated during the embryonic development stage and basically formed after hatching, and pectoral fin, caudal fin and anal fin were fully differentiated, and dorsal fin anlage appeared. The newly hatched larvae were diaphanous and nonpigmented with an ellipticshape yolk sac. At 3 days after hatching, black spots at body surface gathered into blocktype and the yolk sac was nearly exhausted, soon after the larvae can ate exogenousfood such as microalgal diets, paramecia and egg yolk.

 

Comparison of aging methods and discrimination analysis on age classification for Gymnocypris eckloni. 

WEI Chao-jun1,2, SHEN Zhi-xin3, JIA Yin-tao1**, LI Ke-mao3, CHEN Yi-feng1

2015, 34(9):  2537-2541. 

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The ability of precisely determining the age of fish is essential for surveying fish ecological traits and fish conservation. In this study, we compared the readability and consistency of age readings, which obtained from three calcified structures (otolith, dorsal spine and anal scale) of Gymnocypris eckloni from the upper reaches of the Yellow River, China, and established a discrimination equation to age the lowage individuals. The readability ranked in a descending order of otoliths > dorsal spines > anal scales. The maximum ages assigned by the otolith, dorsal spine and anal scale were 25, 17 and 16, respectively. Results indicated that dorsal spine was optimal for the individuals aged 6 or less, while otolith was the most suitable structure for those aged 7 or greater. All the samples aged 6 or less were clustered by total length, weight, length and somatic weight. With stepwise discriminant analysis method, total length and weight with significant discrimination ability were selected to establish a discriminant function. The statistical results showed that 88.90% of original grouped cases were correctly classified, and 88.40% of crossvalidated grouped cases were correctly classified, indicating that G. eckloni aged 6 or less could be directly aged by discriminant analysis of total length and weight, with total length ranging from 93 to 259 mm and weight ranging from 6.25 to 177.10 g.

 

Effects of acute salinity stress on clearance rates of Meretrix meretrix and Cyclina sinensis. 

WEI Wei1,2, TANG Bao-jun1**

2015, 34(9):  2542-2545. 

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The clearance rates of adult and juvenile Meretrix meretrix and Cyclina sinensis under acute salinity stress were investigated using static test method. Four salinity levels (21, 15, 10, 5) were set and the algae Platymonas subcordiformis was employed as the indicator diet for the measurement. The results showed that salinity stress had significant effects on the clearance rates of M. meretrix and C. sinensis (P<0.05). Both M. meretrix and C. sinensis could gradually adapt to the changes of salinity, but the duration for adaptation varied. The adult M. meretrix could adapt the salinity change more rapidly than the juvenile.

Effects of forest succession on rodent diversity in the Dujiangyan region, Southwest China.

YANG Xi-fu1,2, XIE Wen-hua1,2, TAO Shuang-lun1, LI Jun-nian1, XIAO Zhi-shu2**

2015, 34(9):  2546-2552. 

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In order to explore the impacts of forest succession on the community structure and diversity of wild animals, we investigated rodent communities using live traps in 21 forest plots at five succession stages (i.e. 0-5, 6-10, 11-20, 21-30 years old and a natural secondary forest (100 years old)) in Dujiangyan, Southwest China during 2012 and 2013. We trapped 9 rodent species in all the sampled plots, including 1 Cricetidae species and 8 Muridae species. Niviventer fulvescens, Apodemus draco, N. confucianus, A. chevrieri and A. latronum occurred in all five stages of forest succession. Species richness and diversity indexes of rodents were similar among the five stages of forest succession, but the number of individuals was slightly higher in the natural secondary forest than in the other succession forests. Multivariate analysis (NMDS and CCA ordination) showed that community composition of the rodents was similar among the five stages of forest succession, but microhabitat factors such as shrub layer and herb layer coverage may have some impacts on species distribution of rodents. Unlike A. chevrieri, N. fulvescens and A. draco were widely distributed in the study area, while the other rodent species showed some microhabitat preferences. Leopoldamys edwardsi lived mainly in the natural secondary forest, N. confucianus and A. latronum mainly distributed under the shrub layer with high coverage, Micromys minutus and Eothenomys melanogaster lived under the herb layer with high coverage, Rattus nitidus lived in the area where the herb layer and the shrub layer had moderate coverage. The above results indicate that species diversity of rodents was similar among different stages of forest succession, but microhabitats following forest succession may largely influence the distribution and diversity patterns of rodents.

