Loading...
Welcome to Chinese Journal of Applied Ecology! Today is Share:

Table of Content

    18 October 2015, Volume 26 Issue 10
    Seasonal release characteristics of Ca, Mg and  Mn of foliar litter of six tree species in subtropical evergreen broadleaved forest.
    MA Zhi-liang, GAO Shun, YANG Wan-qin, WU Fu-zhong
    2015, 26(10):  2913-2920. 
    Asbtract ( 913 )   PDF (782KB) ( 529 )  
    Seasonal release dynamics of Ca, Mg and Mn during decomposition of foliar litter of Pinus massoniana, Cryptomeria fortunei, Cunninghamia lanceolata, Cinnamomum camphora, Toona ciliate, and Quercus acutissima were investigated in subtropical evergreen broadleaved forest employing the method of litterbag. After oneyear decomposition, the release rates of Ca, Mg and Mn in foliar litter of the studied tree species ranged from -13.8% to 92.3%, from 4.0% to 64.8%, and from 41.6% to 81.1%, respectively. Ca dynamics in foliar litter of P. massoniana, C. camphora exhibited the pattern of accumulating early and releasing later, while that of the other four tree species showed direct release. Similarly, the dynamics of Mg released from foliar litter of C. camphora showed the pattern of accumulating early and then releasing, while that of the other five tree species exhibited continuous release. Meanwhile, the dynamics of Mn released from foliar litter of C. fortunei and T. ciliate exhibited early accumulation, and subsequent release, while that of the other four tree species showed continuous release. The releases of Ca, Mg and Mn in foliar litter were greatly influenced by seasonal rainfall, and varied with tree species. Furthermore, the rates and amounts of Ca, Mg and Mn released from foliar litter were higher in rainy season than in dry season. In conclusion, the initial nutrient concentrations and precipitation were two key factors influencing the release dynamics of Ca, Mg and Mn during decomposition of foliar litter in the subtropical evergreen broadleaved forest.
    Decomposition and nutrient release of root with different diameters of three subalpine dominant trees in western area of Sichuan Province, China.
    TANG Shi-shan1, YANG Wan-qin1, WANG Hai-peng2, XIONG Li1, NIE Fu-yu1, XU Zhen-feng1
    2015, 26(10):  2921-2927. 
    Asbtract ( 1320 )   PDF (604KB) ( 401 )  
    In this study, a buried bag experiment was used to investigate mass loss and C, N and P release patterns of fine (≤2 mm), medium (2-5 mm) and coarse (≥5 mm) roots of 3 subalpine dominant trees, i.e., Betula albosinensis, Abies faxoniana and Picea asperata in the growing and nongrowing seasons. In general, the remaining mass of B. albosinensis was lower than that of A. faxoniana and P. asperata. In addition, root remaining mass increased with the increase of root dia
    meter for the same species. The mass losing rate in the nongrowing season was 52.1%-64.4% of a year. The C release of B. albosinensis was the highest, but that of A. faxoniana was the lowest. Also, C release decreased with the increase of root diameter. N of A. faxoniana and P. asperata were enriched in the nongrowing season but released in the growing season. However, the opposite pattern was found for B. albosinensis. During the nongrowing season, the amount of N enrichment increased with the increase of root diameter. The P release of 3 species was characterized as the enrichmentrelease pattern. P enrichment of A. faxoniana was significantly greater than that of P. asperata and B. albosinensis. Nevertheless, no significant difference was observed between diameter sizes. In conclusion, diameter size had significant effect on root decomposition in the subalpine forests of western Sichuan, and the diameter effect was dependent on tree species and season.
    Spatial distribution pattern of main populations and gap makers in Picea koraiensis and Abies nephrolepis forest of Xiaoxing’an Mountains, Northeast China.
    JING Xin1, DUAN Wen-biao1, CHEN Li-xin1, WANG Ting1, DU Shan2, ZHANG Yu-shuang1, CHEN Qi-min1
    2015, 26(10):  2928-2936. 
    Asbtract ( 932 )   PDF (679KB) ( 597 )  
    Species composition and diameter class structure were investigated in 1.5 hm2 (100 m×150 m) permanent plot in Picea koraiensis and Abies nephrolepis forest of Xiaoxing’an Mountains. The spatial distribution pattern and spatial association of main populations and gap makers were analyzed by using point pattern analysis. The results showed that there were a total of 13 species with diameters at breast height greater than 2 cm in tree layer, and great differences were observed in the densities of main populations. The importance values of A. nephrolepis, P. koraiensis, Betula platyphylla and Acer ukurunduense were ranked in the first 4 in the plot. The diameter class structure of their populations presented an inverse ‘J’ curve. The spatial distribution patterns for A. nephrolepis and P. koraiensis were similar, which changed from aggregated, random to uniform distribution with the spatial scale. For B. platyphylla, the distribution was aggregated at ≤40 m scale, and random at >40 m scale, whereas A. ukurunduense presented an aggregated distribution pattern at the whole research scale. Except that the negative correlation between B. platyphylla and A. ukurunduense existed at the whole research scale, positive correlation between the other populations at small scale and negative correlation at large scale were observed. Only A. nephrolepis and B. platyphylla had significant positive correlation, and generally no significant correlation existed between other populations. Spatial distribution pattern of gap makers was characterized as aggregated distribution at small and middle scales, and random distribution with increasing scale. Spatial point pattern of gap makers formed by uprooting exhibited unimodal type distribution, and random, aggregated, and uniform distribution also occurred. Spatial point pattern of gap makers formed by breaking overall presented a little fluctuation, random and aggregated distributions alternatively appeared at small scale, and random distribution happened at large scale. Their spatial correlation analysis indicated that significant positive correlation existed at ≤32 m scale, and nonsignificant negative correlation at >32 m scale.
    Dynamic changes in soil respiration components and their regulating factors in the Moso bamboo plantation in subtropical China.
    YANG Wen-jia1,2, LI Yong-fu1,2, JIANG Pei-kun1,2, ZHOU Guo-mo1,2, LIU Juan1,2
    2015, 26(10):  2937-2945. 
    Asbtract ( 911 )   PDF (993KB) ( 520 )  
    Dynamic changes (from April 2013 to March 2014) in soil respiration components were investigated by Li8100 in the Moso bamboo plantation in Lin’an City, Zhejiang Province. Results showed that the average annual values for the soil total respiration rate, heterotrophic respiration rate, and autotrophic respiration rate in the Moso bamboo plantation were 2.93, 1.92 and 1.01 μmol CO2·m-2·s-1, respectively. The soil respiration rate and its components exhibited strongly a seasonal dynamic pattern. The maximum appeared in July 2013, and the minimum appeared in January 2014. The annual cumulative CO2 emissions through soil respiration, heterotrophic respiration, and autotrophic respiration were 37.25, 24.61 and 12.64 t CO2·hm-2·a-1, respectively. The soil respiration and its components showed a close relation with soil temperature of 5 cm depth, and the corresponding Q10 values at 5 cm depth were 2.05, 1.95 and 2.34, respectively. Both the soil respiration and heterotrophic respiration were correlated to soil water soluble organic C (WSOC) content, but no significant relationship between autotrophic respiration and WSOC was observed. There were no significant relationships between soil respiration components and soil moisture content or microbial biomass C. The seasonal changes in soil respiration components in the Moso bamboo plantation were predominantly controlled by the soil temperature, and the soil WSOC content was an important environmental factor controlling total soil respiration and soil heterotrophic respiration.
     
    Effects of conversion of natural broad-leaved forest to Chinese fir plantation on soil respiration in subtropical China.
    ZHANG Rui1,2, BAI Yang1,2, LIU Juan1,2, JIANG Pei-kun1,2, ZHOU Guo-mo1,2, WU Jia-sen1,2, TONG Zhi-peng3, LI Yong-fu1,2
    2015, 26(10):  2946-2952. 
