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Table of Content
    Volume 31 Issue 6
    30 November 2007
    Research Articles
    YU Shun-Li, CHEN Hong-Wei, LI Hui
    Chin J Plan Ecolo. 2007, 31 (6):  989-997.  doi:10.17521/cjpe.2007.0126
    Abstract ( 3055 )   PDF (312KB) ( 2100 )   Save
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    Seed mass is a key attribute of plant species, and study of relationships between seed mass and other plant traits and
    ecological characteristics has become a practical problem and an interesting topic in evolutionary biology. Seed mass (or
    size) is related to other plant traits and community characteristics, including seed dispersal capacity, seed dispersal mode,
    plant growth form, leaf area index, abundance of seeds or plant individuals in a community, seed predation, seed dormancy and
    seed persistence in soil seed banks, net primary productivity, etc. Variations in seed mass have been related to latitude,
    longitude, altitude, temperature, precipitation, slope aspect, light environment, etc. Seed mass is thought to have evolved
    as a compromise between seed mass and number for a given amount of energy. Many studies support that seed mass has a closer
    relationship with plant growth types than other characteristics. Species that establish in shade have large seeds. Three
    patterns were found in the relationship between seed mass and seed predation. Four patterns were found in the relationship
    between seed mass and persistence in soil seed banks. During establishment, seedlings from larger-seeded species are better
    able to survive competition from established vegetation, deep shade, defoliation, mineral nutrient shortage, burial under
    soil or litter, drought, etc. Among species with seeds unspecialized for spatial dispersal, seed mass is unrelated to
    dormancy. However, in species with wind- or animal-dispersed seeds those with heavy seeds typically have less dormancy. This
    is consistent with heavy seeds having better establishment success and/or suffering higher levels of herbivory. Future
    research should focus on relations hips between seed mass ecology and 1) plant phylogeny and plant taxonomy, 2) latitude,
    longitude and altitude, 3) community succession, 4) number of plant individuals and seeds, 5) microhabitats or
    microtopography such as forest gaps and slope aspect and 6) global climate changes.
    DU Yan-Jun, PENG Shan-Jiang, XU Guo-Liang, HUANG Zhong-Liang, HUANG Yu-Jia
    Chin J Plan Ecolo. 2007, 31 (6):  998-1006.  doi:10.17521/cjpe.2007.0127
    Abstract ( 2491 )   PDF (482KB) ( 1196 )   Save
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    Aims The Janzen-Connell hypothesis is that seed survival improves with increased distance from the parental plant. Our
    objectives were to determine whether the Janzen-Connell hypothesis (1) is supported by Castanopsis chinensisseed survival,
    (2) can forecast the population’s distribution pattern, and (3) explains the reason for limited recruitment.
    Methods We selected three mature C. chinensis trees in coniferous and broad-leaved mixed forest of Dinghushan, China and
    recorded seed mortality with Open treatments (OP), Small Mammal Exclusion experiments (EM) and pathogen infection treatments
    at 3, 10, and 15 m from the trees. 
    Important findings In the OP treatment, the number of missing seeds was largest at 10 m; however, seed predation was not
    significantly affected by distance from tree and seed size. In the EM treatment, few seeds were missing in the first week,
    and seed predation was not significantly affected by distance and seed size during the study period. In the first two months,
    seeds with Caoton treatment remained intact, and from the third to the sixth month, the number of seeds infected by pathogens
    was significantly affected by distance and disinfecting action. After the sixth month, the number of seeds infected by
    pathogens was relatively constant. These results illustrate that pathogens are related to mortality of seeds of C. chinensis
    and that this mortality is distance dependent, while the mortality caused by vertebrate animals is not distance dependent.
    ZHAO Xue-Jie, TAN Dun-Yan
    Chin J Plan Ecolo. 2007, 31 (6):  1007-1018.  doi:10.17521/cjpe.2007.0128
    Abstract ( 3041 )   PDF (606KB) ( 1833 )   Save
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    Selective abortion in seed plants means selective abortion of developing fruits/seeds based on pollen source, order of
    pollination, location of fruits on plant, number of developing seeds, or some combination of these. In species with linearly
    arranged ovules, such as occurs in members of Fabaceae, embryos at the peduncular, stigmatic, or both ends of the fruit can
    be selectively aborted. Position of fruit within the inflorescence also has a marked effect on abortion. Selective abortion
    has been documented in many species of Fabaceae, Brassicaceae and Boraginaceae. The primary factor causing selective abortion
    of fruit and/or seeds is resource limitation. Competition for limited maternal resources occurs among fruits and seeds. Thus,
    those that are initiated first and have the faster rate of growth can capture more maternal resources and thus are less
    likely to be aborted than those that are initiated later. 
    Genetically correlated factors also can result in selective abortion. In some species, fruits from cross-pollinated
    flowers tend to have more seeds that a re more likely to mature than fruits from self-pollinated flowers. Methods used to
    investigate selective abortion include 1) removing a fraction of the ovules at an early stage, 2) hand-thinning some young
    fruits or flowers, and 3) using molecule techniques of RAPD and isoenzyme analyses. Selective abortion can increase offspring
    quality. Progenies that are selectively matured have higher vigor, germinate to higher percentages, produce more leaves,
    inflorescences and flowers, and mature more seeds than those that are randomly matured. Aborting some seeds also can reduce
    wing load (ratio of fruit weight to fruit surface area), improve dispersal distance, and decrease sibling rivalry. Thus,
    selectively aborting some selfed and/or inferior genotype fruits/seeds increases the fitness of the maternal plant, its
    offspring, or both. Therefore, research on selective abortion is important to understanding patterns of fruit-set and/or
    seed-set and its evolutionary pattern and mechanism in angio sperms. 
    We review recent advances in selective abortion research in angio sperms, with emphasis on 1) patterns of selective abortion;
    2) factors affecting selective abortion; 3) evolutionary, ecological significance of selective abort ion; and 4) primary
    methods used to investigate selective abortion. We also discuss prospects for further research.
