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Table of Content

    08 February 2011, Volume 30 Issue 02
    Articles
    Differential patterns of nutrient elements in rainfall and its redistribution in three typical subtropical forests in South China.
    2011, 30(02):  193-200. 
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    Pinus massoniana forest, mixed P. massonniana-broadleaved forest, and monsoon broadleaved evergreen forest are the three typical subtropical forests at the succession stages from pioneer community to nearly climax in Dinghushan Nature Reserve in South China. In this paper, the differential patterns of five nutrient elements (K, Ca, Mg, N, and P) in rainfall and its redistribution in these forests were studied. The results showed that after the redistribution of rainfall through canopy, the concentrations of test nutrient elements except Ca in throughfall and stemflow had somewhat increase, especially in stemflow. In all the three forests, the Ca concentration in throughfall was lower than that in rainfall. The nutrient concentrations in throughfall and stemflow didn’t show any significant changes in these forests, but the nutrient inputs in stemflow had an increasing trend with the progress of succession. In addition, the nutrient inputs of throughfall and stemflow were generally higher than those of litter fall, especially in the mixed forest and P. massoniana forest. Our results suggested that rainfall not only played an important role in nutrient transfer from forest canopy to soil, but also supplied necessary nutrients for forest growth, especially for that at early succession stage.
    Litter fall mass and its decomposition in typical primary and secondary forests in karst region of Northwest Guangxi.
    2011, 30(02):  201-207. 
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    Litter fall mass and its decomposition plays a key role in nutrient cycling, especially in carbon cycling. This paper compared the litter fall mass and its decomposition characteristics in three primary forests (Platycarya longipes, Distylium macrophyllum, and Pteroceltis tatarinowi; Abbr. P1, P2, and P3) and three secondary forests (Sapium rotundifolium, Alangium chinense and Vitex negundo; Abbr. S1, S2, S3) in karst area of Northwest Guangxi. In all of the forests, leaf litter occupied about 80% of the total litter fall, and was negatively correlated with rainfall, with a peak in dry season. A decomposition experiment was conducted by using litter bags filled with the litter fall from all six forests. The litter bags were re-weighed at 90-day intervals after placed on the floor, and the results showed that the mass loss in primary forest P2 was the least, with 87.6% of the mass remaining un-decomposed after 90-day incubation. The total litter fall mass and the nutrient return were larger in secondary forests than in primary forests except P2 which had the largest litter fall mass and the slowest decomposition rate. The litter fall in secondary forest S1 had the highest N content and the fastest decomposition rate, and thus, the S1 could be a better choice for vegetation restoration and nutrient recovery in degraded lands in karst area of Northwest Guangxi.
    Floristic composition and species diversity of plant communities along an environment gradient in drawdown area of Three Gorges Reservoir after its initial impounding to the water level of 156 m.
    2011, 30(02):  208-214. 
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    Aimed to provide scientific basis for understanding and maintaining the biodiversity in water level fluctuation littoral zone, the Kaixian reach of Pengxihe River was chosen to study the spatial pattern and gradient variation of plant communities in the drawdown area of Three Gorges Reservoir. In the study area, there was an obvious variation in the kind and dominance of dominant and companion species in each plant community. With increasing elevation, the total species richness decreased after an initial increase, and α- and β-diversity had a greater fluctuation, among which, Shannon diversity and Simpson diversity showed a distribution of “M” and “W” types, respectively, while Pielou diversity showed the same variation pattern with species richness. Jaccard index and Cody index all increased after an initial decrease, with the lowest values at middle elevation and the highest values at higher elevation. It was considered that the variation of α-diversity in the study area was originated from the habitat difference induced by the difference in the flooding time caused by different elevation, while the reason of β-diversity change was more complicated, which should be further studied.
    Change pattern and its future trend of vegetation net primary productivity on Qinghai Plateau.
    2011, 30(02):  215-220. 
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    Based on the 1961-2009 meteorological data from 43 stations and the biomass data from 22 observation points in Qinghai Province as well as the future meteorological data estimated under SRES A1B scenario, this paper verified the applicability of Zhou Guang-sheng’s Model in the province, and, by using this model, calculated the vegetation net primary productivity (NPP) on Qinghai Plateau in 1961-2009, 2020s, 2050s, and 2080s. There was a very good correlation between the calculated and measured NPP values, suggesting the good applicability of Zhou’s Model in the province. In 1961-2009, the mean provincial vegetation NPP had an increasing trend, with an increment of 0.067 t·hm-2·10a-1, and the regional vegetation NPP varied greatly, with an increment of 0.077-0.147 t·hm-2·10 a-1 in eastern Chaidamu Basin and of 0.006-0.030 t·hm-2·10 a-1 in most areas of Guoluo. Under the background of climate warming, both the precipitation and the temperature had higher correlations with the NPP, but the influence of precipitation was bigger than that of temperature. In the coming 100 years, the increment of the NPP would be decreased gradually from east to west Qinghai, being 1.35-1.49 t·hm-2·100 a-1 in east Qinghai and 0.59-0.73 t·hm-2·100 a-1 in west Qinghai, especially in Chaidamu Basin and Three-River Source Area. In 2020s, 2050s, and 2080s, the vegetation NPP in Qinghai Province would have an increment of 2.5-7.0, 2.7-7.5, and 2.9-7.8 t·hm-2·a-1, respectively.
