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    10 February 2016, Volume 35 Issue 2
    Vertical distribution of soil organic carbon and its relation to root distribution in five desert shrub communities.
    KUANG Wen-nong1,2, QIAN Jian-qiang1, MA Qun1,2, LIU Zhi-min1*
    2016, 35(2):  275-281. 
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    Exploring the relationship between soil organic carbon (SOC) and root distribution is essential for evaluating carbon stock and sequestration potential in terrestrial ecosystems. However, the relationship between SOC and root in shrub communities in desert grassland of China is not clear yet. In this study, we selected five shrub communities Haloxylon ammodendro and Caragana intermedia with deep root but root biomass concentrated in the shallow soil layer, Nitratia tangutorum with deep root and root biomass not concentrated in the shallow soil layer, Reaumuria songarica with shallow root and root bimass concentrated in the shallow soil layer, Sarcozygium xanthoxylon with shallow root but root bimass not concentrated in the shallow soil layer, to explore the relationship between SOC and root biomass in shrub communities. Root biomass density (RBD) and soil organic carbon density (SOCD) in different soil layers of a 0-100 cm soil profile were investigated. Our results showed that (1) the SOCD in the 0-100 cm soil profile was positively correlated with the RBD in 0-20 cm layer, while it had no significant correlationship with RBD in other layers; (2) the SOCD in 100 cm soil profile of H. ammodendron community was significantly lower than those of the other communities (P<0.01), however, there were no significant differences among the other four communities (P>0.05); (3) the vertical distributon of SOCD in H. ammodendro, C. intermedia and R. songarica communities were similar with the root distribution of communities and their dominant species, but in N. tangutorum community, it was similar with the root distribution of dominant species. In S. xanthoxylon community, it was only similar with the root distribution of community in 0-40 cm soil. This study indicated that the SOC in 0-100 cm soil profile of shrub communities was significantly associated with root biomass in 0-20 cm soil, and the vertical distributions of dominant shrub root system was a key factor affecting the vertical distribution of SOC.
    Change of soil organic carbon fractions  at different successional stages of Betula platyphylla forest in Changbai Mountains.
    ZHANG Xue1,2, HAN Shi-jie1*, WANG Shu-qi1, GU Yue1,2, YUE Lin-yan1,2, FENG Yue1, GENG Shi-cong1,2, CHEN Zhi-jie1,2
    2016, 35(2):  282-289. 
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    In order to understand the change of soil carbon storage during natural restoration succession of coniferous-broadleaved mixed forest communities in Changbai Mountains, five successional stages, including birch young forest, birch middleaged forest, birch mature forest, mature broadleaved Korean pine forest and old broadleaved Korean pine forest, were chosen using the temporalspatial substitution method, to study the soil organic carbon (SOC), readily-oxidized organic carbon (ROC), microbial biomass carbon (MBC) and particulate organic carbon (POC) contents. The results showed that SOC, MBC, ROC, POC and soil total nitrogen, total phosphorus and carbon to nitrogen ratio (C/N) all increased firstly and then remained stable from early to late succession. The contents of SOC, MBC, ROC and POC were significantly decreased (P<0.05) with the increasing soil layer depth. ROC/SOC and POC/SOC ranged between 12.91%-47.95% and 14.21%-69.46% in the five successional stages, respectively. The correlation analysis showed a significant positive correlation (P<0.01) between MBC, ROC, POC and SOC, and a significant positive correlation (P<0.01) between SOC, MBC, ROC, POC and total nitrogen, total phosphorus, carbon to nitrogen ratio. Our results provide data support for clarifying soil organic carbon stability and carbon sequestration potential during the succession of the birch forest.
    Litterfall dynamics of plants in a successional series of evergreen broad-leaved forests in Tiantong region, Zhejiang Province.
    ZHANG Qing-Qing1,2, ZHOU Liu-Li1,2, ZHAO Yan-Tao1,2, XU Ming-Shan1,2, YAN En-Rong1,2*
    2016, 35(2):  290-299. 
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    Litterfall dynamic is one of the functional strategies in plant species. Exploring litterfall dynamics of overlapping (i.e., co-occurring at three successional stages at least) and turnover (i.e., occurring at one successional stage only) species is important for understanding mechanisms underlying species replacement during forest succession.  In this study, seasonal dynamics of litterfall over 4 overlapping species and 6 turnover species were investigated in four successional stages in evergreen broadleaved forests in Tiantong National Forest Park (29.45° N, 121.97° E), Zhejiang Province. Then differences in litterfall dynamics were examined between overlapping species at different successional stages, and between overlapping and turnover species. The results showed that, in addition to Eurya japonica (P>0.05), litterfall dynamics in overlapping species of Pinus massoniana, Schima superba and Castanopsis fargesii (P<0.05) were significantly affected by forest succession. Differences in litterfall dynamics between overlapping and turnover species were successional stagedependent. Specifically, at the first successional stage, there were significant differences in litterfall dynamics among P. massoniana, S. superba, Lithocarpus glaber and Loropetalum chinense (P<0.05). At the secondary successional stage, litterfall dynamics varied significantly between S. superba and Symplocos caudata (P<0.05) and between C. fargesii and C. sclerophylla (P<0.05). At the fourth successional stage, litterfall dynamics of S. superba, C. fargesii, Eurya japonica, Cinnamomum pedunculatum and Camellia cuspidata differed significantly (P<0.05). There was no significant difference in litterfall dynamics between other species. In summary, litterfall dynamics changed partly for overlapping species during forest succession. At the same successional stage, litterfall dynamics differed significantly between overlapping and turnover species. Changes of litterfall dynamics in overlapping and turnover species indicate divergent strategies in leaf phenology for plants to adapt to the microenvironment shift with forest succession.
    Interspecific differences in seedling growth of three main afforestation tree species in response to simulated N deposition.
    PANG Li1,2, ZHOU Zhi-Chun1*, ZHANG Yi1, FENG Zhong-Ping3
    2016, 35(2):  300-307. 
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    The enhanced atmospheric N deposition in recent years has brought the increases in N availability and N/P ratio in forest soils, which would impact the growth and productivity of plants. Pinus massoniana, Cunninghamia lanceolata and Schima superba are the main afforestation tree species with different growth and biological characteristics in southern China. Taking seedlings of the three tree species as test materials, a pot experiment was conducted to simulate low P soil conditions in combination with two N deposition levels, to study interspecific differences in growth and adaptation mechanism to low P stress under N addition. The results showed that: 1) The aboveground part growth of P. massoniana and S. superba was promoted by simulated N deposition, but their root growth and root biomass accumulation were inhibited. The whole plant biomass of P. massoniana and S. superba were not significantly changed under simulated N deposition. The aboveground part and root growth of C. lanceolata were severely inhibited by simulated N deposition, so its whole plant biomass was significantly decreased; 2) The degree of low P stress of the three tree species seedlings was increased by simulated N deposition, which led to the increase of root secreted APase activity and organic acids. The increased degrees of total amount of root secretion of P. massoniana and S. superba were greater than that of C. lanceolata; 3) Simulated N deposition increased leaf N contents of the three tree species, but decreased their leaf P contents, thus increased their leaf N/P ratios. The increased degree of leaf N/P of C. lanceolata was the maximum, and that of P. massoniana was the minimum. The rapid increase of leaf N/P ratio of C. lanceolata resulted in the relative scarcity of its leaf P content and imbalance of leaf N and P nutrients, finally influenced C. lanceolata leaf photosynthesis. The increased degree of leaf N/P ratios of P. massoniana and S. superba were relatively small. The increase of leaf N contents of P. massoniana and S. superba promoted their leaf net photosynthetic rates; 4) Under simulated N deposition, the acidification of surface soil of P. massoniana and S. superba was greater than that of C. lanceolata, while soil hydrolytic N contents of P. massoniana and C. lanceolata were increased as compared to S. superba due to greater N absorption and N leaching of surface soil of S. superba, and stronger surface soil N leaching of P. massoniana compared to C. lanceolata. In addition, soil available P contents of the three species were all decreased, and they were higher in the topsoil than in the subsoil under simulated N deposition.