    LIU Xiao-Feng, TAN Dun-Yan
    Chin J Plan Ecolo. 2007, 31 (6):  1019-1027.  doi:10.17521/cjpe.2007.0129
    Abstract ( 2706 )   PDF (620KB) ( 1320 )   Save
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    Aims Members of Brassicaceae are one of the most important groups of ephemeral plants in the Junggar Basin and serve many
    ecological roles in the desert. However, studies on dispersal syndromes of Brassicaceae, especially the ephemerals, are rare.
    This study addresses the following questions: 1) what are the dispersal unit and the dispersal mode of these species, 2) what
    are the spatio-temporal patterns of dispersal of these species and 3) how are these characters adaptive to the arid desert
    Methods The study was conducted on 24 ephemeral species of Brassicaceae from June to October 2005 and 2006. We observed and
    recorded 1) morphology of the fruit s and seeds, 2) dehiscence mode of the fruit, type of dispersal unit and accessory
    structures and 3) dispersal mode and its duration in natural habitats.
    Important findings The dehiscence mode of fruit depends on degree of lignification. There are three types of dispersal units
    of the species whose pods cannot dehisce. Species whose dispersal unit is the fruit node are autochorous. Species in which
    dispersal occurs by the whole fruit have silicula. Some do not have accessory structures to dispersal, and the dispersal mode
    is autochorous. Others have wings or hairs and disperse by wind. Species whose dispersal unit is a section of the
    infructescence also have silicula with a hard and hook-like beak that can attach to the coat of animals. Species with pods
    that dehisce easily only disperse by seeds. Their seeds have three types. One type is tiny without any accessory structures
    for dispersal, and seeds are dispersed by wind. Seeds in the second type have wings, and their modes of dispersal are
    diverse, but the main one is hydrochory. Seeds in the third type have wings and mucilage and are dispersed by anemochory and
    hydrochory. There are two types of dispersal patterns, depending on duration of dispersal. The first type is the short-term
    dispersal pattern in which all dispersal units on the plant are dispersed from the mother plant mainly in June and July. In
    the second type, dispersal units are shed from the mother plant from June to October or even the next spring. In this
    pattern, pods in the upper and lower positions of one infructescence differ in morphology, degree of lignification, kind of
    dispersal unit, dispersal time and dispersal mode.
    YU Yang, CAO Min, ZHENG Li, SHENG Cai-Yu
    Chin J Plan Ecolo. 2007, 31 (6):  1028-1036.  doi:10.17521/cjpe.2007.0130
    Abstract ( 2631 )   PDF (526KB) ( 1280 )   Save
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    AimsPometia tomentosais the major dominant species in the tropical seasonal rain forests of Xishuangbanna, Southwest
    China. It is listed in the rare and endangered species in China. Research on seed and seedling ecology of P. tomentosamay
    provide information for rare and endangered species conservation and forest restoration.
    Methods Shade house and forest experiments were designed to investigate light effects on seed germination and seedling
    establishment of P. tomentosa. Seedling growth, biomass allocation and physiological properties of P. tomentosa were examined
    in neutral-density shade houses, which were used to mirror different light levels in centers of forest gaps, at edges of
    forest gaps and forest understory.
    Important findings Results showed that final seed germinations in all treatment s were greater than 95% and occurred within
    six days. Seedlings in 30% light treatment had the highest root mass ratio (RMR) and stem mass ratio (SMR). However,
    seedlings in 10% and 3.5% light treatments had the highest leaf mass ratio (LMR). Seedling s grown in low light environments
    (such as 10% and 3.5% light treatments) had a higher leaf area ratio (LAR) than those in high light (30% light treatment).
    Seedlings in 30% light treatment had the highest maximum photosynthetic rate (Pnmax), dark respiration (Rd) and light
    saturation point (Isat), but the compensation point (Icomp) was not significantly different among the three light
    treatments. Seedlings of P. tomentosawere able to grow slowly and survive for a long time; therefore, it is a shade
    tolerant species. Also, seedlings of shade houses showed increased RGRM and RGRH in high light comparing with low light. It
    is concluded that gaps in the forest canopy are probably necessary for successful regeneration of P. tomentosa. Soil moisture
    also may affect the habitat selection of P. tomentosa seedlings.
    WANG Ju-Hong, CUI Xian-Liang, CHEN Xue-Lin, DU Guo-Zhen
    Chin J Plan Ecolo. 2007, 31 (6):  1037-1045.  doi:10.17521/cjpe.2007.0131
    Abstract ( 2871 )   PDF (418KB) ( 1821 )   Save
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    Aims Seed germination and seed size are crucial plant life history traits related to seedling establishment, survival,
    competition and fitness. Study of germination ecology of native species not only increases understanding of seed traits,
    reproductive strategy and physiological adaptation, but also can be applied in ecological restoration. Mesad and siccocolous
    species with different water requirements may have different life-history strategies to respond to different selective
    pressures. Our main purposes were to determine: 1) differences in germination characteristics between mesad and siccocolous
    species in the arid and semiarid zone and 2) relationship of germination to seed size. 
    Methods Seeds of 42 mesad and 22 siccocolous species from the Hexi Corridor of Northwest China were air-dried, cleaned and
    stored at room temperature about 3-4 months and then stored at 2-4 ℃ for 40 d. Germination was determined under an
    alternating temperature regime (25 ℃/5 ℃; 12 h light/dark). Four main germination indices were recorded: germination
    percentage, germination rate, days to first germination and germination period. PCA was used to survey the germination patter
    ns of the 64 species, and Pearson Correlation Analysis was used to determine the relationship of seed size and germination.

    Important findings There are four main germination patterns: rapid, intermediate, slow and low germination. Low germination
    percentages (≤20%) were found in 1 4.28% mesad and 50% siccocolous. There are significant differences in seed size between
    mesad and siccocolous (p=0.003). There also is a significant negative correlation between germination and seed size in mesad,
    with smaller-seeded specie s having higher germination percentages (r=-0.467, p=0.002) than larger-seeded ones, but not in
    siccocolous (p>0.05). Findings indicate that mesad and siccocolous species under different water conditions are subjected to
    different selective pressures and have evolved different life-history strategies.