    Population structure and spatial pattern of Celtis sinensis on Langqi Island of Minjiang Estuary.
    2011, 30(02):  221-226. 
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    Based on the investigation data from 12 plots in Landqi Island of Minjiang Estuary, and by using age structure and aggregation indices, this paper analyzed the population structure, spatial pattern, and recruitment mechanism of Celtis sinensis forest on the island. The results showed that the C. sinensis population was stable, with an expanding age structure, and the seedlings were abundant, exhibiting stronger regeneration ability. The sprouts, accounting for 78% of the total seedlings, played an important role in maintaining population regeneration. There was a high mortality rate in seedling stage and small tree stage, but there were certain adult individuals. The population structure in different plots presented stable or decline type, and the spatial pattern had somewhat differences, with random distribution in plots 2 and 4, even distribution in plot 11, and clumped distribution in the others. The spatial pattern of C. sinensis population differed with developmental stages, showing a tendency of gradual transition from aggregation pattern to random pattern with the growth of C. sinensis seedlings.
    Seasonal dynamics of soil microbial biomass and enzyme activities in four sand-fixation plantations on Horqin sandy land.
    2011, 30(02):  227-233. 
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    In order to approach the seasonal dynamics of soil microbial biomass and enzyme activities in different sand-fixation plantations on Horqin sandy land, 25-year old Caragana microphylla, Hedysarum fruticosum, Artemisia halodendron and Pinus sylvestris var. mongolica plantations were selected, with the seasonal variations of the protease, urease, saccharase, phosphomonoesterase, polyphenol oxidase, nitrate reductase, and dehydrogenase activities as well as the microbial biomass C, N and P in 0-30 cm soil layer studied. The results showed that the activities of the seven enzymes in the four plantations varied significantly with season, i.e., increased gradually in spring, reached the maximum in summer, and decreasing in autumn and winter, with the variation degree being more significant in 0-10 cm soil layer than in other soil layers. The enzyme activities and microbial biomass were the highest in 0-10 cm soil layer, and decreased down the profile. Among the four plantations, C. microphylla had the highest soil enzyme activities and microbial biomass, with the highest capability in improving the biological activity of sandy soil.
    Weed density and its biomass in wheat field under effects of different tillage and fertilization modes.
    2011, 30(02):  234-240. 
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    To understand the effects of different tillage and fertilization modes on the weed growth in wheatmaize rotation system in North China Plain, an investigation was made on the no-tillage wheat field which is set up 5 years ago. No-tillage had a trend of decreasing the total density of weeds and the density of dominant species flixweed at the early stage of wheat growth, but the difference between traditional tillage and notillage was not significant. The weed biomass under no-tillage with straw remained and with straw removed decreased significantly, in which the flixweed biomass decreased by 57% and 73%, respectively, compared with that under traditional tillage. No-tillage also decreased the dry weight per flixweed plant by 27%-53%. Compared with conventional tillage, no-tillage with straw remained and with straw removed decreased the flixweed height by 25% and 19%, respectively. Generally, tillage mode had little effects on the growth of purple mustard and corn gromwell, while concentrated fertilizing decreased the total biomass of weeds by 21%-68%, flixweed biomass by 58%-65%, and corn gromwell biomass by 91%, compared with repeated fertilization. It was concluded that no-tillage could inhibit the growth of several weeds, while topdressing could promote the rapid growth of weeds.
    Correlation analysis on vegetation succession and soil nutrients in abandoned salinized fields in lower reaches of Shiyang River.
    2011, 30(02):  241-247. 
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    Taking the natural vegetations on the salinized fields having been abandoned for different years in the lower reaches of Shiyang River as test objects, this paper studied the dynamic changes and interrelationships of vegetation succession and soil nutrients. Overall, the vegetation type experienced three stages, i.e., field weeds → desert herbages → desert brushes, while the community succession had four stages, i.e., Convolvulus arvensis + Chenopodium album (1-2 years) → Peganum nigellastrum (3-10 years) → Lycium ruthenicum + Kalidium cuspidatum var. sinicum (10-40 years) → Kalidium cuspidatum var. sinicum (climax community). During community succession, the changes of soil nutrients experienced three stages, i.e., consuming → accumulating → consuming, only soil available K not consumed at the early stage. All soil nutrients were consumed at the late stage, and finally, their contents were approached to the levels under natural vegetations in the area. Because of the consuming of the soil nutrients at the early stage, P. nigellastrum had less contribution to the soil nutrients, being significantly negatively correlated with soil available P but positively correlated with soil available K. L. ruthenicum had positive correlations with soil nutrients, especially with soil organic matter, total N, and the available K in 30-60 cm layer. There were significant negative correlations between K. cuspidatum var. sinicum and soil nutrients, suggesting that K.cuspidatum var. sinicum had strong adaptation to the site conditions, being able to be the proper introducing species to accelerate and direct the vegetation succession on abandoned salinized fields.
