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Table of Content
    Volume 35 Issue 5
    01 May 2011

    The Populus euphratica forest at the bank of the Donghe River in Ejin Delta in the lower reach of Heihe River. ZHU et al. investigated quantitative classification and the relationships between plant communities and groundwater environment in this region (Pages 480–489 of this issue). (Photographed by YU Jing-Jie)

      
    Research Articles
    Morphological investigation of desert shrubs of China’s Junggar Basin based on allometric theory
    LI Song, ZHENG Xin-Jun, TANG Li-Song, LI Yan
    Chin J Plan Ecolo. 2011, 35 (5):  471-479.  doi:10.3724/SP.J.1258.2011.00471
    Abstract ( 1961 )   PDF (558KB) ( 2257 )   Save
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    Aims Our objectives were to investigate how shape and structure affect shrub architecture and to understand its function in the desert ecosystem through simulating differences in crown architecture of desert shrubs in China’s Junggar Basin.
    Methods We analyzed shrub height and crown form. The difference between observed crown area and height and the estimated crown model was found to be a good measure of degree of crown development. A Malthusian conceptual model is proposed where crown area and height modify the crown architecture, shrub surface area and volume. We assumed that the three-dimensional structure of desert shrubs is the triaxial ellipsoid and chose shrub desert island in Junggar Basin as our object of study. According to plant allometric theory, we started from the differential form of the Malthusian equation and set up models describing (a) crown area and height growth and (b) surface area and volume growth. In addition, simulations were used for calculating the potential crown architecture of the desert shrub.
    Important findings The assumption that the vertical distribution of desert shrub crown shape is semi-triaxial ellipsoid is valid. Three crown types were identified: flat, nearly hemispherical, and upright. These crown types corresponded well with the vertical distribution patterns of maximum height. The consistency of quantitative relationship between volume and surface area of desert shrubs is suggested as a useful tool for characterizing similar water-use strategy in the same environmental condition.

    Quantitative classification and analysis of relationships between plant communities and their groundwater environment in the Ejin Desert Oasis of China
    ZHU Jun-Tao, YU Jing-Jie, WANG Ping, WANG Zhi-Yong
    Chin J Plan Ecolo. 2011, 35 (5):  480-489.  doi:10.3724/SP.J.1258.2011.00480
    Abstract ( 2277 )   PDF (405KB) ( 2016 )   Save
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    Aims Ejin Desert Oasis is a typical arid oasis in the Hexi corridor of northwestern and northern China. Water resources in the area have changed since 2000. Our objective was to classify the plant community types and determine the relationship between vegetation and environmental factors in order to evaluate the influence of water regulation on vegetation in this region.
    Methods We obtained data on 29 plant species from 151 study plots of natural vegetation of the Ejin Desert Oasis and classified the plant communities by two-way indicators species analysis (TWINSPAN) and correlated them with six groundwater environmental variables using detrended correspondence analysis (DCA) and detrended canonical correspondence analysis (DCCA) ordinations.
    Important findings Six plant associations were identified. The main factor correlated to their distribution was groundwater depth, which had more influence on the distribution of plant species and vegetation than other variables because change of groundwater depth leads to changes in both salinity and mineralization. The first ordination axis was correlated with the gradient of groundwater depth, and the second axis was correlated with pH. Compared with other areas, the scarcity of plant species and the differentiation of plant communities were obvious.