    Asbtract ( 952 )   PDF (612KB) ( 449 )  
    Soil CO2 effluxes in natural broad-leaved forest and the conversed Chinese fir plantation in Linglong Mountains Scenic of Zhejiang Province were evaluated by using static closed chamber and gas chromatography method. The results showed that soil CO2 efflux showed consistent seasonal dynamics in natural broad-leaved forest and Chinese fir plantation, with the maximums observed in summer and autumn, the minimums in winter and spring. Soil CO2 effluxes were 20.0-111.3 and 4.1-118.6 mg C·m-2·h-1 in natural broadleaved forest and Chinese fir plantation, respectively. The cumulative soil CO2 emission of natural broadleaved forest (16.46 t CO2·hm-2·a-1) was significantly higher than that of Chinese fir plantation (11.99 t CO2·hm-2·a-1). Soil moisture did not affect soil CO2 efflux. There was a significant relationship between soil CO2 efflux and soil temperature at 5 cm depth. There was no significant relationship between soil CO2 efflux of natural broadleaved forest and water soluble organic carbon content, while water soluble organic carbon content affected significantly soil CO2 efflux in Chinese fir plantation. Converting the natural broadleaved forest to Chinese fir plantation reduced soil CO2 efflux significantly but improved the sensitivity of soil respiration to environmental factors.
    Spatial distribution pattern and allometric growth of three common species on moving sand dunes in Horqin Sandy Land, China.
    JIA Mei-yu1,2, LI Xue-hua1, Oh Choong-hyeon3, Park Hong-chul3, MIAO Chun-ping1,2, HAN Xu1,2
    2015, 26(10):  2953-2960. 
    Asbtract ( 1406 )   PDF (532KB) ( 425 )  
    Research on fine scale pattern and characteristics of allometric growth could contribute to better understanding plants’ adaptation in moving sandy dunes. The abundance, height and biomass of 3 species Agriophllum aquarrosum, Corispermum candelabrum and Setaria viridis in  twentyeight 1 m × 1 m quadrats of Horqin Sandy Land were identified, mapped and described. The nearest neighbor method and O-ring O(r) function analysis were applied to analyze the spatial patterns. The results showed that the individual spatial pattern was mainly aggregated in 1 m×1 m quadrat at community level but mainly random at population level. At 0-50 cm individual distance scale, both intraspecific and interspecific relationship were facilitation and aggregated distribution occurred at some scales and varied with increasing plant abundance in 1 m×1 m quadrat. In 0-40 cm, the aggregated distribution of S. viridis and A. aquarrosum increased obviously; in 10-20 cm, both intraspecific and interspecific aggregation increased; in 10-30 cm, the occurrence possibility of positive correlations between S. viridis and A. aquarrosum, S. viridis and C. candelabrum all increased; in 40-50 cm, the possibility of positive correlations between A. squarrosum and S. viridis, A. squarrosum and C. candelabrum all increased. Research on the three species components indicated that the growth rate of aboveground was faster than that of underground. S. viridis had the highest ratio of underground biomass to aboveground biomass but its nutritional organs’ biomass ratio was medium. C. candelabrum allocated more biomass to propagative organs and stem, but A. squarrosum allocated more biomass to nutritional organs. Based on the spatial distribution and allometric characteristics, the three common species in moving sand dunes preferred r strategy in their life history.
    Effects of intensive management on abundance and composition of soil N2fixing bacteria in Phyllostachys heterocycla stands.
    HE Dong-hua, CHEN Jun-hui, XU Qiu-fang, SHEN Qiu-lan, LI Yong-chun, MAO Xin-wei, CHENG Min
    2015, 26(10):  2961-2968. 
    Asbtract ( 785 )   PDF (1287KB) ( 351 )  
    Denaturing gradientgel electrophoresis and realtime quantitative PCR (qPCR) were employed to determine the effects of intensive management on soil N2fixing bacteria in a moso bamboo (Phyllostachys heterocycla) plantation. Soil samples were collected from the moso bamboo stands receiving 0 (CK), 10, 15, 20, and 25 years of intensive management. It was found that intensive management caused a strong decrease in soil pH but a general increase in soil available nutrients. The structure of the N2fixing bacterial communities in the soils having received 10 and 25 years of intensive management were quite similar to that from the CK; however, those from 15 and 20 years of intensification differed from the CK. With increasing time of intensive management, the abundance and diversity of the nifH gene at first decreased and then increased, with the minimum values being observed after 15 years of intensive management, indicating the eventual resiliency of N2fixing bacteria to disturbance induced by intensive management. Redundancy analysis indicated that soil available potassium, available nitrogen, nitrite nitrogen, and ammonium nitrogen were more closely related to the changes of N2fixing bacterial community structure compared with the other soil indices measured. In conclusion, the soil N2fixing bacterial community was negatively affected by intensive management in the short term, but could recover in the long term.
    Simulation of the branch biomass for Chinese fir plantation using the linear mixed effects model.
    XU Hao, SUN Yu-jun, WANG Xin-jie, FANG Jing, TU Hong-tao, LIU Su-zhen
    2015, 26(10):  2969-2977. 
    Asbtract ( 1057 )   PDF (647KB) ( 404 )  
    Based on data obtained from 572 branches of 45 Chinese fir trees in Jiangle Forest Farm, Fujian Province, southeast China, prediction models for branch, foliage biomass and total branch and foliage biomass of individual tree were developed by linear mixed effects (LME) method, and tested by independent samples. The results showed that the LME models provided better performance than the multiple linear regression models for the branch, foliage and total biomass prediction of Chinese fir plantation. The LME models with different combinations of the random effects parameters had different fitting precisions. The LME models including variance structures could effectively remove the heteroscedasticity in the data and improved the precision. The LME model with the exponential function as the variance structure had better fitting precisions for the total biomass and foliage biomass models, and that with the constant plus power function as the variance structure had better performance for the branch biomass model. Model validation confirmed that the LME models with the random effects and heteroscedasticity structure could significantly improve the precision of prediction, compared to the multiple linear regression models.
    Effect of air temperature and rainfall on wetland ecosystem CO2 exchange in China.
    CHU Xiao-jing1,2, HAN Guang-xuan1
    2015, 26(10):  2978-2990. 
    Asbtract ( 789 )   PDF (1302KB) ( 406 )  
    Wetland can be a potential efficient sink to reduce global warming due to its higher primary productivity and lower carbon decomposition rate. While there has been a series progress on the influence mechanism of ecosystem CO2 exchange over China’s wetlands, a systematic metaanalysis of data still needs to be improved. We compiled data of ecosystem CO2 exchange of 21 typical wetland vegetation types in China from 29 papers and carried out an integrated analysis of air temperature and precipitation effects on net ecosystem CO2 exchange (NEE), ecosystem respiration (Reco), gross primary productivity (GPP), the response of NEE to PAR, and the response of Reco to temperature. The results showed that there were significant responses (P<0.05) of NEE (R2=50%, R2=57%), GPP (R2=60%, R2=50%) Reco (R2=44%, R2=50%) with increasing air temperature and enhanced precipitation on the annual scale. On the growing season scale, air temperature accounted for 50% of the spatial variation of NEE, 36% of GPP and 19% of Reco, respectively. Both NEE (R2=33%) and GPP (R2=25%) were correlated positively with precipitation (P<0.05). However, the relationship between Reco and precipitation was not significant (P>0.05). Across different Chinese wetlands, both precipitation and temperature had no significant effect on apparent quantum yield (α) or ecosystem respiration in the daytime (Reco,day, P>0.05). The maximum photosynthesis rate (Amax) was remarkably correlated with precipitation (P<0.01), but not with air temperature. Besides, there was no significant correlation between basal respiration〖KG*3〗(Rref)and precipitation (P>0.05). Precipitation was negatively correlated with temperature sensitivity of Reco(Q10, P<0.05). Furthermore, temperature accounted for 35% and 46% of the variations in temperature sensitivity of Reco(Q10) and basal respiration (Rref, P<0.05), respectively.
    Simulation and validation of diffuse radiation in Qianyanzhou area, Jiangxi, China.
    HAN Jia-yin1,2, LI Sheng-gong1, ZHANG Lei-ming1, WEN Xue-fa1, LI Qing-kang1, WANG Hui-min1
    2015, 26(10):  2991-2999. 
