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Table of Content

    18 December 2016, Volume 27 Issue 12
    Responses of plant community structure and species composition to warming and N addition in an alpine meadow, northern Tibetan Plateau, China
    ZONG Ning, CHAI Xi, SHI Pei-li, JIANG Jing, NIU Ben, ZHANG Xian-zhou, HE Yong-tao
    2016, 27(12):  3739-3748.  doi:10.13287/j.1001-9332.201612.007
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    Global climate warming and increasing nitrogen (N) deposition, as controversial global environmental issues, may distinctly affect the functions and processes of terrestrial ecosystems. It has been reported that the Qinghai-Tibet Plateau has been experiencing significant warming in recent decades, especially in winter. Previous studies have mainly focused on the effects of warming all the year round; however, few studies have tested the effects of winter warming. To investigate the effects of winter warming and N addition on plant community structure and species composition of alpine meadow, long-term N addition and simulated warming experiment was conducted in alpine meadow from 2010 in Damxung, northern Tibet. The experiment consisted of three warming patterns: Year-round warming (YW), winter warming (WW) and control (NW), crossed respectively with five N gradients: 0, 10, 20, 40, 80 kg N·hm-2·a-1. From 2012 to 2014, both warming and N addition significantly affected the total coverage of plant community. Specifically, YW significantly decreased the total coverage of plant community. Without N addition, WW remarkably reduced the vegetation coverage. However, with N addition, the total vegetation coverage gradually increased with the increase of N level. Warming and N addition had different effects on plants from different functional groups. Warming significantly reduced the plant coverage of grasses and sedges, while N addition significantly enhanced the plant coverage of grasses. Regression analyses showed that the total coverage of plant community was positively related to soil water content in vigorous growth stages, indicating that the decrease in soil water content resulted from warming during dry seasons might be the main reason for the decline of total community coverage. As soil moisture in semi-arid alpine meadow is mainly regulated by rainfalls, our results indicated that changes in spatial and temporal patterns of rainfalls under the future climate change scenarios would dramatically influence the vegetation coverage and species composition. Additionally, the effects of increasing atmospheric N deposition on vegetation community might also depend on the change of rainfall patterns.
    Carbon storage of forest vegetation and allocation for main forest types in the east of Da-xing’an Mountains based on additive biomass model
    PENG Wei, DONG Li-hu, LI Feng-ri
    2016, 27(12):  3749-3758.  doi:10.13287/j.1001-9332.201612.012
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    Based on the biomass investigation data of main forest types in the east of Daxing’an Mountains, the additive biomass models of 3 main tree species were developed and the changes of carbon storage and allocation of forest community of tree layer, shrub layer, herb layer and litter layer from different forest types were discussed. The results showed that the carbon storage of tree layer, shrub layer, herb layer and litter layer for Rhododendron dauricum-Larix gmelinii forest was 71.00, 0.34, 0.05 and 11.97 t·hm-2, respectively. Similarly, the carbon storage of the four layers of Ledum palustre-L. gmelinii forest was 47.82, 0.88, 0, 5.04 t·hm-2, 56.56, 0.44, 0.04, 8.72 t·hm-2 for R. dauricum-mixed forest of L. gmelinii-Betula platyphylla, 46.21, 0.66, 0.07, 6.16 t·hm-2 for L. palustre-mixed forest of L. gmelinii-B. platyphylla, 40.90, 1.37, 0.04, 3.67 t·hm-2 for R. dauricum-B. platyphylla forest, 36.28, 1.12, 0.18, 4.35 t·hm-2 for L. palustre-B. platyphylla forest. The carbon storage of forest community for the understory vegetation of R. dauricum was higher than that of the forest with L. palustre. In the condition of similar circumstances for the understory, the order of carbon storage for forest community was L. gmelinii forest > the mixed forest of L. gmelinii-B. platyphylla > B. platyphylla forest. The carbon storage of different forest types was different with the order of R. dauricum-L. gmelinii forest (83.36 t·hm-2)> R. dauricum-mixed forest of L. gmelinii-B. platyphylla (65.76 t·hm-2) > L. palustre-L. gmelinii forest (53.74 t·hm-2)> L. palustre-mixed forest of L. gmelinii-B. platyphylla (53.10 t·hm-2)> R. dauricum-B. platyphylla forest (45.98 t·hm-2) > L. palustre-B. platyphylla forest (41.93 t·hm-2). The order of carbon storage for the vertical distribution in forest communities with diffe-rent forest types was the tree layer (85.2%-89.0%) > litter layer (8.0%-14.4%) > shrub layer (0.4%-2.7%) > herb layer (0-0.4%).
    Biomass, carbon storage and nutrient characteristics in Larix kaempferi plantations at diffe-rent stand ages
    CHEN Dong-sheng, SUN Xiao-mei, ZHANG Shou-gong
    2016, 27(12):  3759-3768.  doi:10.13287/j.1001-9332.201612.039
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    Based on 7-, 17-, 30-, and 40-year-old Larix kaempferi plantations, this paper studied the influence of tree age on biomass, carbon storage and nutrient characteristics. There was significant difference in biomass and nutrient concentration of stem, bark, needle, branch and root at different development stages at individual tree level. The biomass of each organ showed a trend of increase with the increasing age. The concentrations of N, P, K decreased, Mg concentration increased at first and then decreased, and Ca concentration continued to rise with the increasing age. There was significant difference in biomass of each organ for dominant, intermediate and suppressed trees, but no significant difference in nutrient concentration. It indicated that nutrient concentration of each organ was not affected by competition. At stand level, the total biomass, carbon storage and nutrient accumulation increased with the increasing age. Compared with young stand, the growth rate of biomass, carbon storage and nutrient accumulation were increased by 217%, 218% and 56% in mature stand, respectively. It indicated L. kaempferi had a high nutrient use efficiency, and could utilize less nutrient to produce more dry matter. Except that the accumulation of P and K had a slight decrease in pre-mature stand (30 years old), other elements increased with the increasing age. N mainly concentrated in needle, Ca concentrated in stem, K and Mg concentrated in root and P was distributed evenly in different organs. The annual accumulation rates of biomass, carbon and nutrient of L. kaempferi stands decreased with the increasing age, from 7.16 t·hm-2, 3.40 t·hm-2 and 104.64 kg·hm-2 for young stand to 3.99 t·hm-2, 1.89 t·hm-2and 28.64 kg·hm-2 for mature stand, respectively. It indicated that L. kaempferi plantations had great carbon sequestration potential and high nutrient consumption during young and middle ages.
    Water repellency and its influencing factors in Manas River Basin, China
    WANG Yi-chen, LI Yi, XIAO Zhen-zhen
    2016, 27(12):  3769-3776.  doi:10.13287/j.1001-9332.201612.004
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    Soil water repellency (SWR) impedes the processes of soil water infiltration and redistribution. Although water repellent soils exist extensively in the world, its causes were not very clear. In this research, three measurement methods including the water droplet penetration time (WDPT), the molarity of ethanol drop (MED) and the contact angle (denoted as θ below) methods, were applied to obtain different SWR indices for the tested soils collected in Manas River Basin, Xinjiang Uygur Autonomous Region, China. The height method and the mass method were conducted to measure θ values. WDPT values of different soil samples were compared to investigate whether WDPT values were affected after being oven-dried or by different bulk densities. The relationships among three SWR indices (WDPT, MED and θ) were compared, and the major soil physico-chemical properties which influenced SWR were analyzed to discuss the intrinsic mechanism that caused SWR. The results showed that WDPT values of higher bulk density were larger than those of lower bulk density, and WDPT values of oven-dried soils were larger than those of air-dried soils. There were correlations between the three SWR indices of WDPT, MED and θ, but MED was insignificantly related to θ, which showed the differences among various SWR indices, although they were related to each other. When measuring θ values of soil-water, θ values obtained using the height method were larger than those obtained using the mass method, and the differences of θ for the three replications with the height method were smaller than those with the mass method. When using octane as the reference liquid for measuring θ values of soil-water, the differences of the three replications were small, being lower than those using ethyl alcohol. Among the studied multi-physico-chemical properties, clay content affected WDPT and θ values more significantly than other soil physico-chemical properties. Concentrations of K+ and Na+ were both positively correlated to θ va-lues, while the content of montmorillonite was negatively correlated to WDPT and MED values. In summary, among the three SWR measurement methods, the WDPT method was quite simple in operation but was susceptible, the MED method shortened the infiltration time but was time-consuming in operation, and the contact angle method was complicated in operation but the results were relatively accurate. When using octane as the reference liquid for the height method, it was more reliable than using the other liquids. Because each index had its inherent nature, it was suggested to use multiple indices to characterize SWR comprehensively.