Effects of nitrogen addition on soil fauna in poplar plantation with different ages in a coastal area of eastern China.

ZHOU Dan-yan1, BU Dan-rong1, GE Zhi-wei1, YAN Jing2, XIAO Han-ran1, RUAN Hong-hua1**, CAO Guo-hua3

2015, 34(9):  2553-2560. 

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Increased atmospheric nitrogen (N) deposition is a serious threat to the structure and function of ecosystems globally. Soil fauna is sensitive to environmental changes, and increased nitrogen deposition may profoundly influence soil faunal communities. We conducted a field experiment with different N addition treatments (0, 5, 10, 15 and 30 g N·m^-2·a^-1, respectively) to examine the effects of N deposition on the structure of soil faunal communities in poplar (Populus deltoides cv. I₃₅) plantations with different ages (7, 11, 18 years old) in a coastal area of eastern China in May 2012. Our results showed that the individual density of soil fauna increased significantly with increasing the stand age, but 11 years old poplar plantations had the greatest number of soil fauna group. The individual density of soil fauna decreased after an initial increase with the increasing N level, and it was the highest at the addition of 15 g N·m^-2·a^-1. Furthermore, the diversity of soil fauna was significantly correlated with soil TOC and TN. Significant effect of N addition on the diversity of soil fauna community was found only in 11 years old poplar plantation. Shannon diversity index and Pielou index showed a decreasing trend with the increasing N concentration, but Simpson index was completely opposite. In conclusion, N addition may cause great effects on the structure of soil fauna community through altering soil nutrition condition. Moderate N addition had a promoting effect on soil fauna community, but high N addition had a negative effect.

Avian diversity and bird strike avoidance at Shenyang Taoxian International Airport.

DING Zhen-jun, LI Dong-lai, WAN Dong-mei, YIN Jiang-xia, ZHANG Lei**

2015, 34(9):  2561-2567. 

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In order to understand the avian community and provide data for airport managers to avoid bird strike accidents, a bird survey was conducted using three transects and seven sampling points within a radius of 7 km at Shenyang Taoxian International Airport during September 2012 and August 2013. In total, 35 species of birds, belonging to 10 orders and 21 families, were recorded in five habitats including residential area, farming land, mountain, forest, and river. The Shannon diversity index, distribution coefficient and importance value of different avian species in the five habitats were calculated. Furthermore, the bird strike risk index for each bird species was calculated by multiplying the importance value and risk index. Accordingly, four risk levels were clarified as severe, heavy, moderate and low. Severe risk species included Passer montanus, Ardea cinerea, Pica pica, Falco tinnunculus. Heavy risk species included Hirundo rustica, Nycticorax nycticorax, Parus major, Columba livia. 16 species (such as Circus cyaneus, Anas platyrhynchos, Dendrocopos major, Cyanopica cyana) were included in the moderate risk group, and 10 species (such as Turdus chrysolaus, Gallinago megala, Coturnix coturnix, Coccothraustes coccothraustes) in the low risk group. This study provided strategies and suggestions for bird strike avoidance in the airport area.

Spatial variability of soil moisture in hilly and gully Loess Plateau.

WANG Xiao-jun, WU Jiang-tao, WANG Bing**, WEN Fen-xiang

2015, 34(9):  2568-2575. 

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By using the methods of classical statistics and geostatistics, the paper studied the spatial variation of soil moisture (0-300 cm) in horizontal and vertical direction, and the effects of land use and terrain factors in a small watershed in hilly and gully Loess Plateau. The results showed that: (1) Soil moisture content in vertical direction presented a trend of decrease to increase, and the coefficient of variation ranged from 11.22% to 21.05%. There was a significant negative correlation between soil moisture content and the coefficient of variation. (2) The layered distribution of terraces and the slope terrain weakened the spatial autocorrelation of soil moisture in horizontal direction. The variation range was from 19 to 102 m. Increasing sampling density could improve the spatial structure information of soil moisture. (3) There was a strong or moderate spatial autocorrelation of soil moisture in vertical direction, with the variation range from 0.67 to 2.64 m. (4) The sill values of different environmental factors showed an opposite variation trend with the average soil water content. The increase of moisture content had certain smoothing effect on the sill value. The impacts of different land use types on the vertical variation of soil moisture were in order of grassland > woodland > abandoned farmland > cultivated land, while ridge > valley for slope position.

