Table of Content

18 December 2012, Volume 23 Issue 12

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Responses of boreal forest landscape in northern Great Xing’an Mountains of Northeast China to climate change.

LI Xiao-na1,2, HE Hong-shi1, WU Zhi-wei1, LIANG Yu1

2012, 23(12):  3227-3235. 

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With the combination of forest landscape model (LANDIS) and forest gap model (LINKAGES), this paper simulated the effects of climate change on the boreal forest landscape in the Great Xing’an Mountains, and compared the direct effects of climate change and the effects of climate warminginduced fires on the forest landscape. The results showed that under the current climate conditions and fire disturbances, the forest landscape in the study area could maintain its dynamic balance, and Larix gmelinii was still the dominant tree species. Under the future climate and fire disturbances scenario, the distribution area of L. gmelinii and Pinus pumila would be decreased, while that of Betula platyphylla, Populus davidiana, Populus suaveolens, Chosenia arbutifolia, and Pinus sylvestris var. mongolica would be increased, and the forest fragmentation and forest diversity would have an increase. The changes of the forest landscape lagged behind climate change. Climate warming would increase the growth of most tree species except L. gmelinii, while the increased fires would increase the distribution area of P. davidiana, P. suaveolens, and C. arbutifolia and decrease the distribution area of L. gmelinii, P. sylvestris var. mongolica, and P. pumila. The effects of climate warminginduced fires on the forest landscape were almost equal to the direct effects of climate change, and aggravated the direct effects of climate change on forest composition, forest landscape fragmentation, and forest landscape diversity.

Prediction on the changes of forest fire danger rating in Great Xing’an Mountain region of Northeast China in the 21stcentury under effects of climate change.

YANG Guang1，2, SHU Li-fu2, DI Xue-ying1

2012, 23(12):  3236-3242. 

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Based on the A2a and B2a climatic scenarios for both the baseline period (1961-1990) and the future scenario periods (2010-2039,  2040-2069, and  2070-2099) from the Hadley Centre’s General Circulation, and by using Delta method, WGEN downscaling methods, and Canadian Forest Fire Danger Rating System, this paper classified the forest fire dangers in Great Xing’an Mountains region of Heilongjiang Province, Northeast China, predicted the changes of the forest fire danger rating in the period 2010-2099 relative to baseline period (1961-1990), and analyzed the uncertainty of the longterm prediction of forest fire danger rating. It was predicted that under the background of climate warming, the mean annual days of extremely high, very high, and medium forest dangers in study region in the 21st century all showed an increasing trend, while the mean annual days of high and low forest dangers were in adverse. Relative to the baseline period of 1961-1990, the mean annual days of extremely high and very high forest dangers in the 2040-2069 and 2070-2099 under the scenarios of SRES A2a and B2a would be increased by 43 and 36, and 62 and 61, respectively.

Remote sensing retrieval of vegetation coverage in arid areas based on multiple endmember spectral unmixing.

LIAO Chun-hua, ZHANG Xian-feng, LIU Yu

2012, 23(12):  3243-3249. 

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Vegetation coverage is an important indicator in the assessment of terrestrial ecosystem and land desertification. By using the data acquired from the novel hyperspectral sensor HIS in Chinese HJ-1 small satellite, the suitable endmember spectrum was extracted by the combination of pixel purity index and endmember average root mean square error. Then, the vegetation coverage (FVC) in Shihezi area of Xinjiang, Northwest China was retrieved by the model of multiple endmember spectral mixture analysis (MESMA). With the comparison of the FVCs retrieved from the linear spectral analysis (LSMA) model and the measurement results, the FVCs retrieved from the MESMA model were evaluated. The results showed that the MESMA model enabled the use of different endmember combinations for different image pixels, and thus, could perform better than the LSMA model in the estimation of regional FVCs. As compared with the LSMA model, the correlation coefficient between the FVCs retrieved from the MESMA model and the measured FVCs increased from 0.766 to 0.838, while the root mean square error decreased from 0.375 to 0.196.

Simulation of vegetation indices optimizing under retrieval of vegetation biochemical parameters based on PROSPECT+SAIL model.

WU Ling, LIU Xiang-nan, ZHOU Bo-tian, LIU Chuan-hao, LI Lu-feng

2012, 23(12):  3250-3256. 

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This study analyzed the sensitivities of three vegetation biochemical parameters \[chlorophyll content (Cab), leaf water content (Cw), and leaf area index (LAI)\] to the changes of canopy reflectance, with the effects of each parameter on the wavelength regions of canopy reflectance considered, and selected three vegetation indices as the optimization comparison targets of cost function. Then, the Cab, Cw, and LAI were estimated, based on the particle swarm optimization algorithm and PROSPECT+SAIL model. The results showed that the retrieval efficiency with vegetation indices as the optimization comparison targets of cost function was better than that with all spectral reflectance. The correlation coefficients (R²) between the measured and estimated values of Cab, Cw, and LAI were 90.8%, 95.7%, and 99.7%, and the root mean square errors of Cab, Cw, and LAI were 4.73 μg·cm^-2, 0.001 g·cm^-2, and 0.08, respectively. It was suggested that to adopt- vegetation indices as the optimization comparison targets of cost function could effectively improve the efficiency and precision of the retrieval of biochemical parameters based on PROSPECT+SAIL model.

Degradation characteristics, patterns, and processes of lakeside wetland in Napahai of northwest Yunnan Plateau, Southwest China.

SHANG Wen, YANG Yong-xing

2012, 23(12):  3257-3265. 

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Two-way indicator species analysis (TWINSPAN) and canonical correspondence analysis (CCA) were employed to analyze the degradation characteristics, patterns, and processes of lakeside wetland in Napahai of northwest Yunnan Plateau. The plant communities in the lakeside wetland could be classified into four associations, according to the TWINSPAN results. The succession patterns of the plant community were represented by aquatic plant community → swamp plant community → swamp meadow plant community → meadow plant community. During the processes of succession, the plant community coverage, density, Shannon diversity index, species richness, and plant aboveground biomass increased, whereas the community height decreased. The succession of the plant hydroecotypes followed the sequence of aquatic → helophyte → hygrophyte → mesophyte. With the succession of the plant community, the wetland water quality indices salinity, alkalinity, and hardness decreased but ammonium nitrogen and total phosphorus concentrations increased, while total nitrogen and nitrate nitrogen concentrations showed no significant changes. Meanwhile, the soil pH and soil organic matter and total nitrogen contents decreased gradually, soil total phosphorous and potassium contents were increasing, whereas soil available phosphorous and potassium contents decreased after an initial increase. The CCA showed that the community species composition and structure were mainly affected by the wetland water gradient. The soil pH and total phosphorus content and the water total nitrogen and ammonium nitrogen concentrations had significant effects on the wetland plant species distribution and plant community succession.

Characters of soil organic matter functional groups in the fields planted with alfalfa (Medicago sativa) for different years in hilly regions of south Ningxia, Northwest China.

LI Ting1,2,3, ZHAO Shi-wei1,2, LI Xiao-xiao2, MA Shuai2

2012, 23(12):  3266-3272. 