    Changes in source-sink relationship of photosynthate in Rehmannia glutinosa Libosch. and their relations with continuous cropping obstacle.
    2011, 30(02):  248-254. 
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    In this study, the currently cropped Rehmannia glutinosa was leaf-clipped to simulate the shortage of photosynthate in successively cropped R. glutinosa, and 14C-istope tracer and ELISA techniques were adopted to analyze the distribution of photosynthate and the levels of endogenous hormones in successive R. glutinosa, aimed to approach the source-sink relationship of the phosynthate and to explore the mechanism of continuous cropping obstacle of R. glutinosa. Leaf-clipping did not have the same impact as continuous cropping obstacle. The volume and activity of phosynthate pool under leaf-clipping were bigger than those under continuous cropping. The photosynthate in continuously cropped R. glutinosa was remained in shoot, suggesting that the low activity of the sink affected the transportation of the photosynthate. The levels of endogenous hormones also changed at the early growth stage of continuously cropped R. glutinosa. Our results suggested that the small volume and low activity of the sink could be an important factor limiting the development of R. glutinosa roots in continuous cropping. The feedback regulation of the sink to source by endogenous hormones inhibited the photosynthesis capacity and the partitioning of photosynthate to sink, resulting in the continuous cropping obstacle.
    Effects of different ratios of mineral nitrogen form on Helianthus tuberosus seedlings physiology under salt stress.
    2011, 30(02):  255-261. 
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    A sand cultural experiment was conducted to study the photosynthetic characteristics and ion absorption of Helianthus tuberosus seedlings under the coupling effects of nitrogen nutrition (NH4+--N/NO3--N ratio 4/1, 1/1, and 1/4) and salt stress. Low concentration salt stress had less effect in inhibiting H. tuberosus growth, while high concentration salt stress inhibited the growth remarkably. Under the same salt concentrations, increasing proportion of NO3--N could mitigate the inhibition effect of salt stress, and increase the fresh and dry weights of H. tuberosus. With the increase of salt concentration, the Na+ concentration in seedling’s shoots and roots increased significantly, while the K+ and Ca2+ concentrations decreased. Increasing the proportion of NO3--N promoted the selective absorption of K+ and Ca2+ and their translocation from roots to shoots, making shoots keep high ratios of K+/Na+ and Ca2+/Na+. Under the three ratios of NH4+--N/NO3---N and with increasing salt concentration, the leaf chlorophyll content, photosynthetic rate, transpiration rate, stomatal conductance, and water use efficiency all decreased significantly, while the intercellular CO2 concentration had a significant increase. With the increase of the proportion of NO3---N and under the same salt concentrations, the chlorophyll content, photosynthetic rate, transpiration rate, stomatal conductance, and water use efficiency increased significantly, while the intercellular CO2 concentration decreased significantly. Nitrogen nutrition at NH4+--N/NO3--N ratio of 1/4 had the best alleviation effect to salt stress, e.g., under 100 mmol·L-1 NaCl stress, the chlorophyll content, photosynthetic rate, transpiration rate, stomatal conductance, and water use efficiency at NH4+--N/NO3--N ratio of 1/4 increased by 1.63, 1.57, 1.39, 1.37, and 1.2 times, respectively, while the intercellular carbon dioxide concentration decreased by 17%, compared with those at the NH4+--N/NO3--N ratio of 4/1. Therefore, relative to NH4+--N, the increase of the proportion of NO3--N was more conducive to maintain the balance of mineral nutrients, promote the photosynthesis, and enhance the resistance of H. tuberosus to salt stress.
    Effects of drought stress on physiological characteristics of Phyllostachys edulis seedlings.
    2011, 30(02):  262-266. 
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    A pot experiment was conducted to study the physiological responses of 1-year old Phyllostachys edulis seedlings to drought stress. Four treatments were installed, i.e., control (CK), light (LS), medium (MS), and heavy (HS) drought stress. With increasing drought stress, the net photosynthetic rate (Pn) and transpiration rate (Tr) decreased significantly by 54.7% and 49.7%, respectively, WUE increased obviously under LS but decreased to some extent under MS and HS, Chl-a and Chl-b contents decreased significantly by 42.1% and 28.2%, respectively, but Chl-a/Chl-b was less affected, and the SOD and CAT activities as well as the MDA content increased significantly. There existed close correlations among these physiological indices. Principal components analysis (PCA) showed that the nine individual drought-tolerance indices could be integrated to two separate, comprehensive ones, and used as a reference to evaluate the drought resistance of P. edulis seedlings.