    Fine-scale spatial patterns of Oxytropis kansuensis population in degraded alpine grassland.
    FENG Wei, ZHAO Cheng-zhang*, DANG Jing-jing, ZHENG Hui-ling, DUAN Bei-bei, HAN Ling, XU Ting
    2016, 35(2):  308-313. 
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    The spatial patterns of plant populations are the results of coordinated adaptation of plants to environment, reflecting the life history strategy of plant populations. The heterogeneity of finescale spatial patterns in Oxytropis kansuensis population was studied by using the methods of community survey and point pattern analysis. Four kinds of alpine grassland were chosen, including undegraded grassland (Ⅰ), lightly degraded grassland (Ⅱ), moderately degraded grassland (Ⅲ) and severely degraded grassland (Ⅳ) in the northern slope of Qilian Mountains. The results showed that, with the increasing degree of natural grassland degradation, the population height, coverage and aboveground biomass and branch density increased, and the proportion of small bunch decreased, while the proportion of big bunch increased. The spatial distribution pattern of O. kansuensis showed a scaleassociated change trend. In the undegraded and lightly degraded grasslands, the distribution pattern of O. kansuensis showed a clumped distribution on a smaller scale, while showed a random distribution on a larger scale. Meanwhile, in the moderate and heavy degradation grasslands, the spatial distribution pattern of the population showed distinct pattern characteristics. With the increasing degree of natural grassland degradation, the clumped distribution patterns of plant populations shifted from a smaller scale to a larger scale, which reflected the dispersion and regeneration strategy of O. kansuensis population.
    Community structure and species diversity of Pinus tabuliformis forest in the Liaoheyuan Nature Reserve.
    WANG Luo-xin, HAN Hai-rong*, CHENG Xiao-qin, KANG Feng-feng
    2016, 35(2):  314-320. 
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    The community structure and species diversity of Pinus tabuliformis natural forest were studied by using quadrat investigation in the Liaoheyuan Nature Reserve, Hebei Province. The results showed that 146 vascular species existed in the sampling plots, belonging to 92 genera and 42 families. The four aged P. tabuliformis natural forest stands exhibited obvious vertical structures. The dominant species in arbor layer, shrub layer, and herb layer were P. tabuliformis, Spiraea pubescens + Quercus mongolica, Carex tristachya, respectively. The richness and diversity indexes were higher in herb layer than in shrub layer. The evenness index was higher in shrub layer than in herb layer in young stands, while the opposite was true for the other stands. The richness and Shannon diversity indexes in shrub layer of the four stands ranked as follows: young forest > mature forest > middle-aged forest > pre-mature forest, Simpson diversity index ranked from high to low as mature forest > young forest > middleaged forest > pre-mature forest, while evenness index had the order of pre-mature forest > middle-aged forest > mature forest > young forest. In herb layer, the richness index followed an order of young forest > pre-mature forest > mature forest > middle-aged forest, while the Shannon diversity index, Simpson diversity index and evenness index showed the order of pre-mature forest > mature forest > middle-aged forest > young forest.
    Alpine meadow plant community traits and niche under the disturbance of anthills in Northwest Sichuan Province, western China.
    XIANG Ze-yu1, ZHANG Li1, LIU Xue-juan2*
    2016, 35(2):  321-329. 
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    As an important ecological disturbance factor in the alpine meadow, anthills can greatly influence the characteristics and ecological niche of plant community in alpine meadow. Alpine meadow plant community with anthill disturbance was studied in September 2012 in Hongyuan, Sichuan. The results showed that the species richness and diversity of the alpine meadow plant community decreased after the anthill disturbance, while the coverage, importance value and niche breadth of Gramineae and Cyperaceae increased. Especially, the niche breadths of gramineous grass Poa pratensis and Elymus nutans were obviously greater than those of the control, becoming the dominant populations. With anthill disturbance, the niche overlap level of alpine meadow plant populations was generally lower, ensuring the longterm ecological coexistence between the dominant populations of Gramineae and Cyperaceae with larger niche breadths and other species. It benefits the disturbed alpine meadow to the succession toward the direction of fine herbage, improving the grazing capacity of the alpine meadow to some extent.
    Spatial patterns of plant community biomass and species diversity in Aerjin Mountain Nature Reserve and their influencing factors.
    SHA Wei1, DONG Shi-kui1*, LIU Shi-liang1, LIU Quan-ru2, SHI Jian-bin1, LI Xiao-wen1, SU Xu-kun1, WU Yu1
    2016, 35(2):  330-337. 
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    Spatial patterns of plant species diversity and plant biomass and their relationships with environmental factors in Aerjin Mountain Nature Reserve (AMNR) were examined in this study. The results indicated that alpine steppe was the major vegetation type in high altitude areas of the southwestern AMNR, swamp meadow and alpine steppe were the major vegetation types in low altitude areas of the northeastern AMNR, and alpine desert was the major vegetation type in middle altitude areas of the northwestern AMNR and low altitude areas of the southeastern AMNR. The species diversity and biomass of plant communities did not vary significantly with the latitude, longitude and altitude gradients. The species diversity index of the plant community was positively correlated to soil total nitrogen, total carbon, organic carbon, and soil moisture. The vegetation biomass of the plant community was positively correlated to soil total nitrogen, soil organic carbon and soil moisture, and negatively correlated to soil bulk density. The integrated effects of geographic, soil and meteorological factors contributed to the spatial heterogeneity of species biodiversity and vegetation biomass of the plant communities in AMNR, and the impacts of soil and meteorological factors were much stronger than that of geographical factors.
    Effects of N addition on soil enzyme activities and microbial biomass beneath Pinus tabuliformis seedlings.
    LU Feng-lian1, XUE Sha2,3, WANG Guo-liang2,3*, JING Hang2
    2016, 35(2):  338-345. 