    Asbtract ( 888 )   PDF (1834KB) ( 426 )  
    Accurate estimation of diffuse radiation is of great significance for evaluating its effect on terrestrial ecosystem carbon exchange. Based on the observed diffuse radiation data in the meteorological observation field in midsubtropical Qianyanzhou, Jiangxi, China from March 1, 2012 to February 28, 2013, the simulated results of five widely used diffuse radiation decomposition models (Reindl-1, Reindl-2, Reindl-3, Boland, BRL) were validated. The results indicated that, on the 30 min scale, all of the five models could well simulate the diffuse radiation of this area overall. But the effect of models decreased significantly with the rising of clearness index (kt). Especially when kt>0.75, each model was unable to simulate diffuse radiation in the region. Regarding the simulation of seasonal change of diffuse radiation, the five models could simulate diffuse radiation well in most months. Relative deviation between simulated and observed values of yearly diffuse radiation of five models had a maximum of 7.1% (BRL), a minimum of 0.04% (Reindl-1), and an average of 3.6%. The simulated values of the five models appeared to be overestimated in the summer when radiation was strongest, temperature was highest, and precipitation was relatively low. For example, in July, the diffuse radiation was overestimated by 14.5%-28.2%, 21.2% on average. This was primarily due to the method of estimating diffuse radiation under the condition of high kt. The uncertainty requires further evaluation in the model application. Considering the results of validation, simulation precision and the accessibility of input variables, the order of the simulation performance of five models was BRL>Reindl-3>Reindl-2>Reindl-1>Boland.
    Differences and sources of CO2 concentration, carbon and oxygen stable isotope composition between inside and outside of a green space system and influencing factors in an urban area.
    SUN Shou-jia1,2, MENG Ping1,2, ZHANG Jin-song1,2, SHU Jian-hua3, ZHENG Ning1,2
    2015, 26(10):  3000-3010. 
    Asbtract ( 918 )   PDF (1622KB) ( 370 )  
    The offaxis integrated cavity output spectroscopy technique was used to measure air CO2 concentration, stable carbon (δ13C) and oxygen (δ18O) isotope ratios on the Fourth Ring Road (FRR) and in the green space system of Beijing Institute of Landscape Architecture (BILA) in summer and winter seasons. The variations of CO2 concentration, δ13C value, δ18O value and the differences of them between the FRR and the BILA, which were correlated with traffic volume and meteorological factors, were analyzed at halfhour timescale. The results showed that traffic volume on the FRR was large both in summer and winter with obvious morning and evening rush hours, and more than 150 thousands vehicles were observed everyday during the observation periods. Diurnal variation of the CO2 concentration showed a twopeak curve both on the FRR and in the green space system of the BILA. In contrast, diurnal variation of δ13C value was a twotrough curve while diurnal variation of δ18O value was a singletrough curve. The differences of CO2 concentration, δ13C value and δ18O value between the FRR and the green space system of BILA in summer were greater than those in winter. The carbon isotope partitioning results showed that in summer vehicle exhaust contributed 64.9% to total atmospheric CO2 of the FRR during measurement time, while heterotrophic respiration contributed 56.3% to total atmospheric CO2 of the green space system in BILA. However, in winter atmospheric CO2 from both the FRR and green space system mostly came from vehicle exhaust. Stepwise regression analysis indicated that differences of CO2 concentration between the FRR and green space system were significantly related to vehicle volume and solar radiation at halfhour timescale, while solar radiation and relative humidity were the main meteorological factors causing δ13C and δ18O differences between the FRR and green space system. Plants in the green space system strongly assimilated CO2 from fossil fuel burning by photosynthesis to maintain carbon and oxygen balance of urban area in the growing season, which played an important role in improving urban ecological environment.
    Compensation effects of regulated deficit irrigation and tillering interference to winter wheat.
    YIN Min-hua, LI Yuan-nong, ZHOU Chang-ming, GU Xiao-bo, ZHANG Tian-le, YANG Dan, WU Guo-jun
    2015, 26(10):  3011-3019. 
    Asbtract ( 770 )   PDF (649KB) ( 390 )  
    Pot experiments were carried out to explore the approach of optimizing crop group performance through restriction of individual growth redundancy and increasing crop yield potential. Two winter wheat varieties of ‘Xiaoyan-22’ (with moderate tillering ability) and ‘Zhengmai-7698’ (with strong tillering ability) were chosen to investigate the effects of two irrigation schedules (full irrigation and regulated deficit irrigation) and three kinds of tillering interference (only retaining the main stem and the biggest tiller at jointing stage; removing all nonbearing tillers at heading stage; and without any interference as the control treatment). Thus, we simulated the compensation effects of different water supplies and unpredictable disturbances on the physiology, growth, yield, and water use efficiency of winter wheat. The results showed that there existed growth redundancy for both varieties. Compared with ‘Xiaoyan-22’, ‘Zhengmai7698’ had relatively higher tillering number but weak panicle traits. Regulated deficit irrigation and removing all nonbearing tillers at heading stage could reduce growth redundancy, weaken competitive ability, change sourcesink relations, and optimize resources allocation. However, excessive elimination of redundancy (e.g. only retaining the main stem and the biggest tiller at jointing stage) could destroy the inherent rootshoot balance and functional structure of plant and lead to inadequate compensation. In contrast to the control treatment (full irrigation and without any disturbance), the combination of regulated deficit irrigation and removing all nonbearing tillers at heading stage could help crops sufficiently exploit and utilize their own regulation potentials at spatial and temporal scales and finally realize compensation growth. The combination above could increase the water use efficiency by 20.4%-25.4% without remarkable impact on grain yield, and hence, could be suitable for wheat growth redundancy reduction.
    Root morphological characteristics of barley genotype with high phosphorus efficiency under phosphorus stress.
    CHEN Hai-ying, YU Hai-ying, CHEN Guang-deng, LI Ting-xuan
    2015, 26(10):  3020-3026. 
    Asbtract ( 1118 )   PDF (592KB) ( 580 )  
    A pot experiment was carried out to test the effects of phosphorus (P) supply levels (25, 50, and 75 mg P2O5·kg-1) with two P genotype (efficient DH110+ and DH147, inefficient DH49) barleys on root morphology and the relationships between root morphology and P uptake. The results showed that barley biomass and P uptake were significantly reduced by low P stress. Efficient genotype barley biomass and P uptake were 1.24-1.70 and 1.18-1.83 times as much as those of inefficient genotype barley respectively. The total root length, total root surface area, average root diameter, adventitious root length and root surface area, lateral root length and root surface area of P efficient genotype barley were significantly reduced with decreasing the P supply level in soil. The total root length, total root surface area, specific root length, lateral root length and surface area of P efficient genotype barley were 1.46-2.06, 1.12-1.51, 1.35-1.72, 1.69-2.42, and 1.40-1.78 times as much as that of those of P inefficient genotype barley, respectively, while the average root diameter was 70.6%-90.2% of P inefficient genotype barley. Principal component analysis showed that the average root diameter, specific root surface area and specific root length could be used to distinguish two P genotype barleys. Partial least squares regression analysis showed that the total root length, total root surface area made great contributions to P uptake of barley in soil. The contribution of the adventitious root length and surface area on P uptake of barley decreased significantly and the average root diameter, specific root length, lateral root length and root surface area increased with the decreasing P supply level in soil. P efficient genotype barley adapted to low P stress through maintaining the lateral root growth, increasing the specific root length and root fineness.
    An early warning method of cucumber downy mildew in solar greenhouse based on canopy temperature and humidity modeling.
    WANG Hui1,2, LI Mei-lan1, XU Jian-ping3, CHEN Mei-xiang2, LI Wen-yong2, LI Ming2
    2015, 26(10):  3027-3034. 
    Asbtract ( 944 )   PDF (857KB) ( 352 )  
    The greenhouse environmental parameters can be used to establish greenhouse mirco-climate model, which can combine with disease model for early warning, with aim of ecological controlling diseases to reduce pesticide usage, and protecting greenhouse ecological environment to ensure the agricultural product quality safety. Greenhouse canopy leaf temperature and air relative humidity models were established using energy balance and moisture balance principle inside the greenhouse. The leaf temperature model considered radiation heat transfer between the greenhouse crops, wall, soil and cover, plus the heat exchange caused by indoor net radiation and crop transpiration. Furthermore, the water dynamic balance in the greenhouse including leaf transpiration, soil evaporation, cover and leaf water vapor condensation, was considered to develop a relative humidity model. The primary infection and latent period warning models for cucumber downy mildew (Pseudoperonospora cubensis) were validated using the results of the leaf temperature and relative humidity model, and then the estimated disease occurrence date of cucumber downy mildew was compared with actual disease occurrence date of field observation. Finally, the results were verified by the measured temperature and humidity data of September and October, 2014. The results showed that the root mean square deviations (RMSDs) of the measured and estimated leaf temperature were 0.016 and 0.024 ℃, and the RMSDs of the measured and estimated air relative humidity were 0.15% and 0.13%, respectively. Combining the result of estimated temperature and humidity models, a cucumber disease early warning system was established to forecast the date of disease occurrence, which met with the real date. Thus, this work could provide the microenvironment data for the early warning system of cucumber diseases in solar greenhouses.

