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Table of Content
    Volume 39 Issue 10
    01 October 2015

    Outlook of a wild Lycium ruthenicum population in Golmud, Qinghai. The deciduous shrubs in the lower left are L. ruthenicum plants. Lycium ruthenicum is an important desert plant in Qaidam. At present, the genetic diversity of L. ruthenicum is being seriously threatened by anthropogenic disturbance. Wang et al. studied the genetic diversity and genetic relationship of the wild L. ruthenicum populations in Qaidam (P

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    Orginal Article
    Contribution of invasive species Spartina alterniflora to soil organic carbon pool in coastal wetland: Stable isotope approach
    WANG Dan,ZHANG Rong,XIONG Jun,GUO Hai-Qiang,ZHAO Bin
    Chin J Plan Ecolo. 2015, 39 (10):  941-949.  doi:10.17521/cjpe.2015.0091
    Abstract ( 638 )   HTML ( 4 )   PDF (504KB) ( 1494 )   Save
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    <i>Aims</i>

    Spartina alterniflora was introduced into China because of its strong sedimentation promotion ability, currently, it became one of the most invasive species along coastal areas. Most researches focused on its high productivity which directly increased soil carbon (C) input. However, little is known about its indirect contribution to soil carbon via increased sedimentation.

    <i>Methods</i>

    Spartina alterniflora patches with different invasion history (4, 6, and 10 years) was selected in Chongming Dongtan wetland, and Phragmites australis and mudflat were chosen as control respectively. The plant, soil and water samples were collected for C and nitrogen (N) analysis. Based on the stable isotope ratio of C and N in plant and soil organic carbon, the contribution of soil organic carbon pool from S. alterniflora patches were estimated by using 2 and 3 sources mixing model, respectively.

    <i>Important findings</i>

    (1) The soil organic C content and stable carbon isotope ratio of S. alterniflora patches increased with time. Spartina alterniflora invasion cumulatively enhanced soil organic carbon pool. The soil C:N ratio decreased with invasion history and became close to the redfield ratio, indicating the important role of sedimentation input. (2) The contribution of invasive S. alterniflora to soil organic carbon pool increased with time, but the sedimentation contribution dropped gradually. In patch with 4 years invasion history, the contribution ratio of sedimentation was more than 90.0%. While in patch invaded 10 years ago, the sedimentation contribution reduced by 18.4%, and in comparison, S. alterniflora contributed up to 73.5% to soil organic carbon pool. These findings suggested that S. alterniflora contributed to soil organic carbon pool mainly by promoting sedimentation in early invasion period, while gradually relied on its own productivity with invasion time.

    Effects of the level and regime of nitrogen addition on seedling growth of four major tree species in subtropical China
    LIU Shuang-E,LI Yi-Yong,FANG Xiong,HUANG Wen-Juan,LONG Feng-Ling,LIU Ju-Xiu
    Chin J Plan Ecolo. 2015, 39 (10):  950-961.  doi:10.17521/cjpe.2015.0092
    Abstract ( 393 )   HTML ( 4 )   PDF (538KB) ( 1231 )   Save
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    <i>Aims</i>

    Numerous studies have been carried out concerning the effects of atmospheric nitrogen (N) deposition on forest ecosystems. However, most of previous experiments were conducted by adding N fertilizer to the surface soil directly. Realistically simulated canopy N deposition and comparison of the effects of soil N addition and canopy N addition on ecosystems were rare. Our purpose is to better understand the effects of two N addition regimes at different N addition levels on seeding growth in major tree species of subtropical China.