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Soil samples were collected from the fields planted with alfalfa for different years in the hilly region of southern Ningxia, and the technique of synchrotron radiationfourier transform infrared spectroscopy (SR-FTIR) was adopted to study the characters of soil organic carbon (SOC) functional groups in different sizes of soil aggregates. Planting alfalfa changed the contents of SOC functional groups and their distribution in soil aggregates. With the increasing year of planting alfalfa, the SOC content, percentage of macroaggregates (>0.25 mm), aggregates stability, and relative content of SOC saturated alkyl all increased, and the saturated alkyl was mainly distributed in 0.25-1 mm aggregates. However, the relative contents of SOC aliphatic-C and alcohol-C decreased with the increase of soil aggregate size. The increased aliphatic-C and alcohol-C were mainly distributed in macro-aggregates, whereas the aromatic-C was mainly distributed in <0.25 mm aggregates. The variation range of the relative contents of the functional groups in macro-aggregates was larger than that in <0.25 mm aggregates, showing that the SOC stability in micro-aggregates was higher than that in macro-aggregates. Continuous planting of alfalfa made the increment of SOC easily oxidizable functional groups (aliphatic-C and alcohol-C) be larger than that of aromatic-C and the chemical stability of SOC increased, with the best effect observed in 8-year planting. The aliphatic-C, alcohol-C, and saturated alkyl in SOC had higher percentages, their variation was most active, and had great contribution to the increase of SOC content.

Relationships of soil organic carbon with its active and non-active components under different land use types in the middle reaches of Heihe River, China.

ZHANG Jun-hua1,2, LI Guo-dong1,2, WANG Yan-song1,2, NAN Zhong-ren3, ZHAO Li-ping4

2012, 23(12):  3273-3280. 

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Taking the seven typical land use types (paddy field, dry land, medium coverage grassland, saline-alkali field, bare land, desert, and sandlot) in the middle reaches of Heihe River as test objects, this paper studied the relationships of soil organic carbon content with its components. In the 0-100 cm soil profile, the contents of soil total organic carbon (TOC), active organic carbon (AOC), and nonactive organic carbon (NOC) decreased with increasing depth. The soil TOC, AOC, and NOC contents differed with land use type. Land use change induced the increase or decrease of soil organic carbon content. The tillage in paddy field was an available way to increase the contents of soil TOC, AOC, and NOC. After land use change, soil NOC rather than AOC contributed more to soil TOC content. For the same land use types, soil AOC and NOC contents increased together with increasing soil TOC content, and the NOC content increased faster than the AOC content. The soil TOC content corresponding to the crossing point of the variation trend lines of soil AOC and NOC contents could be considered as the boundary point of TOC accumulation or loss, and the saturation capacities of soil AOC and NOC could be obtained by the variation trend lines of the AOC and NOC.

Sediment-yielding process and its mechanisms of slope erosion in wind-water erosion crisscross region of Loess Plateau, Northwest China.

TUO Deng-feng1,2, XU Ming-xiang2,3, ZHENG Shi-qing3, LI Qiang3

2012, 23(12):  3281-3287. 

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Due to the  coupling effects of wind and water erosions in the wind-water erosion crisscross region of Loess Plateau, the slope erosion in the region was quite serious, and the erosion process was quite complicated. By using wind tunnel combined with simulated rainfall, this paper studied the sedimentyielding process and its mechanisms of slope erosion under the effects of wind-water alternate erosion, and quantitatively analyzed the efffects of wind erosion on water erosion and the relationships between wind and water erosions. There was an obvious positive interaction between wind and water erosions. Wind erosion promoted the development of microtopography, and altered the quantitative relationship between the sediment-yielding under water erosion and the variation of rainfall intensity. At the rainfall intensity of 60 and 80 mm·h^-1, the sediment-yielding without wind erosion decreased with the duration of rainfall and tended to be stable, but the sediment-yielding with wind erosion decreased to a certain valley value first, and then showed an increasing trend. At the rainfall intensity of 60, 80, and 100 mm·h^-1, the sediment-yielding with the wind erosion at speeds of 11 and 14 m·s^-1 increased by 7.3%-27.9% and 23.2%-39.0%, respectively, as compared with the sediment-yielding without wind erosion. At the rainfall intensity of 120 and 150 mm·h^-1 and in the rainfall duration of 15 minutes, the sediment-yielding with and without wind erosion presented a decreasing trend, but, with the increase of rainfall duration, the sediment-yielding with wind erosion showed a trend of decreasing first and increasing then, as compared with the sediment-yielding without wind erosion. The mechanisms of wind-water alternate erosion were complicated, reflecting in the mutual relation and mutual promotion of wind erosion and water erosion in the aspects of tempora spatial distribution, energy supply, and action mode of erosion forces.

Frost-resistance of subtropical evergreen woody plants: An evaluation based on plant functional traits.

XU Yi-lu1,2, YANG Xiao-dong1,2, XU Yue1,2, XIE Yi-ming1,2, WANG Liang-yan3, YAN En-rong1,2 

2012, 23(12):  3288-3294. 

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Evaluating the frost-resistance of evergreen woody plants is of significance in guiding the species selection in forest management in subtropical region. In this paper, an investigation was made on the functional traits (including specific leaf area, stem wood density, leaf area, leaf dry matter  content, leaf relative electrical conductance, and twig wood density) of 64 common evergreen broad-leaved and coniferous woody plant species in the Ningbo region of Zhejiang Province, East China, after a severe snowstorm in early 2008, aimed to select the evergreen woody plants with high ability of freezetolerance, and to establish a related evaluation system. By using a hierarchy analysis approach, the weight values of the functional traits of each species were determined, and an index system for evaluating the plants tolerance ability against freeze and mechanical damage was established. Based on this system, 23 evergreen plant species with high tolerance ability against freeze and mechanical damage, such as Cyclobalanopsis gilva, Cyclobalanopsis nubium, Neolitsea aurata, and Vacciniuim mandarinorum, were selected. In the meantime, on the basis of the ordering with each of the functional traits, the ordering of the tolerance ability of the 64 plant species against freeze and mechanical damage was made, and a list for the frost-resistance ability of the subtropical evergreen woody plant species in Ningbo region was constituted.

Responses of plant functional traits and soil factors to slope aspect in alpine meadow of South Gansu, Northwest China.

LIU Min-xia1,2, MA Jian-zu3

2012, 23(12):  3295-3300. 

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This paper studied the plant functional traits, soil factors, and their relationships at different slope aspects in the alpine meadow of South Gansu. On the sunny slope, grasses were the dominant functional groups; while on the shady slope, forbs and shrubs dominated. The plant community biomass was significantly higher on shady slope than on sunny slope, while the leaf N/P ratio was in adverse. The leaf phosphorus content, specific leaf area, and plant average height at different slope aspects were in the order of shady slope > partial shady slope > sunny slope, whereas the leaf nitrogen content on different slopes had less difference. The survival strategies of the vegetations on sunny and shady slopes had great changes, reflecting in the differences in the plant leaf traits and dominant functional groups. Soil temperature was in the order of sunny slope > partial shady slope > shady slope, while soil water content was in the order of shady slope> partial shady slope > sunny slope. Soil total phosphorus content increased from the sunny slope to the shady slope, while the other soil nutrients contents showed the sequence of shady slope > sunny slope > partial shady slope. The specific leaf area and plant average height were significantly positively correlated to the soil organic carbon, total phosphorous, and water contents, and significantly negatively correlated to soil pH. Soil water content and soil pH coaffected the distribution patterns of plant functional traits and soil nutrients at different slope aspects of alpine meadow.

Effects of litterfall and root input on  soil physical and chemical properties in Pinus massoniana plantations in Three Gorges Reservoir Area, China.

GE Xiao-gai1,2, HUANG Zhi-lin1, CHENG Rui-mei1, ZENG Li-xiong1, XIAO Wen-fa1, TAN Ben-wang2

2012, 23(12):  3301-3308. 