    WANG Hong-Fei, WEI Yan, HUANG Zhen-Ying
    Chin J Plan Ecolo. 2007, 31 (6):  1046-1053.  doi:10.17521/cjpe.2007.0132
    Abstract ( 2488 )   PDF (429KB) ( 1176 )   Save
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    Aims Salsola bracchita has four types of perianth-enclosed utricles, utricles and seeds. We investigated the role of utricle
    polymorphism in seed dispersal and germination to better understand how S. bracchita is adapted to its desert habitat.
    Methods Twenty plants of S. bracchita were selected randomly to observe the morphology of perianth-enclosed utricles,
    including persistence of perianth and wings, utricle shape and color and location of fruit on mother plant. Seeds of the
    four types were germinated in incubators with 12 h photoperiod and 12 h thermo periods (dark/light) of 5 ℃/15 ℃, 5 ℃/25 ℃
    , and 15 ℃/25 ℃ for 20 d. Type D seed was scarified and then germinated for 20 d at the three different thermo periods to
    determine its dormancy characteristics. 
    Important findings Salsola bracchita produces four types of fruits (utricles) that differ in shape, size, seed color and
    external structure. Type A and B fruits can be dispersed by wind far from mother plants. Germination percentages of type A
    seeds at all three thermo periods were >70%, and there were no significant differences (p>0.05). Germination percentages of
    type B seeds were all >68%, and there were significant differences (p<0.05), with highest germination percentage and
    germination index at 5 ℃/25 ℃ (dark/light) (>80%). Type C fruits have tepals without wings and are dispersed near mother
    plants. Germination percentages of type C seeds were all >80%, and there were no significant differences (p>0.0 5). Rate and
    final percentages of germination of type B and type C seeds were higher than that of type A seeds. Type D fruits also are
    mainly dispersed near mother plants. Freshly matured type D seeds are in physiological dormancy because its germination is
    slow and low (<20%). Seed coat scarification of type D seeds can hasten and increase the seed germination percentage (p<0.01)
    and germination index (p<0.01) in each of the thermo periods.
    LI Xia, LI Xiao-Bing, CHEN Yun-Hao, YING Ge
    Chin J Plan Ecolo. 2007, 31 (6):  1054-1062.  doi:10.17521/cjpe.2007.0133
    Abstract ( 2689 )   PDF (339KB) ( 1397 )   Save
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    Aims Vegetation has strong temporal response to climate variables in some regions. The normalized differential vegetation index (NDVI) is generally recognized as a good indicator of terrestrial vegetation, so it can be used to analyze temporal responses of vegetation to climate variables. This study addresses two key questions: a) How quickly and over what time period does NDVI respond to different patterns of climate variables? b) How does NDVI respond to weather variation for different temperate steppe types of northern China? 
    Methods We calculated 1) linear correlations between monthly climate variables and NDVI for 1983-1997, 2) NDVI-precipitation correlation coefficients, with precipitation in four different time periods (1-4 months) and four different time lags (0-3 month lags) to evaluate the time period over which precipitation most strongly influences on NDVI and 3) NDVI-temperature correlation coefficients for the current and previous month.
    Important findings The correlation coefficients between NDVI and concurrent climate variables were all significant in three temperate steppe types. There is a strong relationship between precipitation and NDVI in temperate steppe of northern China. Correlation coefficients between NDVI and precipitation are high for specific combinations of time duration and lag. In terms of time lag, NDVI was most strongly related to the previous month, although differences existed among different steppe types. In terms of time duration, NDVI was most strongly related to the sum of precipitation over three months than one, two or four month periods. Precipitation from February back to November of the previous year was positively correlated with NDVI early in the growing season in meadow steppe, and there was a strong correlation between NDVI and recipitation for the preceding 1-2 months in the mid and late growing season in desert steppe and typical steppe. Temperature was moderately correlated with NDVI during the growing season, but differences existed among steppe types. For typical steppe and meadow steppe, temperature was positively correlated with NDVI early in the growing season. For desert steppe, NDVI was moderately related with temperature early in the growing season and negatively correlated with temperature in the mid growing season.
    LIU Hai-Jiang, CHENG Wei-Ming, LONG En
    Chin J Plan Ecolo. 2007, 31 (6):  1063-1072.  doi:10.17521/cjpe.2007.0134
    Abstract ( 2333 )   PDF (1226KB) ( 888 )   Save
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    Aims Landscape pattern can indicate ecosystem changes. The Otindag Sandy Land, which is located in the southeastern Inner
    Mongolia Plateau, has been degraded by overgrazing in the past two decades. The purposes of this study are to 1) analyze
    spatial-temporal dynamics of landscape pattern, 2) determine whether landscape pattern can be used as an indicator of
    ecological degradation, and 3) explore underlying ecological processes that triggered alteration of landscape pattern.
    Methods Our approach integrated remote sensing and geographic information system (GIS). The basic sources of data were two
    Landsat TM/ETM+ satellite images from 1987 and 2000 and field data collected in summer 2001 and 2002. From the images, we
    distinguished six landscape types within our study area: grassland, fixed sandy land, semi-fixed sandy land, mobile sandy
    dune, shrub and water body. We performed a supervised classification procedure to derive landscape maps. Using GIS, we
    analyzed the resultant landscape maps by change detection analysis and transition matrix analysis.
    Important findings Great change occurred at our study area from 1987 to 2000. Total area of grassland, fixed sandy land and
    semi-fixed sandy land decreased and patch fragmentation increased. Total area of mobile sandy dune increased about 2.5 times
    and patches expanded and combined into two sand belts. Change detection showed the same tendencies. Transition of landscape
    types included grassland converted mainly to sandy land, fixed sandy land transformed into semi-fixed sand y land and semi-
    fixed sandy land changed mainly to active sandy land. The ecosystem in this region seriously degraded from 1987 to 2000, and
    effective measures should be taken to prevent further environmental deterioration.