    <i>Methods</i>

    A 2-year pot experiment was conducted, with seedlings of four species (Ormosia pinnata, Acacia mangium, Schima superba, Pinus massoniana) grown in pots subjected to treatments of three levels (ambient, medium, and high) and two regimes (in soil vs. on canopy) of N addition, specifically including S-CK (ambient N addition in soil), S-MN (medium N addition in soil), S-HN (high N addition in soil), C-CK (ambient N addition on canopy), C-MN (medium N addition on canopy), and C-HN (high N addition on canopy). The total amounts of added N in the three N levels were 5.6, 15.6 and 20.6 g·m-2·a-1, respectively. Tree basal diameter and tree height were measured in June and December 2012, and November 2013. All trees were harvested in November 2013, and then the biomass was calculated according to the dry-mass of roots, shoots and leaves; the root-shoot ratios were calculated.

    <i>Important findings</i>

    N treatments affected seeding growth, along with significant interactive effects among N addition level, N addition regime and species. Compared to CK, S-MN stimulated the biomass in seedlings of A. mangium and S. superba, but decreased the tree height and biomass in seedlings of P. massoniana; C-MN increased the biomass in seedlings of A. mangium; S-HN promoted the biomass in seedlings of A. mangium, but significantly decreased the biomass, basal diameter and tree height in seedlings of P. massoniana (p < 0.01); C-HN led to the greater growth in seedlings of A. mangium, S. superba and P. massoniana (p < 0.01). N addition responses were dependent upon plant species: while seedlings in O. pinnata and A. mangium grew faster than S. superba and P. massoniana under all N treatments, the differences in the growth of S. superba and P. massoniana seedlings between the two N addition regimes were more pronounced than in O. pinnata and A. mangium seedlings. We concluded that legumes (O. pinnata and A. mangium) grew faster than non-legumes (S. superba). And growth stimulation in broadleaved trees (O. pinnata, A. mangium, and S. superba) by N addition was significantly greater than in coniferous trees (P. massoniana). Our findings suggest that the relatively high and chronic atmospheric N deposition in subtropical forest ecosystems may lead to changes in species composition.

    C, N and P stoichiometry of two dominant seedlings and their responses to nitrogen additions in the montane moist evergreen broad-leaved forest in Ailao Mountains, Yunnan
    SHI Xian-Meng,QI Jin-Hua,SONG Liang,LIU Wen-Yao,HUANG Jun-Biao,LI Su,LU Hua-Zheng,CHEN Xi
    Chin J Plan Ecolo. 2015, 39 (10):  962-970.  doi:10.17521/cjpe.2015.0093
    Abstract ( 520 )   HTML ( 4 )   PDF (514KB) ( 1282 )   Save
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    <i>Aims</i>

    Montane moist evergreen broad-leaved forest is an important vegetation type in the high altitude areas of western China. In this study, total carbon (C), nitrogen (N), phosphorus (P) contents and stoichiometry in roots, stems, and leaves of two dominant seedlings, Symplocos ramosissima and Machilus gamblei, and their responses to different levels of N addition were investigated in the montane moist evergreen broad-leaved forest in Ailao Mountains, Yunnan.

    <i>Methods</i>

    A simulation experiment with four N addition levels T0 (0 kg N·hm-2·a-1), T1 (3 kg N·hm-2·a-1), T2 (6 kg N·hm-2·a-1) and T3 (12 kg N·hm-2·a-1) was carried out in the montane moist evergreen broad-leaved forest in Ailao Mountains. Total C, N and P concentrations in different organs of the two dominant seedlings and soil inorganic N concentration in each treatment were measured after one year’s in situ experiment.

    <i>Important findings</i>

    The C, N and P concentrations of the two seedlings were significantly different (p < 0.05). Machilus gamblei had lower C concentration, but higher N and P concentrations compared with S. ramosissima. N addition had significant effects (p < 0.01) on C, N and P concentrations and their stoichiometry. Significant interactions were detected among N treatments, species and plant organs. N addition increased N concentrations in all organs of the two seedlings, leading to higher ratio of N:P. P concentration of S. ramosissima decreased significantly (p < 0.05) under N addition, while that of M. gamblei increased under medium (T2) and high (T3) N addition treatments. Within a certain range, there was a significant correlation between the N concentrations of seedlings and soil inorganic N concentrations (p < 0.01). Comparisons of homeostasis index among different organs indicated that the N stoichiometry in roots and stems was more stable than that in leaves under N addition.