    Evaluation of the forest ecosystem service values in Qinling, China
    YIN Sha, ZHAO Yong-hua, HAN Lei, WANG Yao-bin, CAI Jian
    2016, 27(12):  3777-3786.  doi:10.13287/j.1001-9332.201612.023
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    Landsat TM images of Mt. Qinling in 1984, 2000, 2005, and 2014 were used to extract land use and land cover type by a supervised classification method in ERDAS software. Equivalent factor of ecosystem service value per unit area was revised regionally in temporal and spatial dimensions, and then was modified pixel by pixel using the vegetation coverage. Forest ecosystem service values from 1984 to 2014 were calculated with RS and GIS techniques, and the results were tested by the sensitivity index. The results showed that from 1984 to 2014, forest area accounted for 77% of the study area, and the area changes in cultivated land and construction land were the most obvious. The total ecosystem service value of Mt. Qinling increased annually and by a total of 1.68×1017 yuan during the study period. The forest ecosystem service value (its growth rate was the biggest) contributed 93.8% of the overall ecosystem service value, while water and grass ecosystem service value contributed 1.6% and 1.3%, respectively. The ecosystem service value tended to increase with increasing distance from the study area boundary, which was consistent with the spatial distribution and per-unit ecosystem service value of land use types in Mt. Qinling. The annual rate of change of each ecosystem service value was insignificant. Among the four ecosystem functions, the service value of regulation accounted for 62.7%-65.8% of the total ecosystem service value, and the service value of climate regulation showed the most dramatic increase by 4.91×1016 yuan over the study period. The sensitivity index was <1, which indicated that the modified service value index was stable and the calculated results were reliable. Overall, the forest ecosystem service value in Mt. Qinling was very large, and strengthening forest protection would be an effective measure for maintaining the stability of the Mt. Qinling ecosystem.
    Spatial-temporal evolvement of ecosystem service value of Dongting Lake area influenced by changes of land use
    LI Tao, GAN De-xin, YANG Zhi-jian, WANG Kuan, QI Zeng-xiang, LI Hui, CHEN Xi
    2016, 27(12):  3787-3796.  doi:10.13287/j.1001-9332.201612.031
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    With the technology of geographic information system (GIS), the ecosystem service va-lue (ESV) coefficient of different types of land use in Dongting Lake area was estimated in this paper by interpreting the remote-sensing image for years and combining its economic development statistics. Meanwhile, the temporal-spatial evolvement characteristics of the ESV were investigated by employing the methods of spatial statistics analysis such as spatial autocorrelation, highland clustering analysis and hotspot analysis. The results showed that the ESV of Dongting Lake area increased slightly during 2000-2013, from 3868.39 billion yuan to 3886.62 billion yuan due to the increase of wetland in the area. The areas with high ESV and low ESV were infiltrated into each other, while the areas with second high ESV embraced those areas with high and low ESV. The characteristics of ESV and its dynamic evolvement in Dongting Lake area were obviously of spatial autocorrelation and high and low value clustering, but the trend was weakened. The focus of ESV hotspot of Dongting Lake area moved to northwest slightly with a “S” track in a obviously phased manner of “quick-slow-quick”.
    Simulating of carbon fluxes in bamboo forest ecosystem using BEPS model based on the LAI assimilated with Dual Ensemble Kalman Filter
    LI Xue-jian, MAO Fang-jie, DU Hua-qiang, ZHOU Guo-mo, XU Xiao-jun, LI Ping-heng, LIU Yu-li, CUI lu
    2016, 27(12):  3797-3806.  doi:10.13287/j.1001-9332.201612.005
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    LAI is one of the most important observation data in the research of carbon cycle of forest ecosystem, and it is also an important parameter to drive process-based ecosystem model. The Moso bamboo forest (MBF) and Lei bamboo forest (LBF) were selected as the study targets. Firstly, the MODIS LAI time series data during 2014-2015 was assimilated with Dual Ensemble Kalman Filter method. Secondly, the high quality assimilated MBF LAI and LBF LAI were used as input dataset to drive BEPS model for simulating the gross primary productivity (GPP), net ecosystem exchange (NEE) and total ecosystem respiration (TER) of the two types of bamboo forest ecosystem, respectively. The modeled carbon fluxes were evaluated by the observed carbon fluxes data, and the effects of different quality LAI inputs on carbon cycle simulation were also studied. The LAI assimilated using Dual Ensemble Kalman Filter of MBF and LBF were significantly correlated with the observed LAI, with high R2 of 0.81 and 0.91 respectively, and lower RMSE and absolute bias, which represented the great improvement of the accuracy of MODIS LAI products. With the driving of assimilated LAI, the modeled GPP, NEE, and TER were also highly correlated with the flux observation data, with the R2 of 0.66, 0.47, and 0.64 for MBF, respectively, and 0.66, 0.45, and 0.73 for LBF, respectively. The accuracy of carbon fluxes modeled with assimilated LAI was higher than that acquired by the locally adjusted cubic-spline capping method, in which, the accuracy of mo-deled NEE for MBF and LBF increased by 11.2% and 11.8% at the most degrees, respectively.
    Hyperspectral inversion of soil water and salt content in soils with different textures
    LI Ya-li, QIAO Jiang-fei, DONG Tian-yu, WANG Hai-jiang
    2016, 27(12):  3807-3815.  doi:10.13287/j.1001-9332.201612.021
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    In order to monitor soil water and salt content of saline soil conveniently and quickly, this paper took the typical salinization irrigation district of Xinjiang as the research object, obtained the spectral curve of soil water and salt content by using portable spectrometers based on the hyperspectral technology, transformed the original spectra of soil using the first order differential, second order differential and continuum removal methods. The results showed that the transformation of the original spectral data was beneficial to fingerprint band extraction of soil properties, and the method was not same in soils with different textures. In loam soil, continuum removal analysis was the best method for extraction of characteristic bands when the soil water content was 0% and 10%, first order differential equations were the best method when the soil water content was 15%, and second order differential equations were the best method when the soil water content was 19%. In sandy soil, continuum removal analysis was the best method for extraction of characteristic bands when the soil water content was 0%, whereas second order differential equations were the best method when soil water content was 10%, 15% or 19%. The transformed data were screened for inversion models of soil water and salt content by using the partial least squares regression method. When thesalinity was < 6.38 mS·cm-1 in loam soil and < 5.94 mS·cm-1 in sandy soil, the decision coefficients (Rcal2), internal cross validation (Rcv2), and external validation (Rval2) were greater than 0.65 (P<0.05). When the soil moisture content was less than 16% in loam soil and 12% in sandy soil, the inversion accuracy of model was higher. The results would provide a reference threshold for si-multaneously monitoring soil water and salt content in salinized areas.
    Variation in δ13C and water use efficiency of plant leaf at different slopes in an alpine mea-dow
    LIU Min-xia, LIU Yang-yang, CHEN Shi-wei, WANG Zhen-qian
    2016, 27(12):  3816-3822.  doi:10.13287/j.1001-9332.201612.029
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    Through the systematical measurements of δ13C values of samples representing 25 families and 86 C3 herb species along the slope aspects in an alpine meadow, the responses of δ13C va-lues and water use efficiency (WUE) for C3 plants to slope aspect changes and influence of environmental factors were analyzed and main environmental factors related to plant δ13C values change were revealed. Along the north-facing to south-facing slope, soil water content decreased gradually, the soil temperature and light intensity increased gradually, and plant community structure also had corresponding change. The δ13C values of C3 plant species in 5 slope aspects were from -31.19‰ to -21.8‰, with an average value of (-27.18±0.13)‰. The average δ13C value was the highest along the south-facing slope, followed by that along the southwest slope, west slope and northwest slope, with the lowest along the north slope during the whole growing season. The difference of δ13C values among the different slope aspects were caused by discrepancy in soil water content, soil temperature and light intensity. Soil water content was the main limiting factor. From north slope to south slope, plant δ13C value increased with the increasing soil temperature, light intensity and the reducing soil water content, which suggested that different species had different strategies to adapt to environmental changes of drought stress in different slope aspects, and water use efficiency was improved gradually in order to adapt to the environment of drought stress.
    Ecological stoichiometry characteristics of leaf-litter-soil in different plantations on the Loess Plateau, China
    BAI Xue-juan, ZENG Quan-chao, AN Shao-shan, ZHANG Hai-xin, WANG Bao-rong
    2016, 27(12):  3823-3830.  doi:10.13287/j.1001-9332.201612.035
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    In order to research into the influence of Grain to Green Project in Ziwuling forest region, this paper took three typical plantations which were Robinia pseudoacacia plantation, Pinus tabuliformis plantation, and Platycladus orientalis plantation in the Ziwuling forest region of Shaanxi Province as research objects and analyzed the carbon, nitrogen and phosphorus contents of leaf, litter and soil among the three plantations. The results showed that the contents of C, N and P in the three plantations were in order of leaf > litter > soil, the contents of N and P in leaf of R. pseu-doacacia plantation were significantly higher than that of P. tabuliformis plantation and P. orientalis. Leaf N:P was 12.21, 5.36 and 6.09 in R. pseudoacacia plantation, P. tabuliformis plantation and P. orientalis plantation, respectively. It was indicated that the three species were all subject to N deficiency. C:N and C:P showed the trend of litter > leaf > soil, and N:P demonstrated the trend of leaf > litter > soil. There were highly significant positive relationships in C:N between leaf and litter in P. tabuliformis plantation. N and P in the leaf development process of R. pseu-doacacia plantation were proportionally absorbed, and proportionally remained in the litter after N and P resorption. R. pseudoacacia was the better plantation species than P. tabuliformis and P. orientalis in the south fo-rest zone on the Loess Plateau.