Impacts of fertilizer application on CO₂ emissions in rubber (Hevea brasilensis) plantation in Xishuangbanna, Southwest China.

DONG Yu-xin1,2, ZHANG Yi-ping1**, SHA Li-qing1, JI Hong-li1, ZHOU Wen-jun1, LIU Yun-tong1, ZHANG Xiang1,2, LIN You-xing1,2

2015, 34(9):  2576-2582. 

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Land management has a significant influence on soil CO₂ emission. Rubber trees have been planted in Xishuangbanna since the 1960s and the application of fertilizers is a major part of plantation management. This study investigated the effects of fertilizer application on soil CO₂ emission in rubber plantations in Xishuangbanna. Four treatments were established within a rubber plantation in Xishuangbanna Tropical Botanical Garden: (i) fertilizer application in spring only, (ii) fertilizer application in autumn only, (iii) fertilizer application in both autumn and spring, and (iv) control (no fertilization). Static chamber gas chromatograph was used to monitor CO₂emissions. The results showed that: (1) The seasonal pattern of soil CO₂ emission was the same under all treatments. (2) For all treatments, soil CO₂ emissions were higher during the rainy season than during the dry season, and the total annual emissions were 7.88-7.93 t C·hm^-2·a^-1. (3) Fertilizations produced higher monthly CO₂ emissions than no fertilization. (4) Fertilizations promoted soil respiration to some extent, and caused an increase in soil CO₂ emission, but the differences were not significant (P>0.05). The results of this study revealed soil carbon cycling in rubber plantation and provided a scientific basis for sustainable management of rubber plantations.

Soil chemical properties and microbial community structure at different succession stages of temperate forest in Changbai Mountains.

YUE Lin-yan1,2, ZHENG Jun-qiang1, HAN Shi-jie1**, YANG Jian-hua1,2, GENG Shi-cong1,2, CHEN Zhi-jie1,2, ZHANG Xue1,2, GU Yue1,2

2015, 34(9):  2590-2597. 

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As a major driver in nutrient cycling and energy flowing of terrestrial ecosystem, soil microorganisms are sensitive to the change of soil chemical property. In this study, by a temporalspatial substitution method, a secondary successional chronosequence of five different stages (young broadleaved forest, midaged broadleaved forest, mature broadleaved forest, mature broadleaved Korean pine mixed forest, and old broadleaved Korean pine mixed forest) in Changbai Mountains was chosen to compare the soil chemical properties and microbial community structure by phospholipid fatty acid (PLFA). The result indicted that soil organic carbon (SOC), total nitrogen (TN) and total phosphorus (TP) contents increased over succession while the C/N ratio decreased gradually. Soil microbial biomass, microbial community structure and composition changed with the forest succession. The total PLFAs, bacterial PLFAs, Grampositive bacterial PLFAs, Gramnegative bacterial PLFAs and Grampositive BactPLFA/Gramnegative BactPLFA (G+/G-) increased significantly, while the fungal PLFAs increased firstly and decreased lately. At the middle stage of the succession (mature broadleaved forest), the quantity of PLFA 18:2ω6c (an indicator of fungal biomass) was highest while the ratio of FungPLFA/BactPLFA was lowest. Correlation analysis showed that the microbial biomass was positively correlated with total carbon (TC), SOC, TN, TP contents and negatively correlated with C/N ratio. Redundancy analysis (RDA) indicated that TC, TN, SOC and C/N ratio were the main factors influencing microbial community structure.

Seasonal variations of soil available nitrogen and nitrogen transformation enzyme activities in forest gaps of Pinus massoniana plantations.

LI Jian-ping1, OU Jiang1,2, SONG Xiao-yan1, DENG Chang-chun1, ZHANG Yan1, ZHANG Jian1, GAO Shun1**

2015, 34(9):  2598-2604. 