     
    Safe wintering and economic and ecological benefit of winter rapeseed in dry and cold areas of northern China.
    LIU Hai-qing, SUN Wan-cang, LIU Zi-gang, WANG Zhi-jiang, FANG Yuan, WU Jun-yan, LI Xue-cai, FANG Yan
    2015, 26(10):  3035-3044. 
    Asbtract ( 842 )   PDF (694KB) ( 479 )  
    The purpose of this study was to realize the security of safe wintering of winter rapeseed in dry and cold regions of northern China. Experiments were conducted with 18 winter rapeseed (Brassica campestris) varieties at 57 sites from 2008 to 2013 to statistically analyze the wintering rate variation of different varieties in dry and cold regions of northern China. The results showed that, the wintering rate varied from 70% to 90% during the study period in different regions, which had no significant difference between different years and varieties, and had high stability and remarkable economic benefit. With Tianshui as a starting point of winter rapeseed planting, the winteringsafe regions included all Gansu Province , the south of Lasa and Linzhi of Xizang, the east of Minhe of Qinghai, up to Urumqi and Baicheng, and the south of Aletai, Tacheng, the east of Kashi of Xinjiang, it also included the regions along Yellow River eastward to Ningxia, the south of Linhe of Inner Mongolia, the north of Shaanxi, the vicinage of Qixian in Shanxi, Daming in Hebei, Tianjin, Beijing, the north of Weifang of Shandong, the south of Huludao of Liaoning and Yanbian of Jilin. Longyou 6, Longyou 7, Longyou 8 and Longyou 9 were the winteringsafe B. rapa varieties.
    Evaluation of zinc deficiency tolerance in different kinds of apple rootstocks.
    FAN Xiao-dan1, LIU Fei1, WANG Yan-an1, FU Chun-xia1, YAN Yu-jing1, SHA Guang-li2, SHU Huai-rui3
    2015, 26(10):  3045-3052. 
    Asbtract ( 1179 )   PDF (622KB) ( 359 )  
    The objective of this study was to screen and evaluate the zinc deficiency tolerance among eight apple rootstocks, i.e., Malus baccata, M. rockii, M. xiaojinensis, M. sikkimensis, M. sieversii, M. robusta, M. hupehensis and Malus ‘Flame’. The experiment took these 8 kinds of rootstocks as the research materials to observe and analyze the index of the rootstock’〖KG-*4〗s height, dry biomass, root architecture and zinc concentration, and with help of the fuzzy membership function to work out a comprehensive evaluation on their zinc deficiency tolerance. The result showed that several obvious zinc deficiency symptoms were observed in three kinds of rootstocks (M. rockii, M. sikkimensis and M. sieversii), such as dwarfed plant and newborn small leaves, while such symptoms were not obvious in M. xiaojinensis and M. ‘Flame’. The plant biomass, height and zinc accumulation of aerial part greatly decreased under zinc deficiency stress, while smaller reduction was observed in M. xiaojinensis than in other rootstocks. M. xiaojinensis and M. baccata had higher zinc concentrations in leaves than others. According to the fuzzy membership function and cluster analysis, the resistance of the eight apple rootstocks to zinc deficiency was ranked: M. xiaojinensis was the highest one; M. ‘Flame’ was the second; M. baccata, M. sikkimensis, M. robusta and M. hupehensis were rather weaker; M. rockii and M. sieversii demonstrated the highest sensitivity to zinc deficiency.
    Effects of sodium naphthalene acetate on growth and physiological characteristics of tomato seedlings under suboptimal temperature and light condition.
    GUO Yun-na, LI Yan-su, HE Chao-xing, YU Xian-chang
    2015, 26(10):  3053-3058. 
    Asbtract ( 1110 )   PDF (511KB) ( 410 )  
    Taking tomato ‘Zhongza 105’ as test material, the influences of sodium naphthalene acetate (SNA) on growth and physiological characteristics of tomato seedlings under suboptimal temperature and light condition were investigated. The results showed that the dry mass, vigorous seedling index, root activity, total nitrogen content, net photosynthesis rate (Pn) of tomato seedlings were significantly decreased by suboptimum temperature and light treatment. In addition, the catalase activity and zeatin riboside (ZR) concentration were also reduced. However, the superoxide dismutase, peroxidase activity and the content of abscisic acid (ABA) were increased. Compared with treatment of the same volume distilled water on tomato seedlings under suboptimum temperature and light condition, the dry mass of whole plant and vigorous seedling index of tomato seedlings were significantly increased by 16.4% and 22.9%, as the total N contents in roots and leaves and Pn were also increased by 8.5%, 28.5%and 37.0%, respectively, with the treatment of root application of 10 mg·L-1SNA. Besides protective enzyme activity and the root activity were improved, the indole acetic acid (IAA) and ZR concentration of tomato were raised, and ABA concentration was reduced. The results indicated that root application of certain concentration of SNA could promote the growth of tomato seedlings by increasing the tomato root activity, protective enzymes activity, Pn and regulating endogenous hormone concentration under suboptimum temperature and light condition.
    Soil dryness characteristics of alfalfa cropland and optimal growth years of alfalfa on the Loess Plateau of central Gansu, China.
    LUO Zhu-zhu1,2, LI Ling-ling2, NIU Yi-ning2, CAI Li-qun1,2, ZHANG Ren-zhi2, XIE Jun-hong2
    2015, 26(10):  3059-3065. 
    Asbtract ( 1147 )   PDF (576KB) ( 380 )  
    This paper investigated soil moisture in alfalfa (Medicago sativa) cropland with different growth years (1, 3, 8, 12 and 14 years) and discussed the optimum growth years of alfalfa on the Loess Plateau of central Gansu. The results showed that the soil moisture along 0-300 cm soil profile of alfalfa croplands with different growth years was obviously lower than that of the local soil stable moisture. The soil water contents in croplands with alfalfa that had grown for 12 and 14 years were only 9.2% and 7.1% of local soil stable moisture, respectively, which were even lower than the lower limit of alfalfa growth. The average soil dryness indexes along 0-300 cm soil profile in 1, 3, 8, 12 and 14 years alfalfa croplands were 125.4%, 30.5%, 18.4%, -34.2% and -83.3% respectively. The results indicated that soil dryness occurred to varying degrees with different growth years except croplands with alfalfa grown for 1 year. With the increase of growth years of alfalfa, the soil dryness intensity increased and the soil dryness rate decreased. According to the soil moisture and alfalfa productivity results in this study, it could be concluded that the optimum growth years of alfalfa are 8-10 years in semiarid areas of the Loess Plateau.
    Effect of long-term fertilization on microbial community functional diversity in black soil.
    LIU Jing-xin1, CHI Feng-qin2,3, XU Xiu-hong1, KUANG En-jun2,3, ZHANG Jiu-ming2,3, SU Qing-rui2,3, ZHOU Bao-ku2,3
    2015, 26(10):  3066-3072. 
    Asbtract ( 1106 )   PDF (606KB) ( 510 )  
    In order to study the effects of longterm different fertilization on microbial community functional diversity in arable black soil, we examined microbial metabolic activities in two soil layers (0-20 cm, 20-40 cm) under four treatments (CK, NPK, M, MNPK) from a 35-year continuous fertilization field at the Ministry of Agriculture Key Field Observation Station of Harbin Black Soil Ecology Environment using Biolog-ECO method. The results showed that: in the 0-20 cm soil layer, combined application of organic and inorganic fertilizer(MNPK) increased the rate of soil microbial carbon source utilization and community metabolism richness, diversity and dominance; In the 20-40 cm layer, these indices of the MNPK treatment was lower than that of the NPK treatment; while NPK treatment decreased soil microbial community metabolism evenness in both layers.  Six groups of carbon sources used by soil microbes of all the treatments were different between the two soil layers, and the difference was significant among all treatments in each soil layer (P<0.05), while the variations among treatments were different in the two soil layers.  Canonical correspondence analysis (CCA) showed that soil microbial community metabolic function of all the treatments was different between the two soil layers, and there was difference among all treatments in each soil layer, while the influences of soil nutrients on soil microbial community metabolic function of all treatments were similar in each soil layer. It was concluded that longterm different fertilization affected soil microbial community functional diversity in both tillage soil layer and down soil layers, and chemical fertilization alone had a larger influence on the microbial community functional diversity in the 20-40 cm layer.