    Climate change risk of nature reserve and its assessment: A case study of Dalinuoer National Nature Reserve in Inner Mongolia Autonomous Region
    ZHAO Wei, SHEN Wei-shou, LIU Hai-yue
    2016, 27(12):  3831-3837.  doi:10.13287/j.1001-9332.201612.003
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    According to the theoretical framework of addressing climate change based on risk mana-gement and the challenge to nature reserve management under climate change, climate change risk of nature reserve was analyzed and defined. Focus on birds and water habitat, grassland habitat, forest habitat, wetland habitat in Dalinuoer Nature Reserve, risk assessment method of nature reserve under climate change was formulated, climate change risks to Dalinuoer Nature Reserve and its habitats were assessed and predicted. The results showed that, during the period from 1997 to 2010, there was significant volatility in dynamic changes of climate change risks to Dalinuoer Nature Reserve and waterbody, grassland, forest, wetland in the region, Dalinuoer Nature Reserve and its habitats were in status of risk in 1999, 2001, 2005 and 2008, wetland habitat was also in status of risk in 2002 and 2004. Under scenario A, B and C, climate change risks to Dalinuoer Nature Reserve and waterbody, grassland, forest, wetland in the region would be more serious in 2020 and 2030, compared with the 2010 level. Climate change risks to different habitats were different significantly, with most serious climate change risk to wetland habitat due to its sensitivity to climate change and rich bird resources. The effect of climate change on nature reserve and related risk would be aggravated by excess utilization of water resource and grassland resource. As climate change risks had appeared in Dalinuoer Nature Reserve, risk management associated with climate change could greatly help to maintain and enhance biodiversity protection function of nature reserves.
    Effects of thinning intensities on reproductive modules of Quercus liaotungensis in Huanglong and Qiaoshan Mountains, Northwest China
    HUANG Cai-zhi, ZHANG Wen-hui, XING Zhong-li, YU Bi-yun, YE Quan-ping, XUE Wen-yan
    2016, 27(12):  3838-3844.  doi:10.13287/j.1001-9332.201612.028
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    Taking the Quercus liaotungensis middle-aged forests in Huanglong and Qiaoshan Mountains as study objects, the average size of individual trees of Q. liaotungensis, yield and rate of its reproductive modules, as well as their spatial distribution characteristics were investigated in five years after thinning at different intensities (CK, 10%, 20% and 30%), in order to demonstrate the impact of thinning intensity on reproductive modules of Q. liaotungensis. Thinning intensity had no significant effect on average height and average DBH, while it had significant positive correlation with crown area and crown volume. The yield of generative shoots, young fruits and mature fruits increased with thinning intensity, but vegetative shoots, staminate inflorescence, staminate flowers and pistillate flowers of Q. liaotungensis had little change. The yield of generative shoots, young fruits and mature fruits had raised significantly under 20% thinning, and reached the maximum under 30% thinning intensity. The rate of generative shoots and fruit setting rate increased with thinning intensity, and reached significant level under 20% or 30% thinning compared with the control. About three-quarters of the generative shoots, female and male flowers centered in the upper canopy, and the rest were in the lower part. Numbers of reproductive modules at sunny side accounted for about 65% of the total. The lower crown, shaded generative shoots, pistillate flowers and staminate inflorescence increased with the increasing thinning intensity, and the upper crown, sunny generative shoots, pistillate flowers and staminate inflorescence showed a decreasing trend with the increasing thinning intensity. Thinning at the intensity of 30% (canopy density 0.6) was the best, which could greatly improve the fruit set percentage of Q. liaotungensis and its mature rate, so as to improve the seed yield and quality, providing the guarantee for the seed collection and natural regeneration of Q. liaotungensis forests.
    Response of seed germination and seedling growth of Chinese fir to different light intensities
    LIU Qing-qing, MA Xiang-qing, LI Yan-juan, ZHUANG Zheng, DU Zi-long, XING Xian-shuang, LIU Bo
    2016, 27(12):  3845-3852.  doi:10.13287/j.1001-9332.201612.034
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    The effect of light intensity on the seed germination and seedling growth of Chinese fir under different light intensities (100%, 40%, 20%, 10%, 5% of full light, and the PPFD was 201.3, 77.0, 37.5, 19.2, 9.8 μmol·m-2·s-1, respectively) was investigated, and the adaptive strategy of seed germination, seedling survival, growth, morphological plasticity, biomass accumulation and allocation under different light intensities was explored in this paper. The results showed that light intensity significantly affected the germination rate, survival rate, establishment rate and germination index. Germination rate reached the maximum under 40% light intensity, while survival rate and establishment rate reached the maximum at 100% light intensity. With the light intensity decreased, the stem length increased, while the root length, cotyledon length, cotyledon thickness and euphylla number declined, and basal stem diameter had no significant difference among diffe-rent light intensities. The total biomass, root biomass, stem biomass and leaf biomass were the highest under 100% light intensity. With the light intensity decreased, the photosynthesis non-photosynthesis biomass ratio and leaf biomass ratio declined, while stem biomass ratio increased, the root to shoot ratio and root biomass ratio had no significant difference among different light intensities. Low light promoted seed germination, but seedlings grew slowly with high mortality under low light. The accumulation of biomass in stem increased the plant tolerance to low light.
    Impacts of rapid warming on radial growth of Larix gmelinii on two typical micro-topographies in the recent 30 years
    BAI Xue-ping, CHANG Yong-xing, ZHANG Xian-liang, MA Yan-jun, WU Tao, LI Jun-xia, CHEN Zhen-ju
    2016, 27(12):  3853-3861.  doi:10.13287/j.1001-9332.201612.036
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    Ravine and slope are the two typical micro-topographies in the Great Xing’an Mountains. Permafrost in the two micro-topographies is extremely sensitive to global warming. To compare the differences in responses of Larix gmelinii radial growth to rapid warming in the recent 30 years, tree-ring samples were collected from northern part of Great Xing’an Mountains in Inner Mongolia and tree ring-width chronologies were developed. The results showed that the divergence between tree growth and temperature occurred in 1980 in Mo’erdaoga and in 2000 in Hanma, respectively. Since 2000, tree growth on ravine sites was greater than that on the slope stands. Chronology of two topographies reached significant level by t test in 1984-2008, the Euclidean distance was 0.937-2.742 between chronologies, and far greater than the average (0.809-1.304). The rapid warming caused a significant radial growth response in L. gmelinii to hydrothermal conditions. On the slope sites, tree growth was mainly controlled by temperature and declined gradually in recent years, while the trees growing in ravines showed an accelerating growth rate with permafrost degeneration. L. gmelinii was undergoing profound environmental pressures caused by rapid warming, and it would experience a complex growth and development process. More seriously, L. gmelinii might disappear in China with a warming climate and permafrost degeneration.
    Comparison of three stand-level biomass estimation methods
    DONG Li-hu, LI Feng-ri
    2016, 27(12):  3862-3870.  doi:10.13287/j.1001-9332.201612.030
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    At present, the forest biomass methods of regional scale attract most of attention of the researchers, and developing the stand-level biomass model is popular. Based on the forestry inventory data of larch plantation (Larix olgensis) in Jilin Province, we used non-linear seemly unrelated regression (NSUR) to estimate the parameters in two additive system of stand-level biomass equations, i.e., stand-level biomass equations including the stand variables and stand biomass equations including the biomass expansion factor (i.e., Model system Ⅰ and Model system Ⅱ), listed the constant biomass expansion factor for larch plantation and compared the prediction accuracy of three stand-level biomass estimation methods. The results indicated that for two additive system of biomass equations, the adjusted coefficient of determination (Ra2) of the total and stem equations was more than 0.95, the root mean squared error (RMSE), the mean prediction error (MPE) and the mean absolute error (MAE) were smaller. The branch and foliage biomass equations were worse than total and stem biomass equations, and the adjusted coefficient of determination (Ra2) was less than 0.95. The prediction accuracy of a constant biomass expansion factor was relatively lower than the prediction accuracy of Model system Ⅰ and Model system Ⅱ. Overall, although stand-level biomass equation including the biomass expansion factor belonged to the volume-derived biomass estimation method, and was different from the stand biomass equations including stand variables in essence, but the obtained prediction accuracy of the two methods was similar. The constant biomass expansion factor had the lower prediction accuracy, and was inappropriate. In addition, in order to make the model parameter estimation more effective, the established stand-level biomass equations should consider the additivity in a system of all tree component biomass and total biomass equations.
    Three dimensional fluorescent characteristics of soil dissolved organic matter (DOM) in Jiaozhou Bay coastal wetlands, China
    ZI Yuan-yuan, KONG Fan-long, XI Min, LI Yue, YANG Ling
    2016, 27(12):  3871-3881.  doi:10.13287/j.1001-9332.201612.027
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    In order to elucidate the structure characteristics of soil dissolved organic matter (DOM) and analyze the sources in Jiaozhou Bay coastal wetlands, four typical types of wetlands around Jiaozhou Bay were chosen, including Spartina anglica wetland, the barren wetland, Suaeda glauca wetland and Phragmites australis wetland. The soil samples were collected in January 2014. The contents of soil DOM were determined and the spectral analysis was made by three-dimensional fluorescent technology. The results showed that the contents of soil dissolved organic carbon (DOC) in four types of wetlands all decreased with the increasing soil depth, and S. anglica wetland ranked the first in the contents of soil DOC, followed by the barren wetland, S. glauca wetland and P. australis wetland. Five fluorescence peaks including B, T, A, D and C were found in the three-dimensional fluorescence spectrum (3DEEMs), indicating tyrosine-like, tryptophan-like, phenol-like, soluble microbial byproduct-like and humic acid-like- substances, respectively. Fluorescence integration (FRI) was applied in the qualitative analysis of five components. The results showed that tryptophan-like, phenol-like and tyrosine-like substances ranked in top three in content, followed by soluble microbial byproduct-like and humic acid-like substances which were not significantly different. Pearson correlation analysis demonstrated that a positive correlation existed between any two of the five components of DOM, and they were all positively related to DOC content. In addition, there existed different correlations between the five components of DOM and total phosphorus (TP), available phosphorus (AP) and total nitrogen (TN). The soil DOM in the four types of wetlands was mainly produced by biotic interactions, and the degree of humification was relatively low.