    Ecological adaptation of root architecture to grassland degradation in Potentilla acaulis
    ZHOU Yan-Song, WANG Li-Qun
    Chin J Plan Ecolo. 2011, 35 (5):  490-499.  doi:10.3724/SP.J.1258.2011.00490
    Abstract ( 2138 )   PDF (408KB) ( 1702 )   Save
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    Aims Our objectives were to 1) examine the ecological adaptability of Potentilla acaulis to grassland degradation from the perspective of root architecture, 2) reveal why it can be a dominant species in extremely degraded grassland and 3) discuss its important roles in vegetation restoration or succession and preventing grassland from desertification.
    Methods We collected relatively complete P. acaulis roots by trenching. The numbers of first vertical roots, length of horizontal root tillering and number of plant tillers were recorded in the field. The root analysis system of WinRHIZO was used to determine total root length, root surface area, total root volume, root average diameter, number of furcations, average branching angle, number of root axes, length of root axes, number of root tips, number of first lateral roots, length of first lateral roots, number of secondary lateral roots, length of secondary lateral roots, root diameters along root length, root surface area and root volume. The data were analyzed by one-way ANOVA and principal component analysis.
    Important findings In degraded grassland typified by Stipa grandis, the function of P. acaulis became more important in the community and its root range, root depth, the number of first vertical roots, the number of plant tillers and the length of horizontal root tillering increased significantly. The parameters of root surface area, length of secondary lateral roots, total root length and the number of furcations explained the adaptability of P. acaulis to grassland degradation. Roots with a diameter <2 mm had a significant effect on root surface area and total root length of single plants of P. acaulis. The three-dimensional root architecture of a broad-waist-inverted centrum was an advantageous configuration for P. acaulis to adapt for grassland degradation and can explain P. acaulis as a constructive species in extremely degraded grassland.

    Different responses of radial growth to climate warming in Pinus koraiensis and Picea jezoensis var. komarovii at their upper elevational limits in Changbai Mountain, China
    LI Guang-Qi, BAI Fan, SANG Wei-Guo
    Chin J Plan Ecolo. 2011, 35 (5):  500-511.  doi:10.3724/SP.J.1258.2011.00500
    Abstract ( 2258 )   PDF (586KB) ( 2030 )   Save
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    Aims Temperature is generally considered the limiting factor for tree growth at species’ upper elevational limits. Our objectives were to determine the upper elevational limit response of radial growth in Pinus koraiensis and Picea jezoensis var. komarovii to climate warming in Changbai Mountain Nature Reserve of China and to elucidate temperature sensitivity of radial growth.
    Methods We selected typical trees at each species’ upper limit for increment coring and established ring-width chronologies for both species. We compared the general trend of the chronologies with temperatures during 1958–2006. To determine species’ response to rising temperature, we analyzed the relationship between chronology and important meteorological factors (temperature, precipitation, growing season length, effective accumulative temperature, etc.) using correlation, response function, moving correlation and pointing year analyses.
    Important findings As temperature rose, ring widths in Pinus koraiensis exhibited the same increasing trend as temperature, while ring widths in Picea jezoensis var. komarovii exhibited decreasing sensitivity to temperature. The increase of temperature and precipitation in the growing season mutually enhance Pinus koraiensis growth. Prolongation of the growing season and rising temperature during the growing season also can accelerate the growth of Pinus koraiensis. For Picea jezoensis var. komarovii, water stress caused by increasing temperature is the main reason for its relationship between ring width and temperature. Correlations between Picea jezoensis var. komarovii ring width and almost all temperature indices are significantly negative. As temperature rose, correlations between ring width and precipitation, especially spring precipitation, changed from negative to positive. High temperature in each month and inadequate precipitation in the middle and late growing season are the important meteorology conditions for narrow rings. Also, the insignificant extension of the growing season may relate to reduced temperature sensitivity in tree ring growth.

