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Table of Content
    Volume 36 Issue 9
    01 September 2012

    The autumn landscape of Tilia amurensis-Pinus koraiensis mixed forest in Changbai Mountain. Tilia amurensis-Pinus koraiensis mixed forest is the typical zonal vegetation type in the Changbai Mountain, which is in the climax of the community succession. The major tree species include Pinus koraiensis, Tilia amurensis, Populus ussuriensis and Abies nephrolepis. Yan et al. investigated the ecological processes that shape species-abund

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    Research Articles
    Species-abundance distribution patterns at different successional stages of conifer and broad-leaved mixed forest communities in Changbai Mountains, China
    YAN Yan, ZHANG Chun-Yu, and ZHAO Xiu-Hai
    Chin J Plan Ecolo. 2012, 36 (9):  923-934.  doi:10.3724/SP.J.1258.2012.00923
    Abstract ( 1394 )   PDF (647KB) ( 1667 )   Save
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    Aims Our objective was to explain processes that dominate species-abundance distribution pattern and mechanism of community assembly in temperate forests.
    Methods We used three 5.2-hm2 permanent plots established in secondary Populus davidiana-Betula platyphylla forest, secondary conifer and broad-leaved mixed forest and Tilia amurensis-Pinus koraiensis mixed forest in Changbai Mountains. Within each plot, we randomly selected 500 subplots within 260 m × 200 m at the scales of 10 m × 10 m, 30 m × 30 m, 60 m × 60 m and 90 m × 90 m. We calculated the mean value of species-abundance distributions taken from the 500 subplots as the observed species-abundance distribution. We estimated the fitted species-abundance distributions by neutral, log-normal, Zipf, broken stick and niche preemption models at different scales. Simulation effects were tested by Chi-square test, Kolmogorov-Smirnov (K-S) test and Akaike Information Criterion (AIC). For the neutral model, we first estimated two parameters θ and m and then simulated 600 species-abundance distributions. The average of these 600 species- abundance distributions was the best-fit result of the neutral model. We employed the 95% confidence envelopes that were approximated by the 2.5 and 97.5 percentiles of the abundances of species of rank em = 1 to S over the 600 simulations to test goodness-of-fit for the neutral model. All of the computations were conducted in R 2.14.1 with UNTB and VAGEN packages.
    Important findings The neutral model fit species-abundance distribution at different successional stages of conifer and broad-leaved mixed temperate forest communities. All five models fit the observed value at the 10 m × 10 m sampling scale, and the goodness of fit of the log-normal, Zipf, broken stick and niche preemption models were better than that of the neutral model. That means at small sampling scale the species-abundance distribution is dominated by neutral process and niche process; however, the niche process is much more important. At other sampling scales (30 m × 30 m, 60 m × 60 m, 90 m × 90 m), the neutral model was the best-fit model. As the sampling scales increased, other models gradually dropped out. At the sampling scale of 90 m × 90 m, none of the models fit well, except for the neutral model. This suggests for north temperate forests in the Changbai Mountains that the random process represented by neutral model is the main ecological process that determines the species-abundance distribution pattern at middle and large sampling scales and that the species-abundance distributions at different sampling scales are likely dominated by different ecological processes.

    Community structure of endemic woody plants in tropical montane rainforest of Jianfengling, Hainan Island, China
    SHENG Da-Yong, ZHUANG Xue-Ying, XU Han, LI Yi-De, HU Yue-Hua, SHI Lei-Lei, LUO Tu-Shou, CHEN De-Xiang, and LIN Ming-Xian
    Chin J Plan Ecolo. 2012, 36 (9):  935-947.  doi:10.3724/SP.J.1258.2012.00935
    Abstract ( 1079 )   PDF (824KB) ( 1348 )   Save
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    Aims Our objective was to understand the endemic woody species and their distribution, population structure, and roles in maintaining the biodiversity of the montane rain forest of Hainan, China.
    Methods We surveyed a 4.8 hm2 permanent plot in the primary montane rain forest of Jianfengling, Hainan and analyzed the species composition, importance value, abundance, and size-class distribution of the community. ANOVA was used to evaluate differences in three diversity indices before and after removing the endemic species.
    Important findings A total of 36 481 woody plants with diameter at breast height (DBH) ≥1.0 cm were recorded. They belong to 65 families, 134 genera, and 247 species. Of these, 24 tree and shrub species are endemic to Hainan Island, comprising 9.7% of the total number of trees in the plot. Most of the endemic species have small abundance and sparse distribution, having minor status in the community composition. Most endemic species had preference to specific habitats, narrow distributions, and their seeds were dispersed mainly by animals. The Margalef and Shannon-Wiener indices declined significantly (p < 0.01) after removing the endemic species, but the Simpson and Pielou indices showed no significant differences. Despite their minor roles in the community, the endemic species are important in maintaining the floristic diversity of the tropical montane rainforest. They are of value for scientific research and conservation.