    Diversity and distribution character of wood-rotting fungi in the secondary forest ecosystem of Liaodong areas, Northeast China
    ZHANG Li-yan, WEI Yu-lian, LI Tong
    2016, 27(12):  3882-3888.  doi:10.13287/j.1001-9332.201612.032
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    During July to September of 2013, field investigations and specimen collections on wood-rotting fungi were carried from three sites in the secondary forests (Qingyuan forest farm, Laotudingzi National Nature Reserve and Baishilaizi Nature Reserve) of eastern Liaoning Province. A total of 1062 specimens were collected and recorded, and 92 species were identified, belonging to48 genera. Among the three studying sites, Baishilaizi Nature Reserve had the most abundant polypore species and the Shannon diversity index was 4.04. The species biogeography of eastern Liaoning could be divided into 4 groups at genus level. The main elements were North temperate element and cosmopolitan element, and floristic analysis showed a distinct north temperate character. White rot species were the dominant decomposers here. Most species distributed in the fallen wood with decay stages 2 and 3. The wood dominant hosts of wood-rotting fungi were the Acer genus in the secondary forests of eastern Liaoning Province, and 243 specimens were collected from maples, occupying 23.2% of the total.
    Effects of mushroom residue compost on growth and nutrient accumulation of Larix principis-rupprechtii containerized transplants
    TENG Fei, LIU Yong, LOU Jun-shan, SUN Qiao-yu, WAN Fang-fang, YANG Chen, ZHANG Jin
    2016, 27(12):  3889-3894.  doi:10.13287/j.1001-9332.201612.033
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    Excessive use of peat may cause some environmental problems. To alleviate the negative effect, an experiment was conducted with the mushroom residue compost to replace peat in Larix principis-rupprechtii containerized transplant production, and the proportion of mushroom residue compost was 0% (T0, control), 15% (T1), 18.75% (T2), 25% (T3), 37.50% (T4), 50% (T5), 56.25% (T6) and 60% (T7), respectively. The physical and chemical features of the substrates and its effect on the vegetative growth and nutrient accumulation of L. principis-rupprechtii containerized transplants were studied. The results showed when the proportion of mushroom residue compost in the substrate accounted for 50% or less, there was no significant difference in the transplant height, diameter, and biomass compared with the control, and the nutrient concentration in T2, T4, T5 treatments was significantly higher than in T0. The pH value was sub-acidic to neutral which was suitable to the transplant growth. When the compost proportion accounted for more than 50%, the pH value was altered to alkali and was not suitable to the transplant growth. When the proportion of mushroom residue compost accounted for 15%, the plant grew best, and the height, diameter, and total biomass got the highest. Therefore, using mushroom residue compost to replace peat in L. principis-rupprechtii containerized transplants cultivation was feasible and the maximum replacement ratio could reach 50%. The high quality transplants could be obtained when the compost replacement ratio was 15%.
    Relationship between leaf anatomical structure and heat resistance of 15 Rhododendron cultivars
    SHEN Hui-fei, ZHAO Bing, XU Jing-jing
    2016, 27(12):  3895-3904.  doi:10.13287/j.1001-9332.201612.013
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    In this study, 17 anatomical structure indexes of 15 Rhododendron cultivars were mea-sured by scanning electron microscope (SEM). Leaf anatomical structure indexes were screened via coefficient of variation, analysis of correlation and hierarchical cluster analysis, and comprehensive evaluation on heat resistance for each cultivar was conducted by the subordinate function. The results showed that the leaves of Rhododendron cultivars were typical bifacial leaf and the epidermal anticlinal walls showed slightly sinuate. The stomata only distributed in the lower epidermis and the shape was ruleless. The anatomical structure indexes all reached a significant level difference among 15 cultivars (P<0.01), except for lower epidermis thickness (P<0.05). Thickness of lamina corneum, stomatal density, stomatal width, the thickness palisade tissue and looseness of leaf spongy tissue were the main factors related to the hardness, while other indexes, such as stomatal length, stoma aperture, stomatal opening, length and thickness of upper epidermis, length and thickness of lower epidermis, thickness of spongy tissue, the ratio of the palisade tissue to spongy tissue, tightness of leaf palisade tissue, leaf thickness and media thickness didn’t show much effect on heat resistance. There were some differences among 15 cultivars in heat resistance, and the order was Rhododendron ‘Song Jiang Da Tao Hong’ > Rhododendron ‘Zhuang Yuan Hong’ > Rhododendron ‘Lv Se Guang Hui’ > Rhododendron ‘Fen Zhen Zhu’ > Rhododendron ‘Wai Guo Hong’ > Rhododendron ‘Lan Yin’ > Rhododendron ‘Bi Zhi’ >Rhododendron ‘Da He Zhi Chun’ > Rhododendron ‘Guo Qi Hong’ > Rhododendron ‘Yu Ling Long’ > Rhododendron ‘Hong Shan Hu’ > Rhododendron ‘Ning Bo Hong’ > Rhododendron ‘Tao Ban Zhu Sha’ > Rhododendron ‘Ai Ding Bao’ > Rhododendron ‘Liu Qiu Hong’. According to the heat hardiness, the cultivars could be divided into 4 groups: R. ‘Song Jiang Da Tao Hong’, R. ‘Zhuang Yuan Hong’ and R. ‘Lv Se Guang Hui’ with high heat resistance, R. ‘Fen Zhen Zhu’, R. ‘Wai Guo Hong’, R. ‘Lan Yin’, R. ‘Bi Zhi’, R. ‘Da He Zhi Chun’, R. ‘Guo Qi Hong’ and R. ‘Yu Ling Long’ with medium heat resistance, R. ‘Hong Shan Hu’, R. ‘Ning Bo Hong’, R. ‘Tao Ban Zhu Sha’ and R. ‘Ai Ding Bao’ with lower heat resistance, R. ‘Liu Qiu Hong’ without heat resistance. However, the accurate heat hardiness evaluation of Rhododendron still needs to consider other factors, including morphological structure, physiological and biochemical indicators and genetic factor of heat resistance, the harmfulness of Rhododendron, and the recovery state after being injured by high temperature.
    Spatial characteristics analysis of Huizhou-Styled Village based on ideal ecosystem model and 3D landscape indices: A case in Chengkan, China
    YAO Meng-yuan, YAN Shi-jiang, WU Yan-lan
    2016, 27(12):  3905-3912.  doi:10.13287/j.1001-9332.201612.010
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    Huizhou-Styled Village is a typical representative of the traditional Chinese ancient villages. It preserves plentiful information of the regional culture and ecological connotation. The Huizhou-Style is the apotheosis of harmony between the Chinese ancient people and nature. The research and protection of Huizhou-Styled Village plays a very important role in fields of ecology, geography, architecture and esthetics. This paper took Chengkan Village of Anhui Province as an exa-mple, and proposed a new model of ideal ecosystem oriented in theories of Feng-shui and psychological field. The new method of characterizing 3D landscape index was introduced to explore the spatial patterns of Huizhou-Styled Village and the functionality of the composited landscape components in a quantitative way. The results indicated that, Chengkan Village showed a spatially composited pattern of “mountain-forest-village-river-forest”. It formed an ideal settlement ring structure with human architecture in the center and natural landscape around in the horizontal and vertical horizons. The traditional method based on the projection distance caused the deviation of the landscape index, such as underestimating the area and distance of landscape patch. The 3D landscape index of average patch area was 6.7% higher than the 2D landscape index. The increasing rate ofarea proportion in 3D index was 1.0% higher than that of 2D index in forest lands. Area proportion of the other landscapes decreased, especially the artificial landscapes like construction and cropland landscapes. The area and perimeter metric were underestimated, whereas the shape metric and the diversity metric were overestimated. This caused the underestimation of the dominance of natural patches was underestimated and the overestimation of the dominance of artificial patches during the analysis of landscape pattern. The 3D landscape index showed that the natural elements and their combination in Chengkan Village ecosystem reflected better ecological function, the key elements and the composited landscape ecosystem preserved higher stability, connectivity and aggregation. The quantitative confirmation showed that the Huizhou-Styled Village represented by Chengkan Village is an ideal ecosystem.
    Dynamic monitoring and analysis of ecological environment in Weinan City, Northwest China based on RSEI model
    SONG Hui-min, XUE Liang
    2016, 27(12):  3913-3919.  doi:10.13287/j.1001-9332.201612.024
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    Based on the data of remote sensing images from Landsat in 1995 and 2015, this paper used the principal component analysis (PCA) method to determine the weights of four ecological indexes (greenness, dryness, wetness and heat), and then selected a evaluation model of remote sensing based ecological index (RSEI) to monitor and analyze the ecological environment quality of Weinan City from 1995 to 2015. The results showed that the mean values of RSEI in Weinan City increased from 0.489 to 0.556 during 1995-2015, which indicated the ecological environment qua-lity had been improved. The improved area of ecological quality was mainly distributed in the central area of Weinan City and its proportion was 49.6%. While the proportion of ecological environment degradation was 15.4%, and such areas were mainly distributed in some mine areas of Hancheng City and the southern Weinan (Weinan Section in North Qinling Mountains). The quality of ecolo-gical environment was greatly influenced by the urban planning and construction in the study area. Generally, the ecological condition of Weinan City had been improved, which benefited from the attention and investment of government.