    WANG Wen-Ying, WANG Qi-Ji, WANG Gang, JING Zeng-Chun
    Chin J Plan Ecolo. 2007, 31 (6):  1073-1078.  doi:10.17521/cjpe.2007.0135
    Abstract ( 2660 )   PDF (270KB) ( 975 )   Save
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    Aims Our objectives were to compare vegetation biomass and total carbon and nitrogen content of severely degraded grassland
    and undisturbed Kobresia meadow, and to measure the relative influence of various rehabilitation practices on vegetation
    biomass and carbon and nitrogen content in early secondary succession. 
    Methods The research was conducted on alpine meadows in Dari County, Qinghai Province, China, using five treatments:
    undisturbed native meadow, severely degraded grassland, and three grasslands rehabilitated by different practices (mixed
    seeded , single seeded and natural recovery). In each treatment, vegetation C and N contents were calculated on an area and
    depth basis from biomass samples and plant concentration analyses. 
    Important findings In the undisturbed native meadow treatment, total aboveground biomass was 265.1 g&#8226;m-2 and root biomass
    in the uppermost 30 cm averaged 6 982 g&#8226;m-2. In the severely degraded grassland treatment, above ground biomass was only
    139.9 g&#8226;m-2 and root biomass was only 916 g&#8226;m-2. Total aboveground biomass in the mixed seeded, single seeded and natural
    recovery treatments was 307.1, 179.9 and 200.4 g&#8226;m-2, and root biomass was 1 323, 1 169 and 1 412 g&#8226;m-2, respectively,
    after seven growing seasons. Total C content of vegetation in the undisturbed native meadow was 3 067.42 g&#8226;m-2, while that
    of the severely degraded grassland treatment was only 414.07 g&#8226;m-2. Therefore, land degradation leads to loss of 86.5% of
    the original plant tissue C. In addition, land degradation leads to loss of 68.3% of the original plant tissue N. Compared
    with the severely degraded land, mixed seeded and natural recovery treatments partly recover C and N content, indicating that
    they may be alternative approaches to sequestering C in former degraded alpine meadow.
    ZHANG Zhi-Dong, ZANG Run-Guo
    Chin J Plan Ecolo. 2007, 31 (6):  1079-1091.  doi:10.17521/cjpe.2007.0136
    Abstract ( 2630 )   PDF (563KB) ( 1205 )   Save
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    Aims Our major objectives were to 1) identify keystone species within the context of functional groups, 2) develop potential
    distributional predict ions for keystone species using ecological niche model, 3) confirm factors determining potential
    distributions of keystone species, and 4) test if the performances of ecological niche model are better than those of a
    random model and differ in predicting different keystone species.
    Methods Based on the investigation of 135 plots in a natural tropical forest landscape, we classified woody plant functional
    groups based on successional status and potential maximum height. Keystone species within each functional group we re
    identified using a dominance index (DI). We used the genetic algorithm for rule-set prediction (GARP) to estimate the
    keystone species’ potential distribution and then used the receiver operating characteristics to evaluate predictive
    performance. Applying multiple linear regression analysis, we identified major factors determining potential distributions of
    keystone species.
    Important findings Identification of keystone species within pioneer species, climax shrub and emergent tree functional
    groups was clearer than within climax subcanopy and climax canopy tree functional groups. Generally, among the eight keystone
    species, pioneer species Melastoma sanquiueum, Aporosa chinensis and Liquidambar formosana (but not Adinandra hainanensis)
    have high probability of occurrence in the north, west and southwest regions of Bawangling. However, climax species
    Psychotria rubra, Ardisia quinquegona and Castanopsis hainanensis (but not Pinus merkusii) have high probability of
    occurrence in the central, southeast and south regions. Minimum and maximum temperature, mean annual temperature and
    precipitation, aspect and altitude were the key factors determining potential distributions of keystone species. Evaluation
    of GARP model’s performance indicated excellent predictive ability of all eight keystone species’ distribution. This study
    suggests the DI method is more suitable to identify keystone species with in woody plant functional groups in which a single
    or a few species are dominant. Findings will assist decision makers in planning conservation and management policies in
    tropical rainforest areas.
    ZHANG Zhi-Dong, ZANG Run-Guo
    Chin J Plan Ecolo. 2007, 31 (6):  1092-1102.  doi:10.17521/cjpe.2007.0137
    Abstract ( 2456 )   PDF (433KB) ( 1072 )   Save
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    Aims The relative influence of ecological factors on the distribution of woody plant functional types in a natural tropical
    forest landscape is rarely explored. The three major objectives of this study were to 1) determine the relative importance of
    environment, anthropogenic disturbance and spatial influences on the distribution of woody plant functional types, 2)
    determine which variables influence distribution of woody plant functional types, and 3) examine the distribution of woody
    plant functional types in different habitats.
    Methods Using data from 135 plots in a natural tropical forest landscape of Hainan Island, South China, we classified woody
    plant functional types using the characteristics of species wood density and potential maximum height. Three sets were used,
    presence-absence, species richness and abundance. Their relations to environment, anthropogenic disturbance and spatial
    factors were analyzed with redundancy analysis (RDA). We then used a partial RDA with variation partitioning to specify which
    proportion of the variation in functional types distribution pattern is explained by each of the three factors individually
    and which proportion is attributable to interactions between factors. 
    Important findings We found that environmental influence, anthropogenic disturbance and interaction between environmental
    and anthropogenic disturbance factors were of similar importance in functional types distribution. However, spatial
    influence and interaction between spatial and other factors were less important. Furthermore, we found that anthropogenic
    disturbance types, topographical factors, soil types, grit content, soil depth and X, Y coordinates all impacted the
    distribution of functional types. Generally, hardwood functional types are abundant in better, undisturbed sites, but
    softwood functional types occur in opposite settings. The distributional range of medium hardwood functional types is wider
    than the other two. Except for softwood shrub functional types, the others have high species richness and abundance in better
    sites, especially where soils are deep. This study suggests that the plant functional type approach enhances understanding of
    the relative influence of environment, anthropogenic disturbance and spatial factors on species distribution. Environment and
    anthropogenic disturbance are more important than spatial influence in the variation of species distribution. These
    conclusions can aid in developing large-scale conservation and management policies in tropical rainforest areas.
