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Table of Content

    08 September 2011, Volume 30 Issue 09
    Articles
    Responses of Nitraria tangutorum population characteristics to sand burial at southeastern fringe of Tengger Desert.
    2011, 30(09):  1851-1857. 
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    By using the methods of experimental ecology and quantitative ecology, this paper studied the Nitraria tangutorum population characteristics under different sand burial depth at southeastern fringe of Tengger Desert, and analyzed the relationships between the population height, coverage, density, and biomass and the depth of sand burial.It was shown that under strong sand burial (at lacustrine basin lowland), the mean values of N.tangutorum population coverage, density, height, and biomass were higher than those under weak sand buried (at alluvial fan), but the coefficient of variation was in adverse. There existed significant correlations between sand burial and the population characteristics except the population density under weak sand burial. The optimum sand burial depth for the development of the population characteristics was higher under strong than under weak sand burial. Whether the sand burial was strong or weak, and whether the optimal sand burial depth was high or low, the development of the population characteristics was all restricted by the optimal sand burial depth. The increase of sand burial depth promoted the development of the population characteristics when the sand burial depth was lower than the optimal depth, but was in adverse when the depth was higher than the optimal. The responses of the population characteristics to sand burial depth were mainly manifested in the height growth and biomass. The development of population coverage and density was not only affected by sand burial, and more importantly, also affected by other factors, especially soil moisture.
    Relationships between epiphyte ferns species diversity and their phorophytes in Mt. Ailao National Nature Reserve.
    2011, 30(09):  1858-1862. 
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    This paper investigated the effects of phorophytes diameter at breast height, plant height, height below twigs, and species diversity on the epiphyte ferns species diversity in Mt. Ailao National Nature Reserve. Partial correlation analysis was conducted on the epiphyte ferns species diversity in terms of a series of the intervals of phorophytes diameter at breast height, and variance analysis was made to evaluate the effects of phorophytes species composition on the species diversity of epiphyte ferns. The results showed that the epiphyte ferns species diversity had significant positive correlations with phorophytes diameter at breast height and plant height, but had negative correlation with the height below twigs of phorophytes, which suggested that a lower height below the twigs of phorophytes benefited the species diversity of epiphyte ferns. Phorophytes species composition had strong effects on the species diversity of epiphyte ferns.
    Competitions between wetland dominant plants in water-level fluctuation zone.
    2011, 30(09):  1863-1867. 
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    Competitions between plants run through plants whole life history, bringing important effects on  plant growth and propagation. Based on the plant survey in the water-level fluctuation zone of Three Gorges Reservoir, this paper analyzed the intra- and inter-specific competitions in dominant species Xanthium sibirium community in the zone. The average height of the community was 1.4 m, the coverage was 90%, and the abundance was 40. The highest height of the individuals was 2.6 m, and the maximum biomass was 1622.3 g. The competition intensity between the plants decreased with distance (P<0.01). When the distance between plants was 0-10 cm, the competition was the strongest; when the distance was 0-30 cm, the competition was strong, and inter-specific competition was stronger than intra-specific competition. With the increasing distance between plants, the individual number and plant height of dominant species increased, and the biomass, seed yield, and branch number increased after an initial decrease. The plant species with high propagation capability and growth rate had the advantage in competition, which ensured their survival in the water-level fluctuation zone.
    Interspecific relationships of dominant species in Caragana communities in semi-arid regions of China.
    2011, 30(09):  1868-1874. 
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    Based on the investigation data of 58 quadrats, and by using χ2-test and Spearman rank correlation coefficient, this paper studied the interspecific relationships of dominant species in Caragana communities in semi-arid regions of China. Among all the dominant species pairs, most of them had negative correlations, and only a few had significant correlations, which suggested that the Caragana communities were under dynamic succession, and tended to fluctuation or even degradation by external disturbances. Based on the interspecific association and correlation analyses, the 20 dominant species were classified into 3 ecological groups. In the same ecological groups, the members all showed stronger positive association, suggesting their inter-dependent relationships with similar resource utilization and ecological demands. On the contrary, the associations between the ecological groups were loose and scattered, showing a distinct regional differentiation.
    Correlation of modular growth and biomass allocation of Pennisetum purpureum cv. Huanan ramets.
    2011, 30(09):  1875-1880. 
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    In order to understand the variation patterns of Pennisetum purpureum ramets modular growth and biomass allocation under conditions of cultivation, an analysis was made on the modular biomass of P. purpureum cv. Huanan ramets measured in June and December 2009. During the growth process of the ramets, the leaf biomass increased in linear pattern, with the determination coefficient R2 ranged from 0.209 to 0.784, and the culm biomass increased in linear or power pattern, with the R2 ranged from 0.687 to 0.989, suggesting that the increasing pattern of the culm biomass was much steadier than that of the leaf biomass. With the increase of ramet total biomass, the increasing rate of the leaf biomass in vegetative period was 3.39 times of that in reproductive period. However, the increasing rate of the culm biomass in reproductive period was 1.13 times of that in vegetative period. In reproductive period, the dead leaf biomass increased steadily in a linear pattern, with the determination coefficient R2 ranged from 0.471 to 0.676. The correlation models of the inflorescence biomass were all non-significant (P>0.05), and the allocation ratio of the inflorescence biomass decreased in a power pattern, with a power value of  -1.037. The allocation ratios of the leaf  and culm biomass in reproductive period changed in power pattern, with the power values of -0.387 and 0.091, respectively.
    Effects of shallow burial on the decomposition of triploid Populus tomentosa leaf litter.
    2011, 30(09):  1881-1885. 