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    With a pot experiment, we compared the effects of N addition (0, 2.8, 5.6, 11.2, 22.4 and 44.8 g N·m-2·a-1) on soil enzyme activities (invertase, urease and alkaline phosphatase) and microbial biomass beneath Pinus tabuliformis seedlings after 6 years consecutive treatment. The results showed that soil invertase and urease activities were improved when the N addition was below 11.2 g N·m-2·a-1, while soil invertase, urease and alkaline phosphatase activities did not increase, even declined with a higher rate of N addition, especially more than 22.4 g N·m-2·a-1. The microbial biomass C significantly increased at N addition ≥5.6 g N·m-2·a-1, while microbial biomass N significantly increased at N addition ≥11.2 g N·m-2·a-1, compared with the control. Significant correlations were found between soil invertase and urease activities and microbial biomass C and microbial biomass N. No significant correlations, however, were found among the three enzyme activities, or between the microbial biomass C and N. Soil enzyme activities and microbial biomass were significantly correlated with aboveground biomass, soil organic carbon and total nitrogen content. Additionally, the growth of P. tabuliformis seedlings reached the maximum at the N addition levels of 5.6-11.2 g N·m-2·a-1. The current N deposition level of 2.06 g N·m-2·a-1 on the Loess Plateau can be favorable to P. tabuliformis growth, and the growth of P. tabuliformis would be improved through appropriately enhanced N fertilization.
    Effects of forest-grass modes on the meso and micro-soil faunal community structure in transforming low-benefit Cupressus funebris Endl. forest. 
    TIE Lie-hua, BAI Wen-yu, FENG Mao-song*, WU Tao, LI Wen-bing, HAN Dong-miao, HUANG Yun, ZHANG Zhong-yu
    2016, 35(2):  346-353. 
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    The spatial distribution and community diversity of meso and micro-soil fauna are of great significance to assessing the ecological restoration of low-benefit forests. A field experiment was conducted to explore the effects of forest-grass measures on the meso and micro-soil faunal diversity in low-benefit Cupressus funebris Endl. forest. Six treatments were employed, including Juglans regia L.+Astragalus adsurgens Pall., J. regia+Sorghum sudanense (Piper) Stapf, J. regia+Melilotus officinalis (L.) Pall., J. regia+Lolium perenne L., J. regia+soilloosening, and low-benefit C. funebris forest as control. The meso and microsoil faunal communities were investigated by using dry and wet funnel method. The results showed that the group number, density and diversity of the meso and microsoil fauna were relatively higher in summer and autumn than in winter and spring in all trestments. Moreover, these variables showed a pattern of J. regia+grass > J. regia+ soilloosening > low-benefit C. funebris forest in four seasons. The meso and micro-soil faunal communities of forestgrass and low-benefit C. funebris forest were moderately dissimilar at the beginning of treatment, and moderately similar with time extension. J. regia+soil-loosening and lowbenefit C. funebris forest were significantly similar in autumn and winter. The soil fauna in J. regia+grass and C. funebris forest was mainly distributed in upper and middle layer soil in four seasons, while the meso and microsoil fauna in forestgrass had a tendency of moving to subsoil in winter. At the early stage, the soil fauna in J. regia+soilloosening was mainly distributed in upper and middle soil layer; as time went by, the soil fauna was likely to migrate to the middle and lower layers gradually. Forestgrass had a great effect on the meso and micro-soil faunal community structure, and this effect was better in J. regia+M. officinalis and J. regia+L. perenne than in the other forest-grass measures.
    Variations of water-carbon exchange at leaf scale and leaf nutrient content of Robinia pseudoacacia with slope aspect and stand age in a small catchment of the Loess Plateau.
    ZHANG Di1*, JIN Tian-tian2
    2016, 35(2):  354-362. 
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    Water-carbon exchange process and major influencing factors of Robinia pseudoacacia plantations in the Yangjuangou watershed of the Chinese Loess Plateau were measured at leaf scale, to explore the variations of watercarbon exchange with slope aspects and stand ages and analyze the potential effects of nutrient contents in leaves on watercarbon exchange process. The results showed that: (1) 11- and 27-year-old R. pseudoacacia were at different growing stages. The former had a higher intensity of watercarbon exchange than the latter. (2) The proportion of R. pseudoacacia individuals with higher net photosynthetic rate, water use efficiency, stomatal conductance and intercellular CO2 concentration was greater on semisunny slope than on sunny slope, suggesting that semisunny slope was more suitable for R. pseudoacacia growth. (3) The variation patterns of N and K contents in different quadrats were as follows: semi-sunny slope>sunny slope, 27-year-old>11-year-old, indicating that R. pseudoacacia grew better on the semisunny slope than on the sunny slope, mature R. pseudoacacia grew better than juvenile R. pseudoacacia. The differences of K content in leaf in different quadrats were significant, suggesting that K content in leaf was sensitive to the changes of slope aspect and stand age. Therefore, compared with the sunny slope, the semisunny slope with more suitable hydrothermal condition should be considered as priority for establishing R. pseudoacacia plantation, and the reforestation on soils with enriched available K could be a potential way for improving plant’s water use efficiency. These results are significantly instructive for the improvement of Grain for Green Project and the management of existing plantations in the arid and semi-arid regions.
    Quantitative analysis of stand spatial structure of a rare species Kmeria septentrionalis in Guangxi.
    PENG Yu-hua1,2, HE Qin-fei1,2, TAN Chang-qiang1,2, SHEN Wen-hui1,2*, QIN Wen-geng3, HE Feng1,2
    2016, 35(2):  363-369. 
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    Three stand spatial structure parameters, including mingling degree, uniform angle and size ratio, were used to analyze species compositions and spatial structure patterns of a rare species Kmeria septentrionalis community in Mulun Reserve, Guangxi. The result showed that the community included 95 woody species, belonging to 55 families, 82 genera, being a typical unevenaged mixed broadleaf forest. The community was dominated by small DBH individuals, and tree numbers decreased as DBH increased, presenting an inverse J shape distribution. In the community, a majority of trees were strongly mingled (with an average mingling degree 0.742), and the size ratio was 0.508. Trees with hierarchical DBHs were evenly distributed in spatial structure, and most trees were of random to uneven distribution (with an average uniform angle 0.549), representing a mild aggregation. K. septentrionalis’ DBH structure also presented an inverse J shape, with decreased individuals in the process from seedlings to young trees. K. septentrionalis population had high mingling degree (0.796), moderate size ratio (0.400) and weak aggregated distribution (uniform angle 0.528). In sum, efficient conservation and appropriate human interference efforts are needed for a sustainable K. septentrionalis population.
    Variation of morphological structure of dominant species in moss crusts in hilly Loess Plateau region. 
    YANG Xue-wei1,2, ZHAO Yun-ge2, XU Ming-xiang2*
    2016, 35(2):  370-377. 
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    Moss-dominated crusts play important roles in ecological restoration in hilly Loess Plateau region, China. Four dominant moss species Didymodon vinealis (Brid.) Zand., Didymodon tectorum (C. Mull.) Saito, Barbula unguiculata Hedw. and Bryum argenteum Hedw. in the community of biological soil crusts in the hilly Loess Plateau region were chosen as objects. The morphological and anatomical structure of the four moss species were observed and measured in this study. The results showed that D. vinealis had greater shoot height (6.1 mm), stem diameter (298.6 μm), midribs width (65.5 μm), leaf width (590.9 μm) and blade thickness (14.8 μm) than the other three species; the stem epidermis cell wall of D. vinealis was obviously incrassate and the cortex cells were distributed in a mosaic pattern. D. tectorum did not show significant advantages in its stem and leaf structure. With coarse stems and leaves, D. vinealis had stronger desiccation tolerance than the other three species, and thus it was easy to adapt to the variability of environmental moisture. The leaf length (3.2 mm) and basal leaf cell size (191.2 μm2) of B. unguiculata were significantly higher than that of the other three species and contained much more chloroplasts. Their midribs were in sharp “v” form, and this morphological structure was closely related to their water harvesting. In B. argenteum, the cortex cell area was 987.8 μm2, and single cortex cell accounted for approximately 3.1% of stem transversesectional area. The leaf hair (274 μm) was significantly longer than that of the other three species and the upper leaf cells and leaf hair of this species were transparent, which endows it to grow in the conditions with periodical drought stress and to resist light radiation. Our study suggested that the differences in stem and leaf morphological structure existed among the four moss species, with different adaptation to various water and light conditions, which may reflect their ecological adaptability. Also, this study may provide reference for species selection in restoration of moss crusts.