    LIN Hua, CAO Min, ZHANG Jian-Hou
    Chin J Plan Ecolo. 2007, 31 (6):  1103-1110.  doi:10.17521/cjpe.2007.0138
    Abstract ( 2493 )   PDF (415KB) ( 1167 )   Save
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    Aims Energy allocation pattern is the basis for understanding energy flow processes in ecosystems. High structure
    complexity and species diversity of tropical forests, however, have resulted in little research on caloric values and energy
    allocation patterns in tropical rain forests. Tropical seasonal rain forest (TSRF) in Xishuangbanna, Southwest Yunnan is
    distributed on the northern edge of tropical Asia, and montane evergreen broad-leaved forest (MEBF) is located in subtropical
    mountain areas of middle Yunnan. Our objectives are to examine the energy allocation pattern of the two forests and test the
    hypothesis of Golley (1961, 1969) that caloric values of vegetation tend to increase with the altitude and latitude. 
    Methods Caloric values were measured with a SDCM-Ⅲa oxygen bomb calorimeter. Energy allocation and sequestration were
    estimated based on biomass and biomass increment in a 1 hm2 plot in each forest. 
    Important findings The caloric value of the TSRF plot was lower than that of the MEBF plot. Caloric values decreased from
    tree layer to shrub layer to herb layer. Leaves showed the highest caloric values of any plant part. Due to an understory
    plantation of Amomum villosum, which had removed almost all saplings and seedlings, the TSRF plot stored less energy than
    the MEBF plot, although it still maintained a high energy sequestration rate for tropical habitats with high temperature,
    humidity and intensive solar radiation. The tree layer stored 97% of the energy in the TSRF plot and 88% in the MEBF plot,
    suggesting that tree layer plays a key role in the maintenance of energy structure in the two forests. Our results support
    Golley’s hypothesis.
    LUO Yun-Jian, ZHANG Xiao-Quan, HOU Zhen-Hong, YU Peng-Tao, ZHU Jian-Hua
    Chin J Plan Ecolo. 2007, 31 (6):  1111-1118.  doi:10.17521/cjpe.2007.0139
    Abstract ( 2349 )   PDF (441KB) ( 1195 )   Save
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    Aims Larix forest is important in northern China. Our objective was to understand its biomass carbon accounting factors:
    biomass conversion and expansion factor (BCEF), biomass expansion factor (BEF), root-shoot ratio ( R) and community biomass
    expansion factor (CBEF). 
    Methods We collected data on biomass and related parameters for natural forests and plantations from published literature,
    calculated carbon accounting factors , and analyzed their relationships to stand age (A), diameter at breast height (DBH) and
    stand density (D). Natural forests and plantations were analyzed separately. 
    Important findings Mean BCEF for Larix forests was 0.683 4 t&#8226;m-3 (n=113, SD=0.355 1), and BCEF for natural stands (0.555 1
    t&#8226;m-3 (n=56,SD=0.058 2)) was significantly smaller than for plantations (0.809 5 t&#8226;m-3 (n=57, SD=0.465 0)) (p<0.05). Mean
    BEF was 1.349 3 (n=134, SD=0.384 4),and plantations had larger meanBEF value (1.176 3 (n=63, SD=0.039 9)) than natural
    stands (1.502 9 (n=71,SD=0.478 0)) (p<0.05) . Values of BCEF and BEF for natural forests increased exponentially with
    increasing A and DBH and decreased exponentially with increasing D. MeanR was 0.245 6 (n=156, SD=0.092 6), and there was no
    significant difference between natural forests (0.237 6 (n=64, SD=0.061 8)) and plantations (0.251 1(n=92, SD=0.109 0))
    (p<0.05). R value of natural stands increased exponentially with increasing A andDBH, but decreased with increasing D.
    Moreover, R values of plantations had no significant correlations to A, DBH and D. Mean CBEF was 1.102 0 (n=51, SD=0.150 5),
    and the CBEF value of natural forests (1.139 8 (n=31, SD=0.177 8)) was larger than plantations (1.043 4 (n=20,SD=0.061 4))
    (p<0.05). Due to significant differences between natural forests and plantations, it is better to account biomass carbon
    stock for natural forests and plantations separately. The relationships of these biomass factors (i.e. BCEF vs. D and BEF vs.
    D of plantations and CBEF of natural forests and plantations) deserve further study.
    MI Na, YU Gui-Rui, WANG Pan-Xing, WEN Xue-Fa, SUN Xiao-Min, ZHANG Lei-Ming, SONG Xia, WANG Shu-Sen
    Chin J Plan Ecolo. 2007, 31 (6):  1119-1131.  doi:10.17521/cjpe.2007.0140
    Abstract ( 2179 )   PDF (940KB) ( 1280 )   Save
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    Aims Seasonal drought frequently occurs in the mid-subtropical region of China and commonly combines with high temperature.
    Our objectives were to test the sensitivity of carbon exchange to this seasonal drought and discuss the influence of seasonal
    drought on carbon assimilation.
    Methods We used flux measurements obtained from eddy covariance technology since October 2002 over a human-planted forest
    ecosystem at Qianyanzhou (QYZ) (26°44′N, 115°03′E, 110.8 m als.). The EALCO (ecological assimilation of land and climate
    observations) model is parameterized to simulate the ecosystem carbon exchange process in the human-planted evergreen forest.
    Simulation results were validated using half-hourly carbon fluxes and daily and annual GPP (gross primary production),NEP
    (net ecosystem production) and TER (total ecosystem respiration) estimated from eddy covariance measurements. 
    Important findings In general, the model can effectively simulate the two years ’ carbon fluxes among soil-plant-atmosphere
    on hourly, daily and annual scales. Both simulations and observations showed strong impact of drought on GPP in 2003.