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    Litter decomposition plays an important role in the nutrient cycling and energy transfer in forest ecosystems. By using litterbag method, this paper studied the leaf litter decomposition in 2-, 4-, and 6 years old Populus tomentosa pulp plantations under the condition of shallow burial, aimed to realize the scientific management of nutrients and to accelerate the decomposition of leaf litter in triploid P. tomentosa pulp plantations. Shallow burial promoted the leaf litter decomposition significantly, as compared to the decomposition on soil surface. The decomposition rate of the leaf litters in 2-, 4-, and 6 years old P. tomentosa pulp plantations under shallow burial for one year increased significantly, being 130%, 194%, and 186% of that on soil surface, respectively. Compared with the decomposition on soil surface, the days needed for 50% leaf litter decomposition in 2-, 4-, and 6 years old triploid P. tomentosa pulp plantations under shallow burial were shortened by 58%, 39%, and 38%, and those needed for 95% decomposition were shortened by 60%, 38% and 36%, respectively, indicating that the promotion effect of shallow burial on the leaf litter decomposition differed with triploid P. tomentosa plantation age.
    Tree species composition and three-dimensional configure in different types of residential areas in Beijing.
    2011, 30(09):  1886-1893. 
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    Taking three types of residential areas in Beijing as the objects, this paper analyzed the tree species composition, relative important value, and three-dimensional configure in diameter at breast height (DBH), height, and crown coverage. In all types of the residential areas, there existed common key tree species, and also, unique dominant species. Populus tomentosa, Sophora japonica, and Platycladus orientalis were the common key species with higher important value; tall and straight species Paulewnia fortunei, Cedrus deodara, P. canadensis, and Ginkgo biloba were the important species in enterprise-institution residential areas; traditionally native species such as Ailanthus altissima, Fraxinus chinensis, and Ziziphus jujube were the essential components in Hutong residential areas; and excellent landscape tree species such as Robinia pseudoacacia, Pinus tabulaeformis, Salix babylonica,  and S. japonica cv. Pendula had valuable traits in mixed residential areas. As for the tree species three-dimensional configure, the overall distribution in DBH, height, and crown coverage in the three types of residential areas all presented a great development potential, being still at a rapid growth phase. With larger green space, enterprise-institution residential areas had significantly higher tree density, crown coverage, average DBH, and height than the other two types of residential areas; due to the limited green land, Hutong residential areas were difficult to increase the green biomass to a higher level; whereas mixed residential areas had considerable potential in the increase of green space.
    Stable isotopic analysis on water utilization sources of Pinus sylvestris var. mongolica plantations in inter-dune lowland in Horqin Sandy Land.
    2011, 30(09):  1894-1900. 
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    Mongolian pine (Pinus sylvestris var. mongolica) has been widely planted on the sandy land in arid and semi-arid areas of North China since the 1950s, but some Mongolian pine forests planted in the 1950s are subject to decline. To examine the variations of habitat water supply and the water utilization strategies of the forests is of significance to understand the mechanisms of the decline. By means of stable isotope analysis, this paper studied the water sources and their seasonal utilization dynamics of Mongolian pine forests planted in the early 1980s in an inter-dune lowland of stabilized sand dune located in southeastern edge of Horqin Sandy Land, analyzed the effects of the variations of precipitation and soil moisture on the water utilization of the forests, and discussed the similarities and differences of Mongolian pine and its companion understory shrubs (e.g., Salix gordejevii) in their water utilization sources. Obvious seasonal variations were observed in the water stable 18O isotope composition (δ18O) of the branches of Mongolian pine and its companion understory shrub S. gordejevii during the observation period from May to October 2008. The water utilization sources of Mongolian pine mainly came from 20-40 cm soil layer or even much deeper soil layers, and there existed strong competition for soil water between Mongolian pine and S. gordejevii. S. gordejevii could earlier utilize the late strong precipitation (>10 mm), giving impact on the water source supply of Mongolian pine. This study had significance for better understanding the decline of Mongolian pine in relation to its water utilization strategy on sandy land.
    Effects of salicylic acid on photosynthesis and ion absorption Helianthus tuberosus seedlings under NaCl stress.
    2011, 30(09):  1901-1907. 
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    In order to understand the regulative effect of salicylic acid (SA) on the salt tolerance physiology of Helianthus tuberosus under NaCl stress, this paper studied the effects of 100 μmol·L-1 salicylic acid (SA) on the photosynthesis and ion absorption of H. tuberosus seedlings under the stress of different concentration NaCl. Applying SA not only effectively alleviated the NaCl stress on the inhibition of H. tuberosus photosynthesis, increased the pigments content, photosynthetic and transpiration rates, stomatal conductance, and water use efficiency, decreased the intercellular CO2 concentration significantly, but also decreased the Na+ accumulation, and promoted the uptake and upward transport of K+ and Ca2+. For example, compared with no SA application under 100 mmol·L-1 NaCl stress, applying 100 μmol·L-1 of SA decreased the Na+ accumulation by 30.6%, and increased the uptake of K+ and Ca2+ by 12.9% and 14.7%, respectively, suggesting that applying definite concentration SA could help to improve the photosynthesis of H. tuberosus seedlings under NaCl stress, maintain the balance of mineral nutrients, and enhance the salt resistance and production of H. tuberosus under NaCl stress.
    Effects of decreased rainfall on Quercus mongolica leaf eco-physiological characteristics.
    2011, 30(09):  1908-1914. 
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    Quercus mongolica is the dominant tree species in the coniferous and broadleaved mixed forests in Changbai Mountains. In this paper, an investigation was made on the effects of decreased rainfall (artificially intercepting 30% of rainfall) on the leaf light-saturated photosynthetic rate, stomatal conductance, transpiration rate, and water use efficiency of Q. mongolica during its growth season (from June to September). In early growth stage (June) when the rainfall was low, there was no significant difference in light-saturated photosynthetic rate between decreased rainfall and the control, though the decreased rainfall decreased soil moisture content by 26.4%. However, the decreased rainfall increased the water use efficiency of Q. mongolica by 40.3%, due to the decrease of transpiration rate. In July-September when the rainfall was abundant, the decreased rainfall had no significant effects on the light-saturated photosynthetic rate, stomatal conductance, transpiration rate, and water use efficiency, because no difference was observed in the soil moisture content between decreased rainfall and the control. Thereby, whether in low rainfall period (June) or in abundant rainfall period (July-September), a 30% decrease of rainfall in Changbai Mountains could less affect the photosynthetic capacity of mature Q. mongolica during its whole growth season. The high photosynthetic rate in August suggested that the relatively high soil moisture content did not limit the water absorption by Q. mongolica. This study showed that Q. mongolica had a wide adaptation to soil moisture content, and could maintain its growth potential in the future climate warming and precipitation fluctuation.