    Biomass allocation strategies within a leaf: Implication for leaf size optimization
    Shao-An PAN, Guo-Quan PENG, Dong-Mei YANG
    Chin J Plant Ecol. 2015, 39 (10):  971-979.  doi:10.17521/cjpe.2015.0094
    Abstract ( 465 )   HTML ( 18 )   PDF (276KB) ( 1164 )   Save
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    <i>Aims</i>

    The variations in leaf size result from the integrated effects of many factors. Study of the mechanism to reach the optimum leaf size could help us better understand plant adaption and evolution, and plant life history strategies. Here we aim to test the hypothesis that leaf size is affected by the biomass allocation strategy within a leaf.

    <i>Methods</i>

    The relationships between leaf size and different biomass partitioning patterns within a leaf were studied for 19 evergreen and 30 deciduous broadleaved woody species from Qingliang Mountain, Zhejiang, China. The standardized major axis estimation method was used to examine the scaling relationship between lamina size and petiole size within a leaf. The relationship between leaf size and support investment ratio within a leaf was estimated by the Model Type I regression analysis.

    <i>Important findings</i>

    Biomass allocation in petiole increased with leaf size similarly in both evergreen and deciduous leaves, which resulted from the significant allometric scaling relationship between petiole mass and lamina mass (and area) with slopes significantly larger than 1.0, independent of leaf habit. However, evergreen species were found to have a greater petiole mass at a given lamina mass or area than deciduous species, which may be due to their higher demand for mechanic support and resistance to freezing-induced embolism in petioles. Results suggest that leaf size could be affected by the fraction of support investment within a leaf.

    Structure and dynamic characteristics of Gymnocarpos przewalskii in different habitats
    Li-Long WANG, Liang WANG, Li-Fang ZHANG, Yu-Yang LIU, Shi-Jian XU
    Chin J Plant Ecol. 2015, 39 (10):  980-989.  doi:10.17521/cjpe.2015.0095
    Abstract ( 591 )   HTML ( 33 )   PDF (483KB) ( 1323 )   Save
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    Aims

    Gymnocarpos przewalskii is a relict plant of the Tethys flora, which is also one of the constructive species in stony desert. Our objective was to determine the structure and dynamic characteristics of G. przewalskii in different habitats.

    Methods

    Based on the equal-area plot investigations in three habitats of G. przewalskii, the static life table was established, survival curves and the function curves derived from the survival analysis were also constructed to evaluate the population characteristics. The population dynamics were predicted by a time-sequence model.

    <i>Important findings</i>

    The survival curves of G. przewalskii appear to approach the Deevey-II type, which indicate that the mortality rate in different size classes was similar, and the population fit in with the growing type in all habitats, but sensitive to environment disturbances. The population size of G. przewalskii was largest in flooding lands, medium in gullies and smallest in the flat desert and the age structure showed that the flooding lands and gullies are better habitats for the growth of G. przewalskii. The survival analysis and the time-sequence model demonstrated that the lack of young individuals could be the major cause for population declines of G. przewalskii in all habitats; moreover, a decline is likely to occur in the flat desert earlier and quicker.

    Orginal Article
    Quantitative classification of the subtropical evergreen-deciduous broadleaved mixed forest and the deciduous and evergreen species composition structure across two national nature reserves in the southwest of Hubei, China
    HUANG Yong-Tao,YAO Lan,AI Xun-Ru,LÜ Shi-An,DING Yi
    Chin J Plan Ecolo. 2015, 39 (10):  990-1002.  doi:10.17521/cjpe.2015.0096
    Abstract ( 657 )   HTML ( 3 )   PDF (496KB) ( 1437 )   Save
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    <i>Aims</i>

    The subtropical evergreen-deciduous broadleaved mixed forest is the largest extant natural vegetation type in southwest Hubei. However, little knowledge exists on the types and compositions (especially the relative ratios of evergreen versus deciduous species) of this forest vegetation. Here, we quantitatively classify the less studied forest vegetation into different community types, compare their size and composition structure, and analyze species-environment relationships which is the basis for further understanding the biodiversity maintenance mechanism and reasonable protection and utilization of this forest.