    Reproductive allocation and fruit-set pattern of seed-heteromorphic plant Suaeda aralocaspica
    WANG Lei, DONG Ming, and HUANG Zhen-Ying
    Chin J Plan Ecolo. 2012, 36 (9):  948-955.  doi:10.3724/SP.J.1258.2012.00948
    Abstract ( 863 )   PDF (433KB) ( 1345 )   Save
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    Aims Suaeda aralocaspica is an annual halophyte native to the inland salt desert of the Junggar Basin, Xinjiang, China. It produces two clearly defined types of fruits and seeds on the same plant. Our objective was to investigate reproductive allocation and fruit-set pattern of this species.
    Methods We randomly selected 11 plants of S. aralocaspica in a population and measured the canopy diameter, shoot length, and root length and biomass allocation. We randomly selected 30 primal branches, 30 secondary branches and 30 tertiary branches, and then counted the fruit number for different node sites. We also determined the position of each fruit (seed) in the infructescence for three consecutive growing seasons.
    Important findings Suaeda aralocaspica had high biomass allocation to reproductive organs and a regular fruit-set pattern that is a cautious strategy. The reproductive allocation of biomass in S. aralocaspica plants reached 56%, which is much higher than that of most annual and perennial plants. A greater proportion of biomass was allocated to oblate brown seeds (opportunistic germination strategy) than to elliptical black seeds (cautious germination strategy). The inflorescence (dichasium) may contain from one to fifteen fruits in one to four orders. The first order contains a single fruit, the second order two fruits, the third four and the fourth eight. Suaeda aralocaspica allocated resources first to black-seeded fruits. Thus, S. aralocaspica has high reproductive allocation and a cautious reproductive strategy that is adapted to the salt desert.

    Dynamics of stem radial growth of Picea meyeri during the growing season at the treeline of Luya Mountain, China
    DONG Man-Yu, JIANG Yuan, YANG Hao-Chun, WANG Ming-Chang, ZHANG Wen-Tao, and GUO Yuan-Yuan
    Chin J Plan Ecolo. 2012, 36 (9):  956-964.  doi:10.3724/SP.J.1258.2012.00956
    Abstract ( 814 )   PDF (539KB) ( 1597 )   Save
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    Aims As an important ecological boundary, treeline ecotone is sensitive and vulnerable to external environmental changes, and tree growth at treeline is strongly constrained by the harsh environment. Our objectives were to analyze the characteristics of the stem radial growth of Picea meyeri during the growing season at the treeline of Luya Mountain, Shanxi, China and investigate the main environmental factors affecting radial growth.
    Methods From May to September 2009, an automatic point dendrometer was used to continuously monitor stem radial growth of P. meyeri. Environmental factors were measured by instruments synchronously.
    Important findings The daily variation pattern, i.e., reversible stem shrinking (day) and swelling (night), was controlled by the daily course of tree transpiration. The cumulative radial variation of P. meyeri during the growing season could be divided into three distinct periods: 1) stem rehydration, 2) stem rapid growth, and 3) stem dehydration contraction. During different growth periods, the major environmental factors controlling the stem radial growth were different. Soil water content, soil temperature, soil temperature and water content were the main environmental factors corresponding to the above mentioned three growth periods, respectively. Soil temperature determined the initiation of stem radial growth of P. meyeri. Photoperiod could act as the constricting factor for the growth rate of P. meyeri at the treeline. The maximum growth rate of P. meyeri occurred in late June, around the time of maximum day length (summer solstice), which may be a survival strategy to avoid frost damage during cold winter conditions at treeline.