    Effects of different application rates of calcium cyanamide on soil microbial biomass and enzyme activity in cucumber continuous cropping.
    ZHANG Xue-peng, NING Tang-yuan, YANG Yan, SUN Tao, ZHANG Shu-min, WANG Bin
    2015, 26(10):  3073-3082. 
    Asbtract ( 1074 )   PDF (1252KB) ( 501 )  
    A 2year field experiment was conducted to study the effects of CaCN2 combined with cucumber straw retention on soil microbial biomass carbon (SMBC), soil microbial biomass nitrogen (SMBN) and soil enzyme activities under cucumber continuous cropping system. Four treatments were used in this study as follows: CK (null CaCN2), CaCN290 (1350 kg CaCN2·hm-2), CaCN260 (900 kg CaCN2·hm-2), CaCN230 (450 kg CaCN2·hm-2). The results indicated that, compared with the other treatments, CaCN290 treatment significantly decreased SMBC in 0-10 cm soil layer at seedling stage, but increased SMBC in 0-20 cm soil layer after earlyfruit stage. Compared with CK, CaCN2 increased SMBC in 0-20 cm soil layer at latefruit stage, and increased SMBN in 0-10 cm soil layer at mid and latefruit stages, however there was no significant trend among CaCN2 treatments in the first year (2012), while in the second year (2013) SMBN increased with the increasing CaCN2 amount after midfruit stage. CaCN2 increased straw decaying and nutrients releasing, and also increased soil organic matter. Furthermore, the CaCN290 could accelerate straw decomposition. Compared with CK, CaCN2 effectively increased soil urease, catalase and polyphenol oxidase activity. The soil urease activity increased while the polyphenol oxidase activity decreased with the increase of CaCN2, and CaCN260 could significantly improve catalase activity. Soil organic matter, urease activity and catalase activity had significant positive correlations with SMBC and SMBN. However, polyphenol oxidase activity was negatively correlated to SMBC and SMBN. Our findings indicated that CaCN2 application at 900 kg·hm-2 combined with cucumber straw retention could effectively improve soil environment, alleviating the soil obstacles under the cucumber continuous cropping system.
    Microbial anaerobic dechlorination of polychlorinated biphenyls in paddy soil slurry.
    YANG Kai, YAO Xiao-yan, CHEN Chen, SHEN Chao-feng, QIN Zhi-hui, HUANG Rong-lang
    2015, 26(10):  3083-3090. 
    Asbtract ( 914 )   PDF (1023KB) ( 376 )  
    We studied the dechlorination process of Aroclor1260, a highchlorinated polychlorinated biphenyls (PCBs) mixture in an anaerobic paddy soil slurry, and further analyzed the related microbial community structures. The Aroclor1260 was reduced up to 55.5% in the natural paddy soil slurry in 128 days, and the reduction percentage dropped to 46.9% after incoculating the paddy soil slurry with a PCBsdechlorination enrichment culture. The dechlorination mainly occurred in congeners of pentachlorobiphenyl, hexachlorobiphenyl, and specially, the heptachlorobiphenyl, with pentachlorobiphenyl accumulated as dechlorination intermediate. Hydrogen gas produced from fermentation of organic matters was maintained at a lower partial pressure due to its consumption during the dechlorination process, so that the methanogens was suppressed as well. The microbial community structure was significantly different between natural and inoculated paddy soils. Introducing the PCBsdechlorination enrichment culture changed the local microbial community by the competition between the exogenetic dchlorinators and the indigenous bacteria, overall decreasing the dechlorination activity.
    Comparison of potential yield and resource utilization efficiency of main food crops in three provinces of Northeast China under climate change.
    WANG Xiao-yu1, YANG Xiao-guang1, SUN Shuang1, XIE Wen-juan1,2
    2015, 26(10):  3091-3102. 
    Asbtract ( 857 )   PDF (2652KB) ( 587 )  
    Based on the daily data of 65 meteorological stations from 1961 to 2010 and the crop phenology data in the potential cultivation zones of thermophilic and chimonophilous crops in Northeast China, the crop potential yields were calculated through stepbystep correction method. The spatiotemporal distribution of the crop potential yields at different levels was analyzed. And then we quantified the limitations of temperature and precipitation on the crop potential yields and compared the differences in the climatic resource utilization efficiency. The results showed that the thermal potential yields of six crops (including maize, rice, spring wheat, sorghum, millet and soybean) during the period 1961-2010 deceased from west to east. The climatic potential yields of the five crops (spring wheat not included) were higher in the south than in the north. The potential yield loss rate due to temperature limitations of the six crops presented a spatial distribution pattern and was higher in the east than in the west. Among the six main crops, the yield potential loss rate due to temperature limitation of the soybean was the highest (51%), and those of the other crops fluctuated within the range of 33%-41%. The potential yield loss rate due to water limitation had an obvious regional difference, and was high in Songnen Plain and Changbai Mountains. The potential yield loss rate of spring wheat was the highest (50%), and those of the other four rainfed crops fluctuated within the range of 8%-10%. The solar energy utilization efficiency of the six main crops ranged from 0.9% to 2.7%, in the order of maize> sorghum>rice>millet>spring wheat>soybean. The precipitation utilization efficiency of the maize, sorghum, spring wheat, millet and soybean under rainfed conditions ranged from 8 to 35 kg·hm-2·mm-1, in the order of maize>sorghum>spring wheat>millet>soybean. In those areas with lower efficiency of solar energy utilization and precipitation utilization, such as Changbai Mountains and the south of Lesser Khingan Mountains, measures could be taken to increase the efficiency of resource utilization such as rational closeplanting, selection of droughtresistant varieties, proper and timely fertilization, farming for soil water storage, optimization of crop layout and so on.
    Temporal and spatial distribution of rice drought in Southwest China.
    ZHANG Jian-ping1, LIU Zong-yuan1,2, HE Yong-kun1, LUO Hong-xia2, WANG Jing3
    2015, 26(10):  3103-3110. 
    Asbtract ( 820 )   PDF (2924KB) ( 407 )  
    Considering the characteristics of rice production and climate conditions in Southwest China, an agricultural drought monitoring model based on wetness index anomaly rate
     (Mp) by calculating the variation of deviation from average values of relative humid index was established, and was used to analyze the spatialtemporal distribution characteristics of the rice drought during the growth season in Southwest China in the past 50 years (1961-2010). The applicability of the Mp model in Southwest China was verified by using this model to monitor the rice drought. The result showed there was a decreasing trend in the frequency of rice drought in term of the decadal variability. The areas with high drought risk mainly concentrated in northwestern and mideastern Yunnan Province, eastern Sichuan Basin, northeastern Chongqing City, and southeastern Guizhou Province. The drought frequency was highest at the stage from transplanting to tasseling, followed by the stage from grain filling to maturity, and was lowest at the stage from tasseling to grain filling. Mp was suitable for monitoring the rice drought in Southwest China, and could be used as a reference for the rice planting areas without irrigation data.
    Improvement of root parameters in land surface model (LSM) and its effect on the simulated results.
    CAI Kui-ye1, LIU Jing-miao2,3, ZHANG Zheng-qiu3, LIANG Hong4, HE Xiao-dong1
    2015, 26(10):  3111-3118. 
    Asbtract ( 759 )   PDF (777KB) ( 368 )  
    In order to improve root parameterization in land surface model, the submodel for root in CERES-Maize was coupled in the SSiB2 after calibrating of maize parameters in SSiB2. The effects of two improved root parameterization schemes on simulated results of land surface flux were analyzed. Results indicated that simulation accuracy of land surface flux was enhanced when the root module provided root depth only with the SSiB2 model (scheme Ⅰ). Correlation coefficients between observed and simulated values of latent flux and sensible flux increased during the whole growing season, and RMSE of linear fitting decreased. Simulation accuracy of CO2 flux was also enhanced from 121 days after sowing to mature period. On the other hand, simulation accuracy of the flux was enhanced when the root module provided root depth and root length density simultaneously for the SSiB2 model (scheme Ⅱ). Compared with the scheme Ⅰ, the scheme Ⅱ was more comprehensive, while its simulation accuracy of land surface flux decreased. The improved root parameterization in the SSiB2 model was better than the original one, which made simulated accuracy of landatmospheric flux improved. The scheme Ⅱ overestimated root relative growth in the surface layer soil, so its simulated accuracy was lower than that of the scheme Ⅰ.