    Does clonal integration help alligator weed resist short-term parasitism by dodder?
    DAI Wen-hong1, SONG Yao-bin1*, WANG Ning2,3, HU Xue-hua2,3, XIAO Yi-an2,3, DONG Ming1
    2016, 35(2):  378-386. 
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    Many studies have focused on how clonal plants cope with stressful environments through clonal integration. We tested the hypothesis that clonal integration can help clonal plants resist parasitism by plants in an experiment in which stoloniferous alligator weed (Alternanthera philoxeroides) experienced partial infection by parasitic dodder (Cuscuta chinensis). Interconnecting ramets of alligator weed were assigned to the following treatments: M+-D- (only mother ramets infected), M--D+ (only daughter ramets infected), M+-D+ (both mother and daughter ramets infected), M--D- (no infection). Relative chlorophyll content, Fv/Fm, number of leaves, stolon length and number of ramets significantly responded to the infection while biomass did not. Our results did not support the hypothesis, which might be due to our relatively short experimental term, suggesting that adaptive expression of clonal integration is not unconditional. Further studies should be able to take both short and longterm effect into account.
    Model fitting of photosynthetic light-response curves in different Quercus variabilis provenances and its parameter comparison.
    DENG Yun-peng1, LEI Jing-pin1,2*, PAN Lei3, WANG Xiao-rong3
    2016, 35(2):  387-394. 
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    In order to improve the accuracy of photosynthetic light-response curve model in data fitting and explore the photosynthetic-physiological characteristics of plants from different provenances under changing habitat conditions, photosynthetic characteristics of Quercus variabilis from six provenances were studied. The research materials were twoyear-old seedlings of Q. variabilis from six provenances, i.e., Zhuanghe of Liaoning Province (LNZH), Pinggu of Beijing (BJPG), Huanglong of Shannxi Province (SXHL), Jiyuan of Henan Province (HNJY), Hefeng of Hubei Province (HBHF), and Anning of Yunnan Province (YNAN). Five photosynthetic lightresponse curve models were chosen, i.e., rectangular hyperbolic model (RHM), non-rectangular hyperbolic model (NHM), exponential model (EM), modified rectangular hyperbolic model (MRHM), and subsection function model (SFM). These models were adopted to fit the photosynthetic light-response curve data of six Q. variabilis provenances. The photosynthetic parameters were compared among the five models and the photosynthetic characteristics of the six provenances were analyzed. The results showed that: (1) among the five models, MRHM and SFM had better fitting results in terms of conformity with measured values; (2) different models obviously affected the initial quantum efficiency (α), maximum net photosynthetic rate (Pnmax) and dark respiration rate (Rd). For example, Pnmax and Rd fitted by EM and SFM were significantly lower than those derived from the other models (P<0.05), and Pnmax fitted by RHM and NHM were significantly higher than those obtained by the other models. Besides, the significance of photoresponsive parameters among different provenances varied with the selected models; (3) there were significant differences of Pnmax and Rd among provenances (P<0.05). For instance, Pnmax of SXHL provenance was significantly higher than those of the other provenances (P<0.05), while Rd of HNJY provenance was significantly higher than those of the other provenances (P<0.05); and (4) the warm temperate provenances except LNZH would adapted better to the tested habitat.
    Effect of water N/P ratio on the response of Alexandrium tamarense to UV radiation.
    LI Lei1, GUAN WAN-chun1, CHEN Shao-bo1,2, XIE Qi-lang1*
    2016, 35(2):  395-400. 
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    Alexandrium tamarense, a typical species around China coastal water zone, was cultured under conditions of five N/P ratios (1∶1, 16∶1, 50∶1, 100∶1, 200∶1) for 14 days. The growth rates and pigment contents were measured at the end of the experiment. Then the cultures were exposed under three types of radiation (visible light, P; visible light + ultraviolet A, PA; visible light + ultraviolet A+B, PAB). The effective photochemical efficiency and exposure response curves (ERC) were detected after 60min exposure. The results showed the fastest growth rate and highest pigment contents (Chl-a: 3.06×10-5 μg·cell-1 and Caro: 2.10×10-5 μg·cell-1) were observed in the 16∶1 (N/P) treatment. However, the growth rates and pigment contents declined significantly when the N/P ratio in the media increased or decreased. The growth rate was a function of N/P ratio according to a twoorder equation (R2>0.98). The variation of effective photochemical efficiency was fitted well by a firstorder exponential equation (R2>0.97). The effective photochemical efficiency decreased under PA and PAB treatments compared to that under P treatment. There was a negative linear relationship between the decreased degree of the effective photochemical efficiency and the ratio of algal cell photosynthetic system II D1 protein repair rate and damage rate (r/k) (R2>0.98). The dependency of UVinduced photoinhibition in A. tamarense on the N/P ratio was fitted well by a two-order equation (R2>0.95). The r/k ratio was the highest and the decreased degree of the effective photochemical efficiency and the photoinhibition rate were the lowest in the 16∶1 (N/P) treatment. Therefore, the N/P ratio of 16∶1 is the optimum condition for the algal cells to defense the UVinduced photoinhibition by the alteration of r/k ratio.
    Physiological and ecological response of Phyllostachys rivalis leaves to normal water supply after long-term waterlogging.
    LIU Yu-fang, CHEN Shuang-lin*, LI Ying-chun, GUO Zi-wu, YANG Qing-ping
    2016, 35(2):  401-406. 
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    To clarify the physiological and ecological mechanism of response of Phyllostachys rivalis to normal moisture condition after longterm waterlogging, the contents of photosynthetic pigments, MDA, soluble protein and nutrients, antioxidant enzyme activity, and relative conductivity in leaves of Ph. rivalis were investigated after three months of resumed water supply to normal level (R3) after threemonth waterlogging (TR3). The results showed that the membrane lipid peroxidation in Ph. rivalis leaves was produced, antioxidant enzyme activity was weakened, cell permeability was enlarged, osmotic adjustment capacity was decreased and the contents of main nutrients and stoichiometric ratio in leaves were adjusted adaptively under TR3 treatment. The antioxidant system of Ph. rivalis could regain effectively under R3 treatment. Compared with TR3 treatment, the SOD activity and soluble protein content under R3 treatment increased by 15.58% and 958%, while the relative conductivity and MDA content decreased by 23.64% and 43.46%, respectively. These indicators all could restore to normal levels. The harm of chloroplast cells could also be repaired to some extent, and the contents of main nutrients and stoichiometric ratios in leaves could get back to normal levels completely. Hence, all results indicated that Ph. Rivalis had an excellent ability to restore growth and could be used for vegetation restoration of wetlands and areas with fluctuating water tables.