    Response of fine root biomass to changes in spatial heterogeneity of soil moisture and nitrogen in Larix principis-rupprechtii forest
    YANG Xiu-Yun, HAN You-Zhi, and WU Xiao-Gang
    Chin J Plan Ecolo. 2012, 36 (9):  965-972.  doi:10.3724/SP.J.1258.2012.00965
    Abstract ( 801 )   PDF (423KB) ( 1159 )   Save
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    Aims Fine root biomass is known to respond to spatial heterogeneity in the distribution of soil characteristics. Cutting disturbance created changes of soil physical and chemical factors, but how the changes affect fine root biomass and turnover processes remain unclear. Our objective was to analyze the relationships of spatial heterogeneity of the fine root biomass with changes of soil moisture and nitrogen by cutting disturbance in Larix principisrupprechtii forest.
    Methods This study was conducted in L. principis-rupprechtii forest of Pangquangou National Natural Reserve, located in Guandi Mountain, Shanxi Province, China. Two plots (32 m × 32 m) were placed. Plot A was a disturbed stand, but plot B was undisturbed. Each soil core (30 cm depth) was separated into 3 sections, 0–10, 10–20 and 20–30 cm. The live fine roots were classified into two categories (≤ 1 and 1–2 mm). The partial correlation and the multi-regression coefficients of the semivariance between fine root biomass and soil moisture, nitrogen and pH were analyzed based on theory and methodology of spatial pattern analysis in geostatistics.
    Important findings Spatial variability of fine root biomass and spatial heterogeneity of soil nitrogen and soil moisture were positively correlated, with the latter being significantly stronger than the former. After cutting disturbance, the correlation became more significant. The correlation between spatial variability of fine root biomass and spatial heterogeneity of soil ammonium (NH4+) and pH was unclear in disturbed and undisturbed stands. Multiple regressions of soil factors against biomass of fine root were statistically significant. However, spatial distribution of biomass of fine roots was largely affected by soil moisture and total nitrogen and nitrate nitrogen after cutting disturbance.

    Arbuscular mycorrhizal fungi improving drought tolerance of maize plants by up-regulation of aquaporin gene expressions in roots and the fungi themselves
    LI Tao and CHEN Bao-Dong
    Chin J Plan Ecolo. 2012, 36 (9):  973-981.  doi:10.3724/SP.J.1258.2012.00973
    Abstract ( 930 )   PDF (476KB) ( 1407 )   Save
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    Aims It has been well demonstrated that arbuscular mycorrhizal (AM) fungi can improve water balance and drought tolerance of host plants under drought stress. However, controversy still exists in mechanisms underlying the mycorrhizal functions. For example, in different experiments AM fungi could up- or down-regulate plant aquaporin gene expression. Furthermore, little information is available on the expression of aquaporin genes in AM fungi under drought stress and its contribution to plant drought tolerance. We investigated the effects of an AM fungus, Glomus intraradices, on expression of a plasma membrane intrinsic protein (PIP) gene family containing 13 PIP genes in maize roots and one aquaporin gene from the AM fungus under simulated drought conditions. Our objectives were to systematically investigate the aquaporin gene expression in the mycorrhizal association in response to drought stress and to help understand the molecular basis for drought tolerance of AM symbiosis.
    Methods Maize plants inoculated with/without AM fungus G. intraradices were grown under different water regimes in a controlled-environment climate chamber for 42 days. At harvest, the leaf water potential (Ψ) was determined with an SKPM 1400 pressure chamber, and then shoots and roots were collected and carefully cleaned with tap water. Three grams of mixed roots were used to estimate the percentage root colonization after clearing with 10% KOH and staining with 0.05% (v/v) trypan blue in lactic acid. One gram of mixed roots was used to extract total RNA by using TRIZOL to synthesize cDNA. Real-time PCR analysis was performed to estimate the expression of Zm PIP genes and GintAQP1. Shoots and the rest of roots were dried at 105 °C for 10 min and 80 °C for 48 h to obtain dry weights. About 0.2 g of dried shoots or roots was digested by HNO3 for 12 h. The P concentration was recorded by using microplate reader spectra at the wavelength of 820 nm. Experimental data were subjected to statistical analysis using SPSS 13.0.
    Important findings Under drought stress, inoculation with AM fungus significantly enhanced expression of eight PIP genes except for Zm PIP1;3, Zm PIP1;4 Zm PIP1;5 and Zm PIP2;2 (Zm PIP2;7 expression not detected), and drought stress also enhanced expression of GintAQP1 cloned from hyphae of G. intraradices. Enhanced aquaporin gene expression was beneficial to improvement of plant water status and increase of leaf water potential.