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An investigation was made on the soil physical and chemical properties in differentaged Pinus massoniana plantations in Three Gorges Reservoir Area under effects of  litterfall and roots. The annual litter production in mature stand was 19.4% and 65.7% higher than that in nearly mature and middle-aged stands, respectively. The litter standing amount was in the sequence of mature stand > middleaged stand ＞ nearly mature stand, while the litter turnover coefficient was in the order of nearly mature stand (0.51) ＞ mature stand (0.40) ＞ middle-aged stand (0.36). The total root biomass, live root biomass, and dead root biomass were the highest in middle-aged stand, and the lowest in nearly mature stand. In middle-aged stand, soil total porosity was the highest, and soil bulk density was the lowest. Soil organic matter and total nitrogen contents were in the order of mature stand > middle-aged stand > nearly mature stand, soil nitrate nitrogen occupied a larger proportion of soil mineral N in nearly mature stand, while ammonium nitrogen accounted more in middle-aged and mature stands. In nearly mature stand, litter production was moderate but turnover coefficient was the highest, and soil nutrient contents were the lowest. In middle-aged stand, root biomass and soil total porosity were the highest, and soil bulk density were the lowest. In mature stand, root biomass was lower while soil nutrient contents were the highest. The increase of root biomass could improve soil physical properties.

Decomposition of different plant litters in Loess Plateau of Northwest China.

LI Yun1,2, ZHOU Jian-bin1, DONG Yan-jie1, XIA Zhi-min1, CHEN Zhu-jun1

2012, 23(12):  3309-3316. 

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Taking the litters of  species Hippophae rhamnoides, Medicago sativa, Populus simonii, Robinia pseudoacaci, Salix psammophila, and Stipa bungeana in the Loess Plateau of Northeast China as test objects, and by using mesh bags, this paper studied the dynamic changes of the litters mass, carbon, and nitrogen during decomposition after buried in the field in semiarid region. The litters buried were from one, two, or three of the plant species, and mixed thoroughly with equal proportion of masses. During decomposition, the mass loss rate, total carbon and nitrogen release rates, and total soluble carbon and nitrogen contents of different litters were higher at the early than at the later decomposition stage. After 412 d decomposition, the average mass loss rate of the litters was in the order of mixed litters of three plant species > mixed litters of two plant species > one plant species litter. By the end of this experiment, the average release rates of the litter total carbon and nitrogen ranked as one plant species litter > mixed litters of two plant species > mixed litters of three plant species, the litter soluble organic carbon content was mixed litters of two plant species > mixed litters of three plant species > one plant species litter, while the litter soluble total nitrogen content was mixed litters of three plant species > mixed litters of two plant species > one plant species litter. Correlation analysis showed that the litter mass loss rate had definite correlation with the litter soluble organic matter, especially soluble organic carbon. From the viewpoint of mass loss rate, the mixture of the litters of P. simonii, H. rhamnoide, and M. sativa was the optimum. It was suggested that in the process of returning farmland into forestland and grassland in the gully and valley region of Loess Plateau, it would be required to rationally increase plant species diversity to improve soil fertility.

Dynamics and modeling of water content of ten shrub species in their growth period in Maoershan Mountain region of Northeast China.

JIN Sen, YAN Xue-jiao

2012, 23(12):  3317-3324. 

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Based on the two successive years observation of the water content of ten representative shrub species in Maoershan Mountain region of Northeast China, this paper studied the dynamics of the water content of these shrub species during their growth period and related affecting factors, with the prediction models of the shrub water content established. For the ten shrub species, their minimal water content during growth period was higher than 100%, and most of the species had a water content higher than 200% within the period from the late phase of leaf-unfolding to early phase of leaf-falling. Euonymus verrucosus, Sorbaria sorbifolia, and Sambucus williamsii were incombustible in their whole growth period due to the extremely high water content, while Syringa reticulate, Philadelphus schrenkii, Euonymus verrucosus, Spiraea chamaedryfolia, Lonicera maackii, Lonicera ruprechtiana, and Rhamnus parvifolia were combustible only in the phases of budding and leaf-falling. Soil moisture content and daily maximum temperature had effects on the water content of most (7) of the ten shrubs, and canopy drought severity index affected the water content of 5 of the ten shrubs. The established 9 prediction models could explain more than 35% of the water content variance of the shrub species, with a mean MRE of 35.9% and a mean MRE of 13.4%.

Effects of short-term fencing on  organic carbon fractions and physical stability of sandy sierozem in desert steppe of Northwest China.

YANG Xin-guo, SONG Nai-ping, LI Xue-bin, LIU Bing-ru

2012, 23(12):  3325-3330. 

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In order to explore the change patterns of organic carbon fractions and physical stability of sandy sierozem in desert steppe at the early stage of fencing, 0-40 cm soil samples were collected from a 5-year fenced desert steppe (inside the fence) and a free grazing steppe (outside the fence) in Yanchi County of Ningxia, Northwest China, with the soil organic carbon, labile organic carbon, and particulate organic carbon contents and soil particle composition analyzed. No significant differences were observed in the soil organic carbon content and soil particle composition inside and outside the fence. The average soil organic carbon inside and outside the fences was 3.25 g·kg^-1, the percentages of sand, silt, and clay were averagely 72%, 16%, and 12%, respectively, and the soil physical stability index was 1.30%-1.31%. The soil active organic carbon showed a significant change in 10-20 cm layer. The soil labile organic carbon content was 0.80 g·kg^-1 inside the fence, which was significantly higher than that outside the fence (0.62 g·kg^-1). The percentage of soil particulate organic carbon was 50.9% inside the fence, which was also significantly higher than that outside the fence (31.7%). The soil texture inside the fence changed from sandy to loam, and the soil labile organic carbon content increased gradually; while the soil texture outside the fence was sandy, and its vertical change was relatively smooth. The organic carbon of sandy sierozem in the desert steppe under the conditions of short-term fencing was still in a balance between consumption and accumulation, the soil texture was relatively stable, and the soil physical stability changed little. It was suggested that the soil active organic carbon content and its relative percentage in 10-20 cm layer could be used as the indicators of early soil quality change of desert steppe.

Estimation of desert vegetation coverage based on multi-source remote sensing data.

WAN Hong-mei, LI Xia, DONG Dao-rui

2012, 23(12):  3331-3337. 

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Taking the lower reaches of Tarim River in Xinjiang of Northwest China as study area and based on the ground investigation and the multisource remote sensing data of different resolutions, the estimation models for desert vegetation coverage were built, with the precisions of different estimation methods and models compared. The results showed that with the increasing spatial resolution of remote sensing data, the precisions of the estimation models increased. The estimation precision of the models based on the high, middle-high, and middle-low resolution remote sensing data was 89.5%, 87.0%, and 84.56%, respectively, and the precisions of the remote sensing models were higher than that of vegetation index method. This study revealed the change patterns of the estimation precision of desert vegetation coverage based on different spatial resolution remote sensing data, and realized the quantitative conversion of the parameters and scales among the high, middle, and low spatial resolution remote sensing data of desert vegetation coverage, which would provide direct evidence for establishing and implementing comprehensive remote sensing monitoring scheme for the ecological restoration in the study area.

High-spectral responses of Myrica rubra seedlings to UV-B radiation stress.

JIN Xin-jie, JIANG Hong, CHEN Jian, SHI Qi-long, ZHANG Qian-qian

2012, 23(12):  3338-3346. 