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The seasonal variations of ammonium nitrogen (NH₄⁺-N), nitrate nitrogen (NO₃^--N), activities of urease and nitrite reductase in differentsized forest gaps (G1: 100 m², G2: 400 m², G3: 900 m², G4: 1600 m²) of Pinus massoniana plantations in hilly area of the upper reaches of the Yangtze River were analyzed. Our results showed that the ammonium nitrogen content gradually increased, and then decreased with the increasing size of forest gap, while the nitrate nitrogen content showed a decrease trend. The NH₄⁺-N, NO₃^--N contents, and urease activity of soil were higher in the forest gaps of 400 m², 100-400 m² and 900-1600 m² than in the other gaps. However, the nitrite reductase activity in the forest gap of 400 m² was lower than in the other gaps. These findings indicated that the NH₄⁺-N and NO₃^--N contents were significantly affected by forest gap size, and smaller size of forest gaps contributed to soil nitrogen mineralization. The NH₄⁺-N content in spring was significantly higher than in other seasons, and the content of NO₃^--N and urease activity were higher in autumn and winter. However, the nitrite reductase activity was highest in autumn. Compared to under tree canopy, the available nitrogen content in smaller forest gaps significantly increased in spring and summer; the enzyme activity was higher but no significant differences were observed except that the nitrite reductase activity in the gap edge was significantly higher than in the center of forest gap. Moreover, the available nitrogen content and enzyme activity were closely related to soil temperature and moisture. Our findings suggested that after the formation of gaps, the improvement of soil moisture may enhance the enzyme activity and further contribute to the transformation of nitrogen in soil.

Effects of litter manipulation on soil microbial community structure in a Pinus sylvestris var. mongolica plantation.

WANG Wei-wei1,2,3, ZHAO Qiong1,2**, ZHAO Xin-ran1,2,3, ZENG De-hui1,2, AI Gui-yan1,2

2015, 34(9):  2605-2612. 

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We used phospholipid fatty acid (PLFA) method to analyze the effects of shortterm (18 months) litter manipulation on soil microbial communities in a Pinus sylvestris var. mongolica plantation. The results showed that removing litter had no significant effect on soil microbial PLFAs, but doubling litter significantly changed the soil microbial community structure. Specifically, doubling litter significantly improved the total PLFAs of soil microbes, PLFAs of Grampositive bacteria (G+), Gramnegative bacteria (G-), and protozoon, but had no significant effects on the PLFAs of fungi and actinomycetes, and on the ratios of bacteria/fungi and G+/G-. Soil total microbial PLFAs and bacterial PLFAs increased by 82.4% and 93.9% by doubling litter, respectively. The Shannon’s diversity index, Pielou’s evenness index, and Simpson’s dominance index were not influenced by litter manipulation. Principal components analysis (PCA) still indicated that litter manipulation changed the soil microbial community structure. PC1 (89.83%) was mainly contributed by PLEAs of bacteria, including 16:1ω5c, 16:1ω7c, cy17:0ω7c, cy19:0ω7c, i14:0, and i15:0.

Soil fungal diversities of two types of forests in Jian’ou Wanmulin Nature Reserve.

HAN Shi-zhong1, GAO Ren1,2**, MA Hong-liang1,2, YIN Yun-feng1,2, LI Ai-ping1, CAI Xian-he1, CHENG Qing-ping1, ZHENG Qun-rui3

2015, 34(9):  2613-2620. 

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Soil fungal diversities were analyzed by PCRDGGE molecular fingerprint technique for a natural forest of Castanopsis fabri and an adjacent plantation of Cunninghamia lanceolata in Jian’ou Wanmulin Nature Reserve in Fujian Province, southeastern China. The two forests had abundant fungal species in the soil, and the diversity index, richness index and evenness index of soil fungal communities were 3.451-3.709, 19-25 and 0.986-0.989, respectively. Basidiomycota was the most dominant group, followed by Ascomycota, Zygomycota and Deuteromycota. Genera Cryptococcus, Pluteus, Coniochaeta, Trichoderma and Geastrum were found common in the two forest soils, and they were also the dominant fungal species of the two forest soils. Principal component analysis showed that both vegetation type and soil depth affected fungal community composition, and the former had a greater effect than the latter.

Differentiation characteristics of three-dimensional landscape pattern in Shenyang.

CHEN Tan1,2, LIU Miao1**, HU Yuan-man1, CHANG Xong-kai3, LI Chun-lin1, XU Yan-yan1,2, SHI Tuo1

2015, 34(9):  2621-2627. 