    Flowering phenology and reproductive features of Chinese endemic species Eomecon chionantha Hance.
    2011, 30(09):  1915-1920. 
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    From March to May 2008, an investigation was conducted on the flowering phenology of five natural Eomecon chionantha Hance populations in  Ciping, Huang’ao, Jingzhushan, Liping and Shuikou at Mt. Jinggang of Jiangxi Province, and the indices such as flowering amplitude, relative flowering intensity, and flowering synchrony were adopted to study the effects of the flowering phenology on the reproductive features of the populations. The flowering period of test populations was from late March to early May, lasting 24-46 days, and Jingzhushan population had a significantly longer flowering period than Ciping population. The flowering duration of individual plants was averagely 11-21 days, but the life span of single flower was usually 3-5 days. The flowering had a single peak, i.e., concentrated in a certain period. Same as the majority of subtropical plants, E. chionantha had a lower relative flowering intensity, being from 10% to 30%. The correlation analysis of flowering indices and reproductive features showed that the onset time of flowering had significant negative correlation with the duration of flowering but significant positive correlations with flower number and fruit set ratio, the duration of flowering also had significant positive correlations with flower number and fruit set ratio, the fruit set ratio was significantly positively correlated flower number, and the flowering synchrony index was negatively correlated with the onset time and duration of flowering and the flower number. The populations with earlier onset flowering date showed a longer duration of flowering than the populations with later onset flowering date, and the populations with more flowers showed a longer flowering duration than those with lesser flowers. There was a higher fruit set ratio for the populations with earlier onset flowering date and longer flowering duration, as compared to the populations with later onset flowering date and shorter flowering duration, and the populations with higher flowering synchrony index showed a later onset flowering date, shorter flowering duration, and fewer flowers. As an endemic plant in China, E. chionantha exhibited a so-called “mass-flowering” pattern, which could be regarded as an adaptation strategy to the environment to ensure its reproductive success.
    Phenological responses of different life form plants in Minqin desert area to climate warming. 
    2011, 30(09):  1921-1929. 
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    Based on the phenological and meteorological data observed in the Minqin desert area since 1974, 22 plant species in the area were classified into 3 life forms, i.e., arbor, shrub, and herb in terms of growth type, and again, divided into phenerophyte, chamaephyte, and hemicryptophyte according to positions where the renewal buds seated. By these two methods, the differences in the phnelogical responses of the 3 life form plants were analyzed. As for the 3 life form plants, whatever either of the two methods adopted, they were more sensitive to temperature change in spring than in autumn, and the differences in their phenological responses were greater when classified according to growth type, with larger differences mainly between arbors and shrub. Both the duration of local growth season and the advancing magnitudes of the phenology of arbor and phaenerophyte in spring were greater than those recorded in other literatures. The higher the renewal buds seated, the more sensitive the responses of the plants to climate warming in current month and in the same year, implying that within the scope of the arbor height above ground, the higher the vertical distance from the ground, the more significant the effect of temperature on the phenology of the plants in spring.
    Ecological functions of sandy shale moss crust in Maotai Town of Guizhou Province, Southwest China.
    2011, 30(09):  1930-1934. 
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    An investigation was conducted on the moss species in the biotic crust of sandy shale in Maotai Town of Guizhou Province, and the biomass, pedogenesis amount, and saturated water absorption amount of dominant moss species were measured, aimed to understand the role of moss crust in soil and water loss control. Six moss species were recorded, belonging to 6 genera of 5 families, among which, Homomallium plagiangium, Grimmia sessitana, Epipterygium tozeri, and Bryum argenteum were the dominant species. The biomass, pedogenesis amount, and saturated water absorption amount of the four dominant moss species ranged in 0.5-104 g·m-2, 1.6-481 g·m-2, 2.8-1987 g·m-2, respectively, and were far higher for H. plagiangium, suggesting its key role in the formation of soil biotic crust on the sandy shale, and its significance in the water and soil loss control in study area.
    Carbon storage and its distribution pattern of evergreen broad-leaved forests at different succession stages in mid-subtropical China.
    2011, 30(09):  1935-1941. 
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    This paper studied the carbon (C) storage and its distribution pattern of Pinus massoniana forest, mixed P. massoniana-broad-leaved forest, and evergreen broad-leaved forest representing three different succession stages of evergreen broad-leaved forests in Yingzuijie National Nature Reserve in Hunan Province. The C storage of the three forest ecosystems was 182.86, 179.84 and 229.12 Mg C·hm-2, respectively. With the largest share in trunk, the carbon stored in tree layers was the main contributor to the C storage, accounting for 59.57%-67.88%, and had an increasing trend with forest succession. The carbon sequestered in soil accounted for 31.05%-36.55%, which also increased with forest succession but had a decreasing proportion with the succession. The carbon storage of understory vegetation and litters had the least share, accounting for 0.41%-3.04% and 0.65%-2.53%, respectively, and decreased with forest succession. The ratio of biomass C to soil C storage of the three forest ecosystems was 1.96, 1.69, and 2.20, respectively, and biomass C played a more and more important role in forest C sequestration during the succession from P. massoniana forest to evergreen broad-leaved forest. It was suggested that to implement near-nature forest management or simulate evergreen broad-leaved forest structure would be the main approach in promoting the carbon sequestering capacity of forest ecosystems in this region.