    Physiologicalbiochemical response of Atractylodes lancea from different habitats to waterlogging stress and comprehensive evaluation of their waterlogging tolerance with TOPSIS approach.
    LI Meng-yang, CHAO Jian-guo*, GU Wei, HOU Hao-ran
    2016, 35(2):  407-414. 
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    In order to provide theoretical basis for selection of waterloggingtolerance varieties of Atractylodes lancea, the effects of waterlogging on physiological indexes, photosynthesis parameters and chlorophyll fluorescence parameters of A. lancea from three different sites were studied. The results showed that: (1) Along with prolonging of waterlogging stress, the activities of superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) in leaves of A. lancea from the different sites increased first and then declined. The activities of SOD and POD reached the highest values on day 2 and day 6, respectively. The activities of CAT of A. lancea from Yingshan and Xinyang reached the highest value on day 2, while that from Jurong was the highest on day 4 and showed longest upward cycle and greatest maximum. The malondialdehyde (MDA) and proline (Pro) contents showed a rising trend, and were significantly higher than those in control group on day 7. (2) Along with prolonging of waterlogging stress, the net photosynthetic rate (Pn), stomatal conductance (Gs), transpiration rate (Tr) and stomatal limitation (Ls) decreased and were significantly lower than those in control group on day 7, but there was no obvious difference among the different site groups. (3) The maximum photochemical efficiency of PSⅡ (Fv/Fm) and potential photochemical efficiency (Fv/Fo) decreased, and these two indexes from Jurong site were significantly higher than those from the other two sites. Waterlogging stress had greater effects on the Fv/Fo than on the Fv/Fm. Actual photochemical efficiency of PSⅡ (Fv′/Fm′), electron transport rate (ETR), photochemical quenching coefficient (qP) and nonphotochemical quenching coefficient (NPQ) increased in the earlier days and then declined with prolonging time. Each group’s Fv′/Fm′ and ETR reached the highest values on day 1; the qP and NPQ reached the highest values on day 1 for Yingshan and Xinyang site groups, but on day 3 for Jurong site group. The assessment of physiological indexes, photosynthesis parameters and chlorophyll fluorescence parameters of A. lancea from the different sites using TOPSIS method indicated that the order of waterloggingtolerance of A. lancea varieties was Jurong> Yingshan> Xinyang.
    Effects of limited irrigation on dry matter translocation and filling characteristics of intercropping wheat in Hetao irrigated region.
    ZHANG Zuo-wei1, SHI Hai-bin1*, LI Xian-yue1, LI zhen1, YAN Jian-wen1, LI Jie-jun2
    2016, 35(2):  415-422. 
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    In order to explore the characteristics of spring wheat grain filling and dry matter translocation under the condition of limited irrigation and the factors limiting the grain filling of spring wheat, and thus to increase the water productivity of intercropped spring wheat, the influences of limited irrigation (four levels: 298, 328, 358, 388 mm) of two intercropping modes (spring wheat intercropped with maize or sunflower) on the characteristics of spring wheat grain filling were studied based on the present situation of water shortage in Hetao irrigated region, Inner Mongolia. The results showed that under same irrigation conditions, the dry matter translocation yield of wheat stem and leaf intercropped with sunflower were 1.08-1.86 times and 1.12-2.17 times as high as that intercropped with maize, respectively, while the dry matter translocation yield of wheat glume and cob under the maizeintercropped model was 1.00-1.19 times as high as that under the sunflowerintercropped model. The process of wheat grain filling was consistent with the “S” growth curve that could be simulated by a Logistic equation under different water treatments and planting modes. The wheat intercropped with maize reached a peak grain filling rate after 25-30 d of flowering, with 1.26-2.85 d in advance compared to the control treatment (wheat monoculture with 388mm irrigation). The wheat intercropped with sunflower reached a peak grain filling rate after 25-30 d of flowering, with 1.80-2.44 d in advance compared to the control treatment. The maximum grain filling rate and average grain filling rate of wheat under the two intercropping modes with various water treatments were all higher than those under the control treatment, and the time needed for maximum grain filling rate decreased. The lower rates of irrigation (298-328 mm) were found to be conducive to extension of the active filling stage of wheat intercropped with maize, while the higher rates of irrigation (358-388 mm) were conducive to extension of the active filling stage of wheat intercropped with sunflower.
    Species composition and dominant species of macrobenthic fauna in intertidal zone of Zhelin Bay-Nanao Island in winter and summer.
    SHU Li-ming1,2,3, CHEN Pi-mao1,2,3*, QIN Chuan-xin1,2,3, LI Xiao-guo1,2,3, ZHOU Yan-bo1,2,3, FENG Xue1,2,3, YU Jie1,2,3, YUAN Hua-rong1,2,3, LI Guo-ying1,2,3
    2016, 35(2):  423-430. 
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    Species composition and dominant species of macrobenthic fauna were investigated in the intertidal zone of Zhelin Bay-Nanao Island in August 2011, February 2012, and February and August 2013. A total of 112 species belonging to 7 phyla were identified in the four surveys. The top 3 phyla in species number were Mollusca (59.82%), Arthropoda (18.75%) and Annelida (13.39%). The species number was higher in summer and lower in winter. Significant difference in species number existed between two summer surveys (P<0.05), and no significant difference between two winter surveys (P>0.05) and between winter and summer (P>0.05). Species replacement was obvious from winter to summer and community stability was lower during this period. There were 23 dominant species in the four surveys and Mollusca (>50%) was dominant. Macrobenthic fauna species and distribution was determined by the bottom sediment types in intertidal zone of Zhelin Bay-Nanao Island, and human activities caused certain pressure on the organisms and their ecology in the intertidal zone.
    Community structure and diversity of crabs in Ma’an Archipelago area.
    LIANG Jin-ling, ZHANG Shou-yu*, WANG Zhen-hua, XU Sheng-nan, DENG Ming-xing, XI Xiao-qing, ZENG Xu
    2016, 35(2):  431-440. 
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    Seasonal variations of crab assemblage, composition of dominant species, species diversity and richness in Ma’an Archipelago area were studied, based on sampling data collected by shrimp trawls from July (summer) and October (autumn) in 2013 to March (winter) and May (spring) in 2014. The relationship between crab community structure and environmental factors were analyzed. The results showed that 22 crab species were collected belonging to 15 genera and 11 families. The numbers of crab species in different seasons were in order of summer (20 species) > autumn (16 species) > spring (9 species) > winter (8 species). Charybdis japonica and Charybdis bimaculata were the most dominant species in the all seasons, Portunus trituberculatus was the subdominant species both in summer and autumn. The Margalef richness index (D) of crab community ranged from 0.43 to 1.01, and the Shannon diversity index (H) ranged from 0.34 to 0.94. These two indices were the highest in autumn and lowest in winter. The Pielou evenness (J) reached the maximum value in spring (0.70), followed by winter and autumn, and the lowest in summer (0.35). Bottom temperature was the most important factor affecting crab community structure. Cluster and nMDS analysis showed that there were no significant differences in crab community structure among seasons, which suggested that the crab community structure in Ma’an Archipelago area was relatively stable.