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A simulated field experiment with three treatments, i.e., ambient light (control), reduced UV-B radiation, and enhanced UV-B radiation, was conducted to evaluate the effects of solar ultraviolet (UV-B) radiation on the seedlings of Myrica rubra, a typical woody species in subtropical region. The leaf chlorophyll content, spectral reflectance and spectral characteristic parameters were measured and analyzed. As compared with the control, enhanced UV-B radiation decreased the seedling chlorophyll content while reduced UV-B radiation significantly increased the chlorophyll content, and these effects reflected in the spectral reflectance. Under the effects of the three gradients of UV-B radiation, the differences in the reflectance at visible region mainly occurred around the green peak and red edge on the reflectance curve, and the peak wavelength of the red edge shifted to longer wavelength. Enhanced UV-B radiation had an accumulated temporal effect on M. rubra. The invertedGaussian model parameters R₀,_λ₀,λ_p,R_s, and б were the useful guides to reveal the spectral responses of M. rubra seedlings under UV-B radiation stress, among which, R_s performed the best. The differences in the spectral reflectance under different UV-B radiation levels could be effectively distinguished with the vegetation indices composed of the spectral reflectance of narrow wave bands or the reflectance at specific wavelengths.

Soil and water losses and phosphorus output at the places between ridges in sloping peanut land under different planting modes in Yimeng mountainous area of Shandong Province, East China.

LI Jian-hua1,2, YU Xing-xiu1, LIU Qian-jin1, WU Yuan-zhi1

2012, 23(12):  3347-3354. 

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Taking the typical land use type, sloping Arachis hypogaea land, in Yimeng mountainous area of Shandong as study object, an insitu fixedpoint field experiment was conducted to study the characteristics of soil and water losses and phosphorus output at the places between ridges in the sloping land under different planting modes (Arachis hypogaea + Cynodon dactylon,Ⅰ; A. hypogae +Melilotus officinalis,Ⅱ; A. hypogaea + Lolium multiflorum, Ⅲ; A. hypogaea + Trifolium repens, Ⅳ; A. hypogaea + blank control,Ⅴ). Planting grasses at the places between ridges could effectively decrease the soil and water losses. The runoff was 55.1%-61.3% of the control, and decreased in the order of Ⅱ>Ⅰ>Ⅳ>Ⅲ. The sediment loss was 3.4%-32.3% of the control, and decreased in the order of Ⅳ>Ⅱ>Ⅰ>Ⅲ. A. hypogaea + L. multiflorum was effective in storing water and retaining sediment. During the early period of planting L. multiflorum, the sediment loss was more affected by rainfall and presented a fluctuated variation, but in late period, the sediment loss decreased continuously and performed more stable, and accordingly, the sediment retention increased continuously. Planting grasses effectively decreased the output of phosphorus, with the decrease of total phosphorus (TP) output being 52.8%-75.3% of the control, and was in the order ofⅠ>Ⅱ>Ⅳ>Ⅲ. As compared with the control, planting grasses decreased 27.5%-67.0% of the output of particle phosphorus (PP), but relatively increased the output of dissolvable phosphorus (DP). A. hypogaea + L. multiflorum had the best effect in decreasing the output of phosphorus, with the outputs of TP and PP being 58.4% and 27.5% of the control, respectively. In the growth period of the vegetations, the losses of different phosphorus forms differed, and the dissolvable inorganic phosphorus  was the main form of the output of DP during whole rain season. After the peanut harvested, the output of different phosphorus forms in the first rainfall was much higher than that in the maximum intensity rainfall.

Responses of soil enzyme activities to re-vegetation in gully Loess Plateau of Northwest China.

LI Lin-hai1,2, QIU Li-ping3, MENG Meng4

2012, 23(12):  3355-3360. 

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In combining field investigation with laboratory analysis, this paper studied the distribution characteristics of soil enzyme activities along the soil profiles and natural slopes with different re-vegetation treatments in gully Loess Plateau, aimed to assess the responses of the soil enzyme activities to re-vegetation. In the study area, the activities of soil urease, invertase and alkaline phosphatase along natural slopes were highly varied, but the activity of soil catalase was in adverse. The profile distribution of the soil enzyme activities varied significantly with vegetation type, and with increasing soil depth, the activities of soil urease, invertase and alkaline phosphatase decreased while the catalase activity increased. There existed significant positive correlation among the three hydrolases activities. The activities of the three hydrolases were all significantly negatively correlated with soil physical properties and positively correlated with soil chemical properties, while the soil catalase activity was positively correlated with soil moisture content and pH and negatively correlated with other soil physiochemical properties. It was suggested that the activities of soil urease, invertase and alkaline phosphatase in gully Loess Plateau could be used as the sensitive indicators for the soil responses to the re-vegetation in the Plateau, and re-vegetation could improve the biological properties in both surface and deeper soil layers.

Remote sensing techniques of apple orchard information extraction based on linear spectral unmixing with measured data.

DONG Fang1,2, ZHAO Geng-xing1, WANG Ling1, ZHU Xi-cun1, CHANG Chun-yan1

2012, 23(12):  3361-3368. 

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Taking Qixia City, Shandong Province of China as the research region, and by using pixel unmixing for the TM image at apple flowering stage, the apple orchard information was extracted. Based on the measured spectral end-members, wavelet transform was adopted to improve the linear unmixing model. The improved linear spectral unmixing model, measured end-member based linear spectral unmixing model, and TM image end-member based linear spectral unmixing model were employed to extract the apple orchard information, and the ALOS data were used for accuracy estimation. After the accurate atmospheric and topographic correction, it was feasible to use the measured spectral end-members for pixel unmixing, and the area precision of apple orchard information acquisition was greater than 97%. The regression analysis on the NDVI of abundance image and the average NDVI of ALOS data showed that the R² was higher than 0.8. Therefore, using wavelet transform to improve the linear spectral unmixing model could improve the unmixing accuracy to a certain degree.

Effects of nitrogen fertilization and root separation on the plant growth and grain yield of maize and its rhizosphere microorganisms.

ZHANG Xiang-qian1, HUANG Guo-qin2, BIAN Xin-min1, ZHAO Qi-guo3

2012, 23(12):  3369-3376. 

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A field experiment with root separation was conducted to study the effects of root interaction in maizesoybean intercropping system on the plant growth and grain yield of maize and its rhizosphere microorganisms under different nitrogen fertilization levels (0.1, 0.3, 0.5, and 0.7 g·kg ^-1). Root interaction and nitrogen fertilization had positive effects on the plant height, leaf length and width, and leaf chlorophyll content of maize. Less difference was observed in the root dry mass of maize at maturing stage between the treatments root separation and no root separation. However, as compared with root separation, no root separation under the nitrogen fertilization levels 0.1, 0.3, 0.5, and 0.7 g·kg ^-1 increased the biomass per maize plant by 8.8%, 6.3%, 3.6%, and 0.7%, and the economic yield per maize plant by 17.7%, 10.0%, 8.2%, and 0.9%, respectively. No root separation increased the quantity of rhizosphere fungi and azotobacteria significantly, as compared with root separation. With increasing nitrogen fertilization level, the quantity of rhizosphere bacteria, fungi, and actinomycetes presented an increasing trend, while that of rhizosphere azotobacteria decreased after an initial increase. The root-shoot ratio of maize at maturing stage was significantly negatively correlated with the quantity of rhizosphere bacteria, fungi, and actinomycetes, but less correlated with the quantity of rhizosphere azotobacteria. It was suggested that the root interaction in maize-soybean intercropping system could improve the plant growth of maize and increase the maize yield and rhizosphere microbial quantity, but the effect would be decreased with increasing nitrogen fertilization level.

Effects of partial root excision on the growth, photosynthesis, and antioxidant enzyme activities of maize under salt stress.

ZHANG Hong1,2, CUI Li-na1, MENG Jia-jia1, ZHANG Hai-yan1, SHI De-yang1, DONG Shu-ting1, ZHANG Ji-wang11, LIU Peng

2012, 23(12):  3377-3384. 