    Spatio-temporal variations of CO2 concentration within the canopy in a temperate deciduous forest, Northeast China
    JIAO Zhen, WANG Chuan-Kuan, WANG Xing-Chang
    Chin J Plan Ecolo. 2011, 35 (5):  512-522.  doi:10.3724/SP.J.1258.2011.00512
    Abstract ( 2015 )   PDF (489KB) ( 1561 )   Save
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    Aims Although temperate broadleaved deciduous forest accounts for two-thirds of the forest area in northeastern China, its spatio-temporal variations of CO2 concentration ([CO2]) have not been quantified. Our objectives were to quantify diurnal and seasonal variations and vertical gradients of [CO2] and explore controlling factors.
    Methods A [CO2] flux tower with an 8-level [CO2] profile system (at 0.5, 2.0, 4.0, 8.0, 16.0, 20.0, 28.0 and 36.0m) was installed at the Maoershan Forest Ecosystem Research Station in Heilongjiang Province (45°24′ N, 127°40′ E) in 2007. [CO2] at each level was measured with a LI-COR LI-840 infrared gas analyzer (IRGA) by drawing it from each level with a sample pump through tubes of equal length. The IRGA was controlled and data were collected with a datalogger. Automatic calibration was done for the IRGA once a day. A Vaisala GMP343 was installed at 36.0 m to monitor ambient [CO2] for quality control of the [CO2] profile data. We simultaneously measured micrometeorological variables, including wind speed, air temperature, relative humidity, photosynthetically active radiation, vapor pressure, soil temperature and water content.
    Important findings At a daily scale, maximum [CO2] occurred at night or sun rise, while the minimum occurred in the afternoon at all levels. This pattern was predominant in the summer. The diurnal course of the [CO2] was “V”-shaped in winter but “U”-shaped in other seasons. [CO2] decreased with increasing height, particularly on summer nights. During the daytime of summer, daily mean [CO2] within the canopy was substantially lower than the ambient [CO2], suggesting that the vegetation acted as a CO2 sink due to its photosynthesis. Daily mean [CO2] above the canopy peaked in spring and autumn and reached a minimum in summer, while that near the forest floor showed a unimodal seasonal pattern with its maximum in summer. The diurnal dynamics of [CO2] and their vertical gradients during the growing season were jointly controlled by the atmospheric boundary layer (ABL) and forest carbon metabolism, while those during the dormant season were controlled mainly by ABL. The seasonal dynamics of the [CO2] near the forest floor were determined mainly by soil respiration, while those above the canopy were jointly controlled by canopy photosynthesis and ecosystem respiration.

    Nitrogen supply mitigates the effects of elevated [O3] on photosynthesis and yield in wheat
    CHEN Juan, ZENG Qing, ZHU Jian-Guo, LIU Gang, CAO Ji-Ling, XIE Zu-Bin, TANG Hao-Ye, KAZUHIKO Kobayashi
    Chin J Plan Ecolo. 2011, 35 (5):  523-530.  doi:10.3724/SP.J.1258.2011.00523
    Abstract ( 2057 )   PDF (588KB) ( 1690 )   Save
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    Aims Our objective was to study the interactive influences of ozone (O3) and nitrogen (N) on photosynthesis and yield in winter wheat (Triticum aestivum).
    Methods The winter wheat was exposed to two levels of O3 (ambient and 1.5 ambient) and two levels of N supply (210 and 250 kg·hm–2) under field conditions.
    Important findings O3 exposure significantly reduced the net photosynthetic rate (Pn), stomatal conductance (Gs) and transpiration rate (Tr) of wheat leaves in the filling stage by 28.95%, 31.79 % and 23.17%, respectively. O3 exposure also significantly reduced the content of chlorophyll a (Chl a), chlorophyll b (Chl b), carotene (Car), total chlorophyll (Chl t) and soluble protein in the filling stage by 58.89%, 68.64%, 22.89%, 60.31% and 32.00%, respectively, while intercellular CO2 concentration (Ci) changed slightly. Biomass in the maturing stage and yield of the wheat were also reduced by elevated O3 by 12.23% and 12.63%, respectively. High N availability significantly increased Pn, Chl a, Chl b, soluble protein, biomass and yield of the wheat leaves by 25.66%, 83.05%, 121.57%, 30.33%, 14.94% and 10.67%, respectively, while Gs, Ci, Tr and Car were influenced slightly by high N, which indicated that the increase of Pn was mainly caused by the increment of Chl a, Chl b and soluble protein. The interactive effects of O3 and N on the concentrations of Pn, Chl a, Chl b and soluble protein were significant. These results suggest that sufficient N supply can modify the effects of elevated O3 on photosynthesis and yield in wheat.