     
    Freezing resistance and injury indices for different cultivars of winterspring wheat in HuangHuaiHai Plain. Ⅰ. Comparison of  freezing resistance for different cultivars of winterspring wheat during midwinter period.
    MU Chen-ying1,2, YANG Xiao-guang1, YANG Jie1, LI Ke-nan1, ZHENG Dong-xiao1
    2015, 26(10):  3119-3125. 
    Asbtract ( 915 )   PDF (597KB) ( 395 )  
    The relationships between mortality rate and low temperature for different cultivars of winterspring wheat during midwinter period were identified through twoyear outdoor potting experiments and indoor manually controlled freezing experiments. We defined the lethally critical temperature and the density of antifreeze capability when the mortality rate reached 10%, 20% and 50% for different cultivars of winterspring wheat during midwinter period.  The strongwinterness wheat (Yanda 1817 and Jing 411) showed the best freezing resistance and the 50%lethal temperatures (LT50) of these two cultivars were -21.5 ℃ and -21.2 ℃, respectively. The freezing resistance of winterness wheat and weakwinternes wheat were worse than that of strongwinterness wheat. The LT50 of winterness wheat cultivars Nongda 211 and Nongda 5363 were -21.1 ℃ and -20.3 ℃, while that of weakwinterness wheat cultivars Zheng 366 and Ping’an 8 were -18.5 ℃ and -18.4 ℃, respectively. Springness wheat (Zheng 9023 and Yanzhan 4110) showed the worst freezing resistance, and the LT50 were -15.4 ℃ and -14.7 ℃, respectively. When temperature declined to freezing injury occurred, mortality rate increment for weakwinterness wheat was the highest for each 1 ℃ decrease. The mortality rates of weakwinterness wheat cultivars Zheng 366 and Ping’an 8 increased by 16.8% and 25.8%, and that of winterness wheat cultivars Nongda 211 and Nongda 5363 increased by 14.7% and 18.9%. The mortality rate of strongwinterness wheat cultivars Yanda 1817 and Jing 411 increased by 15.4% and 13.1%, and that of springness wheat cultivars Zheng 9023 and Yanzhan 4110 increased by 13.8% and 15.1%. Comparatively, if temperature decreased continuously after the occurrence of freezing injury, the weakwinterness wheat would suffer greater risk.
    Assessment of landscape ecological security and optimization of landscape pattern based on spatial principal component analysis and resistance model in arid inland area: A case study of Ganzhou District, Zhangye City, Northwest China.
    PAN Jing-hu, LIU Xiao
    2015, 26(10):  3126-3136. 
    Asbtract ( 1282 )   PDF (1842KB) ( 567 )  
    Starting from ecological environment of inland river in arid area, the distribution of ecological security pattern of Ganzhou District was obtained by using the theory of landscape ecology, spatial principal component analysis (SPCA) and GIS techniques. Ten factors such as altitude, slope, soil erosion, vegetation coverage, and distance from road, were selected as the constraint conditions. According to the minimum cumulative resistance (MCR) model of landscape, the ecological corridor and nodes were established to optimize the structure and function of ecological function network. The results showed that the comprehensive ecological security situation of the research area was on the average. Area of moderate level of security was 1318.7 km2, being the largest and accounting for 36.7% of the research area. The area of low level of security was mainly located in the northern part and accounted for 19.9% of the study area. With points, lines and surfaces being interlaced, a regional ecological network was constructed, which was consisted of six ecological corridor, 14 ecological nodes, a large ecological source region and a plurality of small area source region, and could effectively improve ecological security level of the study area.
    Ecosystem services valuation of Qinghai Lake.
    JIANG Bo1,2, ZHANG Lu1, OUYANG Zhi-yun1
    2015, 26(10):  3137-3144. 
    Asbtract ( 893 )   PDF (1126KB) ( 628 )  
    Qinghai Lake is the largest inland and salt water lake in China, and provides important ecosystem services to beneficiaries. Economic valuation of wetland ecosystem services from Qinghai Lake can reveal the direct contribution of lake ecosystems to beneficiaries using economic data, which can advance the incorporation of wetland protection of Qinghai Lake into economic tradeoffs and decision analyses. In this paper, we established a final ecosystem services valuation system based on the underlying ecological mechanisms and regional socioeconomic conditions. We then evaluated the ecoeconomic value provided by the wetlands at Qinghai Lake to beneficiaries in 2012 using the market value method, replacement cost method, zonal travel cost method, and contingent valuation method. According to the valuation result, the total economic values of the final ecosystem services provided by the wetlands at Qinghai Lake were estimated to be 6749.08×108 yuan RMB in 2012, among which the value of water storage service and climate regulation service were 4797.57×108 and 1929.34×108 yuan RMB, accounting for 71.1% and 28.6% of the total value, respectively. The economic value of the 8 final ecosystem services was ranked from greatest to lowest as: water storage service > climate regulation service > recreation and tourism service > nonuse value > oxygen release service > raw material production service > carbon sequestration service > food production service. The evaluation result of this paper reflects the substantial value that the wetlands of Qinghai Lake provide to beneficiaries using monetary values, which has the potential to help increase wetland protection awareness among the public and decisionmakers, and inform managers about ways to create ecological compensation incentives. The final ecosystem service evaluation system presented in this paper will offer guidance on separating intermediate services and final services, and establishing monitoring programs for dynamic ecosystem services valuation with the aim of helping improve management outcomes.
    Relationships between characteristics of ground bryophyte communities and environmental factors in urban area of Chongqing, China.
    LIU Yan, PI Chun-yan, TIAN Shang
    2015, 26(10):  3145-3152. 
    Asbtract ( 1035 )   PDF (636KB) ( 440 )  
    The present study focused on bryophyte species composition, species diversity and the relationship between bryophyte communities and environmental factors in urban area of Chongqing City, by using biodiversity indices and the canonical correspondence analysis (CCA), based on the data of 44 plots. The results revealed that 86 species belonging to 43 genera and 25 families were found in saxicolous bryophyte communities, while 46 species belonging to 28 genera and 22 families were found in terricolous ones. The diversity indices of both saxicolous and terricolous bryophyte communities from campuses were higher than those of parks, natural scenic resorts, Jinyunshan National Nature Reserve. TWINSPAN classified saxicolous and terricolous bryophyte communities into three and two groups, respectively. CCA results showed canopy density was the major environmental factor of saxicolous bryophyte communities influencing bryophyte distribution in parks and campuses, whereas altitude, relative humidity and human disturbance were the major environmental factors in natural scenic resorts and nature reserve. Soil pH, canopy density and human disturbance were the major environmental factors in terricolous bryophyte communities in parks and campuses, whereas altitude, relative humidity and water content of the soil were the major environmental factors in those of natural scenic resorts and nature reserve.
    Improvement on the growth and nutrient absorption of Iris hexagona by exogenous salicylic acid under Cd stress.
    HAN Ying1, DEN Peng2, CHEN Gang2
    2015, 26(10):  3153-3159. 
    Asbtract ( 803 )   PDF (560KB) ( 359 )  
    The effects of exogenous salicylic acid (SA) pretreatment on the biomass, water content, photosynthesis, root vigor, Cd accumulation, nutrient absorption and antioxidant enzyme activity of Iris hexagona under Cd stress were studied by using Hoagland solution culture. The results showed that SA pretreatment promoted dry mass, root vigor and net photosynthetic rate of Cdstressed I. hexagona seedlings. Compared with only Cd treatment, the Cd accumulation of Cdtreated plants with SA pretreatment remained unaffected, however, SA pretreatment increased contents of N, P, S, and decreased K content. Activities of antioxidant enzymes of Cdtreated seedling root were increased under SA pretreatment. In conclusion, the improvement on growth of I. hexagona by SA pretreatment under Cd stress was attributed to improving Cd tolerance rather than reducing Cd uptake. The regulation of mineral element accumulation and the increase of antioxidant enzyme activities could be explained for Cd resistance improvement induced by salicylic acid.