    Effects of different corn/wheat year-round tillage modes on post-anthesis dry matter accumulation and transfer and grain yield of wheat in rain-fed farming area of Southern Henan Province.
    2011, 30(09):  1942-1948. 
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    A 4-year (2006-2009) field experiment was conducted to study the effects of different corn-wheat year-round tillage modes on the post-anthesis dry matter accumulation and transfer, grain-filling, and grain yield of winter wheat in a rain-fed farming area of southern Henan Province. Six modes including traditional tillage (T1), non-straw mulching and pre-sowing shallow plough for corn + straw mulching and non-tillage for wheat (T2), straw mulching and pre-sowing shallow plough for corn + non-straw-mulching and non-tillage for wheat (T3), non-straw mulching and pre-sowing deep plough for corn + non-straw mulching and non-tillage for wheat (T4), straw mulching and pre-sowing deep plough for corn + straw mulching and non-tillage for wheat (T5), and non-straw mulching and pre-sowing shallow plough for corn + burying smashed straw in soil and rotor tillage (T6) were examined. Among the test modes, T1 and T5 showed the best effects, under which, the leaf staying-green period of winter wheat was the longest, and the dry matter accumulation in vegetative organs was significantly higher (P<0.05) than that under other modes. Also, the transfer amount of the pre-anthesis assimilates in vegetative organs under T1 and T5 was higher, and the transfer amount and rate of post-anthesis assimilates in the vegetative organs were 11.9% and 11.7%, and 11.6% and 11.4% higher than those under T3 and T6, respectively (P<0.01). Under T1 and T5, the contribution of the post-anthesis assimilates to the grain yield of winter wheat was 8.4% and 7.9%, and 8.8% and 8.3% higher than that under T3 and T6 (P<0.05), and the grain yield was 7545.0 and 7480.5 kg·hm-2, being 14.8% and 13.8% higher than that under T6, respectively (P<0.01). Overall, mode T5 had the best effect in promoting the dry matter accumulation in winter wheat vegetative organs and the transfer of post-anthesis assimilates to the grain, and also, played important roles in soil water conservation and fertility improvement, being considered as the high-efficient and high-yielding tillage mode for wheat production in the rain-fed farming area of southern Henan Province.
    Change characteristics of soil salt content in salinized farmlands in Tianjin.
    2011, 30(09):  1949-1954. 
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    Based on the analysis of the salt content and its composition in farmland soils of Tianjing, this paper studied the characteristics of the salt composition and its accumulation in the salinized farmland soils of the City. Compared with that in non-salinized soils of Jixian County, the salt composition in salinized soils of Dongli, Jinnan, and Hangu districts had obvious difference. In non-salinized soils, salt accumulated in top soil, and decreased with soil depth; while in salinized soils, desalination was obvious in topsoil whereas salt accumulation was observed in subsoil.HCO3- was the major anion in both non-salinized and salinized soils, while cations showed a significant difference between non-salinized and salinized soils. Ca2+ was the major cation in non-salinized soils, but Na+ gradually became the primary cation in salinized soils. The ion composition in salinized soil profiles had a notable spatial variation, e.g., Na+, Cl-, and SO42- had low concentrations in topsoil but high concentrations in subsoil. Moreover, the soil pH value, residual sodium carbonate content, sodium adsorption ratio, and exchangeable sodium percentage in salinized soils were higher, representing the synchro occurrence of salinization and alkalization.
    Soil enzyme activities in typical vegetation zones along an altitude gradient in Wuyi Mountains.
    2011, 30(09):  1955-1961. 
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    This paper measured the activities of soil urease, sucrase, acid phosphatase, and catalase in four typical vegetation zones, i.e., evergreen broadleaf forest (EBF), coniferous forest (CF), sub-alpine dwarf forest (SDF), and alpine meadow (AM), along an altitude gradient in the Natural Reserve of the Wuyi Mountains in Fujian Province of East China. In the four zones, there were no significant seasonal variations in the activities of test enzymes except acid phosphatase, whose activity was significantly higher in autumn than in any other seasons. The activities of test enzymes differed significantly with altitude, but less affected by the interaction of season and altitude. The enzyme activities showed an overall increasing trend with the altitude, being significantly higher in AM zone than in EBF and CF, and decreased with soil depth. The soil urease activity in the four zones was in the range of 1.28-3.87 mg·g-1·24 h-1, and in the order of AM>EBF>SDF>CF; soil sucrase activities was in the range of 36.18-244.08 mg·g-1·24 h-1, and in the order of AM>CF>EBF>SDF; acid phosphatase and catalase activities were in the ranges of0.18-0.62 mg·g-1·2 h-1 and 1.78-1.98 ml·g-1·20 min-1, respectively, and in the order of AM>CF>SDF>EBF. The soil enzyme activities were significantly positively correlated with soil total organic carbon and total nitrogen, and had complicated correlations with soil temperature, moisture, and pH.
    Soil labile organic carbon and carbon pool management index as affected by different years no-tilling with straw mulching. 
    2011, 30(09):  1962-1968. 
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    A field experiment (2000-2010) was conducted at the Heyang Dryland Farming Experimental Station in Shaanxi Province of China to study the effects of no-tillage with straw mulching on soil labile organic carbon (LOC) and carbon management index (CMI), and further, to search the appropriate years for no-tillage with straw mulching. Five treatments of different years no-tillage with straw mulching, i.e., 1 year (S1), 3 years (S3), 5 years (S5), 8 years (S8), and 10 years (S10), and two treatments of conventional cultivation (CK) and 10 years no-tillage with zero straw mulch (CK0) were installed. In treatments S1, S3, S5, S8, and S10, the organic carbon (TOC) content in 0-10 cm soil layer increased by 7.6%, 13.5%, 25.4%, 48.6%, and 79.0%, LOC content increased by  40.1%, 51.5%, 102.4%, 78.4%, and 75.3%, and CMI increased by  49.4%, 61.2%, 126.8%, 85.4% and 75.3%,  respectively, compared with CK. The spring maize grain yield, total nitrogen, total phosphorus, and available phosphorus had significant correlations with soil LOC and CMI (P <0.01), but less correlation with soil TOC. As compared to soil TOC, soil LOC and CMI could more rapidly and objectively reflect the effects of no-tillage with straw mulching on soil carbon pool and maize grain yield, and be used as the indices to assess the ecological effects of no-tillage with straw mulching. The appropriate years for no-tillage with straw mulching in Weibei dryland area of China could be 5-8 years.