    Population genetic diversity and species divergence of Pinus massoniana and P. hwangshanensis at two nucleotide loci
    ZHANG Li-Rui, PENG Yan-Ling, REN Guang-Peng, ZHOU Yong-Feng, LI Zhong-Hu, LIU Jian-Quan
    Chin J Plan Ecolo. 2011, 35 (5):  531-538.  doi:10.3724/SP.J.1258.2011.00531
    Abstract ( 2287 )   PDF (401KB) ( 2201 )   Save
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    Aims Our objective was to examine population genetic diversity and species divergence of two pine species (Pinus massoniana and P. hwangshanensis) with overlapping distributions in southeastern China.
    Methods We estimated levels of nucleotide diversity and an analysis of molecular variance (AMOVA) of the two species based on sequence data of two nuclear loci for 88 individuals from 22 populations of the two species across most of their range of distribution. Gene genealogies of each locus were constructed by coalescent simulations using the Median-Joining model.
    Important findings Both species exhibit low levels of nucleotide diversity at two nucleotide loci, and the level of silent nucleotide diversity is two times higher in P. hwangshanensis (πsil = 0.003 40) than that in P. massoniana (πsil = 0.001 71). The population differentiation (FST) is also significantly different between the two species (P. massoniana, 0.059; P. hwangshanensis, 0.339, p < 0.05). These genetic differences in the population structure of the two species may result from their differences in distribution and habitat preference. Hierarchical AMOVA revealed that the average of variance components between species is 48.86% based on the two loci and is significantly higher at locus GI (77.24%) than locus C3H (20.48%). In addition, shared haplotypes were only observed in C3H rather than GI. Thus we speculate that GI (control of flowering time) may have experienced speciation- related selection, which further accelerated its lineage-sorting divergence between the species.

    Overyielding of fine root biomass as increasing plant species richness in subtropical forests in central southern China
    LIU Cong, XIANG Wen-Hua, TIAN Da-Lun, FANG Xi, PENG Chang-Hui
    Chin J Plan Ecolo. 2011, 35 (5):  539-550.  doi:10.3724/SP.J.1258.2011.00539
    Abstract ( 2457 )   PDF (378KB) ( 2067 )   Save
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    Aims The objectives were to compare the fine root biomass, necromass and their distributions in the soil profile and examine the effects of plant species diversity on the morphological properties of live fine roots at different soil depths among four forests along a gradient of increasing plant species richness in subtropical southern China.
    Methods The fine root samples were collected in March 2010 in four forests: coniferous monoculture (Cunninghamia lanceolata), coniferous pioneer species (Pinus massoniana-Lithocarpus glaber), deciduous (Choerospondias axillaris) and evergreen broadleaved (Cyclobalanopsis glauca-Lithocarpus glaber). In each forest, three soil cores containing fine roots were taken at each of three soil depth (0–10, 10–20 and 20–30 cm) at each of upper, middle and lower slope positions. Living and dead roots were manually separated and then oven dried at 75°C to constant mass to determine weight. Living roots were scanned with a Win-RHIZO 2005C to measure morphological parameters, including total root length, total root volume, number of root tips and forks.
    Important findings Fine root biomass tended to increase along the gradient from the plantation to evergreen broadleaved forest. Total fine root biomass within the 0–30 cm soil depth differed significantly among the forests, but there were no significant differences in living root biomass. Fine root biomass density decreased exponentially with soil depth at similar rates among the forests. With exception of the plantation, fine root biomass showed clear differences in their distribution in the soil layers, indicating significant belowground spatial niche segregation of the vertical root distribution patterns in the more species-rich stands. Differences in root biomass did not lead to significant differences in fine root morphology on a stand area basis.