    Compared with 2004, the annual GPP in 2003 was 12.9% lower according to observations (1 610 vs. 1 865 gC&#8226;m-2) and 11.2%
    lower according to model results (1 637 vs.1 844 gC&#8226;m-2). The diurnal variations ofNEP from both observations and
    simulations during the period of soil water deficit showed asymmetric format, i.e., the peak value of carbon exchange accrued
    at a certain time in the morning and t hen decreased with time. Modeling results indicated that water stress has more
    influence on photosynthesis than TER, which led to the decrease of NEP. Further analysis suggested that deep soil water
    content controls canopy photosynthesis in sunny days before noon during soil water stress. Afternoon, both high temperature
    and deep soil water content eliminate the GPP, and their elimination percents are equal. On cloudy days, radiation and deep
    soil water content primarily determine the photosynthesis, and temperature becomes a generally minor controlling factor.
    LI Yi-Jun, XU Zhen-Zhu, WANG Yun-Long, ZHOU Li, ZHOU Guang-Sheng
    Chin J Plan Ecolo. 2007, 31 (6):  1132-1144.  doi:10.17521/cjpe.2007.0141
    Abstract ( 2433 )   PDF (859KB) ( 1406 )   Save
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    Aims Agroecosystems are influenced strongly by human activity and climate change. In order to scientifically manage
    agroecosystems under climate change, it is important to understand water exchange and energy transfer between agroecosystems
    and the atmosphere. We analyze latent and sensible heat fluxes of a maize agroecosystem as a case study.
    Methods Latent and sensible heat fluxes were measured in a maize agroecosystem using a 3.5 m eddy covariance tower from
    June 2004 to December 2005 at the Jinzhou maize agricultural ecosystem field observation station (Liaoning Province, China).
    Meteorological factors were recorded using sensors at 2.3 and 4.1 m using a micrometeorological tower. 
    Important findings Diurnal and annual variations of latent heat fluxes and sensible heat fluxes had the same characteristics
    as net radiation and could be expressed as hyperbola curves. Their peak values appeared at 12∶00-13∶00. The maximum latent
    heat flux was about 655 w&#8226;m-2 (at 13∶00 July 8, 2004), and the maximum sensible heat flux was 369 w&#8226;m-2 (at 13∶00 May 31,
    2004). The intensities of latent heat fluxes and sensible heat fluxes had close relationships with environmental factors.
    Latent heat flux was negatively correlated with atmospheric pressure, and sensible heat flux was positively correlated with
    air temperature. Fluxes of latent and sensible heat were very sensitive to precipitation. Latent heat flux was greatly
    affected by the intensity and timing of precipitation, regardless of seasonal and daily changes. Energy of the maize
    agroecosystem was unbalanced with the loss of about 15.5%, possibly because of lack of knowledge of 0-5 cm soil heat reserve
    and canopy heat reserve. The energy balance had obvious differences between cloudy and rainy days, with the loss of energy
    much less on rainy than cloudy days, especially with a surplus of energy on rainy days in August.
    WANG Hai-Tao, HE Xing-Dong, GAO Yu-Bao, LU Jian-Guo, XUE Ping-Ping, MA Di
    Chin J Plan Ecolo. 2007, 31 (6):  1145-1153.  doi:10.17521/cjpe.2007.0142
    Abstract ( 2394 )   PDF (594KB) ( 1138 )   Save
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    Aims Using environmental spatial heterogeneity to explain the heterogeneity of vegetation is an important issue in ecology.
    We approached relationships between the spatial heterogeneity of soil moisture, organic matter and densities of Artemisia
    ordosica and A. frigida in a successional community of A. ordosica.Our objective was to discuss stability mechanisms of
    the plant community based on changes in spatial heterogeneity.
    Methods The study area is located at Tengri Desert (arid zone), which belongs to Alashan League of Inner Mongolia. Our
    sample plot was 80 m× 80 m, which contained 400 quadrats (4 m×4 m). In every quadrat, we determined soil moisture at 40 cm
    depth (oven-drying method) and soil organic matter at 0-5 cm top soil (potassium dichromate volumetric method), and recorded
    density of A. ordosica and A. frigida. We analyzed densities in response to the spatial heterogeneity of soil moisture and
    organic matter using statistics and geostatistics.
    Important findings The spatial heterogeneities of densities of A. ordosica and A. frigida were related to soil moisture and
    organic matter at the plot-scale (80 m×80 m). There were a significant positive linear correlation between the
    heterogeneities of the density of A. frigida and moisture and a significant positive power cortelation between heterogeneties
    of the density of A. ordosica and soil organic matter. We suggest that A. ordosica enriched the content of organic matter,
    thus promoting establishment of A. frigida.Both A. frigida and A. ordosica had clumped distributions, which enhanced soil
    spatial heterogeneity. Findings indicate a competitive displacement relationship between the two species. Thus, changes of
    soil spatial heterogeneity are factors in A. ordosica community succession in semi-desert zone.
    JIN Sen
    Chin J Plan Ecolo. 2007, 31 (6):  1154-1160.  doi:10.17521/cjpe.2007.0143
    Abstract ( 2328 )   PDF (395KB) ( 968 )   Save
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    Aims Anand & Orlóci (1996) proposed a method measuring the total, disordered and organized complexity of community structure
    using the mean length o f Huffman code, the 12th order of Rényi entropy, and the difference between the se two measures,
    respectively. This method is quite different from measures based on community biodiversity and is potentially of great
    significance. Although some properties of the measures were discussed by Anand & Orlóci (1996), a thorough study has not been
    conducted, especially on their ecological meaning. The purpose of the paper is to reveal: 1) factors affecting the measures
    and their ecological meaning, 2) relationship between complexity and biodiversity, and 3) effect of species number on
    structural complexity.