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Studies on urban three-dimensional landscape are helpful to the development of landscape ecology at threedimensional scale, which can provide the scientific support for urban planning. Threedimensional information of buildings in Shenyang City was extracted from QuickBird imageries. Five indexes (average building height, landscape height standard deviation, floor area ratio, building shape coefficient and building coverage ratio) and spatial statistical analysis were used to study spatial landscape pattern characters at threedimensional scale. The results showed that bungalow and multistory buildings were the dominant architecture landscape types. Over midtall story buildings distributed in each district, but aggregated in Tiexi District. The different height buildings presented an aggregate distribution and a significant spatial positive correlation. Meanwhile, the different height buildings in different districts also presented an aggregate distribution in their corresponding districts. A significant difference happened between the values of building coverage ratio and floor area ratio in spatial distribution. The area proportion with high building coverage ratio and high floor area ratio had a relatively small proportion. Urban landuse intensity would have some space for improvement.

Spatial and temporal change of landscape pattern and its driving force in Liaoning coastal regions.

XIANG Ying-qi1,2, LIU Miao2**, HU Yuan-man2, CHEN Tan2, CHANG Yu2, ZHANG Dan-hua2

2015, 34(9):  2628-2635. 

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The effect of national or local polices on landscape pattern change is the current research focus. This study discussed the landscape pattern change in coastal regions of Liaoning Province following the policy of “fivepoint and one line”. Through using transition matrix and landscape metrics, this paper studied the change of landscape pattern of coastal areas and its driving force from 2000 to 2010 based on RS and GIS technology. Results showed that the urban area  increased, while the farmland and wetland area were decreased. The landscape kept changing among different categories frequently. Landscape changes in different cities maintained similar dynamics. The landscape patterns developed equalized, the different landscape categories distributed relatively evenly, and the shape of patches became more complex. At the same time, the landscape fragmentation of coastal areas in Huludao, Yingkou and Jinzhou were more serious. Among which, the landscape fragmentation of coastal area was increased in Huludao and Jinzhou, while Yingkou kept a reverse trend. The landscape fragmentation in Dalian, Dandong and Panjin went down gradually. The landscape pattern change was mainly affected by human disturbance. Natural factors were also an important element which could not be ignored. This study provides reference for ecological, economic and social sustainable development and regional planning in Liaoning coastal regions.

Landscape patch scale effect based on fractal theory in Honghe County of Yunnan Province.

YANG Huan, LIU Xue-lu**

2015, 34(9):  2636-2644. 

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Based on fractal theory and grid method, this study examined the number of landscape patch, relative frequency, average fractal dimension and stability index in Guipu Village, Honghe County of Yunnan Province. The results showed that the landscape patches were mainly composed of shrub land, dry land, paddy field, and other grassland, among which paddy field had the largest area, and bare land smallest. The number of each landscape patch and index of stability increased progressively while the variation of relative frequency and average fractal dimension decreased gradually as the observational scale (grain) decreased from 4000, 2000, 1333, 1000, 800, to 667 m. The fractal dimension of each landscape patch varied from 1.029 to 1.959, with rivers the most complicated shapes and rural residential area the simplest. The fractal dimension of landscape patches showed medium or small variation affected by scales, and the number of landscape patches was more significantly affected by observational scales than by the fractal dimension of each landscape patch, which illustrated the spatial distribution pattern of landscape patches in the research area.

 

Accumulation characteristics of Sb and As in cattail growing in antimony mine tailings.

CHEN Jun-feng1, WU Pan1,2**, ZHANG Meng1, ZHANG Chi-peng1,2, HAN Zhi-wei1,2

2015, 34(9):  2645-2649. 

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A field survey was conducted in an antimony tailing pond in Guizhou Province of China. The samples of tailing residue and cattail growing in the mine tailing were collected and the concentrations of Sb and As were determined. The results showed that average contents of Sb and As in slag were 3216.49 and 27.12 mg·kg^-1, respectively. Their average contents were 617.64 and 19.87 mg·kg^-1 in cattail roots, and 183.63 and 0.41 mg·kg^-1 in leaves, respectively. Moreover, the average content of Sb in stems was 97.63 mg·kg^-1. Correlation analysis showed that there was a remarkable relationship between the contents of Sb in cattail leaves and stems and between the contents of As and Sb in slag. The study revealed that cattail was highly tolerable to Sb and As. It was estimated that the annual amount of Sb transfer by cattail was 1278 mg·m^-2 (342.71 mg·m^-2 in aboveground part, and 935.29 mg·m^-2 in underground part), and the annual amount of As transfer by cattail was 31.46 mg·m^-2 (0.75 mg·m^-2 in aboveground part, and 30.71 mg·m^-2 in underground part). Therefore, cattail can be applied as one of the target plants for ecological restoration of the areas contaminated by Sb and As.