    Fractional vegetation cover of invasive Spartina alterniflora in coastal wetland using unmanned aerial vehicle (UAV)remote sensing
    ZHOU Zai-ming, YANG Yan-ming, CHEN Ben-qing
    2016, 27(12):  3920-3926.  doi:10.13287/j.1001-9332.201612.006
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    The effective management and utilization of resources and ecological environment of coastal wetland require investigation and analysis in high precision of the fractional vegetation cover of invasive species Spartina alterniflora. In this study, Sansha Bay was selected as the experimental region, and visible and multi-spectral images obtained by low-altitude UAV in the region were used to monitor the fractional vegetation cover of S. alterniflora. Fractional vegetation cover parameters in the multi-spectral images were then estimated by NDVI index model, and the accuracy was tested against visible images as references. Results showed that vegetation covers of S. alterniflora in the image area were mainly at medium high level (40%-60%) and high level (60%-80%). Root mean square error (RMSE) between the NDVI model estimation values and true values was 0.06, while the determination coefficient R2 was 0.92, indicating a good consistency between the estimation value and the true value.
    Effects of drought stress on biosynthesis of isoflavones in soybean seedling
    QIN Wen-ting, ZHANG Jing, WU Hai-jun, SUN Guang-ze, YANG Wen-yu, LIU Jiang
    2016, 27(12):  3927-3934.  doi:10.13287/j.1001-9332.201612.018
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    In this present study, two soybean cultivars with different drought tolerance in serial number of JP-6 (high drought-tolerant species) and JP-16 (low drought-tolerant species) were researched. The HPLC and real-time PCR analyses were used to determine the isoflavone contents and relative expression levels of key genes, which encoded isoflavone synthesis relative enzymes in lea-ves and roots under different drought stress levels, respectively. The results indicated that the isoflavone contents in roots were significantly higher than that in leaves, whereas the relative expression of isoflavone synthetic enzyme related genes in leaves was significantly higher than that in roots. Analysis of isoflavone accumulation by comparing two different drought tolerance soybean cultivars found that the isoflavone accumulation in roots of JP-6 was greater than that in others. With increa-sing levels of the drought stress, there were significant differences in both isoflavone synthesis and accumulation between JP-6 and JP-16 soybean cultivars. In JP-6, the isoflavone accumulation in root and leaf increased after slight decreasing, while the opposite result was obtained in JP-16, in which the isoflavone accumulation in different parts were decreased after slight increasing. The expression of isoflavone synthesis relative enzyme genes presented a trend that decreased and then gradually increased with the increasing level of drought stress, except C4H, 4CL and IFS2 which were synthesis genes upstream of isoflavones in leaves of JP-6. Soybean isoflavones were mainly synthesized in leaves, little was synthesized in roots. The isoflavone synthesis and accumulation of low drought-tolerant species were scare, while those of high drought-resistant variety were relatively higher. The variety with high isoflavone accumulation in the root was more drought-resistant.
    Climatic suitability of spring maize planted in the “sickle bend” area of China and regulation suggestion
    MAO Liu-xi, ZHAO Jun-fang, XU Ling-ling, YAN Hao, LI Sen, LI Ya-fei
    2016, 27(12):  3935-3943.  doi:10.13287/j.1001-9332.201612.026
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    The “sickle bend” area is a typical dry farming and excellent livestock development area, with fragile ecological environment. It includes 13 provinces (autonomous regions) in the north and the southwest of China. The climate suitability and the climatic potential productivity of spring maize from 1981 to 2010 in this area were quantitatively assessed. The daily data from 650 meteorological stations and grid data (1 km×1 km) in the “sickle bend” area from 1981 to 2010, and recognized indicators of agricultural meteorology were used in this study. The agro-ecological zoning mo-del (AEZ) which was currently very popular in estimating crop climatic potential productivity internationally was also applied, as well as land use classification information monitoring from satellite remote sensing. Then, based on biological characteristics of spring maize and agricultural climate resources, scientific countermeasures on reasonably adjusting agricultural production structure in subsuitable and unsuitable areas were proposed. The results showed that: 1) the climatic potential productivity of spring maize in the northern growing areas showed the “big-medium-smaller-small” distribution pattern from the east to the west from 1981 to 2010. However, the climatic potential productivity of spring maize in the southern growing areas had no significant distribution law, fluctuating between “smaller” and “ medium ” in general. 2) It presented the “most suitable-suitable-subsuitable-unsuitable” distribution pattern from the southeast to the northwest in the northern maize growing region of the “sickle bend” area on the whole from 1981 to 2010. In contrast, the southern planting area showed the “unsuitable-subsuitable-suitable-most suitable” distribution pattern from the southeast to the northwest. The most suitable and suitable planting areas of spring maize were mainly located in the most areas of Northeast China and North China, and the southeastern areas of Northwest China. The subsuitable or unsuitable regions mainly included Inner Mongolia, northern Xinjiang, western Gansu and Guangxi. 3) The most suitable planting area of spring maize was the largest (47%), followed by subsuitable area (23%), unsuitable area (17%) and suitable area (13%). 4) According to the analysis of climatic conditions, we proposed to mainly decrease the spring maize planting in the subsuitable and unsuitable areas. These subsuitable and unsuitable regions were low climatic potential productivity areas, including the arid windstorm region of Northwest, the cold area of Northeast, agro-pastoral area and the rocky desertification region of Southwest.
    Effects of cotton straw returning on soil organic carbon, nitrogen, phosphorus and potas-sium contents in soil aggregates
    WANG Shuang-lei, LIU Yan-hui, SONG Xian-liang, WEI Shao-bin, LI Jin-pu, NIE Jun-jun, QIN Du-lin, SUN Xue-zhen
    2016, 27(12):  3944-3952.  doi:10.13287/j.1001-9332.201612.015
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    To clarify the effects of cotton straw returning on the composition and contents of nu-trients in different particle sizes of aggregates, two treatments with or without cotton straw returning were tested in continuous three years. After three years straw treatments, we collected undisturbed soil within 0-5, 5-10, 10-20 and 20-30 cm soil layers, and to measure the composition, soil organic carbon, nitrogen, phosphorus and potassium contents in different particle sizes of aggregates classified using dry sieving. Returning cotton straw into the field significantly increased particle contents of 2-5 mm and >5 mm aggregates in 0-5 cm soil layer, while the content of <0.25 mm micro-aggregates was decreased. Cotton straw returning significantly improved soil organic carbon, nitrogen, and potassium contents by 19.2%, 14.2% and 17.3%, respectively, compared to no returning control. In 5-10 cm soil layer, cotton straw returning increased the contents of 2-5 mm and >5 mm aggregates, reduced the content of <0.25 mm micro-aggregate, but significantly increased contents of soil organic carbon, available nitrogen and potassium by 19.6%, 12.6% and 23.4%, compared to no straw returning control. In 10-20 cm soil layer, cotton straw returning significantly reduced the content of <0.25 mm micro-aggregates, and significantly enhanced soil organic carbon, nitrogen, and potassium contents by 8.4%, 10.9% and 11.5%, compared to the control. However, in 20-30 cm soil layer, cotton straw returning only increased soil available potassium content by 12.0%, while there were no significant changes in particle size, organic carbon, nitrogen and phosphorus contents. We concluded that cotton straw returning could significantly improve the structure of surface soil by increasing the number of macro-aggregates, contents of organic carbon, available nitrogen and potassium in aggregates, while decreasing micro-aggregate content. The enhancement of the contribution of macro-aggregates to soil fertility by returning cotton straw could improve soil physical structure, fertility and then increase cotton yield.
    Effects of postponed basal nitrogen application with reduced nitrogen rate on grain yield and nitrogen use efficiency of south winter wheat
    ZHANG Lei, SHAO Yu-hang, GU Shi-lu, HU Hang, ZHANG Wei-wei, TIAN Zhong-wei, JIANG Dong, DAI Ting-bo
    2016, 27(12):  3953-3960.  doi:10.13287/j.1001-9332.201612.020
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    Excessive nitrogen (N) fertilizer application has led to a reduction of nitrogen use efficiency and environmental problems. It was of great significance for high-yield and high-efficiency cultivation to reduce N fertilizer application with modified application strategies. A two-year field experiment was conducted to study effects of different N application rates at basal and seedling application stages on grain yield and nitrogen use efficiency. Taking the conventional nitrogen application practice (240 kg N·hm-2 with application at basal, jointing, and booting stages at ratios of 5:3:2, respectively) as control, a field trial was conducted at different N application rates (240, 180 and 150 kg N·hm-2, N240, N180 and N150, respectively) and different application times [basal (L0), fourth (L4) and sixth leaf stage (L6)] to investigate the effects on grain yield and nitrogen use efficiency. The results indicated that grain yield decreased along with reducing the N application rate, but it had no significant difference between N240 and N180 while decreased significantly under N150. Nitrogen agronomy and recovery efficiency were all highest under N180. Among different N application stages, grain yield and nitrogen use efficiency were highest under L4. N180L4 had no signifi-cant difference with control in grain yield, but its nitrogen use efficiency was significantly higher. The leaf area index, flag leaf photosynthesis rate, leaf nitrogen content, activity of nitrogen reductase and glutamine synthase in flag leaf, dry matter and N accumulation after jointing of N180L4 had no significant difference with control. In an overall view, postponing basal N fertilizer application at reduced nitrogen rate could maintain high yield and improve nitrogen use efficiency through improving photosynthetic production capacity and promoting nitrogen uptake and assimilation.