    Population difference of polypores in northwest and southeast of China.
    WANG Xiao-yan, WEI Yu-lian
    2015, 26(10):  3160-3166. 
    Asbtract ( 838 )   PDF (1639KB) ( 446 )  
    Polypores are an important group of woodrotting fungi and play a key role in decomposing wood in the forest ecosystem. Based on field investigations and laboratory analysis, fungal flora and diversity composition of polypores in Tianshan Moutains, Qilian Mountains, Baotianman Nature Reserve and Wuyi Mountains were analyzed. In total, 72 polypore species were found in Tianshan Mountains, 99 in Qilian Mountains, 124 in Baotianman Nature Reserve and 156 in Wuyi Mountains. There were fourteen common species in the four zones. The biogeography could be divided into 4 groups at genera level of the four zones, the important elements were North temperate element and cosmopolitan element, and floristic analysis showed a distinct north temperate character. The proportion of white rot polypores in the four zones increased from northwest to southeast of China, while the proportion of brown rot polypores decreased. Polypores preferentially grew on angiosperm trees compared to gymnosperm trees. Among the four zones, polypores in Baotianman had the highest proportion of species living on angiosperm trees. Rare and threatened species in Tianshan Mountains and Qilian Mountains were mainly found on conifer trees, while in the other two zones, most rare and threatened species were found on broadleaf trees. Generally, the distinctions of these four areas were mainly affected by the forest type.
    Inhibition of Bacillus pumilus AR03 on Alternaria alternata and Erysiphe cichoracearum on tobacco.
    WANG Jing1, TIAN Hua1,2, KONG Fan-yu1, WANG Yi-hong1,2, ZHANG Cheng-sheng1, FENG Chao1
    2015, 26(10):  3167-3173. 
    Asbtract ( 797 )   PDF (1721KB) ( 445 )  
    This study aimed to evaluate the efficiency of Bacillus pumilus AR03 against Altenaria alternata and Erysiphe cichoracearum. The antagonistic activities were studied in the way of coculture on plate, inhibition of pathogen conidia germination on concave slides and LB agar medium. In the investigation, the water suspension of living cells of strain AR03, at 3×108 cfu·mL-1 had a remarkable inhibition effect on hyphae growth and conidia germination of A. alternata and caused hyphae deformation, shorter and swollen nodes, winding hyphae accumulation, abnormal tubes with tips expanded or deformed. Conidia did not germinate and the tissues of compartment became swollen or formed a round spherical bubble. In addition, the inhibition rate of conidia germination of E. cichoracearum was 91.3% and 69.3%, respectively when treated with strain AR03 at 1×107cfu·mL-1 and 1.5×106 cfu·mL-1. Conidia treated by living cells of AR03 became swollen, deformed, the protoplasm of conidia shrinked, disintegrated gradually and separated from the conidia wall. And some conidia were hollow because the protoplasm leaked out from inside. Greenhouse results revealed that the effects of living cells of AR03 with different concentrations were significantly different. Bacterial suspension of AR03 at 3×108 cfu·mL-1 was strongly antagonistic to E. cichoracearum with the control efficiencies 7 days and 15 days after treatment of two spays being 83.8% and 90.3%, respectively, while the control efficiencies of AR03 at 3×106 cfu·mL-1 were 70.0% and 73.3%, respectively. Strain AR03 had a long persistence against powdery mildew more than 30 days.
    Evaluation of ivermectin’s reproductive toxicity to male Carassius auratus.
    WANG Di, LI Shao-wu, GENG Long-wu, LU Tong-yan
    2015, 26(10):  3174-3180. 
    Asbtract ( 831 )   PDF (4049KB) ( 343 )  
    As a new type of antiparasitic drugs, ivermectin (IVM) has been widely applied in agriculture, stock raising and aquaculture in China because of its broad spectrum and high efficiency. In order to evaluate the IVM’s reproductive toxicity to male Crucian carp (Carassius auratus), IVM was orally given to the experimental fish with different dosages and the gonadosomatic index (GSI), sexual hormone contents (including testosterone and estradiol) in serum and testis, γaminobutyric acid content in serum and brain tissues, ultrastructure of spermatozoa and gonadal tissue in fish were determined in this study. The experimental fish were classified into A, B, C and D groups corresponding to the different dosages of IVM (0, 0.3, 0.9 and 1.5 mg·kg-1, respectively once a day for 3 days continuously). Several indices in fish were detected after 8 days selfpurification. The results indicated that GSI gradually decreased with the increase of drug dosage, and GSI in groups C and D was significantly lower than that in group A. The contents of testosterone, estradiol and γ-aminobutyric acid exhibited a trend of first increasing and then decreasing and reached the peak at group B. Sperm longevity gradually decreased and the motion time also decreased in Ⅱ, Ⅲ and Ⅳ level sperms with the increasing dosage of IVM, which appeared to be especially obvious in group C and D. No obvious differences were found in the ultrastructure of spermatozoa and gonadal tissues. In conclusion, this study suggested that IVM had no obvious reproductive toxicity to male Crucian carp at the normal therapeutic dosage but could cause serious potential reproductive toxicity to fish at a high concentration.
    Vermicomposting of different organic materials and three-dimensional excitation emission matrix fluorescence spectroscopic characterization of their dissolved organic matter.
    YANG Wei1,2, WANG Dong-sheng3, LIU Man-qiang1,2,4, HU Feng1,2, LI Hui-xin1,2, HUANG Zhong-yang3, CHANG Yi-jun3, JIAO Jia-guo1,2,4
    2015, 26(10):  3181-3188. 
    Asbtract ( 953 )   PDF (3046KB) ( 369 )  
    In this experiment, different proportions of the cattle manure, tealeaf, herb and mushroom residues, were used as food for earthworm (Eisenia fetida) to study the growth of the earthworm. Then the characteristics and transformation of nutrient content and  threedimensional excitation emission matrix fluorescence (3DEEM) of 〖JP〗dissolved organic matter (DOM) during vermistabilization were investigated by means of chemical and spectroscopic methods. The result showed that the mixture of different ratios of cattle manure with herb residue, and cattle manure with tealeaf were conducive to the growth of earthworm, while the materials compounded with mushroom residue inhibited the growth of earthworm. With the increasing time of verimcomposting, the pH in vermicompost tended to be circumneutral and weakly acidic, and there were increases in electrical conductivity, and the contents of total nitrogen, total phosphorus, available nitrogen, and available phosphorus, while the total potassium and available potassium increased first and then decreased, and the organic matter content decreased. 3DEEM and fluorescence regional integration  results indicated that, the fluorescence of proteinlike fluorescence peaks declined significantly, while the intensity of humiclike fluorescence peak increased significantly in DOM. Vermicomposting process might change the compositions of DOM with elevated concentrations of humic acid and fulvic acid in the organics. In all, this study suggested the suitability of 3DEEM for monitoring the organics transformation and assessing the maturity in the vermicomposting.
    Exogenous Sr2+ sedimentation on otolith of chum salmon embryos.
    WANG Chen1,2, LIU Wei1, ZHAN Pei-rong1, WANG Ji-long1, LI Pei-lun1,2
    2015, 26(10):  3189-3194. 
    Asbtract ( 741 )   PDF (4414KB) ( 329 )  
    To explore the exogenous Sr2+ sedimentation on otolith of chum salmon embryos, chum salmon embryos were exposed to culture water contained Sr2+ at Sr2+concentration of 50, 100, 200 or 400 mg·L-1 for 48 h to imitate Sr2+ sedimentation. After a culturing period of 12 d and 100 d, the otoliths of the chum salmon were taken to detect exogenous Sr2+ sedimentation with electroprobe microanalyzer (EPMA). The results showed that obvious deep red strontium signatures were produced in the otolith of chum salmon at different concentrations of Sr2 +. The mean and extreme values of peak strontium area were not stable for the same Sr2+ dose, but the lowest of all the peak values was 35.1 times as much as that of control. Overall, the strontium value increased with the increase of Sr2+ concentration. The strontium peak had no signs of abating after a culture period of 100 d. The results also showed that strontium was gradually deposited in the otolith, and had obvious hysteresis to immersion. Strontium sedimentation could also return to a normal level after the peak. These characteristics accorded exactly with the requirement of discharge tag technology, which indicated that exogenous Sr2+ was suitable in the marking of salmon otolith.