    Effects of nitrogen addition on ammonia volatilization and nitrate leaching of a sandy grassland.
    2011, 30(09):  1969-1974. 
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    With enclosed and static chambers and ion exchange resin bags, this paper studied the effects of water addition (W), nitrogen addition (N), and water and nitrogen addition (WN) on the ammonia volatilization and nitrate leaching of a sandy grassland in southeastern Keerqin Sandy Land, taking no water and nitrogen addition as the control (CK). Treatments N and WN promoted the ammonia volatilization significantly, and the maximum ammonia volatilization rate was significantly higher than that of the control (P<0.05). The cumulative amount of ammonia volatilization in treatments N and WN was 111.80 mg·m-2 and 148.64 mg·m-2, accounting for 1.1% and 1.5% of the nitrogen added, respectively. The cumulative amount of the ammonia volatilization was significantly higher in treatment WN than in treatment N (P<0.05), but had no significant difference between treatments W and CK. Treatments N and WN increased the leaching amount of nitrate-N at 20 cm soil depth significantly (P<0.05), being 1.96 and 4.22 times of the CK, respectively. No significant difference was observed in the leaching amount of nitrate-N at 40 cm soil depth among the treatments W, N, WN, and CK (P>0.05). The results suggested that both nitrogen addition and water and nitrogen addition promoted the ammonia volatilization, but had little effects on the nitrate leaching of the sandy grassland.
    Identification and nitrogen fixation effect of symbiotic Frankia spp. isolated from Casuarina spp.
    2011, 30(09):  1975-1981. 
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    A total of 14 symbiotic bacterial strains were isolated from the root nodules of Casuarina equisetifolia and C. cunninghamiana in Zhejiang Province. All the strains exhibited typical Frankia morphological characteristics, including filamentous hyphae, vesicles, and multilocular sporangia borne terminally or in intercalary position. The 16S rDNA sequencing showed that all the strains were of Frankia, 4 of them belonging to physical group A, 7 belonging to physical group B, and the other 3 belonging to physical group AB. All the strains presented nitrogenase activity, but the activity differed significantly with the strains. Strain ZCN192 had the highest nitrogenase activity (2.897 μmol·mg-1·h-1), while ZCN199 had the lowest one (0.056 μmol·mg-1·h-1). After in vivo inoculated with all the strains, the plant height, basal diameter, and dry biomass of C. equisetifolia and C. cunninghamiana increased significantly, and overall, the strains with higher nitrogenase activity exhibited more obvious nitrogen fixation effect in vivo.
    Distribution characteristics and source analysis of PAHs in topsoil of Guiyang City, Southwest China.
    2011, 30(09):  1982-1987. 
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    Topsoil samples were collected from the urban and suburban areas of Guiyang City to determine the concentrations of 16 polycyclic aromatic hydrocarbons (PAHs) by high performance liquid chromatography, with the distribution characteristics, pollution levels, and origins of the PAHs discussed. The total PAHs concentration in the samples varied from 61 to 1560 μg·kg-1, being 247-1560 μg·kg-1 for urban and 61-339 μg·kg-1 for suburban soils, respectively. In all the samples, PAHs were dominantly composed of 4- and 5-ring PAH species. Referred to some foreign environmental standards, the topsoil of Guiyang City was PAHs-contaminated to some extent. The analysis with correlation coefficient method and triangle drawing discriminance based on typical sources showed that the possible sources of PAHs in the topsoil of Guiyang were mainly the combustion of coals and the combined contamination of coal combustion and traffic exhaust.
    Preparation of activated carbon-loaded nano zero-valent iron adsorbent for As(V) removal.
    2011, 30(09):  1988-1992. 
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    Taking activated carbon as a carrier, an activated carbon-loaded nano zero-valent iron (NZVI/AC) adsorbent was prepared for arsenate (As(V)) removal. With the removal rate of As(V) as the target, an optimization was conducted on the particle size of activated carbon, the species and concentrations of iron salts, the reaction temperature and reaction rate, the marinated duration of iron salts in activated carbon, and the equilibrium time of reaction. In considering of the As(V) removal rate and the practical utilization of NZVI/AC, the prepared NZVI/AC could have the best efficacy (98% removal of As(V)) when the particle size of activated carbon was 20-40 mesh, KBH4 drop-addition speed was 1 ml·min-1, the marinated duration of ferrous sulfate with a mass concentration 6.9% in activated carbon at 25 ℃ was 30 min, and the equilibrium time of reaction was 30 min.
    Heavy metal pollution and its ecological risk assessment of riparian soils.
    2011, 30(09):  1993-2001. 