    Effects of enhanced-efficiency nitrogen fertilizers on nitrous oxide emissions from cotton field under plastic mulched drip irrigation in Xinjiang,China
    MA Zhi-wen, GAO Xiao-peng, GUI Dong-wei, KUANG Wen-nong, WANG Xi-he, LIU Hua
    2016, 27(12):  3961-3968.  doi:10.13287/j.1001-9332.201612.016
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    The effect of enhanced-efficiency nitrogen (N) fertilizers on emissions of nitrous oxide (N2O) from the grey desert agricultural soils of Xinjiang is uncertain. In this study, the enhanced-efficiency fertilizers, polymer-coated urea (ESN), and stabilized urea with urease and nitrification inhibitors (U+I) were compared to conventional urea (U) for N2O emissions from cotton under plastic mulch drip irrigation near Urumqi, Xinjiang. ESN was added once at planting but the other treatments were added multiple times with drip irrigation during the growing season. Gas samples were collected and analyzed twice per week during the growing season, using the static chamber-chromatography methodology. The results showed that generally, ESN significantly increased soil cumulative N2O emissions during the growing season by 47%-73% compared to other treatments. In the first four months after fertilization, soil ammonium (NH4+-N) and nitrate (NO3--N) concentrations under ESN treatment were generally higher than under other treatments. Thereafter, NH4+-N and NO3--N concentrations under all treatments gradually decreased to similar levels. ESN all added at planting was likely responsible for high NH4+-N and NO3--N concentrations and highest N2O emissions. The U+I treatment reduced soil N2O emission by 9.9% in comparison with U, whereas the difference was not statistically significant. In addition, soil NO3--N contents of the U+I treatments were generally lower than those of the ESN and the U treatments. The cumulative N2O emissionsover the growing season ranged from 300 to 500 g N2O-N·hm-2, generally lower than emissions reported for other agricultural ecosystems. Drip irrigation successfully kept moisture conditions below levels for appreciable N2O emissions. Multiple applications of N via drip irrigation seemed to be effective to lower emissions than all N applied at planting. Therefore, for cotton field under plastic mulch drip irrigation in arid land of Northwest China, the benefit of enhanced efficiency N ferti-lizers on N2O mitigation is limited.
    Effect of tobacco straw incorporation on rice yield and nutrient absorption and its substitute for potassium fertilizer
    JIANG Chao-qiang, SHEN Jia, WANG Huo-yan, LI De-cheng, LI Tian, WANG Wen-jie, ZU Chao-long
    2016, 27(12):  3969-3976.  doi:10.13287/j.1001-9332.201612.014
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    Field trails were carried to study the effects of tobacco straw incorporation and potassium (K) fertilizer on rice yield, K uptake and use efficiency, and its substitute for K fertilizer under different paddy soil K levels in tobacco-rice rotation areas. Results showed that both tobacco straw incorporation (2250 kg·hm-2) and K fertilizer application (75 kg K2O ·hm-2) could increase grain yield and aboveground K uptake of rice. The treatment of tobacco straw incorporation with K fertilizer (St+NPK) got the best effect on rice yield compared with the control (NP). In this treatment (St+NPK), rice yields were increased by 13.3%, 17.1% and 13.5% for low-K soil (available potassium content < 100 mg·kg-1), middle-K soil (available potassium content 100-150 mg·kg-1) and high-K soil (available potassium content > 150 mg·kg-1), respectively, compared with NP. Tobacco straw incorporation (St+NP) could increase K fertilizer recovery efficiency and K fertilizer agronomic efficiency. Under the current practice of applying 75 kg K2O·hm-2, St+NPK showed no significant effect on K fertilizer recovery efficiency and K fertilizer agronomic efficiency, demonstrating that the recommended rate of K fertilizer might be more than the actual demand of rice growth. More importantly, data of tobacco straw substitute for K fertilizer showed that tobacco straw incorporation could replace 10%-22% K fertilizer during rice growing season, i.e. K fertilizer could be reduced by 7.2-16.5 kg·hm-2 for rice under the condition of tobacco straw incorporation. Therefore, it was suggested that straw incorporation could reduce the rate of K fertilizer for high-K soil, but the current K fertilizer inputs (75 kg K2O·hm-2) should be supplied to get high rice yield and maintain the soil potassium balance for low-K soil and middle-K soil.
    Differences in nitrogen utilization characteristics of different peanut genotypes in high fertility soils
    ZHENG Yong-mei, SUN Xiu-shan, WANG Cai-bin, ZHENG Ya-ping, WU Zheng-feng, SUN Xue-wu, YU Tian-yi, SHEN Pu
    2016, 27(12):  3977-3986.  doi:10.13287/j.1001-9332.201612.009
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    A total of twenty genotypes of peanut (Arachis hypogaea) were used to investigate the differences in nitrogen (N) utilization characteristics in a pot experiment with 15N isotope tracing analysis. Results showed the main N sources for peanut in high fertility soils following as soil N source > N fixed by root nodule source > fertilizer N source. The N uptake and accumulation in peanut from total N and the three N supplied sources (fertilizer N, soil N and N fixation) varied among the different genotypes. N fixation source had the largest genetic variation among the twenty genotypes while genetic variation for fertilizer N source and soil N source were lower and similar. Significant differences showed among the twenty genotypes in pod producing efficiency of N and N use efficiency, and the highest values were respectively 3.6 and 2.1 times of the lowest values. There were also significant differences among the twenty genotypes in the harvest indexes of total N, fertilizer N source, soil N source and N fixation source, and the largest variation showed in the harvest index of N fixation source. The pod yields significantly or extremely significantly corrected with N accumulation amounts from different N sources, N harvest index, pod producing efficiency of N, and N use efficiency. According to N uptake and accumulation and pod yield, four major types of peanut were classified, namely high total N accumulation & high yield type, high fertilizer N source & high yield type, high soil N source & high yield type, and high N fixation source & high yield type. Four of the twenty genotypes had all characteristics of the four major types.
    Effect of exogenous γ-aminobutyric acid on NO3--N assimilation in muskmelon under Ca(NO3)2 stress
    ZHEN Ai, HU Xiao-hui, REN Wen-qi, SU Chun-jie, JIN Xiao-qing, SUN Xian-peng
    2016, 27(12):  3987-3995.  doi:10.13287/j.1001-9332.201612.017
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    The effect of exogenous γ-aminobutyric acid (GABA) on NO3--N assimilation in muskmelon under Ca(NO3)2 stress was investigated in ‘ Yipintianxia 208’, a salt-sensitive melon variety cultured under deep flow hydroponics which simulated soil salinization. The results showed that under Ca(NO3)2 stress, the activities of nitrate reductase (NR), glutamate synthetase (GS) and glutamate amino transferase (GOGAT) in muskmelon seedlings were significantly reduced, while the activities of glutamate dehydrogenase (GDH), glutamate oxaloacetate transaminase (GOT) and glutamate pyruvate aminotransferase (GPT) were enhanced, leading to increased contents of NH4+-N and total amino acids, and decreased contents NO3--N and soluble protein in muskmelon, which further severely inhibited plant growth and photosynthesis of muskmelon seedlings. Exogenous GABA effectively improved the absorption of NO3--N in muskmelon roots and its transportation from root to shoot under Ca(NO3)2 stress, and improved NH4+-N assimilation by enhancing NR, GS and GOGAT activities in muskmelon seedlings. Exogenous GABA also reduced NH4+ release by limiting GDH deamination, thus further alleviated the toxication of NH4+-N induced by Ca(NO3)2 stress. In addition, foliage spraying of GABA could regulate amino acids metabolic pathways and promote protein synthesis. The results suggested that exogenous GABA could improve NO3--N assimilation and regulate amino acids metabolism to alleviate Ca(NO3)2 stress damage in muskmelon seedlings.
    Effects of calcium and ABA on photosynthesis and related enzymes activities in cucumber seedlings under drought stress
    CHEN Lu-lu, WANG Xiu-feng, LIU Mei, YANG Feng-juan, SHI Qing-hua, WEI Min, LI Qing-ming
    2016, 27(12):  3996-4002.  doi:10.13287/j.1001-9332.201612.025
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    To investigate the effect of calcium and ABA on photosynthesis and the activities of antioxidant enzymes in cucumber seedlings under drought stress, the cucumber was used as the expe-riment materials, normal nutrient solution culture was considered as the control, and PEG-6000 application in the nutrient solution simulated the drought stress. There were five different treatments which were spraying water, ABA, CaCl2+ABA, LaCl3(calcium channel inhibitor)+ABA and EGTA (calcium ion chelating agent)+ABA under drought stress. The results showed that drought stress inhibited the growth of cucumber seedlings, and reduced the activities of antioxidant enzymes, nitrate reductase, net photosynthetic rate and fluorescence parameters of the cucumber seedlings leaves. The application of ABA reduced the inhibition of activities of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT) and ascorbate peroxidase (APX), photosynthesis (Pn, gs) and the fluorescence parameters (Fv′/Fm′, qP and ETR), and decreased the damage of drought stress on plant. Spraying CaCl2+ABAsignificantly promoted the positive effect of ABA, while EGTA+ABA and LaCl3 +ABA didn’t show the promoting effect.