    Niche and interspecific association of nekton in the south coastal waters of Cangnan, Zhejiang, China.
    HU Cheng-ye1, SHUI Yu-yue2, DU Xiao3, SHUI Bo-nian1
    2015, 26(10):  3195-3201. 
    Asbtract ( 819 )   PDF (853KB) ( 459 )  
    In this paper, the interaction between the species population were analyzed based on the data of major nekton species in the south coastal waters of Cangnan in spring and autumn 2014. A series of methods including niche breadth, niche overlap, χ2 test and association coefficient (AC) based on a 2×2 contingency table were used. The results showed that the major nekton species in the south coastal waters of Cangnan were classified into three groups, i.e. wide niche breadth species, moderate niche breadth species and narrow niche breadth species based on the niche breadth values. The wide niche breadth species of nekton were Harpodon nehereus, Portunus trituberculatus, mantis shrimp and other 2 species. The moderate niche breadth species of nekton were Collichthys lucidus, Parapenaeopsis hardwickii, Parapenaeopsis tenella and other 5 species. While the species with narrow niche breadths were Charybdis japonica, Amblychaeturichthys hexanema, Palaemon gravieri and other 7 species. There were great differences in the niche overlap values among the major nekton populations, with the maximum value of 0.93 and the minimum of 0, which indicated that resource utilization competition in some nekton might exist. The results of variance ratio analysis for major nekton in the south coastal waters of Cangnan showed that they were significantly positively correlated. χ2 test results showed that there were significantly interspecific association for 78 species pairs (χ2≥3.841), among which more association coefficients (AC) of species pairs are positive.
    Effects of high temperature on Bt protein content and nitrogen metabolic physiology in boll wall of Bt cotton.
    WANG Jun1, Eltayib H.M.A. Abidallah1,2, HUA Ming-ming1, HENG Li1, LYU Chun-hua1, CHEN De-hua1
    2015, 26(10):  3202-3206. 
    Asbtract ( 779 )   PDF (582KB) ( 345 )  
    Bt cotton cultivar Sikang 1 (a conventional cultivar) and Sikang 3 (a hybrid cultivar) from China, and 99B (a conventional cultivar) and Daiza 1 (a hybrid cultivar) from USA were selected as experimental materials, the ball wall Bt protein content and nitrogen metabolic physiology were investigated under different high temperature levels at peak boll stage. The results showed that the Bt protein content of boll wall decreased with the increasing temperature. Compared with the control (32 ℃), the boll wall Bt protein content decreased significantly when the temperature was above 38 ℃ for the conventional cultivars and above 40 ℃ for the hybrid cultivars. The Bt protein contents of cultivar Sikang 1 and 99B decreased by 53.0% and 69.5% respectively with the temperature at 38 ℃, and that of cultivar Sikang 3 and Daiza 1 decreased by 64.8% and 54.1% respectively with the temperature at 40 ℃. Greater reductions in the boll wall soluble protein contents and GPT activities, larger increments for the boll wall free amino acid contents and proteinsase activities were also observed when the boll wall Bt protein content was significantly reduced. Therefore, high temperature resulted in the reduction of Bt protein synthesis and increase of the insecticidal protein degradation in the boll wall significantly, which caused the reductions in boll wall Bt protein content and insect resistance.
    Research progress on water footprint in agricultural products.
    LU Yang1,2, LIU Xiu-wei1,2, ZHANG Xi-ying1
    2015, 26(10):  3207-3214. 
    Asbtract ( 1032 )   PDF (460KB) ( 534 )  
    Water is one of the important resources in human activities. Scientifically and rationally evaluating the effects of human activities on water resources is important for sustainable water resource management. The innovative concepts of water footprint (WF) distinguished the human water consumption into green water, blue water and grey water which extended the evaluation methods in sustainable utilization of water resources. Concepts of WF based on virtual water (VW) and based on life cycle assessment (LCA) both combined water quality and water quantity are now the focuses in agricultural water management researches. Theory of WF based on VW includes the calculation of green, blue and grey WF as well as the evaluation of the sustainability of water environment. Theory of WF based on LCA reflects the overall impact of consumptive and degradative water use on the environment. The purpose of this article was to elaborate the research progresses in theoretical calculation methods and environmental sustainability assessment of the two water footprint theories and then to analyze the differentiation of these two methodologies in describing the consumptive water use in agriculture and its effects on environment. Finally, some future research aspects on water footprint were provided.
    Novel transmission element of antibiotic resistance genes ISCR and its ecological risk.
    CHEN Linlin, LI Bao-quan
    2015, 26(10):  3215-3225. 
    Asbtract ( 987 )   PDF (2312KB) ( 453 )  
    Antibiotic resistance genes (ARGs) as emerging environmental pollutants have become the focus of attention of many disciplines. The transmission and dissemination of ARGs in various environmental media has great hazards to environment and poses serious threat to human health. ISCR (insertion sequence common regions) elements are newly discovered resistance genes transmission elements. Because of the special genetic structure, ISCR elements can move any adjacent DNA sequences by rollingcircle replication and homologous recombination, and have become the efficient transmission elements of ARGs among different DNA molecules or bacterial species. Around the world, 27 members of the ISCR family have been discovered up to now. A lot of circumstantial evidence has indicated that ISCR elements may be associated with the mobility and transmission of kinds of ARGs, especially multiple drug resistance genes (MDR). In this review, we described some aspects of ISCR elements, including the horizontal transfer of ARGs, structural characteristics of ISCRs, classification of ISCRs and their related ARGs, research methods of these elements, possible ecological risk of ISCRs and proposal of research directions, hoping to provide help for further related research in the future.
    Mechanisms of Cr(Ⅵ) toxicity to fish in aquatic environment: A review.
    CHEN Hong-xing, WU Xing, BI Ran, LI Li-xia, GAO Mi, LI Dan, XIE Ling-tian
    2015, 26(10):  3226-3234. 
    Asbtract ( 764 )   PDF (568KB) ( 688 )  
    With increasing consumption and applications of chromium in metallurgy, electroplating, tanning process and stainless steel industry, chromium contamination has become a global environmental problem. In general, Cr(Ⅵ) has higher permeability across the cell membrane than Cr(Ⅲ) and hence is considered more toxic than Cr(Ⅲ). Oxidative stress could be induced following reactive oxygen species (ROS) normally produced in fish under Cr(Ⅵ) exposure due to its variable valences. Furthermore, the intermediates of Cr, e.g. Cr(Ⅴ) and Cr(Ⅳ), produced by cellular reduction processes can bind with DNA and result in mutagenic effects. These combined effects will threaten the growth, development and population structure of different fish species. In this paper, we reviewed published results on the toxic effects of Cr(Ⅵ) in fish at levels of molecules, tissues, organs and individuals. The mechanisms of toxicity and detoxification of Cr(Ⅵ) in various aspects were discussed. In addition, we also put forward perspectives on the toxicity of chromium in aquatic organisms.
     
    Biosynthesis and endocrine regulation of sex pheromones in moth.
    WANG Bo1, LIN Xin-da1, DU Yong-jun2
    2015, 26(10):  3235-3250. 
    Asbtract ( 737 )   PDF (2148KB) ( 445 )  
    The crucial importance of sex pheromones in driving mating behaviors in moths has been well demonstrated in the process of sexual communication between individuals that produce and recognize species specific pheromones. Sexpheromone molecules from different moth species are chemically characteristic, showing different terminal functional groups, various carbon chain lengths, different position and configuration of double bond system. This review summarized information on the biosynthetic pathways and enzymes involved in producing pheromone molecules in different moths. Then we listed the components and their ratios in the sex pheromones of 15 moth species belonging to different subfamilies in Noctuidae. We also discussed the various viewpoints regarding how sex pheromones with specific ratios are produced. In the discussion we attempted to classify the pheromone molecules based on their producers, characteristics of their functional groups and carbon chain lengths. In particular, composition and ratio variations of pheromones in closely related species or within a species were compared, and the possible molecular mechanisms for these variations and their evolutionary significance were discussed. Finally, we reviewed the endocrine regulation and signal transduction pathways, in which the pheromone biosynthesis activating neuropeptide (PBAN) is involved. Comparing the biosynthetic pathways of sex pheromones among different species, this article aimed to reveal the common principles in pheromone biosynthesis among moth species and the characteristic features associated with the evolutionary course of individual species. Subsequently, some future research directions were proposed.