    Responses of growth and sexual reproduction of Phragmites australis and Spartina alterniflora to salinity stress.
    2011, 30(02):  267-272. 
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    Two coastal plants, native Phragmites australis and exotic Spartina alterniflora, were grown in fresh water and the waters with salinity 15‰ and
    30‰ to study their yearly dynamics of growth and sexual reproduction characteristics, aimed to explore the adaptation strategies of the two plants in response to increasing water salinity. Throughout the two-year experimental period, the aboveground biomass of S. alterniflora in all treatments was higher than that of P. australis. The aboveground biomass, shoot height, and ramet number of S. alterniflora and P. australis decreased with increasing water salinity. P. australis did not flower in the first year, but flowered in freshwater and medium salinity water in the second year. In the first year, the number of flowering ramets of S. alterniflora showed no difference among all treatments, but the inflorescence biomass decreased significantly in the water with high salinity. In the following year, the sexual reproduction of S. alterniflora was still inhibited by high salinity. The P. australis grown in fresh water and medium salinity water was taller than the S. alterniflora grown in the same waters in the second year, though the plant height of P. australis was shorter than that of S. alterniflora in the first year. Except P. australis in high salinity treatment, the aboveground biomass, shoot height, flowering ramet number, and inflorescence biomass of the two plants were higher in the second year than in the first year. Compared with P. australis, S. alterniflora had a relatively stronger growth ability and stronger tolerance to water salinity. The growth and sexual reproduction of the two plants increased with the time after establishment, but high salinity inhibited the increments for P. australis. In freshwater and medium salinity water, P. australis showed an advantage of shoot height in the second year.
    Seasonal changes of bird communities in different habitats in desert region of Fukang, Xinjiang.
    2011, 30(02):  273-280. 
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    An investigation was conducted to study the seasonal changes of bird communities in the natural and artificial habitats in Junggar Basin and near-foothills of Tianshan Mountains (Fukang, Xinjiang) from March 2009 to February 2010.Twelve line transects were installed in five habitats. A total of 147 species belonging to 17 orders, 38 families, and 90 genera were recorded. The amounts of summer visitors, residents, passersby, and winter visitors occupied 49.8%, 31.1%, 13.2%, and 5.9%, respectively, indicating that the study region was mainly inhabited by summer visitors. Of the total species number, residents occupied 13.9% and distributed in various kinds of habitat, suggesting that relative to other species, residents were more likely to become the dominant species in the region. Having the highest Shannon index (4.861) and species richness (106 species),lakes were the most important breeding grounds and stopovers for summer visitors. Based on the Morisita similarity index, all habitats were clustered into three typ
    es, i.e., lake, desert, and farmland. Lake and desert habitats belonged to natural ones, in which, the seasonal turnover rate of birds peaked between spring and summer and declined then; while farmland, as an artificial habitat, attracted 68.5% of winter visitors, with the lowest turnover rate of birds between spring and summer (0.934) and the highest turnover rate of birds between summer and autumn (1.154). To preserve and plant Elaeagnus angustifolia forest belt would help to the increase of winter visitors’ diversity in the farmlands in Fukang, Xinjiang.

    Effects of rice-planting neighboring with vegetable crops on the population dynamics of Cnaphalocrocis medinalis, plant hopper, and their predatory enemies.

    2011, 30(02):  281-289. 
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    A field experiment was conducted to study the effects of mosaic arrangement of paddy rice neighboring with white melon, tomato, corn, amaranth, flowering Chinese cabbage, and spinach on the population dynamics of Cnaphalocrocis medinalis, plant hopper, and their predatory enemies. All the six mosaic arrangements decreased the abundance of C. medinalis and plant hopper significantly, compared with the control (paddy rice neighboring with fallow). In early rice growth season, the abundance of C. medinalis adults, larvae and eggs, and of plant hopper under the arrangement of paddy rice neighboring with white melon and tomato had the largest decrement, being 84.3%, 38.9%, and 24.3%, respectively; in late rice growth season, the largest decrement of the abundance under the arrangement of paddy rice neighboring with amaranth and flowering Chinese cabbage was 79.5%, 49.8% and 13.4%, respectively. Paddy rice neighboring with white melon and flowering Chinese cabbage also had a significant effect on the increase of the abundance of predatory enemies. Therefore, planting paddy rice neighboring with white melon and flowering Chinese cabbage could have the best effect in insect pest control and predatory enemies’ conservation.
    Flower-visiting behavior and pollination ecology of different bee species on greenhouse strawberry.
    2011, 30(02):  290-296. 