    Methods First, >4 000 000 simulated communities with different structures were constructed by two methods: evenly
    distributed mode and dominated mode. Then the three complexity measures were computed. Correlation analyses were conducted
    between these measures and potentially related factors such as Shannon-Wiener index, coefficient of variation and logarithmic
    proportion of most dominated species. Multiple linear regressions between the complexity measures and combination of these
    factors were carried out to explore the relationship between complexity and biodiversity. Communities with different species
    number were then constructed and tested to explore the effect of species number on complexity measures.
    Important findings The three complexity measures are strongly correlated with the Shannon-Wiener index, coefficient of
    variation and logarithmic proportion of the most dominated species. For total complexity, the correlation coefficient between
    it and the Shannon-Wiener index is nearly 1 (0.996), so is that between the 12th order of Rényi entropy and logarithmic
    proportion of the most dominated species. The determining coefficient of multiple linear regression between organized
    complexity and Shannon-Wiener index and logarithmic proportion of the most dominated species is also near 1 (0.97). These
    findings suggest that all three measures of community structural complexity are affected by the Shannon-Wiener index,
    coefficient of variation and logarithmic proportion of the most dominated species. For organized structural complexity, it
    can be expressed as a linear combination of Shannon-Wiener index and logarithmic proportion of the most dominated species.
    Biodiversity can explain 41~46% of variation of organized structural complexity. Although the three complexity measures
    increase with number of species, they do not increase as much as described by Anand & Orlóci (1996), and it does not affect
    the relationship between the complexity measures and related factors.
    HUANG Gang, ZHAO Xue-Yong, SU Yan-Gui
    Chin J Plan Ecolo. 2007, 31 (6):  1161-1167.  doi:10.17521/cjpe.2007.0144
    Abstract ( 2925 )   PDF (307KB) ( 1272 )   Save
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    Aims We selected three representative grasses in Horqin Sandy Land and measured their root dynamic by minirhizotrons, a
    nondestructive, in situ method for directly viewing and studying root dynamics. 
    Methods The experiment was conducted on three quarters (2 m×2 m) of Naiman Desertification Research Station, Chinese
    Academy of Sciences during the 2005 growing season. The sandy soil was transported from a sandy dune and sifted through a 0.5
    mm sieve. On May 15, seeds of Setaria viridis, Artemisia scoparia and Agriophyllum squarrosum were cultivated in each
    quarter, respectively. Three minirhizotrons (50 cm long and 7 cm outer diameter) per treatment were installed at right
    angles. A black cover blocked light from entering the section of the transparent tube left above ground. For each treatment,
    three tubes were installed in the center parallel to the plant row, 10 cm from the row. Each quarter was supplied with enough
    water until June 5, and thereafter precipitation was the only water source. According to plant needs, seedlings of three
    grasses were kept 15 cm apart in rows and 20 cm apart between rows. The number of roots on the minirhizotron wall was
    obtained using a mirror, and root length was estimated counting the number of intersections of roots with a 1 cm-mesh grid,
    using the modified Newman-Line-Intersect method.
    Important findings The curves of total root number of S. viridis and Artemisia scoparia after seed germination fitted a
    cubic regression model, while that of Agriophyllum squarrosum showed exponential increase. The production of S. viridis and
    Artemisia scoparia peaked by the end of July or the beginning of August and then decreased, while Agriophyllum squarrosum
    showed an opposite trend. Roots of S. viridis were concentrated within the top 30 cm of the soil profile where the maximum
    root length intensity achieved 2.23 cm&#8226;cm-2. Vertical root distribution of S. scoparia had an almost symmetrical pattern. At
    the prophase of growth period, it preferentially developed superficial roots, while at the end of the growth period, roots
    occurred dominantly in deep soil. In contrast, Agriophyllum squarrosum showed an opposite growth process. S. viridis had the
    highest root length intensity during the prophase and early in the growth period, but root length intensity of Agriophyllum
    squarrosum was higher than S. viridis at the end of the growth period.
    LIU Xue-Yan, XIAO Hua-Yun, LIU Cong-Qiang, LI You-Yi
    Chin J Plan Ecolo. 2007, 31 (6):  1168-1173.  doi:10.17521/cjpe.2007.0145
    Abstract ( 2587 )   PDF (272KB) ( 1346 )   Save
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    Aims We investigated the new and senescent tissues of moss and the soil rhizosphere to determine 1) the elemental and
    isotopic composition characteristics during senescence and 2) the final contribution to soil.
    Methods C and N contents and isotopic composition (δ13C andδ15N) of Haplocladium microphyllum and its soil rhizosphere
    were analyzed at Guiyang, China.
    Important findings The C and N contents were higher in new growing tissues than in senescent tissues, and there were
    significant correlations between the two types of tissues, indicating physiological malfunction (e.g., loss of
    photosynthesis) and internal element redistribution during moss senescence. No significant difference was found between new
    and senescent tissues in isotopic composition, but theirδ13C values orδ15N values were correlated, suggesting special
    isotopic regulation in the simple and nonvascular structure of mosses. In contrast, there was no C or N correlation between
    the moss tissues and soil. This was attributed to long-term nutrient retention and slow deposition to form soil, indicating
    the moss layer in this area has a small contribution to soil carbon and nitrogen.
    ZHANG Tao, SUN Yu, TIAN Chang-Yan, FENG Gu
    Chin J Plan Ecolo. 2007, 31 (6):  1174-1180.  doi:10.17521/cjpe.2007.0146
    Abstract ( 2494 )   PDF (337KB) ( 899 )   Save
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    Aims Ephemerals are important in desert ecosystems, playing a key role in ecosystem stabilization. Previous research has
    concentrated on spring ephemerals. Little is known about biological and ecological characteristics of ephemerals that
    germinate in spring and autumn and about the significance of autumn ephemerals in stabilizing desert ecosystems. 
    Methods We marked plants of Plantago minuta and Erodium oxyrrhynchum, species that germinate in spring and autumn. We
    investigated their crowns, leaves and phenological characteristics in the field during their growing seasons and measured
    their dry weights and mean arbuscular mycorrhizal colonization rates in the lab oratory. 
    Important findings Leaves, flowers, fruits, seeds and dry weights of autumn plants are larger than those of spring plants.