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A pot experiment was conducted to study the effects of partial root excision on the growth of two maize cultivars (Zhengdan 958 and Denghai 9) throughout their growth period and the photosynthesis and leaf antioxidant enzyme activities at grainfilling stage under salt stress. Four treatments were installed, i.e., control (no salt), low salt (0.2% NaCl), moderate salt (0.4% NaCl), and high salt (0.6% NaCl). Under low salt stress, the grain yield of Zhengdan 958 and Denghai 9 with partial root excision was increased by 13.1% and 31.4%, respectively, as compared with that of the cultivars with no root excision. At jointing stage, the growth of the cultivars with partial root excision was restrained, the root and shoot dry masses under the same salt stresses being lesser than those of the cultivars with no root excision, but the growth under the conditions of no salt and low salt recovered quickly. At milk-ripe stage and under no salt and low salt conditions, the root and shoot dry masses, leaf area, total root length, total root surface area, root activity, leaf chlorophyll content, and ear leaf net photosynthetic rate, stomatal conductance, transpiration rate, and CAT and POD activities of the cultivars with partial root excision were significantly larger than those of the cultivars with no root excision, while the shoot diameter and ear leaf MDA content were in adverse. Moderate and high salt stresses had greater effects on the cultivars with partial root excision. The root and shoot dry masses, root morphology, and photosynthesis indices of the cultivars with partial root excision were smaller than those of the cultivars with no root excision, so did the grain yields. Throughout the growth period of the cultivars, the growth of the cultivars with partial root excision depended on the salt concentration, i.e., was promoted under no and low salt, and inhibited under moderate and high salt conditions.

Spatial distribution characteristics of China cotton fiber quality and climatic factors based on GIS.

XIONG Zong-wei1,2, GU Sheng-hao3, MAO Li-li3, WANG Xue-jiao3, ZHANG Li-zhen3, ZHOU Zhi-guo1

2012, 23(12):  3385-3392. 

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By using geographical information system (GIS), the cotton fiber quality data from 2005 to 2011 and the daily meteorological data from 1981 to 2010 at 82 sites (counties and cities) in China major cotton production regions were collected and treated with spatial interpolation. The spatial information system of cotton fiber quality in China major cotton production regions was established based on GIS, and the spatial distribution characteristics of the cotton fiber quality and their relationships with the local climatic factors were analyzed. In the northwest region (especially Xinjiang) of China, due to the abundant sunlight, low precipitation, and low relative humidity, the cotton fiber length, micronaire, and grade ranked the first. In the Yangtze River region and Yellow River region, the specific strength of cotton fiber was higher, and in the Yangtze River region, the cotton fiber length and specific strength were higher, while the micronaire and grade were lower than those in the Yellow River region. The cotton fiber quality was closely related to the climate factors such as temperature, sunlight, rainfall, and humidity.

Spatiotemporal distribution of  air temperature and precipitation in rice growth period in Fujian Province of East China and the effects of this distribution on  rice planting pattern. 

JIANG Min1, JIN Zhi-qing2, YANG Hui3, SHI Chun-lin2, ZHU Chao-zhi1, LIN Wen-xiong1

2012, 23(12):  3393-3401. 

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In order to investigate the effects of climate change on the rice production and rice planting pattern in Fujian Province, an analysis was made on the spatiotemporal distribution of air temperature and precipitation in rice growth period  in the Province, and the possible changes of the local rice planting pattern in the future, based on the A2, B2, and A1B scenarios of IPCC Special Report on Emission Scenario (SRES). In the future, the rice growth period’s air temperature in the Province tended to be increased, and the increment would be increased with time, with the maximum for single cropping rice and being 0.3-2.4 ℃ and 1.5-3.4 ℃ in 2011-2030 and 2031-2050, respectively. For early rice and late rice, the increment of their growth period’s air temperature would be 0.2-0.9 ℃ and 0.7-1.7 ℃ in 2011-2030 and 0.3-2.1 ℃ and 0.5-3.6 ℃ in 2031-2050, respectively, but the annual fluctuation of the mean daily temperature would be most obvious for late rice. The rice growth period’s precipitation in most parts of the Province also tended to be increased, and the increment for early rice, single cropping rice, and late rice would be 10%-40%, 10%-30%, and 10%-20%, respectively. The annual fluctuation of the precipitation would be most obvious for the early rice in southeastern Fujian. The elevated air temperature in the future could induce the increase of ≥10 ℃ accumulated temperature, and lengthen the rice growth season, making it possible to replace early and medium-maturity varieties with late-maturity  varieties, and to adopt double-rice planting pattern instead of single-rice planting pattern.

Community characteristics of soil nematode in Abies georgei var. smithii forest in Sejila Mountain of Tibet, Southwest China.

XUE Hui-ying1, LUO Da-qing2, YU Bao-zheng1

2012, 23(12):  3402-3408. 

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In order to understand the present status of nematode diversity in soil ecosystem of Abies georgei var. smithii forest, the typical forest type in subalpine zone of southeastern Tibet, an investigation was made on the nematode community in different soil layers of 0-30 cm depth from the summer, 2010 to the spring, 2011. The nematode individual density, diversity index, and trophic group index were taken  to analyze the composition and structural characteristics of the soil nematode community. A total of 7915 soil nematodes belonging to 2 classes, 6 orders, 38 families, and 67 genera were collected by shallow dish method. The nematode individual density was averagely 620 nematodes·100 g^-1 dry soil, and the nematode individuals in surface soil layer (0-5 cm) accounted for 56.9% of the total, indicating the obvious surface gathering characteristics of the nematode community. Tylencholaimus, Helicotylenchus, and Plectus were the dominant genus. Plant-parasite nematode was the dominant trophic group, while fungi-feeding nematode had the largest proportion among the non plantparasite nematodes. Soil organic matter was mainly decomposed by fungi. The ANOVA analysis indicated that there were no significant differences in the Shannon, Pielou, Margalef, and Simpson indices of soil nematode community among different seasons. The Pielou index had no significant difference among different soil layers, while the differences of Shannon, Margalef, and Simpson indices tended to be increased with increasing soil depth. It was concluded that the A. georgei var. smithii forest ecosystem in Sejila Mountain had a high maturity, with strong resistance to environment disturbances.

Genetic diversity of Ascochyta anemones isolates in Liaoning Province of Northeast China.

SU Dan, FU Jun-fan

2012, 23(12):  3409-3413. 

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Windflower leaf spot is a newly reported leaf disease in China, and becomes very serious in the protected field of windflower (Pulsitilla chinensis) in Liaoning Province. In this study, a random amplified polymorphic DNA (RAPD) analysis was made on the 25 Ascochyta anemones isolates from 5 main P. chinensis production areas in the Province and 5 Ascochyta spp. isolates presented by the Chinese Academy of Agricultural Sciences. A total of 108 polymorphic DNA bands sized 200-2000 bp were obtained by using 11 random primers. The NTSYS cluster analysis showed that the genetic similarity coefficient of the 30 Ascochyta isolates was 0.56-0.98, and these isolates could be divided into 4 genetic groups when the similarity coefficient was 0.62, suggesting that the pathogens of windflower leaf spot in the Province had rich genetic diversity. There existed definite correlations between the RAPD clustering groups and their geographic distribution, and an obvious genetic difference among the isolates from different host sources.

Effects of Festuca arundinacea on the microbial community in crude oil-contaminated saline-alkaline soil.

LI Xin, ZHANG Hui-hui, YUE Bing-bing, XU Nan, ZHU Wen-xu, HU Ju-wei, SUN Guang-yu

2012, 23(12):  3414-3420. 