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    A comparative study was made on the flower-visiting behavior and pollination ecology of Apis mellifera, Bombus hypocrita, and Bombus terrestris on greenhouse strawberry in Beijing. As for A. mellifera, the temperature at which the bee left nest, temperature for initial working, visiting duration on a single flower, and time interval between visiting two flowers were all significantly higher (P<0.01), compared with B. hypocrita or B. terrestris, while the latter two bee species had no significant differences in these behaviors (P>0.05). The proportion of the pollens carried to the nest by the three bee species ranked as A. mellifera > B. hypocrita > B. terrestris, and the activity of the pollens carried by the bees ranked as A. mellifera > B. hypocrita = B. terrestris. The initial working time of B. hypocrita and B. terrestris was earlier than that of A. mellifera, and the working time within a day was longer for B. hypocrita and B. terrestris than for A. mellifera. B. terrestris had the highest working frequency within a day (P<0.01). The nutritional quality of the fruits via the pollination by the three bee species showed no significant difference (P>0.05) with the control, but after the pollination, the strawberry had a lower rate of malformed fruit and a higher single fruit weight than the control. The strawberry visited by B. hypocrita and B. terrestris had a lower rate of malformed fruit than that visited by A. mellifera (P>0.05). For the pollination of greenhouse strawberry, native bumble bee species B. hypocrita could be effectively used in place of introduced A. mellifera or B. terrestris.
    Spatial distribution and seasonal variation of macrobenthos in intertidal flat of Sheyang estuary, Yancheng Nature Reserve.
    2011, 30(02):  297-303. 
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    From November 2008 to October 2009, the macrobenthic community in the intertidal flat of Sheyang estuary, Yancheng Nature Reserve was sampled monthly. A total of 16 species belonging to 15 families, 4 classes, and 3 phyla were collected, which were mollusks, crustaceans, and polychaetes. The species number found at 4 sampling sites (intertidal zone with Spartina alterniflora, and high, middle, and low tidal flats without plants) was 6, 7, 13, and 7, respectively. Two-factor ANOVA was used to analyze the effects of sampling site and season on the species number, density, and biomass of macrobenthic community, and the biodiversity indices (Margalef, S; Shannon, H; Pielou, J; and Simpson, D). There were significant differences in the species number (P<0.01), density (P<0.01), and biomass (P<0.01) among sampling sites, but less difference was observed among seasons. The H (P<0.01), D (P<0.05), and S (P<0.05) were all significantly affected by sampling site but less affected by season, while the J was less affected either by sampling site or by season. The hierarchical clustering of between-groups linkage and the non-matric multi-dimensional scaling showed that the macrobenthic community in high and middle tidal flats without plants had no distinct dividing line, while that in intertidal zone with S. alterniflora and in low tidal flat without plants was in adverse. Our results revealed that, comparing with seasonal variation, habitat difference was much more important for the difference in the macrobenthic community composition in intertidal flat.
    Changes of soil algal composition and their affecting factors in the periphery of gangue yard within a coal mining area in central Guizhou Province.
    2011, 30(02):  304-310. 
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    Soil samples were collected from the periphery of gangue yard within the coal mining area in Maiping township of Huaxi District, Guiyang City to study
     the changes of soil algal composition, diversity, and biomass, and their correlations with soil factors. In un-contaminated soils, the observed algae consisted of five phyla and forty-three genera, with thirteen genera of Cyanophyta, seventeen genera of Chlorophyta, and seven genera of Bacillariophyta. After the contamination of coal gangue, the richness and individual density of soil algae decreased obviously. At seriously contaminated sites, Cyanophyta only had three genera, and Chlorophyta only had four genera. The Shannon index of soil algae had significant correlations with soil available Fe, Mn, and P, while the species richness had significant correlations with soil pH and available P. The chlorophyll content of soil algae at seriously contaminated sites was decreased by 93.1%, compared with that at un-contaminated sites. The algal biomass was significantly positively correlated with soil pH and negatively correlated with soil available Fe, suggesting that soil pH and available Fe were the important factors affecting the soil algal growth in the periphery of coal gangue yard.
    Effects of maize residue return in combination with S024 on soil microbial population and wheat sharp eyespot.
    2011, 30(02):  311-314. 
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    A field experiment was conducted to study the effects of maize residue return and its combination with biocontrol actinomyces agent S024 (Streptomyces sp.) on the soil microbial population, wheat sharp eyespot (Rhizoctonia cerealis), and wheat yield. Returning maize residue into soil had significant effect on the increase of the amounts of soil bacteria and actinomyces. The combination of maize residue return with S024 inoculation increased the amount of actinomyces at shooting stage by 50% and decreased the amount of wheat sharp eyespot by 20%, compared with the control (no maize residue return). Returning maize residue into soil showed a better control effect on wheat sharp eyespot at shooting stage, and the treatment of doubled residue return (9000 kg·hm-2) combined with S024 inoculation had the best effect, with the disease index decreased by 57.4%. Returning maize residue into soil had definite effect in increasing wheat yield. Doubled residue return combined with S024 inoculation increased the yield most, and the increment reached 23.1%.
    Screening of PAHs-degrading bacterial strains and determination of their capability in degrading PAHs.
    2011, 30(02):  315-319. 