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    Riparian soil samples were collected from forest-dominated Jinshui River basin, a tributary of the upper Hanjiang River, to determine the total contents of several heavy metals in soil and the ion contents in soil water solution. Pollution index and ecological risk index were used to evaluate the riparian soils heavy metals pollution. Within the basin, riparian soils heavy metals pollution was from moderate to severe, and the ecological risk was from minor to moderate. Among different land use types, flood plain had the highest contents of soil V (130.89 mg·kg-1) and Cr (363.29 mg·kg-1), whereas grassland had the highest contents of soil Ni (32.52 mg·kg-1), Pb (24.61 mg·kg-1), Ti (4378.09 mg·kg-1), Mn (1289.62 mg·kg-1), Zn (91.44 mg·kg-1), and Cu (29.71 mg·kg-1), mainly due to the effective adsorption and accumulation of these heavy metals by the flood plain and grassland soils and the increasing human activities. The Cr, Pb, and Zn contents in the riparian soils were over the limits of National Standard (GB 15618-1995). In addition, the albic brown earth and calcic-skeletol soil in flood plain had high content of calcium carbonate which had strong capability in adsorbing and solidifying Pb and Zn. The heavy metals pollution of the riparian soils increased the potential risk of regional ecosystem and agriculture security. It would be important to increase soil humus content to alleviate the pollution and enhance the soil self-purification.
    Genetic diversity of two wild  Penaeus monodon broodstock populations.
    2011, 30(09):  2002-2006. 
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    By using RAPD and mtDNA 16S rRNA gene sequence analysis, this paper studied the genetic diversity and differentiation of two Penaeus monodon wild broodstock populations collected from Hainan and Malaysia. Using 15 random primers, a total of 82 RAPD loci were detected. For the Hainan and Malaysia populations, the proportion of polymorphic loci was 75.90% and 76.83%, heterozygosity was 0.199 and 0.218, and genetic diversity index was 0.276 and 0.288, respectively, and the genetic distance between the two populations was 0.015. The genetic variation revealed by 16S rRNA gene sequence analysis was low. he nucleotide diversity of the Hainan and Malaysia populations was 0.011 and 0,respectively, and the genetic distance between the two populations was 0.008. Phylogeographic pattern analysis indicated that Malaysia population had a higher genetic diversity than Hainan population, and the Hainan population could be derived from Malaysia population. Therefore, the broodstock imported from Malaysia could be used as the founder in genetic breeding programs.
    Genetic diversity of 15 Macrobrachium nipponense populations in Poyang Lake based on microsatellite analysis.
    2011, 30(09):  2007-2013. 
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    By the method of microsatellite analysis, an investigation was conducted on the genetic diversity of 15 wild populations of oriental river prawn(Macrobrachium nipponense) in Poyang Lake. The 10 microsatellite loci were highly polymorphic, and a total of 129 alleles were detected. The tests of departure from Hardy-Weinberg equilibrium indicated that at least 5 loci for each population were in significant heterozygosity deficiency. For all the populations, there existed significant deviation from Hardy-Weinberg equilibrium. The 15 populations all showed high genetic diversity; the genetic diversity in Dabawai and Xinchi populations was relatively higher compared with the Wanhu and Hukou populations. Bottleneck effect and mutation-drift equilibrium tests indicated that the M.nipponense populations in the Lake did not suffer bottleneck effect, and had no decline in their quantity in recent time. The FST and AMOVA analysis across all the populations suggested that there was a significant genetic differentiation among the 15 populations (FST=0.04709, P<0.01). This study showed that the M.nipponense populations in Poyang Lake had high genetic diversity, with greater potential for breeding.
    Feeding habits and growth characteristics of pond-cultured Coilia nasus fingerlings.
    2011, 30(09):  2014-2018. 
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    By the methods of growth measurement and feeding rhythm evaluation, this paper studied the feeding habits and growth characteristics of pond-cultured Coilia nasus fingerlings, aimed to provide basic biological data of C. nasus, and supply reference to the large-scale pond culture of the fish species. Our results showed that after 153 days growth, the C. nasus fingerlings had an average length from 12.41±2.21 cm to 21.25±2.08 cm, and gained an average body weight from 5.83±0.91 g to 40.58±12.98 g. The body length had a linear correlation with age (L=0.0558t+13.102, R2=0.97), and the body weight had an exponential correlation with age (W=6.5699e0.0123tR2=0.98) and a power function relationship with body length (W=0.0006L3.5924). C. nasus fingerlings had an obvious diurnal feeding rhythm, with the peak from 4:00 am to 8:00 am, stopped feeding at noon, and feeding again from 16:00 pm. Cladoceran, copepod, macrobrachium nipponensis, and gobioidei were the appropriate feeding organisms for C. nasus fingerlings, but the appropriate diets varied with the growth stages of the fingerlings. The feeding quantity was highly correlated to the prey species and their availability.
    Feeding of rotifer Brachionus plicatilis enriched with microalgae.
    2011, 30(09):  2019-2025. 
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    By the methods of experimental ecology, this paper studied the dynamic changes of the filtration and ingestion rates of Brachionus plicatilis enriched with single and mixed microalgal diets at optimum concentrations. The microalgal concentration, microalgal species, and culture duration all had significant effects on the filtration and ingestion rates of B. plicatilis. The filtration and ingestion rates of  B. plicatilis to the diets decreased with increasing culture duration. Under the experimental conditions, the filtration rate of B. plicatilis to the microalgae within 6 hours was in the order of Chlorella sp. > Isochrysis galbana > Chaetoceros muelleri, while that within the whole experimental duration (12 hours) was Isochrysis galbana > Chlorella sp. > Chaetoceros muelleri. The predation of B. plicatilis fed by mixed microalgal diet was with a preferential order of Isochrysis galbana > Chlorella sp. > Chaetoceros muelleri.
    Spatiotemporal distribution pattern of Chaetoceros community in Zhanjinag Bay and  affecting factors.
    2011, 30(09):  2026-2033. 