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By using the routine soil physical and chemical analysis methods and the Biolog technique, this paper studied the effects of Festuca arundinacea growth on the pH value, total salt content, and microbial community in the rhizosphere of crude oil-contaminated saline-alkaline soil in Songnen Plain of Northeast China. Crude oil contamination resulted in the increases of average well color development (AWCD), Shannon index (H), and carbon source utilization richness index (S), and altered the utilization patterns of carbon sources by the microbes. F. arundinacea had greater potential to remediate crude oilcontaminated soil. This plant could decrease the soil pH and soil total petroleum hydrocarbon (TPH) content, and increase the soil water content. The AWCD and S in
F. arundinacea rhizosphere soil were obviously higher than those in the soil of naked land, providing a suitable environment for the growth and development of rhizosphere soil microbes.

Calling and mating behaviors of bamboo shoot borer Kumasia kumaso.

SHU Jin-ping1, TENG Ying1, ZHANG Ai-liang2, ZHANG Ya-bo1, DENG Shun1, WANG Hao-jie1

2012, 23(12):  3421-3428. 

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The calling and mating behaviors of Kumasia kumaso were studied in laboratory at (25±1) ℃ and (60±10) % RH under a cycle 14 L:10 D photo period, and the EAG response of male K. kumaso to female K. kumaso sex gland extracts was also tested. The calling and mating behaviors of K. kumaso could only be observed in scotophase. The females began calling at the first scotophase following emergence, and the peak of calling occurred during the second scotophase and decreased thereafter. The calling of the females commenced 0-4 h after dark, reached the maximum between the 5th and the 7th hour of the scotophase, and terminated during the last 1-2.5 h of the scotophase. Moth age had significant effects on the calling patterns. With increasing moth age, the onset time of calling advanced gradually, and the mean number of calling bouts as well as the calling length per bout had a gradual increase from calling day 1 to day 4 but decreased on day-5. The peak time and terminated time of calling advanced with increasing moth age. The mating of K. kumaso adults initiated during the first scotophase and terminated till the 5th scotophase following -emergence, and the peak of mating was observed during the second scotophase. The peak of mating was observed 5.5-7.0 h after dark, and advanced with increasing moth age. Moth age affected the mean onset time of mating and the copulation duration significantly. With increasing moth age, the mean onset time of mating advanced, and the copulation duration decreased. Sex ratio had significant effects on the mating behavior as well. Treatment 2♀:1♂ showed a significantly higher mating percentage, but an earlier onset time of mating and shorter copulation duration, as compared with treatment 1♀:1♂. The results of EAG test indicated that the male adults showed a significant EAG response to the sex gland extracts of 2-day-old virgin females.

Resistance risk and resistance stability of Frankliniella occidentalis to imidacloprid, emamectin benzoate, and phoxim.

WANG Sheng-yin1, YU Yi2, LIU Yong-jie1, MA Jing-yu3

2012, 23(12):  3429-3434. 

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In order to effectively control the damage of Frankliniella occidentalis (Pergande), Phaseolus vuglaris was dipped with imidacloprid, phoxim, and emamectin benzoate, respectively to select the resistance populations of F. occidentalis from its susceptible population, and the resistance inheritance and resistance risk were analyzed with the resistance reality heredity. After 32, 32, and 24 generations’ selection, the F. occidentalis populations obtained 13.8fold, 29.4fold and 39.0fold resistance to imidacloprid, phoxim, and emamectin benzoate, respectively. The resistance reality heritability to imidacloprid, phoxim, and emamectin benzoate was 0.112, 0.166, and 0.259, respectively. The resistance development rate to emamectin benzoate was the fastest, followed by to phoxim, and to imidacloprid. The higher the resistance levels of the selected populations, the lower the differences between the larva and adult susceptibility to imidacloprid, phoxim, and emamectin benzoate. Stopping selection for 12 continuous generations, the resistance level of the selected resistance populations to imidacloprid, phoxim, and emamectin benzoate had definite decline, but it was difficult to regain the original susceptibility. F. occidentalis had a greater potential to gain high level resistance to imidacloprid, phoxim, and emamectin benzoate. Compared with the resistance of F. occidentalis to phoxim and emamectin benzoate, the resistance to imidacloprid increased slower and decreased faster, and thus, imidacloprid was more appropriate to control F. occidentalis in practice.

Inhibition effect of Ag-antibiotic 702 on plant pathogenic fungi and related mechanisms.

WEI Sai-jin1,2, DU Ya-nan1, NI Guo-rong2, ZHANG Hui-wen1, TU Guo-quan1, PAN Xiao-hua2

2012, 23(12):  3435-3440. 

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To explore the practical application value and action mechanisms of Ag-antibiotic 702 against pathogenic fungi, the inhibition spectrum of Ag-antibiotic 702 was studied by measuring the mycelium growth rate of pathogenic fungi, and the effects of Ag-antibiotic 702 on the membrane permeability of Rhizoctonia solani, a typical pathogenic fungus, were investigated, with the variations of mycelium electrolyte leakage and protein, nucleic acid, and Mg²⁺ and K⁺ contents under the action of Ag-antibiotic 702 determined, and the effects of Ag-antibiotic 702 on the cell membrane ergosterol biosynthesis and ultramicrostructure observed. The results showed that the active products of Ag-antibiotic 702 had stronger inhibition effect on 13 test pathogens, among which, Sclerotinia sclerotiorum was most sensitive, with the EC₅₀ being 0.23 μg·mL^-1. As compared with the control, the relative electric conductivity of R. solani treated with Ag-antibiotic 702 was increased by 72.2%, the contents of protein, nucleic acid, and Mg²⁺ and K⁺ leaked from the R. solani cells were all increased, while the ergosterol content was decreased by 92.0%. The cell membrane outline was not clear, organelles were badly damaged, and vacuole appeared. It was suggested that the inhibition of ergosterol biosynthesis and the increase of membrane permeability could be the main action mechanisms of Ag-antibiotic 702 against pathogenic fungi.

Ciliate diversity and spatiotemporal variation in surface sediments of Yangtze River estuary hypoxic zone.

ZHAO Feng1,2, XU Kui-dong1, MENG Zhao-cui1

2012, 23(12):  3441-3448. 

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By using denaturing gradient gel electrophoresis (DGGE) and sequencing as well as Ludox-QPS method, an investigation was made on the ciliate diversity and its spatiotemporal variation in the surface sediments at three sites of Yangtze River estuary hypoxic zone in April and August 2011. The ANOSIM analysis indicated that the ciliate diversity had significant difference among the sites (R=0.896, P=0.0001), but less difference among seasons (R=0.043, P=0.207). The sequencing of 18S rDNA DGGE bands revealed that the most predominant groups were planktonic Choreotrichia and Oligotrichia. The detection by Ludox-QPS method showed that the species number and abundance of active ciliates were maintained at a higher level, and increased by 2-5 times in summer, as compared with those in spring. Both the Ludox-QPS method and the DGGE technique detected that the ciliate diversity at the three sites had the similar variation trend, and the Ludox-QPS method detected that there was a significant variation in the ciliate species number and abundance between different seasons. The species number detected by Ludox-QPS method was higher than that detected by DGGE bands. Our study indicated that the ciliates in Yangtze River estuary hypoxic zone had higher diversity and abundance, with the potential to supply food for the polyps of jellyfish.

Ichthyofauna and its community diversity in volcanic barrier lakes of Northeast China. 

YANG Fu-yi1, Lu Xian-guo1, LOU Yan-jing1, LOU Xiao-nan1, XUE Bin2, YAO Shu-chun2, XIAO Hai-feng3

2012, 23(12):  3449-3457. 