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    Eight PAHs-degrading bacterial strains were screened out from the enriched culture with PAHs-contaminated soils in Benxi City of Liaoning Province, Northeast China, and the capability of the strains in degrading phenanthrene, phyrene, and benzo[a]pyrene with an initial concentration of 50, 50, and 5 mg·L-1 in medium was determined after 28-day incubation at 28 ℃. Among the strains screened out, B3 showed the best degrading effect, with the degradation rate of phenanthrene, phyrene, and benzo[a]pyrene being 88.4%, 54.0%, and 68.4%, while the degradation rate of these compounds by the mixed 8 strains was 87.7%, 35.3%, and 42.0%, respectively. The strain B3 was identified as Pseudomonas sp., based on its physiological and biochemical characteristics and the sequence analysis of 16S rRNA.
    Landscape gradient change in a typical town of south Jiangsu Province.
    2011, 30(02):  320-326. 
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    Based on the 2009 Quickbird satellite image and the GIS spatial analysis techniques, we selected land use degree index and landscape pattern metrics, combining with gradient analysis, to study the land use intensity and landscape structure change of urban-rural gradient in a typical town (Xinzhuang town) of south Jiangsu. The results showed that in Xinzhuang region, paddy field was the dominant landscape type, while rural construction land, fish pond, and water body were the main landscape types. The land use intensity in town area was significantly greater than that in rural area, while the land use degree index decreased gradually with the increasing distance from the town center. In town area, the landscape space aggregation degree was greater, landscape structure was more regular, and fragmentation degree was lower; while in rural area, the landscape space had a larger dispersion degree, with more complex shape and serious fragmentation, and the landscape pattern was under optimization. The land use intensity showed significant negative correlations with patch density and landscape shape index (P<0.05), significant positive correlations with Shannon diversity and evenness index (P<0.01), and significant correlation with aggregation index, suggesting that with the increasing intensity of land development, the town landscape was towards more diversified and homogeneous, construction land became dominant landscape, and spatial aggregation was increasingly enhanced.
    Nonmarket valuation of forest resources in Guiyang City of Guizhou Province based on comparative analysis of WTP and WTA.
    2011, 30(02):  327-334. 
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    Contingent valuation method (CVM) was adopted to investigate the residents’ willingness to participate, to pay, and to accept the compensation in the process of protecting the forest resources in Guiyang City of Guizhou Province, Southwest China. Based on this investigation, the major socio-economic factors affecting the willingness to pay (WTP) and the willingness to accept compensation (WTA) were analyzed, and the models of the residents’ basic status and their WTP or WTA were built to estimate the nonmarket valuation of forest resources in the city. It was expected that this study could provide scientific basis for the establishment of the standards in protecting and eco-compensating the forest resources in Guiyang, and accordingly, lead to the decrease of the economic losses from environmental damage and the healthy and orderly evolvement of forest eco-environment.
    Spatiotemporal variation characteristics and related affecting factors of architecture landscape in Tiexi District of Shenyang.
    2011, 30(02):  335-342. 
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    To study the spatiotemporal variation characteristics of urban architecture landscape is of significance in the reasonable adjustment of urban planning. In this paper, the buildings’ three-dimension information of Tiexi District, Shenyang was extracted by using Barista software and GIS and RS techniques, and the spatiotemporal variation characteristics and related affecting factors of architecture landscape in the district were analyzed with the indices of build-up area ratio, average building height, building coverage ratio, building shape index, and spatial center of gravity transfer model. From 1997 to 2008, the build-up area for resident and commerce in the district increased, while that for industry decreased. The buildings’ shape became more regular, building coverage ratio decreased, and buildings were growing in vertical direction. Spatially, the centroid of the architecture landscape change shifted from residential area to industrial estate, and then, from the center to the outskirts of the district. Economic development and population growth had positive correlations with average building height, and negative correlation with building density. The implement of urban renewal policy had significant effects on the variation of the architecture landscape. With the increasing distance from roads, the average building height decreased and the building coverage ratio decreased after an initial increase.
    Emergy analysis of Tianzhu ecological-economic system.
    2011, 30(02):  343-348. 
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    Emergy theory provides a new theory and method to study the structure and function of ecological-economic systems. In this paper, an emergy analysis was performed on the ecological-economic system of Tianzhu County, Gansu Province, aimed to quantitatively describe the overall characteristics of ecological-economic pattern and its development status of the County, and give comparison with other countries and districts. The main emergy indices calculated were total emergy consumption, emergy/money ratio, emergy self-sufficiency ratio, emergy per capita, and emergy per unit area. In 2008, the total amount of emergy of Tianzhu County was 2.38×1021 sej, and the emergy consumption per capita was 1.03×1015 sej, far lower than those of other countries and districts; while the emergy self-sufficiency rate was 88.87%, and theemergy/money ratio was 3.41×1013 sej·$-1, being higher than those of the cities in coastal developed provinces of China. These results indicated that the economic development of Tianzhu County was based on the over-reliance on and the excess utilization of local resources, and that the ecological-economic system of the county was a closed, inactive, unsustainable system. A series of measures and suggestions were given to promote the sustainable development of Tianzhu County.