    Effects of temperature acclimation on preferred swimming behavior in crucian carp (Carassius auratus).
    WU Qing-yi, ZENG Ling-qing, FU Shi-jian*
    2016, 35(2):  441-445. 
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    Temperature changes usually induce the adaptive regulations of physiological function and swimming behavior of fish. The aim of present study was to investigate the effects of temperature acclimation on preferred swimming behavior in crucian carp (Carassius auratus). To achieve our goal, experimental fish were firstly videoed individually in a selfmade preferred water velocity determining device, i.e., a 1.5m long conical raceway with water speed gradually increasing from 11.86 to 65.45 cm·s-1 (which was evenly divided into five velocity intervals) at (25±1) ℃ and (15±1) ℃. The videos were then analyzed by the software Ethovision XT19, and those parameters, including frequency (F), the average duration of each fish stayed (T) and the percent time stayed (Pt) at each water velocity interval were calculated. Our results showed that Pt of crucian carp reached 47% at the fourth water velocity interval when acclimated at 25 ℃, and it was significantly higher than those at the other water velocity intervals due to the combinative effects of increased water velocity on F and T. However, when acclimated at 15 ℃, the F showed no significant change from the first to the third water velocity intervals, but the F of the fourth and fifth water velocity intervals dropped significantly. Meanwhile, the maximal value of the T appeared at the first water velocity interval. Hence, the Pt of the first water velocity interval was 37%, which was higher than those of other intervals (P<0.05). The F of 25 ℃ group was significantly lower than that of 15 ℃ group from the first to third water velocity interval, and the T of 25 ℃ group was larger than that of 15 ℃ group at the fourth water velocity interval (P<0.05). Thus, the Pt of 25 ℃ group was lower than that of 15 ℃ group at first and second water velocity intervals, whereas the Pt value of 25 ℃ group was higher than that of 15 ℃ group at the fourth and fifth water velocity intervals (P<0.05). The present study suggests that the preferred swimming speeds of the experimental fish were 27.91-41.30 and 11.86-15.18 cm·s-1 at 25 and 15 ℃, respectively. The preferred swimming speed of the crucian carp decreased with water temperature, which may be related to the downregulation of the physiological functions of fish acclimated at the cold environment.
    Combined effects of temperature and salinity on hatchability of fertilized eggs of Sepia pharaonis based on response surface methodology.
    HUANG Jian-sheng, CHEN Gang*, ZHANG Jian-dong, WANG Zhong-liang, ZHOU Hui, TANG Bao-gui, WU Fu-hua
    2016, 35(2):  446-452. 
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    Using central composite design (CCD) and response surface methodology, the combined effects of temperature (24-32 ℃) and salinity (25-35) on hatchability and average hatching time of fertilized eggs from Sepia pharaonic were evaluated on the basis of singlefactor tests. The results showed that the linear and quadratic effects of temperature and salinity and their interactive effects significantly affected hatchability and average hatching time (P<0.05). The hatchability increased first and then decreased as temperature or salinity increased. The average hatching time decreased as temperature increased, while it increased after an initial increase as salinity increased. The model equation of hatchability and average hatching time towards temperature and salinity were established, with the coefficients of determination (R2) being 0.9791 and 0.9774, respectively. The optimized results of regression equation based on a reliability of 0.985 showed that the hatchability was 88.11% when temperature was 27.6 ℃ and salinity was 31.1, and the average hatching time was 21.8 d when temperature was 26.2 ℃ and salinity was 29.6. Our results suggest that the hatching of fertilized eggs of S. pharaonis can be improved by rearing with an optimal combination of temperature and salinity with the range of 26-28 ℃ and 29-31, respectively.
    Correlation between the numbers of different Solenopsis invicta instars on nest surface layer and ant mound size.
    LIN MIAO-feng1,2,3, GUO Qiang4, HAN Shi-chou1,2,3, JIANG Lu4, YE Jing-wen1,2,3, DAI Jian-qing1,2,3, LI Jun1,2,3*
    2016, 35(2):  453-457. 
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    Solenopsis invicta is one of the most devastative invasive pests. In order to clarify the correlation between the numbers of different S. invicta instars on nest surface layer and ant mound size, 180 nests from six sites in Panyu, Guangzhou were investigated by digging method. The results demonstrated that in terms of mound volume, 57.78% of the nests were less than 5000 cm3, 20.56% between 5000 and 10000 cm3, and 21.67% greater than 10000 cm3. In terms of mound surface layer base area, 32.78% of the nests were less than 500 cm2, 42.78% between 500 and 1000 cm2, 24.44% and greater than 1000 cm2. For an area of 1 cm2 mound layer base and a volume of 1 cm3 mound, there were 3 and 22 ants, respectively. The number of each instar and total population increased with the increase of mound volume and mound surface base area. The positive correlations of the number of worker ants with the mound volume and the mound surface layer base area were more obvious than that of any other instars of S. invicta. The correlation of the amount of S. invicta with the mound volume was better than that with the mound surface layer base area.
    Effects of different color fruit bags on defending bird damage.
    WEN Li-jia1, GUO Yu-min1*, GAO Yong-hong1, PENG Yang-jing1, LIU Run-ze2, QU Hong2, HUANG San-xiang2, HUANG Jian1
    2016, 35(2):  458-462. 
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    To investigate whether the color of packaging bags can reduce bird damage and economic losses of apples, we bagged the apples with different colors in Foyukou orchard, Yanqing County, Beijing during 2013 and 2014. The total number of bags was 1713 for the experimental group and 1787 for the control group. The results showed that there was a significant difference (P<0.001) between treatments, and the bags with a cobalt blue color had the best protection against bird damage. The destruction ratio of apples was 1.30% with cobaltblue bags, followed by bright red and white with destruction ratios of 2.11% and 2.60%, respectively, which were still lower than the destruction ratio (4.40%) of the primary fruit bag color (the control). Bags with black, ultramarine blue, brown and pale purple had lower effects on protecting against bird damage compared with the control group, with destruction ratios of 9.21%, 8.60%, 8.11% and 6.90%, respectively. Therefore, we suggest that bags with cobalt blue can be used for the protection of orchard harvest.
    Pollution characteristics and potential ecological risk of heavy metals in the sediments of urban river in Yuxi, Yunnan.
    WANG Bei1, YU Yang2, LU Dong-mei2, REN Yong-qi2, ZHANG Cui-ping3, LI Shu-ying3, ZHOU Yuan-qing3, WU Zhao-lu1*
    2016, 35(2):  463-469. 