    Effects of intensive and extensive management on soil active organic carbon in bamboo forests of China
    MA Shao-Jie, LI Zheng-Cai, WANG Gang, LIU Rong-Jie, FU Mao-Yi, ZHOU Ben-Zhi
    Chin J Plan Ecolo. 2011, 35 (5):  551-557.  doi:10.3724/SP.J.1258.2011.00551
    Abstract ( 2090 )   PDF (230KB) ( 1812 )   Save
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    Aims Our objective was to determine the effects of intensive cultivation on soil organic carbon (SOC) in bamboo (Phyllostachys heterocycla ‘Pubescens’) forests.
    Methods We used the reference land unit method and collected soil samples in intensively and extensively managed bamboo forests in the spring.
    Important findings Under intensive management, total organic carbon (TOC) decreased by 7.01% and 18.90% and readily oxidized carbon (ROC) decreased by 31.22% and 46.03% in 0–10 and 10–20 cm soil layers, respectively. Also, light fraction organic matter (LFOM) decreased 19.87% in the 0–20 cm soil layer. Soil organic carbon under the two types of management decreased with increasing soil depth, but the ranges of decrease were different. The vertical distribution of ROC under extensive management paralleled that of TOC, while both were different under intensive management. LFOM tended to accumulate in surface layers (0–20 cm). TOC, ROC and LFOM were strongly correlated with soil nutrients (p < 0.01), and TOC was significantly related to available P (p < 0.05). After intensive management, the percentage of ROC to TOC and activity of carbon pool significantly dropped by 26.01% and 50.52% (p < 0.05), respectively, in the 0–10 cm soil layer and dropped by 35.51% and 54.41% respectively in the 10–20 cm soil layer. Therefore, a mixture of organic and inorganic manures with the proper ratio should be applied to promote SOC and improve biological and chemical soil activity.

    Root growth and distribution in rice cultivars as affected by nitrogen and water supply
    GU Dong-Xiang, TANG Liang, XU Qi-Jun, LEI Xiao-Jun, CAO Wei-Xing, ZHU Yan
    Chin J Plan Ecolo. 2011, 35 (5):  558-566.  doi:10.3724/SP.J.1258.2011.00558
    Abstract ( 1851 )   PDF (415KB) ( 1628 )   Save
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    Aims Quantitative study of root growth pattern in rice (Oryza sativa) is of great significance for guiding management regulation and genetic improvement. Our objective was to elucidate the characteristics of root growth and distribution in rice under different conditions of cultivation.
    Methods We conducted pot experiments involving different nitrogen rates, water regimes and rice cultivars with the root shelf method. Root indices were measured at the jointing and heading stages, including total dry weight (TRW), adventitious root number (ARN), and morphological indices (length, surface area and volume) of three types of roots (adventitious, fine and coarse lateral roots).
    Important findings The observed root indices increased from the jointing stage to the heading stage in all treatments. There were significant differences in root indices among the three nitrogen rates, and each index increased with increasing nitrogen rates at both stages. In the water regime experiment, there was no significant difference in ARN between irrigation (W2) and constant water (W1), but the other indices of W2 were highest at both stages. There were no significant differences in TRW and morphological indices of coarse lateral roots between W1 and dry cultivation (W3) at the jointing stage. The other indices at the jointing stage and all indices at the heading stage were lowest with W3. All indices were significantly highest in the ‘Yangdao 6’ (V3) cultivar, but similar in ‘Nipponbare’ (V1) and ‘Wuxiangjing 14’ (V2) cultivars. In addition, the roots extended more deeply into soil from the jointing to the heading stage, but were mainly distributed in the top 5 cm. Lower nitrogen and water supply would promote spreading of roots in the subsoil (<5 cm) and enhance the proportions of fine and coarse lateral roots. As compared with V3, the roots of V1 and V2 extended more deeply into soil. We concluded that proper nitrogen fertilization and water control could optimize the growth and distribution characteristics of different types of rice roots and this could be influenced by the specific cultivar.