    Shoot-branching control with strigolactones: Research progress.
    2011, 30(02):  349-356. 
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    Plant can regulate the formation and subsequent outgrowth of axillary buds in axils via endogenous hormones or environmental cues, and accordingly, control the characteristics of shoot-branching. Strigolactones (SLs), previously known as the principal plant-derived signals triggering the seed germination of parasitic plants and promoting the arbuscular mycorrhizal symbiosis, are the carotenoid-derived signals exuded from plant roots. Recent studies demonstrated that strigolactones can move upwards to the stem, and, together with endogenous auxin and cytokinin, directly or indirectly inhibit the outgrowth of axillary buds. Now, strigolactones are thought to be a new kind of hormone. In this paper, the research progress in the structure, synthesis pathway, and bioactivity of strigolactones was reviewed, and the prospects in the applied fields such as how to use strigolactones to inhibit parasitic weeds, develop new herbicides, promote the symbiosis of plants and beneficial fungi, and control the branching and architecture of crop plants were also discussed.
    Psammophyte architecture and its relations with anti-wind erosion capability: A review.
    2011, 30(02):  357-362. 
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    Psammophyte plays an important role in wind erosion control. The long-term adaptation of psammophyte to wind erosion makes the plant have specific architecture characteristics. Previous studies mainly focused on the effects of the individuals or a group of psammophyte on the near surface air flow field and sand fixation and resistance. As for the architecture characteristics of psammophyte, the research covered all of the adaptation strategies, lacking of quantitative research and systematic analysis on the discrepancy against wind erosion. This paper reviewed the research progress on psammophyte architecture and its relations with the capability of anti-wind erosion, and pointed out the key issues needed to be further studied to provide scientific basis for perfecting the mechanisms of sand plant resistance to wind erosion.
    Applications of molecular biotechnology in monitoring toxic cyanobacteria in water environment.
    2011, 30(02):  363-368. 
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    Toxic cyanobacteria can form blooms in fresh, brackish, and marine waters, giving threats to water environment, and also, to human and animal health. Owing to its simple, fast, and economic advantages, molecular biotechnology has become the focus of concern in monitoring toxic cyanobacteria in water environment. This paper summarized the research progress in this field from the aspects of 1) monitoring toxic cyanobacteria by using traditional molecular biotechnology, 2) molecular detection according to the synthetase gene of cyanotoxin, and 3) detection of toxic cyanbacteria by using DNA microarray technology. Compared with conventional molecular biotechnology, the DNA microarray technology offers a rapid, economic, and high-throughout option for detecting toxic genotypes in complex samples, and thus, would bring a new revolution in detecting toxic cyanobacteria.
    Environmental quality standard of BTEX: A review.
    2011, 30(02):  369-375. 
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    BTEX is a general designation of benzene, toluene, ethylbenzene and three xylene isomers (o-, m-, and p-xylene). Because of its wide existence in air, water, and soil environment, BETX has caused threat to related ecosystems and human health, being highly concerned by many relevant environmental agencies. In this paper, some environmental quality standards of BTEX were summarized. In addition, through the introduction of indoor air, surface water, and soil quality standards of BTEX formulated by developed countries (USA, Australia, and Canada) and international organizations (WHO and EU), and through the comparison of China’s standards with the former ones, some problems and shortcomings in China’s standards were pointed out. Finally, the future research on environmental quality criteria of BTEX was propounded.
    Applications of eco-exergy in ecological modeling and assessment of aquatic ecosystems.
    2011, 30(02):  376-383. 
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    Eco-exergy is defined as the amount of work that a system can perform when the system is brought into thermodynamic equilibrium from a given state. It can be used to measure the complex biochemical components and ecological structure. A system with more exergy will present better ordering and stability. Eco-exergy and specific eco-exergy can be used to assess the status of aquatic ecosystem health, and indicate the certain succession stage in aquatic ecosystem restoration. This paper presented the definitions and ecological meanings of eco-exergy and specific eco-exergy as well as the calculation methods of eco-exergy and weighting factor fi, summarized the applications of eco-exergy as a goal function in structural dynamic models (SDMs) and as an ecological indicator for ecosystem health assessment and ecological restoration of aquatic ecosystems, and discussed the limitations and future development of eco-exergy. Furthermore, the unified translation of “eco-exergy” and “specific eco-exergy” in Chinese was suggested.
    Dynamic diameter distribution simulation and optimal management of broadleaved Korean pine mixed forest in Changbai Mountain.
    2011, 30(02):  384-388. 