Effects of copper stress on the growth and genomic DNA methylation of Arabidopsis thaliana seedlings.

CHEN Rui-juan1,2, HE Lei3, SUN Li-zong1,2, WANG He-tong1, SONG Jie3, LIU Wan1**

2015, 34(9):  2650-2657. 

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In this study, the changes of DNA methylation levels and patterns in Arabidopsis thaliana seedlings under 0-3.0 mg·L^-1 Cu²⁺ stress were studied using methylationsensitive amplified polymorphism (MSAP) technique, and the sensitivity of the fresh weight and root growth of seedlings to Cu stress were compared. The results showed that: (1) Under Cu stress (0.25, 1.0 mg·L^-1) for 15 days, no significant changes were observed in root growth and fresh weight of A. thaliana seedlings compared with the control group, but the genomic MSAP rate first increased and then decreased with the increase of Cu²⁺ concentration. The MSAP rates were 15.93%, 16.28% and 15.83% at 0, 0.25, 1.0 mg·L^-1 Cu²⁺, respectively; (2) At the high concentration of Cu²⁺ (3.0 mg·L^-1), the root length was shortened, the fresh weight was significantly decreased and the MSAP rate was reduced to 14.26%; (3) Under Cu stress (0.25-3.0 mg·L^-1), the number of methylation (M) type and demethylation (D) type sites increased significantly, and Msp I was more sensitive to stress response compared to Hpa II. Therefore, the MSAP of A. thaliana was sensitive to low concentration Cu²⁺ stress, which could be used for early diagnosis and ecological risk assessment of Cu pollution.

Temporal and spatial variation of urban airborne microbes analyzed by canonical ordination methods.

WANG Jia-nan1, MENG Jia-wei2, YANG Feng-xia3, CAI Zhang3,4, LIU Jie3**

2015, 34(9):  2658-2664. 

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The natural sedimentation method was employed to monitor airborne microbial concentration of different functional areas in Tianjin EconomicTechnological Development Area (TEDA, Tianjin) from March 2012 to February 2013. The results showed that bacteria were predominant (76.5%), followed by fungi (19.4%) and actinomyces (4.1%). Canonical ordination analysis was performed to elucidate the temporal and spatial distribution of urban airborne microbes. The results indicated that microbes had a dramatically spatial cluster based on urban function (five types of clusters), among which 46.0% of variation could be explained by first and second axis, with the highest microbial concentration in constructing and industrial area and the lowest in residence zone; on the other hand, microbes had a remarkable temporal cluster according to seasons (three clusters), in which 78.7% of variation could be interpreted by first and second axis with the highest microbial concentration in summer and the lowest in winter. Airborne microbial concentration had a significant positive correlation with temperature (P<0.01). The study showed that airborne microbial variation in temporal distribution was higher than that in spatial distribution, illustrating that the effect of seasonality was stronger than that of area function. In addition, the results revealed that PM₁₀ concentration was positively correlated to SO₂ concentration (P=0.011) in TEDA, Tianjin, suggesting SO₂type smog in this area.

Isolation, identification and biosorption ability of three Pb²⁺ and Zn²⁺ tolerant bacterial strains.

CHEN Yong-hua, XIANG Jie, WU Xiao-fu**, FENG Chong-ling, YUAN Si-wen

2015, 34(9):  2665-2672. 