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Based on the investigations of fish resources in Jingpo Lake and Wudalianchi Lakes in 2008-2011 and the historical data, this paper analyzed the characteristics of ichthyofauna and its community diversity in volcanic barrier lakes of Northeast China. The ichthyofauna in the volcanic barrier lakes of Northeast China was consisted of 64 native species, belonging to 47 genera, 16 families, and 9 orders, among which, one species was the second class National protected wild animal, four species were Chinese endemic species, and five species were Chinese vulnerable species. In the 64 recorded species, there were 44 species of Cypriniformes order and 37 species of Cyprinidae family dominated, respectively. The ichthyofauna in the volcanic barrier lakes of Northeast China was formed by 7 fauna complexes, among which, the eastern plain fauna complex was dominant, the common species from the South and the North occupied 53.1%, and the northern endemic species took up 46.9%. The Shannon, Fisher-α, Pielou, Margalef, and Simpson indices of the ichthyofauna were 2.078, 4.536, 0.575, 3.723, and 0.269, respectively, and the abundance distribution pattern of native species accorded with lognormal model. The Bray-Curtis, Morisita-Horn, Ochiai, S-rensen, and Whittaker indices between the communities of ichthyofauna in the volcanic barrier lakes of Northeast China and the Jingpo Lake were 0.820, 0.992, 0.870, 0.862 and 0.138, respectively, and those between the communities of ichthyofauna in the volcanic barrier lakes and the Wudalianchi Lakes were 0.210, 0.516, 0.838, 0.825, and 0.175, respectively. The ichthyofauna in volcanic barrier lakes of Northeast China was characterized by the mutual infiltration between the South and the North, and the overlap and transition between the Palaeoarctic realm and the Oricetal realm. It was suggested that the ichthyofauna community species diversity in the volcanic barrier lakes of Northeast China was higher, the species structure was more stable, but the species richness trended to decrease.

Distribution and seasonal dynamics of meiofauna in intertidal zone of Qingdao sandy beaches, Shandong Province of East China.

LI Jia, HUA Er, ZHANG Zhi-nan

2012, 23(12):  3458-3466. 

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An investigation was conducted on the abundance, group composition, and distribution of meiofauna at the Second Beach of Taiping Bay and the Shilaoren Beach in Qingdao in January, April, July, and October 2008, aimed to analyze the distribution and seasonal dynamics of meiofauna in the intertidal zone of Qingdao sandy beaches. The measurements of environmental factors, including sediment grain size, interstitial water salinity, interstitial water temperature, organic matter content (TOC), and chlorophyll a (Chl a) content, were made simultaneously. There existed obvious seasonal differences in the environment factors, which could be clustered into two groups, i.e., springwinter group (January and April) and summerautumn group (July and October). At the Second Beach of Taiping Bay, the mean annual abundance of meiofauna was (1167.3±768.3) ind·10 cm^-2, and the most dominant group wasNematoda, accounting for 91% of the total. The meiofaunal group composition and abundance at the Second Beach differed horizontally, with the abundance ranked as high tide zone < middle tide zone < low tide zone. The meiofaunal group composition and abundance also varied seasonally, with high values in spring/winter and low values in summer/autumn (spring > winter > autumn > summer). The vertical distribution of the meiofauna in the high and middle tide zones of the Second Beach varied seasonally too. The meiofauna migrated downward with increasing temperature, concentrated in surface layer in winter and migrated downward in summer. At the Shilaoren Beach, the mean annual abundance of meiofauna was (1130.2±1419.1) ind·10 cm^-2, and Nematoda accounted for 85% of the total. There was a great similarity of the environmental factors in the middle tide zone of the Second Beach and Shilaoren Beach, which led to no differences in the meiofaunal group composition and abundance. However, the vertical distribution of the meiofauna differed between the two beaches. When the temperature decreased, the meiofauna at Shilaoren Beach migrated downward. The ANOVA and BIOENV analyses showed that the TOC and MD-Φ were most responsible for the distribution of meiofauna among the tidal zones, the interstitial water temperature, MD-Φ, and TOC were the main causes of the seasonal variation of meiofaunal group composition and abundance, whereas the sediment Chl a affected the vertical migration of meiofauna. Tourisminduced sediment variation was another factor affecting the meiofaunal abundance, group composition, and distribution.

Joint effects of water temperature and salinity on the expression of gill Hsp70 gene in Pinctada martensii (Dunker).

WANG Ya-nan, WANG Hui, ZHU Xiao-wen, LUO Ming-ming, LIU Zhi-gang, DU Xiao-dong

2012, 23(12):  3467-3473. 

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By using central composite experimental design and response surface method, the joint effects of water temperature (16-40 ℃) and salinity (10-50) on the expression of gill Hsp70 gene in Pinctada martensii (Dunker) were studied under laboratory conditions. The results showed that the linear and quadratic effects of temperature on the expression of gill Hsp70 gene were significant, the linear effect of salinity was not significant, while the quadratic effect of salinity was significant. The interactive effect of temperature and salinity was not significant, and the effect of temperature was greater than that of salinity. The model equation of the gill Hsp70 gene expression was established, with the R², Adj. R², and Pred. R² as high as 98.7%, 97.4%, and 89.2%, respectively, suggesting that the overarching predictive capability of the model was very satisfactory, and could be practicably applied for prediction. Through the optimization of the model, the expression of the gill Hsp70 gene reached its minimum (0.5276) when the temperature was 26.78 ℃ and the salinity was 29.33, with the desirability value being 98%. These experimental results could offer theoretical reference for the high expression of gill Hsp70 gene in P. martensii, the maintenance of cell internal environment stability, and the enhancement of P. martensii stress resistance.

Ecological adaptability of Hordeum jubatum to magnesite dust.

FANG Ying1,2, ZHAO Qiong1, TAI Pei-dong1, WU Hai-yan3, LI Pei-jun1, QIN Qin1,2, DENG Xin1,2

2012, 23(12):  3474-3478. 

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Hordeum jubatum  was potcultured with the soil sprayed with different amounts of magnesite dust (0, 1%, 5%, 10%, 15%, 20%, and 30%) to study the magnesium (Mg) tolerance of the plant. After sprayed onto soil surface, the magnesite dust could rapidly form a crust. When the amount of the sprayed dust was bigger than 20%, soil pH increased significantly, soil conductivity had a gradual decrease, whereas soil organic matter content increased after an initial decrease. With the increasing amount of sprayed magnesite dust, the leaf chlorophyll content of H. jubatum increased first and decreased then, while the leaf soluble protein content showed a trend of increase  decrease  increase. H. jubatum had stronger tolerance to Mg. When the soil Mg content was as high as 4.61 g·kg^-1, H. jubatum could still grow  well, indicating that this plant species could be used as an appropriate candidate for the ecological restoration of waste lands in magnesite mining areas.

Evaluation on the eco-economic benefits of small watershed in Beijing mountainous area: A case of Yanqi River watershed.

XIAO Hui-jie1, WEI Zi-gang2, WANG Qing2, ZHU Xiao-bo1

2012, 23(12):  3479-3487. 