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    The objective of this paper was to investigate the characteristics of heavy metal pollution in sediments of Yuxi River during dry and wet seasons, and to evaluate their potential ecological risk. The average concentrations of As, Hg, Cu, Pb, Cr, Ni, Cd and Zn were 75.2, 1.528, 84.4, 107.1, 65.6, 28.4, 9.00 and 738 mg·kg-1 respectively, which were all above the soil background values of Yunnan Province except Ni. The concentration of Cd was significantly positively correlated with TP, and the concentrations of As, Hg, Pb, Cu, Cr, Zn and Ni were significantly correlated to each other, indicating that these heavy metals had the same sources. The sequence of potential ecological risk of heavy metals was Cd > Hg > As > Pb > Cu > Zn > Ni >Cr. Average potential ecological risk index of the sediments of the whole river was 2362.2 (ranging 151-12621), suggesting a very high ecological risk. In addition, the ecological risk indexes were higher in the upriver than in the downriver. The main heavy metals in the sediments of Yuxi River were mainly from the industrial discharge from Hongta district of Yuxi.
     
    Influence of Cu, Zn on the growth of water spinach (Ipomoea aquatica Forsk.) and the antidotal effect of selenium.
    HAN Cheng-hua, PAN Rui-rui, LIU Ye, JIANG Jie-zeng*, YAN Wu-wei, TIAN Qiu-fang, SHI Ru-qiong
    2016, 35(2):  470-477. 
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    A hydroponic experiment was carried out to study the influence of Cu and Zn on water spinach growth and the antidotal effect of Se. Physiological indexes, yield, Cu and Zn contents in two water spinach varieties (wideleaf and narrowleaf water spinach), and the antidotal effect of Se were investigated. The results indicated that lowconcentration Cu and Zn accelerated the growth of water spinach, and highconcentration Cu and Zn restrained the growth by decreasing root activity, antioxidative enzyme activities and net photosynthetic rate (Pn) and increasing MDA content. The yield of water spinach decreased significantly when Cu concentration was 4.00 mg·L-1 and Zn concentration was 8.00 mg·L-1. Cu was more harmful to water spinach than Zn. The narrowleaf water spinach had a higher antioxidation ability than the wideleaf variety. Cu and Zn contents in the two water spinach varieties increased with the increasing concentrations of Cu and Zn in nutritive medium. SOD, POD, CAT and proline played a cooperative role in alleviating lowlevel Cu and Zn toxicity. Highconcentration Cu and Zn restrained the antioxidant enzyme system, while the alleviation was dominated by the nonenzymatic system. Se improved the resistibility of water spinach under Cu and Zn stress, resulting in the decrease of MDA content and increases of proline and phytochelatins (PCs) content, yield, root activity, Pn and antioxidant enzyme activity. When water spinach was slightly affected by Cu or Zn, 5.00 mg·L-1 Se could increase the yield of water spinach and provide Seenriched production. However, excess Se could exacerbate the toxicity of Cu and Zn.
    Diurnal variation characteristics of precipitation of Xinjiang in summer during 2008-2013.
    ZHU Xiao-fan, ZHANG Ming-jun*, WANG Sheng-jie, DU Ming-xia, QIANG Fang, JIN Xiao-gang, WANG Jie
    2016, 35(2):  478-488. 
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    The diurnal variation characteristics of precipitation (such as hourly precipitation amount, frequency and intensity) of Xinjiang in summer during 2008-2013 were analyzed with 0.1° gridded hourly precipitation dataset merged from automatic weather stations in China and the Climate Precipitation Center Morphing (CMORPH) precipitation product. The results showed that the diurnal variation features of hourly precipitation amount and frequency were similar; both indexes were much larger in northern Xinjiang than in southern Xinjiang and much larger in mountains than in basins, but the higher values of hourly precipitation intensity occurred more in arid basins. The values of hourly precipitation amount, frequency and intensity in most areas of Xinjiang were the largest in June and the least in August. In addition, the peak time of hourly precipitation amount and frequency had a parallel spatial pattern, and the latter was more prominent, in which the peak time of both indexes happened from 18:00 to 23:00 in mountains and from 0:00 to 5:00 in basins. Additionally, the precipitation amount in daytime and nighttime showed a similar spatial pattern. Moreover, the correlation between hourly precipitation amount and frequency was the highest, secondly by the correlation between hourly precipitation amount and intensity, while the correlation between hourly precipitation frequency and intensity was poor, especially in arid basins.
    Spatiotemporal variation of agriculture critical temperature of China from 1961 to 2013.
    GUO Fen-fen1, XIAO Jing-jing2*, ZHANG Lei3, MA Hao2, JIN Zhi-feng2, LI Zheng-quan2
    2016, 35(2):  489-498. 
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    Using datasets of daily average temperature of 559 meteorological stations over China during 1961 and 2013, the spatiotemporal distribution of variations and trends for beginning day, ending day, accumulated temperature, and average duration days between neighboring temperatures of the agriculture critical temperature were studied with statistically diagnostic methods such as 5day running mean, climatic tendency analysis as well as GIS tool. Also, the changes of different meteorological variables under different guarantee rates were studied. The characteristics of the climatic tendency rates and variation coefficients of the beginning day, ending day, accumulative temperature of the agriculture critical temperature were investigated to provide a scientific basis for making full use of climate resources, optimizing agricultural layout and crop introduction. The  results showed that the beginning day and ending day shifted earlier and later, respectively; the duration became longer and accumulative temperature gradually increased from 1961 to 2013. The magnitude of variation was closely related to latitude and geographical features of research region. The variations of the beginning day under different agriculture critical temperatures (i.e. 0, 5, 10, 15, and 20 ℃) were within the range of 97 to 123 days in northern and southern China, and the ending day, duration, and accumulative temperature were within the range of 37 to 50 days, 75 to 106 days, and 2081 to 2506 ℃·d, respectively. Additionally, the amplitude of the beginning day, ending day, duration, and accumulative temperature ranged from 25.7 to 42.9 days, 11.1 to 31.7 days, 36.7 to 60.7 days, and 157 to 1221 ℃·d, respectively in the adjacent regions with neighboring agriculture critical temperature. With the increase of guarantee rate, the beginning day, ending day, and accumulative temperature exhibited various changes in different areas. Over the Yangtze River valley, the change of beginning day above 0 ℃ was the most distinct and the magnitude could reach 2.4 to 16.3 days, while appeared slightest in South China with the magnitude was less than 1 day with the guarantee rate equal to or less than 95%. Climatic tendency rates of the beginning day, ending day, and accumulative temperature during 1961 and 2013 ranged from -7.6 to 37.3, -47.1 to 40.9, and -250 to 456 d·10 a-1, respectively; the values of their average relative variability ranged from 0 to 146.0, 4.8 to 24.5, and 1.2 to 196.2, respectively.
    Analysis of driving forces of Baiyangdian wetland evolution during 1984-2013.
    ZHANG Min1,2,3, GONG Zhao-ning1,2,3*, ZHAO Wen-ji1,2,3
    2016, 35(2):  499-507. 
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    Wetland is an ecosystem formed by the interaction of land and water, whose size is highly susceptible to climate change and human activities. In this report, we sampled Baiyangdian wetland, the largest natural lake wetland in the North China, by extracting and analyzing wetland information from the eleven remote sensing images during 1984-2013. Thirteen parameters derived from the climate, economic, population and agricultural aspects were evaluated by principal component analysis and the major driving forces affecting the wetland size were determined. The results revealed that the wetland size increased first and then decreased, followed by a slow and gradual increase with an overall descendent trend. The total area of Baiyangdian wetland was on average 25008 hm2 during 1984-1997 and 21573 hm2 during 1998-2013. Social and economic development, agricultural development and precipitation reduction were major driving factors, and social and economic developments were the most significant contributing factor. To curb the decreasing trend of the wetland size, we should effectively control the use of upstream water, improve water use efficiency, and essentially reduce the pressure of human activities on the wetland, thus naturally increasing water input in the wetland.