    Effects of waterlogging on growth, porosity and radial oxygen loss of three tree species
    WANG Gui-Bin, CAO Fu-Liang, and WANG Yuan
    Chin J Plan Ecolo. 2012, 36 (9):  982-991.  doi:10.3724/SP.J.1258.2012.00982
    Abstract ( 769 )   PDF (501KB) ( 1125 )   Save
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    Aims Flooding reduces soil oxygen content, and leads to oxygen deprivation in the root system of plants. Since oxygen is essential for mitochondrial respiration, this process cannot be maintained under anoxic conditions and must be replaced by other pathways. Our objective was to understand flooding adaptation mechanisms of baldcypress (Taxodium distichum), Chinese tallow tree (Sapium sebiferum) and pecan (Carya illinoensis) under waterlogged conditions.
    Methods One-year seedlings of baldcypress, Chinese tallow tree and pecan were grown in pots, and three treatments were implemented: CK (control, common soil water content), WA (waterlogging, water level equal with soil surface) and FL (flooding, water level 8 cm above soil surface). Treatments lasted 65 days, and indexes of growth, porosity and root oxygen consumption were determined at different times after treatment.
    Important findings We found that WA and FL treatments inhibited growth of both Chinese tallow tree and pecan, but biomass and biomass increment of baldcypress increased under WA condition, indicating that baldcypress was more tolerant to flooding. Root/shoot ratio of the three tree species increased significantly under WA and FL treatments, which was primarily due to the decrease of stem and leaf biomass. WA and FL treatments also stimulated aerenchyma formation in the roots, stems and leaves of the three tree species, thereby the porosity in the roots, stems and leaves of the three tree species increased significantly under WA and FL conditions. The aerenchyma formation and increased porosity enhanced O2 diffusion to roots and rhizosphere. Our results indicate that baldcypress, Chinese tallow tree and pecan exhibit several adaptive mechanisms in response to waterlogging, including formation of new roots, aerenchyma formation, increased porosity of the roots, stems and leaves, and increased O2 release into the rhizosphere.

    Correlation between quality of Pyrola decorata and its ecological factors based on hierarchyvector analysis
    Lü Zhen-Jiang, WANG Dong-Mei, and LI Deng-Wu
    Chin J Plan Ecolo. 2012, 36 (9):  992-1003.  doi:10.3724/SP.J.1258.2012.00992
    Abstract ( 814 )   PDF (527KB) ( 1299 )   Save
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    Aims Plant secondary metabolites have played a significant role in drug discovery and development. Their production and accumulation are affected by environmental factors. Our objective was to determine the dominant ecological factors influencing functional components content of Pyrola decorata, the relationships among ecological factors, the contents of functional components and antioxidant activity.
    Method The HPLC method was used to determine the contents of tannin, quercetin and hyperoside. Total flavoniods content was evaluated by NaNO2-Al(NO3)3 spectrophotometric determination. The antioxidant activity was measured by DPPH radical assay in vitro. The hierarchy-vector analysis was applied to determine relationships between the quality of P. decorata and ecological factors.
    Important findings The contents of functional components as well as the antioxidant activity in different regions were significantly different. Tannin, quercetin and hyperoside as the key factors affecting the antioxidant activity showed negative correlation with the antioxidant ability; their correlation coefficients were –0.829, –0.378 and –0.749, respectively. There was a positive correlation between DPPHIC50 value and the total flavoniods content (p = 0.260). DPPHIC50 values decreased while the functional components contents increased, which indicated the enhancement of antioxidant activity. Nine ecological factors contributed significantly to the functional components contents: annual mean air temperature, January mean air temperature, annual accumulated air temperature, annual extreme high air temperature, frost-free period, soil total nitrogen, available nitrogen, available phosphorus and organic matter. The soil factors made greater contributions to the contents of the four effective components than did climatic factors, and they also had a large impact on the content of tannin and quercetin compared with hyperoside. Therefore, selecting a suitable habitat, especially appropriate soil, could effectively improve the quality of P. decorata.

    Review
    Review of advances in radial patterns of stem sap flow
    XU Fei, YANG Feng-Ting, WANG Hui-Min, and DAI Xiao-Qin
    Chin J Plan Ecolo. 2012, 36 (9):  1004-1014.  doi:10.3724/SP.J.1258.2012.01004
    Abstract ( 1002 )   PDF (448KB) ( 1480 )   Save
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    Variability in radial patterns of sap flow is the main source of error in evaluating individual and stand transpiration using thermal techniques. Thus, it is necessary to understand and quantify radial patterns of stem sap flow before accurate estimation of forest transpiration can be conducted. We discuss the methods used to determine radial patterns of sap flow and summarize four main patterns of stem sap flow. We also review the effects of inner structure characteristics and environmental factors on radial patterns of sap flow. In addition, we present the diurnal and seasonal variability in radial patterns of sap flow. Lastly, we propose possible problems in resent research on radial patterns of stem sap flow.


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