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Based on the theory of harmonious development of ecological economy, a total of 13 evaluation indices were selected from the ecological, economic, and social sub-systems of Yanqi River watershed in Huairou District of Beijing. The selected evaluation indices were normalized by using trapezoid functions, and the weights of the evaluation indices were determined by analytic hierarchy process. Then, the ecoeconomic benefits of the watershed were evaluated with weighted composite index method. From 2004 to 2011, the ecological, economic, and social benefits of Yanqi River watershed all had somewhat increase, among which, ecological benefit increased most, with the value changed from 0.210 in 2004 to 0.255 in 2011 and an increment of 21.5%. The eco-economic benefits of the watershed increased from 0.734 in 2004 to 0.840 in 2011, with an increment of 14.2%. At present, the watershed reached the stage of advanced ecosystem, being in beneficial circulation and harmonious development of ecology, economy, and society.

Natural forming causes of China population distribution.

FANG Yu, OUYANG Zhi-yun, ZHENG Hua, XIAO Yi, NIU Jun-feng, CHEN Sheng-bin, LU Fei

2012, 23(12):  3488-3495. 

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The diverse natural environment in China causes the spatial heterogeneity of China population distribution. It is essential to understand the interrelations between the population distribution pattern and natural environment to enhance the understanding of the man-land relationship and the realization of the sustainable management for the population, resources, and environment. This paper analyzed the China population distribution by adopting the index of population density (PD) in combining with spatial statistic method and Lorenz curve, and discussed the effects of the natural factors on the population distribution and the interrelations between the population distribution and 16 indices including average annual precipitation (AAP), average annual temperature (AAT), average annual sunshine duration (AASD), precipitation variation (PV), temperature variation (TV), sunshine duration variation (SDV), relative humidity (RH), aridity index (AI), warmth index (WI), ≥5 ℃ annual accumulated temperature (AACT), average elevation (AE), relative height difference (RHD), surface roughness (SR), water system density (WSD), net primary productivity (NPP), and shortest distance to seashore (SDTS). There existed an obvious aggregation phenomenon in the population distribution in China. The PD was high in east China, medium in central China, and low in west China, presenting an obvious positive spatial association. The PD was significantly positively correlated with WSD, AAT, AAP, NPP, AACT, PV, RH, and WI, and significantly negatively correlated with RHD, AE, SDV, SR, and SDTS. The climate factors (AAT, WI, PV, and NPP), topography factors (SR and RHD), and water system factor (WSD) together determined the basic pattern of the population distribution in China. It was suggested that the monitoring of the eco-environment in the east China of high population density should be strengthened to avoid the eco-environmental degradation due to the expanding population, and the conservation of the eco-environment in the central and west China with vulnerable eco-environment should also be strengthened to enhance the population carrying ability of these regions and to mitigate the eco-environmental pressure in the east China of high population density.

Ecological effect of plant root exudates and related affecting factors: A review.

LUO Yong-qing1, ZHAO Xue-yong1, LI Mei-xia2

2012, 23(12):  3496-3504. 

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The formation of plant root exudates is a vital physiological phenomenon in the metabolic processes of plant, and an important link of material turnover in “plantsoil” system. To study the plant root exudates is of significance in understanding the matter and energy flow, carbon and nitrogen balance, and improvement of primary production in terrestrial ecosystems. This paper reviewed the ecological effect of plant root exudates, such as the effect on plant physiological processes, soil microorganisms, soil matter turnover, and degradation of soil organic contaminants, and summarized the related affecting factors, including soil heavy metals and nutrient contents, soil moisture, light, and heat conditions, plant gene type, soil microorganisms, and input of exogenous organic contaminants. Based on the present research status of plant root exudates, the future research directions about the objects, methods, and effect assessment were prospected.

Research advances in microbial dechlorination of polychlorinated biphenyls.

CHEN Chen1, CUI Jing-lan1, QIN Zhi-hui1,2, YU Chun-na3, CHEN Xi1, SHEN Chao-feng1,2, CHEN Ying-xu1,2

2012, 23(12):  3505-3513. 

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Polychlorinated biphenyls (PCBs) are the typical persistent organic pollutants (POPs) in the environment. As a ubiquitous attenuation course of chlorinated organic compounds in anoxic environment, the microorganism-mediated reductive dechlorination process plays an important role in PCBs transformation, especially the transformation of higher chlorinated PCBs. The higher chlorinated PCBs can be dechlorinated in anaerobic condition, and thus, their persistence and toxicity can be decreased. The resultant lower chlorinated PCBs from the dechlorination can be further degraded and completely mineralized in aerobic condition. This paper summarized the research advances of PCBs microbial reductive dechlorination, introduced the mechanisms and characteristics of the dechlorination and the related specific microorganisms, and approached the affecting factors of PCBs bio-dechlorination, as well as the significances of anaerobic dechlorination coupling with aerobic degradation. The future research directions, including the complex metabolic networks of dechlorinating microbial populations, the screening of novel specific dechlorinators and their practical applications in the remediation of PCBs contaminated sites were also prospected.

Migration and transformation of anthropogenic platinum group elements in environment: A review.

LI Pei-miao1,2, GAO Xue-lu1

2012, 23(12):  3514-3525. 

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Anthropogenic platinum group elements (PGEs) are widely applied in vehicle exhaust catalytic converters (VECs), industrial catalysts, and pharmaceutics, making the PGEs, especially Pt, Pd, and Rh, become the newly environmental pollutants in some  fields. Given the positive correlations between the Pt/Pd and Pt/Rh ratios in various environmental samples and the active components of VECs, the VECs containing PGEs as catalysts are regarded as the primary source of PGEs pollution. Sufficient reports indicated that in the past three decades, there was a significant increase of PGEs concentrations in diverse environmental matrices like airborne particulate matters, aquatic ecosystem components (e.g., river water, rain water, groundwater, seawater, and sediments), soils, road dusts, and organisms. It was generally assumed that anthropogenic PGEs behave in inert manner, and the health risks associated with the environmental exposures to PGEs are minimal. However, the recent studies on PGEs toxicity and environmental bioavailability indicated that once entering environment, anthropogenic PGEs might easily be mobilized and transformed into more toxic forms under the actions of various biogeochemical processes, and thereby, enhanced their bioavailability and posed potential health risks to human beings through food chain. This paper summarized the research results about the sources, distribution, and biogeochemical behaviors of PGEs in various environmental media, and it was considered that to establish the standards of PGEs for human health risks, to develop standard substances of PGEs for environmental measurements, to study the PGEs in the sediments of marginal seas, and to assess the toxicity of PGEs to marine mollusks, the present contamination status of PGEs in foods, and the risks of PGEs to human health would be the hot research topics in the future.

Strategies and mechanisms of soil springtails in adapting lower temperature environment: Research progress.

LIU Jing, WANG Yun-biao, WU Dong-hui

2012, 23(12):  3526-3532. 

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Low temperature and drought are the main environmental factors threatening the animals living in arctic area and cold temperate regions. To adapt the severe environment, the animals should adopt appropriate strategies. As a group of arthopods with freeze-avoiding strategy, soil springtails have the similar ecological mechanisms and modes of cold resistance/tolerance as insects, manifesting in the cold acclimation and drought tolerance to decrease the damage of ice crystal formation. During cold acclimation, there are a rapid increase of glycerol, a rapid decrease of fucose and glucose, and the production of anti-freeze proteins (AFP), and exists the inter-transformation of different kinds of lipids to improve the flow of cell membrane to protect the cell from low temperature injury. In addition, soil springtails have their own specific modes and mechanisms to tolerate low temperature stress, mainly the vertical migration under the protection of snow cover and the excretion of ice nucleator from haemolymph, illustrating that it’s of significance to research the cryobiology of soil springtails. This paper summarized the modes and mechanisms of soil springtails in tolerating low temperature environment, reviewed the research progress on the eco-physiology of the springtails, discussed the existing problems of the researches on the low temperature tolerance of the springtails, and prospected the research directions of the springtails low temperature ecology under the background of global change.