    Vegetation fractional coverage change in Daxinganling Genhe forest reserve of Inner Mongolia.
    YAN Min1, LI Zeng-yuan1*, CHEN Er-xue1, TIAN Xin1, GU Cheng-yan1, LI Chun-mei1,2, FAN Wen-wu1,3
    2016, 35(2):  508-515. 
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    The estimations of thirteenyear interval vegetation fractional coverage (VFC) of Genhe forest reserve area were conducted using Landsat-5 TM data acquired in 2000 and GF-1 images in 2013 based on the dimidiate pixel model. The changes of VFC and the relationships between VFC and topographical factors were analyzed. Validated against the field measurement conducted in August 2013, the estimation of VFC using GF-1 image was reliable (R2=0.52, RSE=0.54). The factor that was most positively correlated to the VFC was the altitude, followed by the slope. The VFC declined generally from 2000 to 2013 and the high level of VFC experienced the most obvious change. In particular, both VFCs in 2000 and 2013, as well as their differences which were mostly positive, increased with the altitude until 1027 m, above which the VFC changed slightly. Forest fires, rich drainage and forest tending had great impacts on the decrease of VFC in the lowaltitude mountainous region.
    Environmental DNA and its application in protecting aquatic ecosystems.
    MA Hong-juan1*, STEWART Kathryn1, MA Li-min1, REN Wen-wei1,2, ZHAO Jian-fu1
    2016, 35(2):  516-523. 
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    Environmental DNA (eDNA) refers to DNA that can be directly extracted from environmental samples (such as soil, water, air and ice core). As such, eDNA has been utilized as a new biological survey method which is comprised of capturing eDNA, gene analysis and result analysis and can be used to monitor the distribution of organisms by detecting speciesspecific target DNA. Compared with traditional biological survey methods, eDNA has been demonstrated to be more sensitive, efficient, effective and noninvasive, and importantly does not depend on ecological or natural history expertise from researchers. To date, the eDNA method has seen myriad applications such as (1) the presence/absence of rare species (invasive and endangered species), (2) the estimation of population biomass, and (3) the monitoring of aquatic ecosystem biodiversity, among others. Despite having shown brilliant potential for conservation management and the protection of ecosystems, this method has only been applied in some advanced countries and warrants expansion worldwide. eDNA methods vary from different researchers and need to be improved to standards. As a survey method, its temporal and spatial precision should also be further evaluated. The accuracy of harnessing eDNA to estimate biomass is still low; we recommend researchers understand the dynamics of eDNA generation and degradation firstly and then search the method to improve the accuracy.
    The temporal-spatial variation characteristics and influencing factors of absorbing air particulate matters by plants: A review.
    LU Ling-yue, LI Hong-yuan*, YANG Jia-nan
    2016, 35(2):  524-533. 
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    Plants can absorb and retain air particulate matters. They play an important role in reducing air pollution of particulate matters and improving air quality. Recently, studies on the plant adsorption function for sizefractionated airborne particulate matters have become a hotspot in the fields of urban ecology and environmental science. Beginning with the adsorption pathway and mechanism of the plants, this review elaborates the plant adsorption characteristics, temporal and spatial variation patterns for differentsized particles. We emphasize the analyses of crucial factors affecting particle-retaining capability, such as plant internal factors (surface property of plant leaves, plant species and their physical properties, plant community characteristics), the size and composition of air particulate matters and their pollution levels, and meteorological conditions (the velocity and direction of wind, precipitation, temperature and humidity). It is recognized that researches on adsorption mechanism and quantitative analysis methods should be strengthened in order to select and configure ideal plant species to remove particulate matters.
     
    Periphytic algae ecology in freshwater lake: A review.
    SONG Yu-zhi1,2*, ZHANG Ya-dong1, ZHENG Jian-wei2, GAO Yong-xia1
    2016, 35(2):  534-541. 
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    Periphytic algae are the major component of primary producer in freshwater ecosystems, and play an important role in nutrient cycling and distribution of submerged macrophytes. Based on the previous studies in periphytic algae ecology, we elucidated the community composition, ecological function and their main affecting factors, pointed out that periphyton algae could adapt to various environmental conditions by changing the composition of dominant species in the community, and elaborated the role of periphytic algae in nutrient cycling and the interaction between periphytic algae and submerged macrophyte. With regard to lake eutrophication, the future research topics about freshwater periphytic algal ecology include: interaction effects of main factors such as weak light and high concentration of nutrients on periphytic algae, the role of epiphytic algae in the biogeochemical cycling of carbon, nitrogen and phosphorus in lakes by insitu experiments, and the mechanism of the interaction between periphytic algae and submerged macrophyte in the eutrophic lakes.
    Research review on the characteristics of mast seeding in forest trees and its influencing factors.
    YIN Dong-sheng1,2, SHEN Hai-long1*
    2016, 35(2):  542-550. 
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    Mast seeding is one of the most peculiar reproductive behaviors observed in trees with high interannual variation at the population level following irregular intervals. Mast seeding has several demonstrated fitness benefits, including adjusting the predator population, enhancing pollination rate, increasing attraction of seed dispersers and reducing the impact of seed predators. It is an evolutionary strategy beneficial for the reproductive success of a population, but disadvantageous to high and stable yield in seed and fruit production. This paper reviewed the characteristics of mast seeding and its effects on vegetative growth and resource consumption of trees, and analyzed the main factors impacting mast seeding, including carbohydrates, mineral nutrients, hormone levels, and climate factors. Finally, the research directions for mast seeding in forest trees in China were proposed.
    Effect of male mating history on female reproductive fitness in moths: A metaanalysis.
    ZHANG Shi-yu, LI Dong, ZENG Ju-ping, WU Xian-fu, LIU Xing-ping*
    2016, 35(2):  551-558. 
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    In this study, we use a metaanalysis approach to clarify female fitness parameters (fecundity, fertility and longevity) from 29 experimental studies conducted on 27 moth species, examining how male mating history affects different components of female fitness and to determine whether the effect of male mating history is influenced by both moth family and female mating strategy. Our results clearly show that male mating history has significant negative effects on male spermatophore size or sperm numbers and female fitness consequences. These negative effects are strongly influenced by both moth family and mating strategy. Mating with experienced males significantly reduces female fecundity in Plutellidae, Crambidae, Pyralidae, Lyonetiidae, Psychidae, but not in Tortricidae, Noctuidae, while female fertility significantly decreases in Lyonetii
    dae, Psychidae, Tortricidae, Noctuidae, but not in Plutellidae, Crambidae, Pyralidae. Female longevity significantly decreases in Plutellidae, Crambidae, but increases in Tortricidae, Noctuidae when mated with experienced partners. Although male mating history has significant negative effects on female fecundity and fertility in monandrous and polyandrous moth species, mating with experienced males significantly reduces longevity in monandrous females but increases longevity in polyandrous females. Our results strongly support that male mating history is one of the crucial factors influencing female fitness consequences in moth species.