    Photosynthetic characteristics of canopy-dwelling vines in lower subtropical evergreen broadleaved forest and response to environmental factors
    JIANG Hao, ZHOU Guo-Yi, HUANG Yu-Hui, LIU Shi-Zhong, TANG Xu-Li
    Chin J Plan Ecolo. 2011, 35 (5):  567-576.  doi:10.3724/SP.J.1258.2011.00567
    Abstract ( 1864 )   PDF (370KB) ( 1553 )   Save
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    Aims Vines are important floristic and ecological elements in forests of tropical and subtropical areas; however, few studies have provided information on the photosynthetic characteristics of vines. Our purpose is to characterize the photosynthetic traits of major canopy-dwelling vines in the lower subtropical evergreen broad-leaved forest in southern China.
    Methods We compared the photosynthetic characteristics of two upper-canopy vines (Dischidia chinensis and Psychotria serpens) and two lower-canopy vines (Fissistigma glaucescens and Piper hancei) in Dinghushan Nature Reserve. We measured maximum photosynthetic rate (Amax), light saturation point (Lsp), light compensation point (Lcp), respiration in light (Rday), convexity (K), apparent quantum yield (Φ), transpiration rate (Tr) and water utilization efficiency (WUE) using a LI-6400 system. We also determined environmental factors inside and outside the canopy.
    Important findings Differences of photosynthetic characteristics between the upper and lower canopy-dwelling vines can be largely explained by differences in environmental factors such as photosynthetic active radiation (PAR), temperature and humidity within the forest canopy. Vines located in the upper canopy have lower annual mean Amax and LSP compared with those located in the lower canopy. Amax values of the upper canopy vines D.chinensis and Psychotria serpens are (2.9 ± 0.6) and (6.3 ± 1.3) μmol CO2·m–2·s–1, respectively, and their LSP values are (168.5 ± 83.4) and (231.4 ± 147.8) μmol·m–2·s–1, respectively. The Amax values of F. glaucescens and Piper hancei are (8.9 ± 2.9) and (8.6 ± 2.3) μmol CO2·m–2·s–1, respectively, and the LSP values are (491.6 ± 230.8) and (402.3 ± 112.8) μmol·m–2·s–1, respectively. The lower canopy vines have lower LCP compared with the upper canopy vines. The LCP values are (5.6 ± 1.9) and (5.4 ± 1.7) μmol·m–2·s–1 for F. glaucescens and Piper hancei, respectively and (16.1 ± 5.9) and (10.1 ± 5.7) μmol·m–2·s–1 for D. chinensis and Psychotria serpens, respectively. WUE values showed the same pattern, with values of (6.7 ± 1.8) and (6.8 ± 1.3) μmol CO2·mmol·H2O for F. glaucescens and Piper hancei, respectively, and (11.5 ± 3.9) and (8.7 ± 1.6) μmol CO2·mmol–1 H2O for D. chinensis and Psychotria serpens, respectively.

    Vegetation recovery dynamics of tropical lowland rain forest in Bawangling of Hainan Island, South China
    DING Yi, ZANG Run-Guo
    Chin J Plan Ecolo. 2011, 35 (5):  577-586.  doi:10.3724/SP.J.1258.2011.00577
    Abstract ( 2092 )   PDF (1367KB) ( 1530 )   Save
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    Aims Our objective was to elucidate the trajectory and pattern of tree succession on lands abandoned after multiple cycles of shifting cultivation in comparison to old-growth communities.
    Methods We established seven 100 m × 100 m plots in lowland sites. There were two old-growth forest plots, one 12-year-old fallow plot, two 25-year-old fallow plots, and two 55-year-old fallow plots. We recorded species, diameter at breast height (DBH), and height of all woody stems (excluding lianas) ≥1 cm DBH in 100 subplots (10 m × 10 m) in each plot. Analysis methods included non-metric multidimensional scaling (NMS).
    Important findings NMS showed large differences in community composition between fallow and old-growth forest, even after 55 years of natural recovery. Saplings (DBH < 5 cm) showed more convergence with old-growth forest composition than did adult trees (DBH ≥10 cm). Species accumulation rates for all three ages of fallow plots were slower than for old-growth forests. The recovery of community structure was relatively faster, especially for tree height, but structural complexity did not reach that of old-growth forests. Sprouting stems accounted for 39.9% of density and 55.9% of basal area in the 12-year-old fallow plot, but less in older plots. The proportion of three functional groups (pioneer, non-pioneer light-demanding and shade-tolerant species) showed directional patterns of change during succession, indicating that pattern of recovery was determined by life-history traits. However, cessation of recovery during mid succession indicated that return to pre-disturbance species composition may take centuries or never occur. This should be considered when structuring successional models and predicting carbon accumulation in tropical forest.


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