    For example, in autumn P. minuta and E. oxyrrhynchum produced 13.0 and 4.4 times as many seeds and flowered 14 and 7 days
    earlier, respectively, than spring plants. In addition, mean arbuscular mycorrhizal colonization rates were higher in autumn
    than spring plants, accelerating the absorption of phosphorus. Autumn plants had greater capability of reproduction and
    ecosystem stabilization, allowing them to play an important role in stabilizing the desert ecosystem.
    YANG Ming-Bo, YANG Jie, YANG Jiu-Yan, LIANG Na, QING Hua
    Chin J Plan Ecolo. 2007, 31 (6):  1181-1189.  doi:10.17521/cjpe.2007.0147
    Abstract ( 2331 )   PDF (457KB) ( 1026 )   Save
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    Aims Although Caragana davazamcii is an important nitrogen-fixing plant in North China, few studies have focused on its
    epidermal structure and genetic diversity along a precipitation gradient. Our aims are to determine how changes of epidermal
    structure of C. davazamcii leaves are related to changes o f genetic diversity in different habitats, what role environments
    play in this relationship, and whether these populations have potential to become adapted to their local environments in
    different ways. 
    Methods We established 20 m×20 m plots along the precipitation gradient and randomly collected leaves of C. davazamcii from
    natural populations. We studied leaf epidermal structure using a light microscope (LM) and a scanning electron micro scope
    (SEM) and used ISSR-PCR genetic diversity analysis to study differentiation among populations.
    Important findings The leaf epidermis of C. davazamcii in different habitats was significantly different as a result of
    environmental effects. Trichome density, stomatal density, stomatal index and cuticle coarseness increased with changes in
    average annual rainfall from east to west, as did genetic diversity of populations. Caragana davazamcii showed significant
    phenotypic plasticity in different habitats, and this may play a critical role in the ecological adaptability of C.
    davazamcii populations.
    MU Li-Qiang, LIU Ying-Nan
    Chin J Plan Ecolo. 2007, 31 (6):  1190-1198.  doi:10.17521/cjpe.2007.0148
    Abstract ( 2269 )   PDF (366KB) ( 1421 )   Save
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    Aims Tilia amurensis is one of the II-grade Chinese protected plants with an important economic value and ecological
    significance. The population of T. amurensis has gradually declined due to overdrafting. Our objectives were to 1) study the
    genetic diversity of six natural populations varying in longitude and latitude and six varying in altitude and 2) discuss
    strategies to conserve germplasm resources.
    Methods The newly developed inter-simple sequence repeats (ISSR) marker was used to examine genetic diversity.
    Important findings The results of 14 ISSR primers showed that polymeric percentage of the six populations was 93.85%, the
    gene diversity (H) was 0.243 3 and Shannon Index of diversity (I) was 0.380 3. The genetic diversities of T. amurens is
    decreased with increasing altitude, had a single-peak curve with increasing latitude, and were higher in the central region
    than in the edges. Analysis of molecular variance (AMOVA) revealed that the majority of genetic variation occurred within
    populations. Genetic distance and geographic distance were uncorrelated. We concluded that the genetic diversity of T.
    was high and mainly with in populations. Also, the major factors threatening the development of T. amurensis
    included direct damage to natural populations due to destruction of habitat and poor regeneration ability caused by innate
    biological and ecological characteristics. Habitat should be protected, as individuals, especially in core areas.
    WANG Hong-Wei, DENG Hui-Sheng, TAN Hai-Ming, QIN Kun, ZHANG Ding-Heng, GE Song
    Chin J Plan Ecolo. 2007, 31 (6):  1199-1204.  doi:10.17521/cjpe.2007.0149
    Abstract ( 2331 )   PDF (264KB) ( 783 )   Save
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    AimsCathaya argyrophyllais one of the most endangered conifers endemic to China. Previous studies showed that this
    species was characterized by unusually low fertility and high embryonic mortality, which may be factors leading to its
    endangerment. Because knowledge of pollen viability is important for successful reproduction of plant species, we
    investigated pollen viability in natural populations of C. argyrophylla.
    Methods We collected pollen samples from 16 individuals of seven populations in two locations, Dayaoshan (DYS) in Sichuan
    and Huaping (HP) in Guangxi. We evaluated pollen viability using the TTC method and analyzed its variation based on ANOVA.
    Important findings Pollen viability of C. argyrophylla is comparable to other gymnosperms. Viability was stable in dry and
    low temperature conditions, and the optional sucrose concentration for pollen germination was about 13%. We found low
    variation of pollen viability among individuals within populations (p>0.0 5) but significant differentiation between
    populations within regions and among regions (p<0.05). The pollen viability of C. argyrophylla is normal and thus not likely
    relevant to its endangerment. We proposed artificial crossings between genetically distinct populations as a potential
    conservation strategy for the population recovery of this endangered species.
    XU Hong, YANG Jing-Cheng, CHEN Sheng-Bin, JIANG Gao-Ming, LI Yong-Geng
    Chin J Plan Ecolo. 2007, 31 (6):  1205-1213.  doi:10.17521/cjpe.2007.0150
    Abstract ( 2258 )   PDF (376KB) ( 1337 )   Save
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    Ozone (O3) is highly beneficial in many ways, such as filtering ultraviolet radiation in the upper atmosphere, but O3 at
    ground level is a serious pollutant. High O3 concentration causes the damage to plants ranging from minimal visible symptoms
    to substantial inhibition of productivity, and species-or cultivar-specific responses exist. Interactions between plants and
    herbivorous insect pests or plant pathogens may be affected by O3. Decreased carbon flow above- and below-ground in high O3
    environment could significantly decrease biodiversity. Therefore, O3 will affect terrestrial ecosystems substantially. The
    following aspects are suggested to be further studied in China: 1) the comparison and selection of plant species or
    cultivars with high O3 resistance, 2) the possible methods which can alleviate O3 damage to plants, 3) O3 effects on the
    natural ecosystems in China, and 4) the positive function of vegetation in decreasing O3 pollution.

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