    Influence of a new phosphoramide urease inhibitor on urea-N transformation in different texture soil
    ZHOU Xuan, WU Liang-huan, DAI Feng
    2016, 27(12):  4003-4012.  doi:10.13287/j.1001-9332.201612.019
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    Addition of urease inhibitors is one of the important measures to increase nitrogen (N) use efficiency of crop, due to retardant of urea hydrolysis and reduction of ammonia volatilization loss. An incubation experiment was conducted to investigate the urease inhibition effect of a new phosphoramide urease inhibitor, NPPT (N-(n-propyl) thiophosphoric triamide) in different texture soils under dark condition at 25 ℃, and NBPT (N-(n-butyl) thiophosphoric triamide) was obtained to compare the inhibition effect on urease in different soil textures by different dosages of urea adding. Results showed that the effective reaction time of urea was less than 9 d in the loamy and clay soil. Addition of inhibitors for retardation of urea hydrolysis was more than 3 d. In sandy soil, urea decomposition was relatively slow, and adding inhibitor significantly inhibited soil urease acti-vity, and reduced NH4+-N content. During the incubation time, the inhibition effect of high dosage urea in the soil was better than that of low dosage. At day 6, the urease inhibition rate of NBPT and NPPT (N 250 mg·kg-1) were 56.3% and 53.0% in sandy soil, 0.04% and 0.3% in loamy soil, 4.1% and 6.2% in clay soil; the urease inhibition rate of NBPT and NPPT (N 500 mg·kg-1) were 59.4% and 65.8% in sandy soil, 14.5% and 15.1% in loamy soil, 49.1% and 48.1% in clay soil. The urease inhibition effects in different texture soil were in order of sandy soil > clay soil> loamy soil. The soil NH4+-N content by different inhibitors during incubation time increased at first and then decreased, while soil NO3--N content and apparent nitrification rate both showed rising trends. Compared with urea treatment, addition of urease inhibitors (NBPT and NPPT) significantly increased urea-N left in the soil and reduced NH4+-N content. In short, new urease inhibitor NPPT in different texture is an effective urease inhibitor.
    Effects of As stress on contents of saponin and flavonoid, key enzymes activities of Panax notoginseng and its proteomic analysis
    ZU Yan-qun, MEI Xin-yue, MIN Qiang, SU Yuan, MA Ni, FENG Guang-quan, LI Yuan
    2016, 27(12):  4013-4021.  doi:10.13287/j.1001-9332.201612.040
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    Field plot experiments were conducted to study the effect of two-year consecutive As stress [As(V): 0, 20, 80, 140, 200 and 260 mg·kg-1] on contents of As, saponin and flanovoids, the enzyme activities of phenylalanine ammonia lyase (PAL), chalcone synthase (CHS), and squalene synthase (SS) in main root, fibrous root and rhizome and shoot, and proteome of three-year old Panax notoginseng in Wenshan prefecture, Yunnan Province, China. The results showed that total saponin content of fibrous root decreased with increase in As treatment concentration. Total saponin contents of shoot and rhizome increased with 140 mg·kg-1 As treatment compared with control. SS activity of rhizome was higher than that of shoot. Flavonoid contents of diffe-rent plant parts decreased with increase in As treatment concentration. With 140 mg·kg-1 As treatment, activities of PAL and CHS in rhizome were higher than that in shoot. CHS activities in shoot and rhizome were lower, and PAL activities were higher than those of the control. As contents in different plant parts of P. notoginseng increased with increase in As treatment concentration. The highest As content was observed in fibrous root. With 140 mg·kg-1 As treatment, twenty-one diffe-rential proteins (ratio >2, P<0.05) were identified in the inoculated compared to the control. The down-regulated proteins included phosphoribulokinase, heat shock protein, NAD(P)-binding rossmann-fold superfamily proteinisoform, monodehydroascorbate reductase and cytochrome b6-f complex iron-sulfur subunit. The up-regulated proteins included CDC27 family protein, acidic endochitinase isoform, symbiosis receptor-like kinase precursor, isoflavone reductase-like protein, phospho-2-dehydro-3-deoxyheptonate aldolase, putative protein kinase superfamily protein, malate dehydrogenase, glyoxalase I isoform and glutamine synthetase cytosolic isozyme. In general, with two-year consecutive As stress, As contents in different plant parts of P. notoginseng increased, which not only affected the photosynthesis and energy, but also decreased the antioxidation and resilience, and induced the increased expression of protein involved in detoxication, resulted in decrease in the contents of flavonoid and saponin. The tolerant threshold value of P. notoginseng for As was 140 mg·kg-1.
    Colonization of grape leaves by endophytic Bacillus subtilis JL4 and its control of grape downy mildew
    SHEN Hong-miao, LI Zheng-nan, JIA Zhao-shan, YANG Jia-yao, RAN Long-xian
    2016, 27(12):  4022-4028.  doi:10.13287/j.1001-9332.201612.038
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    In order to understand the colonization pattern of Bacillus subtilis JL4 both on and inside grape leaves, and its control of grape downy mildew, a shuttle vector pGFP78, carrying the GFP gene, was transformed into B. subtilis JL4, and a GFP-labelled transformant designated as JL4-gfp was obtained successfully. The stability of the marker and antagonistic activity to Plasmopara viticola of JL4-gfp were tested. JL4-gfp was spray inoculated on grape leaves in a vine yard and colonization of the leaves was investigated by dilution plating on selective medium. Leaves treated with JL4-gfp were collected and taken to the laboratory for inoculation of a sporangial suspension of P. viticola, to determine its control effect on grape downy mildew. The green fluorescence of the marked strain was stable for at least 10 subcultures, and JL4-gfp maintained wild type antagonistic activity against P. viticola. JL4-gfp was recovered from the grape leaves by dilution plating on medium supplemented with antibiotics. Numbers recovered from the leaf surface of grape leaves were 3.6×105, 2.7×105 and 3.1×103 CFU·g-1 at 0, 3 and 7 days after inoculation, and the population density inside the leaf tissue reached a maximum of 9.6×104 CFU·g-1 at 3 days after inoculation, but could not be recovered after 14 days. The efficiency of downy mildew control by the marked strain was more than 88.0% at 3 days after inoculation, but no significant control effect was observed after 7 days. Our results suggested that there was a positive correlation between the JL4-gfp population density and control efficiency of grape downy mildew, and a threshold colonization level at 105 CFU·g-1 was a prerequisite for this Bacillus strain to present efficient control effects.
    Rhizosphere microbial impacts of alleviating faba bean Fusarium wilt with inoculating AM fungi
    DONG Yan, DONG Kun, YANG Zhi-xian, TANG Li, ZHENG Yi
    2016, 27(12):  4029-4038.  doi:10.13287/j.1001-9332.201612.022
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    Greenhouse pot trials were conducted to investigate the effects of arbuscular mycorrhizal fungus (Glomus mosseae, Glomus tortuosum, Glomus intraradices and Glomus etunicatum) inoculation on the seedling growth, occurance of Fusarium wilt, population of Fusarium oxysporum and rhizosphere microbial community functional diversity in faba bean rhizosphere soil. Results showed that after inoculation of G. mosseae, G. tortuosum, G. intraradices and G. etunicatum, the shoot and root fresh mass of faba bean seedlings increased significantly, the disease index of faba bean fusarium wilt decreased significantly by 94.0%, 60.0%, 64.0% and 94.0%, respectively, the amount of F. oxysporum of faba bean rhizosphere decreased significantly by 98.6%, 74.3%, 77.8% and 90.4%, respectively. The best inhibitory effects to Fusarium wilt were with G. mosseae and G. etunicatum treatments. Inoculation of G. mosseae, G. tortuosum and G. etunicatum significantly increased carbon sources utilization ability of carbohydrates, amino acids, carboxylic acids and phenolic acids, with the average well color development (AWCD) value being increased by 34.4%, 31.5% and 50.8% respectively, but such significant differences were not observed with inoculation of G. intraradice. Principal component analyses showed that inoculation of G. mosseae, G. tortuosum and G. etunicatum fungi changed the rhizospheric microbial community composition. Correlation analyses showed that the utilization of carbohydrates carbon sources (β-Methyl-D-glucoside, D-Galacturonic acid, D-Mannitol, N-Acetyl-D-Glucosamine, D-Cellobiose,) and carboxylic acids carbon sources (D-Galactonic acid-γ-Lactone) were significantly increased after inoculation of G. tortuosum, and the utilization of L-Arginine and 4-Hydroxy benzoic acid significantly increased after inoculation of G. mosseae and G. etunicatum. Carbohydrates, carboxylic acids were main carbon sources utilized by rhizosphere microbes after G. tortuosum and G. intraradices inoculation, and amino acids and phenolic acids were main carbon sources utilized by rhizosphere microbes after G. mosseae and G. etunicatum inoculation. Inoculation of AM fungi significantly increased the activities of rhizosphere microbes, changed soil microbe community functional diversity, and thus inhibited the growth of F. oxysporum. The inhibitory impacts of AM fungi inoculations depended on the changes of microbes utilizing carbon sources.