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Rhizosphere soil samples were collected from plants Nerium indicum, which grew well in a pot experiment with lead and zinc slag as substrates. The bacterial strains resistant to lead and zinc were isolated and identified, and the factors influencing lead and zinc adsorption and the adsorption mechanism were discussed. The results showed that: (1) Three bacterial strains (B1, B4, B14) could grow on the beef extract peptone medium that concentrated Pb²⁺ and Zn²⁺ (600 mg·L^-1). Based on morphology and molecular biology, B1, B4, and B14 were identified as Bacillus cereus or B. anthracis, Aneurinibacillus aneurinilyticus and Micrococcus luteus. (2) Three factors including pH, adsorption time and the initial bacterial amount which may influence the Pb²⁺ and Zn²⁺ biosorption ability were analyzed. Under the conditions of pH 5.0, adsorption time 50 min, and initial bacterial amount 0.06 g, the rates of removing Pb²⁺ and Zn²⁺ by the strain B1 reached 84.22% and 70.66%, respectively. Under the conditions of pH 6.0, adsorption time 50 min, and initial bacterial amount 0.18 g, the rates of removing Pb²⁺ and Zn²⁺ by the strain B4 reached 72.63% and 54.17%, respectively. Under the conditions of pH 4.0, adsorption time 60 min, and initial bacterial amount 0.10 g, the rates of removing Pb²⁺ and Zn²⁺ by the strain B14 reached 77.56% and 50.63%, respectively. (3) The results of scanning electron microscope (SEM) and Fourier transform infrared (FT-IR) spectroscopy revealed that the biosorption process mainly happened on the cell surface and internal biosorption also existed. The main active groups that adsorb, complexate and chelate metal ions or atoms were the hydroxyl, amino, alkyl and amide groups. The combination reaction between heavy metals and active groups on the surface of the bacteria was the main mechanism of Pb²⁺ and Zn²⁺ adsorption.

Research advance in low-dose and nonmonotonic effects of xenoestrogens.

LIU Jun, XU Zhi-xiang, HUANG Bin, PAN Xue-jun

2015, 34(9):  2673-2680. 

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In the traditional sense, any material may produce biotoxicity as long as it reaches a certain quantity or concentration, while it doesn’t have the corresponding toxicity when it is lower than the safe threshold. For many years, toxicologists have believed that higher doses of chemicals will cause greater effects than lower doses, while multiple researches on xenoestrogens (XEs) have demonstrated that XEs are capable of eliciting biphasic dose responses (inverted U shape curve) with different endpoints at many organization levels, especially inducing lowdose and nonmonotonic interference effects. XEs are a class of typical environmental endocrine disruptors (EDCs), leading to disturbance of normal endocrine function mainly through simulating or interfering with the synthesis, metabolism and transport of body’s normal endogenous estrogen. XEs induce lowdose and nonmonotonic effects by the combination of genomic and nongenomic pathways. This paper summarized the lowdose estrogenic effects of XEs on individual organism and molecular cell levels. The estrogenic effect mechanisms (i.e., genomic and nongenomic effects) were presented, and the analysis methods of environmental XEs trace concentrations were described. Finally, the future research direction of the lowdose and nonlinearity effects was prospected, providing theoretical guidance for ecological safety and human health research of XEs.

Coupling relationships of resource consumption, environmental pollution and economic growth in loess plateau region of eastern Gansu Province: A case study of Qingyang City.

LU Chen-yu1**, WANG Chun-juan1, ZHANG Zi-long2, LI Heng-ji3, LU Cheng-peng4, XUE Bing4

2015, 34(9):  2681-2690. 

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The relationship among environmental pollution, resource consumption and economic growth has always been a hot research focus in environmental economics and resources economics. But there are few researches combining these relationships as a whole, especially for smallscale areas. The purpose of this article is to investigate the coupling relationship of the economic growth, resource consumption and environmental pollution. With the data of pollution discharge, resource consumption and per capita GDP from 2000 to 2013 in Qingyang City, Gansu Province, the cointegration test, variance decomposition and impulse response function based on vector autoregressive (VAR) model were employed. The results showed that there was a longterm equilibrium among economic growth, environmental pollution and resource consumption. The chemical oxygen demand and soot emissions had no significant effect on the economic growth, but the sulfur dioxide emission, energy consumption and water consumption had a great influence on the economic growth. The economic growth in Qingyang City was at the expense of increased pollutants emissions and resource consumption, and thus it was an important reason for environmental pollution and resource consumption. This indicates that economic growth has a strong dependence on resource and environment. A decoupling relationship has not occurred among economic growth, resource consumption and environmental pollution, while a coupling relationship of mutual promotion exists.