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    Taking the original broad-leaved Korean pine forest in Changbai Mountain of Northeast China as test object, and by using density-dependent matrix model, this paper simulated the temporal dynamics of diameter distribution of the stand under natural growth scenario, analyzed the effects of a selection harvest scenario on the diameter distribution, and calculated the recover periods of seven harvest scenarios. The  forest was relatively stable, but still had a slow natural growth. The stand density declined, which accorded with the self-thinning law of forest. The change rate of the tree number of each diameter class weakened gradually over time, and the stand density became relatively fixed, which validated the theory of succession climax. Based on the indices for assessing the effect of forest management, including harvest level, structure of preserved stands, and harvest cost, it was considered that, 20% harvest intensity with an interval of 35 years and 25% harvest intensity with an interval of 45 years would be the two of the most optimal harvest scenarios.
    Evaluation of stomatal conductance models based on leaf-level measurements.
    2011, 30(02):  389-394. 
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    Plant leaf stomatal conductance (g) is an important factor controlling the energy and water exchanges between canopy and atmosphere, while air humidity is a key environmental variable controlling the g. In last decade, the stomatal conductance- humidity relationships in Ball-Woodrow-Berry (BWB) and Leuning models were widely used. In this study, a new diagnostic parameter f(H) was adopted to assess the response of g to air humidity. Based on the leaflevel measurements in a cropland ecosystem, the performance of the BWB, Leuning, and newly developed power-h and power-D models was examined. The results showed that the BWB model which employs a linear relationship between g and relative humidity (hs) led to a larger underestimate of g when the air was wet, while the Leuning model which employs a nonlinear function of water vapor pressure deficit (Ds) decreased this bias but still not adequately captured the significant increase of g under the wet condition. Compared with BWB and Leuning models, the newly developed power-h and power-D models that employ a power function of Dsand a power function of relative humidity deficit (1-hs), respectively, showed better performance. The results also indicated that the models based on Ds generally performed better, compared with those based on hs.
    Analytical methods for synthetic musk in wastewater and sewage sludge.
    2011, 30(02):  395-400. 
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    The discharge of municipal wastewater and sewage sludge is the main pathway of synthetic musk entering soil environment. Parameters for the discharge are necessary for ecological risk assessment models, but few have been reported regarding the ecological risk assessment of synthetic musk in soil partly due to the shortage of convenient, quick and efficient techniques for the detection of synthetic musk in the environment. To promote the analytic methodology of synthetic musk, we compared and optimized the techniques for extracting two typical kinds of synthetic musk, galaxolide (HHCB) and tonalid (AHTN), in municipal wastewater by solid-phase extraction and liquid-liquid extraction, and in dehydrated sludge by soxhlet extraction and accelerated solvent extraction (ASE). The results showed that liquid-liquid extraction and ASE followed by silica gel column cleaning process had higher recovery in detecting synthetic musk in water and sludge samples. The two optimized methods were adopted to detect the HHCB and AHTN concentrations in the inflow and effluent water and the dehydrated sludge from a Beijing sewage treatment plant, and their concentrations were 897-1270 ng·L-1 and 331-488 ng·L-1 in inflow water, 201-226 ng·L-1 and 65-130 ng·L-1 in effluent water, and 137-348 ng·g-1 and 64-138 ng·g-1 in dehydrated sludge, respectively.
    Dynamic drought-monitoring index based on soil moisture simulation model and its applicability.
    2011, 30(02):  401-407. 
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    According to the principles of soil water balance, Penman-Monteith function was adopted to calculate potential evapotranspiration. The daily soil available moisture was simulated, and the daily dynamic drought-monitoring index was put forward based on soil moisture (SM). With the comparison of the standardized precipitation index (SPI), relative moisture index (MI), and combined meteorological drought index (CI) recommended by the ‘meteorological drought levels of National Standards’ (GB/T 20481-2006), the applicability of the daily dynamic drought-monitoring index based on SM in Guangdong was evaluated, and the results showed that the drought season (from November to next April) based on SM lagged one month, compared to rain-less period (from October to next March). The SM index could describe the lag effect and gradual change characteristics of drought relative to the annual change of precipitation, and objectively reflect the seasonal distribution of drought frequency in Guangdong. The drought index based on SM automatically implied the time cumulative effect of precipitation-evaporation process, and thereby, could describe the start, development, and end of drought process in detail. In terms of progressive development, precipitation sensitivity, and integrity of drought course, the drought index based on SM was of good application value.
    Using simulated annealing algorithm to optimize the parameters of Biome-BGC model.
    2011, 30(02):  408-414. 
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    Ecological process model based on defined mechanism can well simulate the dynamic behaviors and features of terrestrial ecosystem, but could become a bottleneck in application because of numerous parameters needed to be confirmed. In this paper, simulated annealing algorithm was used to optimize the physiological and ecological parameters of Biome-BGC model. The first step was to choose some of these parameters to optimize, and then, gradually optimized these parameters. By using the optimized parameters, the model simulation results were much more close to the observed data, and the parameter optimization could effectively reduce the uncertainty of model simulation. The parameter optimization method used in this paper could provide a case and an idea for the parameter identification and optimization of ecological process models, and also, help to expand the application area of the models.