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    By the methods of water sampling, net sampling, and microscope identification, a seasonal investigation was conducted on the phytoplankton community in Zhanjiang Bay of Guangdong, China in February-November 2009, with the spatiotemporal distribution of Chatoceros community in the Bay and  affecting factors analyzed. A total of 32 Chatoceros species were collected, including 17 red tide causative species. The dominant species in the Chatoceros community were C. curvisetus, C. pseudocurvisetus, and C. muelleri. Temporally, the species richness and cell abundance of Chaetoceros were characterized by a typical seasonal pattern, with the highest in spring and summer and the lowest in autumn and winter. Spatially, the species richness and cell abundance decreased from outer bay to inner bay. The cell abundance of Chaetoceros was significantly positively correlated with water temperature, salinity, pH, chlorophyll a, and cell abundance of phytoplankton, and significantly negatively correlated with water DIN and silicate, but had no significant correlation with water phosphate. The seasonal variation of Chaetoceros cell abundance was mainly controlled by water temperature, and also, affected by the interspecific competition and the feeding pressure from zooplankton produced by seasonal alternation; while the spatial distribution of Chaetoceros cell abundance was affected by illumination, water salinity, pH, and the feeding pressure from high-density cultured shellfish.
    Effects of tail loss on locomotor ability and selected body temperature of common lizard Lacerta vivipara.
    2011, 30(09):  2034-2038. 
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    Tail autotomy is an effective anti-predator strategy adopted by many lizards, but can induce the decrease of their body mass and the changes in their energy balance, giving effects on their locomotor ability and body temperature adjustment. In this paper, a common lizard (Lacerta vivipara) population was collected from Xiaoxing’an Mountains in Heilongjiang Province of Northeast China in May 2006 to examine the effects of tail loss on the L. vivipara locomotor ability and selected body temperature. At experimental temperature 30 °Cand 24 °C, the tail loss of L. vivipara resulted in an obvious reduction in its locomotor performances. More specifically, the frequency of stopping locomotion increased whereas the maximum distance of continuous locomotion and the sprint speed decreased. To some extent, the effects of tail loss, experimental temperature, and sex on the locomotor ability of L. vivipara were independently. Tail loss was the main factor affecting the locomotor ability, but had little effects on the selected body temperature.
    Birds in farmland and slope land in Jieyang of Guangdong and their impacts on local electric transmission.
    2011, 30(09):  2039-2044. 
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    In June 2009-April 2010, five surveys with transect method were conducted on the birds in the farmland and slope land along four electric transmission lines in Jieyang of Guangdong. A total of 73 bird species were recorded, 43 species of which were on the electric transmission lines and had a high similarity in their composition. Tree Sparrow (Passer montanus) and Red-rumped Swallow (Hirundo daurica) were the dominant species in the farmland and slope land and on the electric transmission lines. Though the bird species richness and abundance were higher in non-breeding period than in breeding period, the conk out times of electric transmission were more in breeding period because of the nest-building, feces, and nest material slide of the birds on the tower supports. Black-collared Starling (Gracupica nigricollis) was the most common species impacting the electric transmission in Jieyang.
    Roles of photodegradation in litter decomposition.
    2011, 30(09):  2045-2052. 
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    In recent years, it has recognized that photodegradation possibly plays a key role in litter decomposition. This paper summarized the action mechanisms of photodegradation, roles of photodegradation in carbon and nutrient cycling, relationships between photodegradation and microbial decomposition, and factors affecting photodegradation. Photodegradation has both positive and negative effects on litter decomposition. The positive effects lie in the photolysis and photooxidation of organic matter, leading to the changes of litter chemistry, fragmentation, and facilitation to leaching, whereas the negative effects are related to the inhibition of microbial decomposition induced by strong light radiation. The CO2 produced by the photochemical mineralization in the process of photodegradation is the main mechanism of the C loss from ecosystems. Besides UV, the blue and green light-wave bands in visible light can affect litter photodegradation. The photodegradation is affected by water status, litter chemical properties, and litter exposed area. It was suggested that the related research priorities in the future could be the research methods of photodegradation, the interactions between photodegradation and environmental factors, the spatial variance of photodegradation, and the relationships between photodegradation and microbial decomposition in the process of litter decomposition.
    Methods of measuring plant community functional diversity. 
    2011, 30(09):  2053-2059. 
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    Plant community functional diversity is based on plant traits, and has been proposed as a key component of predicting ecosystem function. According to the constitution of species diversity, plant community functional diversity is usually described by functional richness, functional evenness, and functional divergence. This paper introduced these three kinds of indices used in plant community ecology, in hopes of better understanding the relationships between biodiversity, environment, and ecosystem functioning.
    Research progress on allometric models.
    2011, 30(09):  2060-2065. 
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    Recently, the discussion on allometric model becomes a hotspot again, with the focus on the scaling exponent and theoretical explanation. This paper summarized the related researches on WBE 97, BMR(99)model, and introduced in especial the MGL model and its deduced results. From the deduction of MGL model, the metabolic rate of whole organism has no obvious dependence on the mass of the whole organism, and the scaling exponent of mass-specific metabolic rate common to most taxa is not a fix value but in \[2/3, 1\]. There exists the value of minimal mass-specific metabolic rate, which determines the maximum size the organism could attain. A theoretical model based on the minimal mass-specific metabolic rate was presented, which can describe the relationship between organism’s body size and temperature, and was proofed by empirical justification.
    Observation and measurement of plant root architecture in situ: A review.
    2011, 30(09):  2066-2071. 
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    Root system is the important organ of plant for absorbing and transporting nutrients and water from soil to the plant body. However, the opaque attributes of soil hinder the observation of root system, and the lack of root system observation methods in situ has become the technological bottleneck for the in-depth study of root system. In view of the technical needs of root system research, this paper summarized the destructive root system research method (traditional method), non-destructive two-dimensional root system observation method (minirhizotron), and three-dimensional root system architecture observation methods in situ, including X-ray computed tomography (XCT) and magnetic resonance imaging (MRI), and generalized their advantages and disadvantages, with the focus on the comparison XCT and MRI. Some literatures indicated that MRI was not suitable for the observation of three-dimensional root system architecture. It was suggested that applying XCT to quantitatively analyze the three-dimensional root system architecture in natural soil media would be the development trend of related researches in the future.