    SSR analysis on stress effect of transgenic hybrid poplar 741 on Clostera anachoreta (Fabricius) (Lepidoptera: Notodontidae)
    LIU Jun-xia, SONG Xiao-ying, JIANG Wen-hu, ZHOU Guo-na, GAO Bao-jia
    2016, 27(12):  4039-4044.  doi:10.13287/j.1001-9332.201612.011
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    The genetic differentiation of the experimental population of Clostera anachoreta fed on different resistant transgenic 741 poplar leaves was analyzed by SSR molecular marker technique to investigate stress effect of transgenic poplar Bt gene as food on target insect. The experimental population of C. anachoreta fed on transgenic 741 poplar high resistant strains ‘Pb29’, medium resis-tant strains ‘Pb17’ and non-transgenic poplar (CK), and the screened ten pairs of SSR primers were used. The results showed that 76 alleles were observed in ten pairs of primers. The average allele was 7.6, the average effective number of alleles was 2.2, the average observed heterozygosity was 0.5167, the average expected heterozygosity was 0.5167, and the average percentage of polymorphic loci was 96.7%. The genetic diversity level of C. anachoreta experimental population fed on transgenic poplar 741 was significantly higher than that fed on non-transgenic populations, and C. anachoreta fed on high resistance had the lowest genetic similarity with CK samples, which showed an increasing trend of the genetic diversity of the experimental population fed on transgenic Bt poplar. It was thus clear that transgenic hybrid poplar 741 had stress effects on genetic differentiation of C. anachoreta experimental population by SSR.
    Effects of cadmium on protein tyrosine phosphorylation of mouse spermatozoa and the protective role of EGTA
    WANG Li-rui, YANG Qiang-zhen, LI Yu-hua, LI Si-si, ZHANG Yu-kun, FU Jie-li, ZHEN Lin-qing, LI Xin-hong
    2016, 27(12):  4045-4051.  doi:10.13287/j.1001-9332.201612.001
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    In this study, we explored the effects of cadmium (Cd) on mouse sperm motility parame-ters, protein tyrosine phosphorylation and the location of tyrosine-phosphorylated targets using computer-assisted sperm analysis (CASA), western blot (WB) and immunofluorescence technique coupled to sperm in vitro culture method, respectively. The results showed sperm motility was inhibi-ted by Cd in a dose-dependent manner and when Cd increased to 1.0 μmol·L-1, sperm motility was inhibited significantly (P<0.05). Simultaneously, protein tyrosine phosphorylation was enhanced by Cd and in particular, the tyrosine phosphorylation of ~55 kDa proteins was greatly promoted when Cd concentrations were greater or equal to 1.0 μmol·L-1 (P<0.05). Importantly, these tyrosine-phosphorylated proteins were mainly localized in the middle piece of mouse sperm. However, when sperm was incubated with 30 μmol·L-1 ethylene glycol tetraacetic acid (EGTA) and 10 μmol·L-1 Cd concurrently, both the tyrosine phosphorylation of ~55 kDa proteins and sperm motility were not changed obviously (P>0.05). These results suggested that Cd may inhibit sperm motility by inducing the tyrosine phosphorylation of ~55 kDa proteins in the middle piece and EGTA could chelate Cd ions to relieve its toxicity. This study demonstrated that Cd induced the tyrosine phosphorylation of a specific subset of proteins and thus decreased sperm motility. Interes-tingly, EGTA acted as an inhibitor to block Cd from entering the sperm, which provided a novel research method for revealing the molecular mechanisms of reproductive toxicity caused by Cd.
    Spatial point patterns of Antarctic krill fishery in the northern Antarctic Peninsula
    YANG Xiao-ming, LI Yi-xin, ZHU Guo-ping
    2016, 27(12):  4052-4058.  doi:10.13287/j.1001-9332.201612.008
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    As a key species in the Antarctic ecosystem, the spatial distribution of Antarctic krill (thereafter krill) often tends to present aggregation characteristics, which therefore reflects the spatial patterns of krill fishing operation. Based on the fishing data collected from Chinese krill fishing vessels, of which vessel A was professional krill fishing vessel and Vessel B was a fishing vessel which shifted between Chilean jack mackerel (Trachurus murphyi) fishing ground and krill fishing ground. In order to explore the characteristics of spatial distribution pattern and their ecological effects of two obvious different fishing fleets under a high and low nominal catch per unit effort (CPUE), from the viewpoint of spatial point pattern, the present study analyzed the spatial distribution characteristics of krill fishery in the northern Antarctic Peninsula from three aspects: (1) the two vessels’ point pattern characteristics of higher CPUEs and lower CPUEs at different scales; (2) correlation of the bivariate point patterns between these points of higher CPUE and lower CPUE; and (3) correlation patterns of CPUE. Under the analysis derived from the Ripley’s L function and mark correlation function, the results showed that the point patterns of the higher/lo-wer catch available were similar, both showing an aggregation distribution in this study windows at all scale levels. The aggregation intensity of krill fishing was nearly maximum at 15 km spatial scale, and kept stably higher values at the scale of 15-50 km. The aggregation intensity of krill fishery point patterns could be described in order as higher CPUE of vessel A > lower CPUE of vessel B >higher CPUE of vessel B > higher CPUE of vessel B. The relationship of the higher and lo-wer CPUEs of vessel A showed positive correlation at the spatial scale of 0-75 km, and presented stochastic relationship after 75 km scale, whereas vessel B showed positive correlation at all spatial scales. The point events of higher and lower CPUEs were synchronized, showing significant correlations at most of spatial scales because of the dynamics nature and complex of krill aggregation patterns. The distribution of vessel A’s CPUEs was positively correlated at scales of 0-44 km, but negatively correlated at the scales of 44-80 km. The distribution of vessel B’s CPUEs was negatively correlated at the scales of 50-70 km, but no significant correlations were found at other scales. The CPUE mark point patterns showed a negative correlation, which indicated that intraspecific competition for space and prey was significant. There were significant differences in spatial point pattern distribution between vessel A with higher fishing capacity and vessel B with lower fishing capacity. The results showed that the professional krill fishing vessel is suitable to conduct the analysis of spatial point pattern and scientific fishery survey.
    Relationship between morphological traits and body mass of Miichthys miiuy
    LIU Feng, LOU Bao, CHEN Rui-yi, XU Qi-xiang, MA Tao, ZHAN Wei, WANG Li-gai, MAO Guo-min, XU Dong-dong
    2016, 27(12):  4059-4066.  doi:10.13287/j.1001-9332.201612.002
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    Miichthys miiuy Basilewsky is a commercially important marine fish in China. To understand the relationship between body mass and morphometric traits of M. miiuy, body mass (Y, g) and other eight morphometric traits (cm), e.g., total length (X1), body length (X2), head length (X3), trunk length (X4), tail length (X5), tail handle length (X6), tail handle height (X7), and body height (X8) of 524 individuals of about 12-month-old M. miiuy were measured in this study. The methods of correlation analysis, multiple regression analysis, and path ana-lysis were used to analyze the data. Also, the best model reflecting the relationship between morphometric traits and body mass were obtained through model fitting screening. The results showed that the correlation coefficients between every two traits ranged from 0.834 to 0.941, and all reached significance level (P<0.01). And body length was ruled out from the multiple regression analysis by the method of multicollinearity diagnosis. We established a regression equation using the rest morphologi-cal traits as variables and body mass as dependent variable, in which direct and indirect path coefficients and determinant coefficients were calculated. Four morphometric traits achieved highly significant levels (P<0.01), and they were the main decisive morphometric traits linked to body mass. The multiple linear regression model equation was established as Y=-444.188 +7.943X1+12.861X4 +38.254X7 + 42.722X8. Among them, the trait with the strongest direct effect on body mass was the body height (0.351), then the total length (0.335). In addition, the best model fitted for the individuals was y=0.013 x2.891 for total length, y=2.028 x2.751 for body height. The method of model fit test showed the accuracy of total length estimated body mass was higher than that of body height. This research may provide an important reference for the effective use of morphological traits for breeding of M. miiuy.
    Selenium (Se)uptake and transformation mechanisms and physiological function in plant: A review
    JIANG Ying, ZENG Zhao-hai, YANG Qi-sheng, ZHAO Jie, YANG Ya-dong, HU Yue-gao
    2016, 27(12):  4067-4076.  doi:10.13287/j.1001-9332.201612.037
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    Selenium (Se) is an essential nutrient for many organisms, including microbe, animal and human, but the Se uptake and transformation mechanisms and physiological roles in plant still are controversial until now. Se could improve the growth and tolerance of plant at an appropriate le-vel, but could be toxic at higher levels. Research concerning Se uptake and metabolism in plant were promoted by Se biofortification and Se phytoremediation induced by the issues of Se deficiency in food and Se pollution in special areas. Recently, the results of Se uptake and transformation in plant have indicated that there are significant differences of Se accumulation and physiological roles in various plants and significant influence of soil conditions on Se uptake of plant. In addition, the process of Se metabolism in Se hyperaccumulators and its regulation were revealed gradually with the studies on improvement of Se uptake in plant. According to the results of Se biofortification in crop and Se phytoremediation so far, we summarized the advances in the studies with the reference to Se distribution in environment, the detail process of Se uptake, key regulators of transformation and its physiological roles in plant. We hope this can provide a novel insight to further research upon Se in plant.