    <i>Methods</i>

    We established 92 20 m × 20 m plots of subtropical evergreen-deciduous broadleaved mixed forest in two national nature reserves in Enshi, Hubei Province, China. All species with stems ≥1 cm diameter at breast height (DBH) in each plot were identified and mapped. These plots were classified by using two-way indicator species analysis (TWINSPAN) and detrended correspondence analysis (DCA). The species richness, abundance, basal area and importance value were chosen to compare structure, species composition and evergreen and deciduous ratio. Permutation-based multiple regression on distance matrices and multiple stepwise regression analysis were used to examine the relationship between species distribution and environmental factors.

    <i>Important findings</i>

    Our results showed that the subtropical evergreen-deciduous broadleaved mixed forest in the southwest of Hubei could be classified into five community types based on quantitative methods: i.e. Cyclobalanopsis glauca-Eurya alata + Camellia cuspidate (community type I), Carpinus fargesiana + Cyclo- balanopsis glauca-Eurya alata (community type II), Carpinus fargesiana + Cyclobalanopsis glauca-Weigela japonica (community type III), Fagus lucida + Cyclobalanopsis multinervis-Eurya alata (community type IV) and Carpinus fargesiana + Daphniphyllum macropodum + Lithocarpus cleistocarpus-Eurya alata (community type V). Species richness, abundance, basal area and importance value of evergreen and deciduous species in each community types were different. Deciduous species in community II, community III and community V were significantly higher than evergreen species in terms of species richness, stem abundance, basal area and importance value, but they had no significant differences in community I and community IV. The richness of deciduous species in most community types were higher than those of evergreen species, meanwhile the abundance, basal area and importance value of deciduous species in the small size classes (1 cm ≤ DBH < 5 cm) in each community types were lower than those of evergreen species. In middle size classes (5 cm ≤ DBH < 10 cm), the richness, abundance, basal area and importance value of deciduous species were higher than those of evergreen species in community II, community III and community V. However, in community I and community IV, the evergreen species were larger than deciduous species in the four indexes. The richness of deciduous species in majority of the community types were higher than those of evergreen species in large size classes (DBH ≥ 10 cm). The elevation, slope and aspect, soil total nitrogen content, soil total phosphorus content, soil available nitrogen content and soil available phosphorus content were the major factors affecting evergreen and deciduous species distribution across the five community types.

    Population genetic diversity of wild Lycium ruthenicum in Qaidam inferred from AFLP markers
    WANG Jin-Nan,CHEN Jin-Fu,Chen Wu-Sheng,Zhou Xin-Yang,XU Dong,LI Ji-Hong,QI Xiao
    Chin J Plan Ecolo. 2015, 39 (10):  1003-1011.  doi:10.17521/cjpe.2015.0097
    Abstract ( 464 )   HTML ( 2 )   PDF (380KB) ( 1203 )   Save
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    <i>Aims</i>

    Lycium ruthenicum is a perennial shrub plant. It grows among rocks in deserts, and its populations are spatially scattered in the distribution range. The objectives of this study were investigating the population genetic diversity and genetic structure of L. ruthenicum in Qaidam and determining relationships between genetic diversity and environmental factors.

    <i>Methods</i>

    We analyzed the genetic diversity of 120 individuals from 5 natural populations using amplified fragment length polymorphism (AFLP) markers.