    Wetland methane and carbon dioxide emission and affecting factors.
    2011, 30(09):  2072-2079. 
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    Wetland ecosystem plays an important role in global carbon cycle. Its unique soil, hydrology, and vegetation make the wetland able to constantly accumulate carbon in the hypoxic environment, and also, release large amount of greenhouse gases CH4 and CO2. Wetland carbon emission has become a hotspot in the study of global climate change. The differences in the soil status, hydrological condition, and vegetation type in wetland result in a strong spatiotemporal variability of CH4 and CO2 emission from wetland. It’s observed that the  CH4 and CO2 emission is positively correlated with soil temperature, and affected by water level to a certain extent. Within a certain range, soil anaerobic condition leads to the increase of CH4 emission and the decrease of CO2 emission. Vegetation affects all aspects of the greenhouse gases production, oxidation, and emission, and the affecting degree varies with plant species.
    Influence of Spartina alterniflora invasion on soil ecosystem: A review.
    2011, 30(09):  2080-2087. 
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    Spartina alterniflora is one of the most successful invasive weeds in global estuaries and coastal wetland areas, and also,has major impacts on the coastal wetland soil ecosystems in China. This paper summarized the recent researches about the influence of S. alterniflora invasion on the soil ecosystems in estuaries and coastal wetland areas, mainly from the aspects of soil structural constituents (soil microbes and soil animals) and matter (carbon, nitrogen, phosphorus, and heavy metals) cycles. The shortcomings of the ongoing researches were discussed, and the future research emphases, e.g., the influence of the invasion on soil microbes, the integration of the studies of above- and below-ground resources competition between S. alterniflora and native plants and related ecological processes, as well as the simulation and prediction about the invasion dynamics of S. alterniflora under the background of global climate change, were suggested.
    Soil animals in abandoned mine land: A review.
    2011, 30(09):  2088-2092. 
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    The invasion and settlement of soil animals is an important pathway of the formation of soil animal community structure in abandoned mine land. With the increasing duration of discarding, the abandoned mine land has a changing soil animal community structure,which plays an important role in the ecosystem succession and ecological restoration of the abandoned land. This paper reviewed the ecological environment, settlement, and community succession of soil animals in abandoned mine land, the effects of soil animals’ activity on soil processes, as well as the responses and indications of soil animals to the environment. Based on the comprehensive analysis of related researches, some problems to be urgently solved on the study of soil animals in abandoned mine land were analyzed, and future research directions needed to be strengthened were proposed.
    GIS model for eco-environmental sensitivity assessment of the areas along Qinghai-Tibetan railway.
    2011, 30(09):  2093-2098. 
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    GIS has a substantial advantage for the spatial overlay analysis in eco-environmental sensitivity assessment. In this paper, the traditional eco-environmental sensitivity assessment methodology was logically improved by adopting ArcGIS Model Builder to incorporate GIS modules capable of multi-cycle eco-environmental sensitivity assessment, and the assessment capacity of the improved methodology was tested in Qinghai-Tibetan railway area. By identifying environmental problems, determining indices and weights, and preprocessing spatial data, the GIS modules were easy and quick to run. The test results showed that the improved methodology could effectively illustrate the spatial pattern of the eco-environmental sensitivity areas along Qinghai-Tibetan railway. The highly eco-environmental sensitivity areas were mainly near the wildlife pathways on the both sides of the railway, and formed a linear distribution in a larger scale. The accuracy and reliability of our results were validated, and showed a strong compassion to the previous field researches in the region, implying that the improved methodology could supply a technical support for the quick eco-environmental sensitivity assessment of linear construction project.
    Simulation of water and carbon fluxes in Harvard forest area by using improved Biome-BGC model.
    2011, 30(09):  2099-2106. 
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    Using Biome-BGC model can simulate vegetation productivity through the coupling of water and CO2 exchange processes between vegetation,soil and atmosphere, but the soil water balance module is not perfect enough, leading to a large deviation between simulated and observed values under condition of a long time no precipitation. Aiming at this problem, this paper improved and adjusted the equation of stomatal conductance stressed by soil water, the calculation formula of evapotranspiration, and the process of soil water loss in Biome-BGC model. Using this improved model, the evapotranspiration and vegetation productivity in Harvard Forest area were simulated, and compared with field observations. The accuracy of simulated results by the improved model enhanced obviously, with the evapotranspiration R2 between simulated and observed values increased from 0.483 to 0.617, NEE R2 increased from 0.658 to 0.813, root mean square error (RMSE) of annual evapotranspiration decreased averagely by 48.7%, and annual sum squared error (ASSE) of NEE decreased averagely by 39.8%, which suggested that the simulated results by using the improved model were more close to the observed results.
    SLEUTH model-based prediction of urban growth of Shanghai.
    2011, 30(09):  2107-2114. 
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    In this paper, SLEUTH model and the urban land use datasets in 1989-2005 derived from high spatial resolution (2.5 m) color-infrared aerial photos of Shanghai were employed to simulate the urban growth of the City in 2006-2035 under four land resources protection scenarios, as well as the effects of urbanization on the urban landscape pattern. Under the four land resources protection scenarios, the areas of different urban land use types all kept increasing, but the increments decreased with increasing protection degree. The main urban growth type was the edge expansion of existing urban area, followed by the diffusive growth and road-influenced growth in suburban areas. The future urban growth would mainly occur in the northwestern part of Shanghai, and then in the southwestern and southeastern parts. Urbanization would affect the urban landscape pattern markedly. At the early stage of the urbanization, it could induce landscape fragmentation, landscape diversification, and the increase of landscape heterogeneity; while at the late stage, urbanization could decrease the urban landscape diversity and heterogeneity, and result in urban landscape homogenization. To increase the protection degree of agricultural land and urban green space could mitigate the decline of urban landscape diversity and heterogeneity, and hence, avoid the urban landscape homogenization.