    <i>Important findings</i>

    We obtained 1691 unambiguous bands from the nine pairs of selected primers, 1678 bands (99.23%) of which were polymorphic across all individuals. At the species level, the Nei’s gene diversity was 0.3649, and the Shannon’s information index was 0.5422. Analysis of molecular variance (AMOVA) analysis indicated that most variations (92.0%) existed within populations, with only a small proportion of total variations residing among populations (8.0%, genetic differentiation coefficient is 0.08). The genetic similarity among the populations ranged from 0.9709 to 0.9922 with an average of 0.9835. Results of the Mantel test (γ = 0.3368, p = 0.8064) and unweighted pair group method with arithmetic mean (UPGMA) cluster of the Qaidam populations indicated that the correlation between geographical distance and genetic distance was not significant. Principal coordinate analysis of all sampled individuals showed that individuals from each population did not cluster together. The genetic diversity of the same population indicated that the L. ruthenicum of Nomhon had high level of genetic variations, which indicated Nomhon is the center of the Qaidam wild L. ruthenicum populations.

    Effects of external nitrogen additions on soil organic carbon dynamics and the mechanism
    LI Rong,CHANG Rui-Ying
    Chin J Plan Ecolo. 2015, 39 (10):  1012-1020.  doi:10.17521/cjpe.2015.0098
    Abstract ( 587 )   HTML ( 1 )   PDF (340KB) ( 1461 )   Save
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    What would be the impact of external nitrogen additions on soil carbon, an issue still under debating, as reported experimental results were either positive, negtive or neutral. Several factors may be related to these seemingly controversial results: differences in ecosystem types and soil properties, soil carbon detection methods, soil depths, and contents of soil labile and recalcitrant carbon that affect the responses to nitrogen additions, all could cause discrepancies and variations in carbon sequestration. The several processes that contribute to enhance soil organic carbon storage include increasing litter input, decresing soil carbon output, particularly, by supressed decomposition of recalcitrant carbon, promoting soil humifiction and formation of recalcitrant carbon storage. However, there are still many uncertainties associated with these issues. To improve our understanding, the research about carbon in deep soil layers, dissolved organic carbon leaching and accumulation, and the effect of labile and recalcitrant soil C ratios on N addition responses, should be further investigated in the future studies.

    Trade-offs between plant leaf hydraulic and economic traits
    JIN Ying,WANG Chuan-Kuan
    Chin J Plan Ecolo. 2015, 39 (10):  1021-1032.  doi:10.17521/cjpe.2015.0099
    Abstract ( 619 )   HTML ( 13 )   PDF (434KB) ( 1522 )   Save
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    Leaf is the most important organ for carbon-water coupling of a plant because it is the primary medium for photosynthesis. It also acts as the hydraulic bottleneck and safety valve against hydraulic catastrophic dysfunctions. The leaf economics spectrum, which reflects the balance between investments and returns of leaf economic traits, provides a useful framework for examining species strategies as shaped by their evolutionary history. Changes in leaf hydraulic traits will influence leaf economic traits as well as plant survival and growth. Exploring trade-offs between leaf hydraulic and economic traits is thus of significance for modeling carbon-water relations, understanding the mechanisms of water/carbon investments, and extending the leaf economic spectrum. In this review, we first examined the trade-offs between leaf hydraulic and economic traits. Specially, we analyzed the relationships between leaf hydraulic conductivity and hydraulic vulnerability, water potential at the turgor loss point, water capacitance, safety margin, and leaf morphological, structural and functional traits. We then discussed potential mechanisms regulating leaf hydraulic and economic traits from leaf morphology, anatomy, venation, and stomatal functions. Finally, we proposed future research to: (1) develop an integrated whole-plant economics spectrum, including carbon-nitrogen-water resources and root-stem-leaf hydraulic transport system that will help revealing ecophysiological mechanisms of plant structure-functional coupling, carbon sequestration and water use; (2) explore a generalized trade-offs among leaf hydraulic safety, hydraulic efficiency and carbon fixation efficiency to advance our understanding of the relationships between biophysical structure and physiological metabolism in plant leaf construction under drought stress; and (3) explore the carbon-water metabolic relationship and coupling of water transport and growth rate for the metabolic theory and predictions at community scale.


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