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Table of Content
    Volume 32 Issue 1
    30 January 2008
      
    Research Articles
    CHARACTERISTICS OF LITTERFALL IN RELATION TO SOIL NUTRIENTS IN MATURE AND DEGRADED EVERGREEN BROAD-LEAVED FORESTS OF TIANTONG, EAST CHINA
    YAN En-Rong, WANG Xi-Hua, ZHOU Wu
    Chin J Plan Ecolo. 2008, 32 (1):  1-12.  doi:10.3773/j.issn.1005-264x.2008.01.001
    Abstract ( 5552 )   PDF (971KB) ( 1576 )   Save
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    Aims Litterfall plays an important role in linking aboveground and belowground processes in forest ecosystems. Nutrients

    absorbed by plants can be released to the soil and re-utilized by plants via litter decomposition. Although litterfall

    composition and dynamics have been widely studied in the past two decades, the relationship among litterfall, nutrient

    cycling and vegetation types is poorly understood. Therefore, we studied litterfall in evergreen broad-leaved forests (EBLF)

    to enrich our knowledge of the relationship.
    Methods The research was conducted in Tiantong National Forest Park (29 °52′N, 121°39′E, 200 m a.s.l),Zhejiang, East

    China. We chose secondary and young EBLF (Schima superba community), coniferous and evergreen broad-leaved mixed forest

    (Pinus massoniana+Schima superba community), coniferous forest (Pinus massoniana community) and shrubland (Lithocarpus glaber

    + Loropetalum chinense community) to represent forests at different degradation stages and mature EBLF (Castanopsis fargesii

    community) to represent reference climax forest. Productivity, composition, nutrient concentration and total nutrient amount

    of the litterfall were measured each month from November 2003 to October 2004. Litterfall traits were correlated with soil

    total N, total P, total inorganic N, N mineralization and nitrification rates.
    Important findings Degradation of EBLF significantly reduced litterfall productivity from 13.03 Mg·hm-2 in mature EBLF to

    6.38 Mg·hm-2 in shrubland, and significantly reduced N concentration in litterfall. In contrast, P concentration showed no

    consistent pattern. Total N and total P amounts returned via litterfall decreased significantly with degradation. Soil total

    N was positively correlated with annual litterfall productivity but not litter N concentration. Soil total P was positively

    correlated with both annual litterfall productivity and litter P concentration. Soil inorganic N was not correlated with

    either productivity or litter nutrient concentration. Soil N nitrification rate was positively correlated with annual

    litterfall productivity and total amounts of nutrients returned, but was not correlated with litter N concentration. Soil N

    mineralization was not correlated with any litterfall traits. These results suggested that, during degradation of EBLF,

    shifting of plant functional types and simplifying of community structure reduced the quality and quantity of litterfall to a

    low level and consequently reduced soil nutrient pools.

    N∶P STOICHIOMETRY IN SECONDARY SUCCESSION IN EVERGREEN BROAD-LEAVED FOREST, TIA NTONG, EAST CHINA
    YAN En-Rong, WANG Xi-Hua, ZHOU Wu
    Chin J Plan Ecolo. 2008, 32 (1):  13-22.  doi:10.3773/j.issn.1005-264x.2008.01.002
    Abstract ( 4598 )   PDF (405KB) ( 1435 )   Save
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    Aims It is well documented that nitrogen (N) and phosphorus (P) are the two main growth-limiting nutrients for plants in many natural environments. Plant N∶P ratio has proved useful as an indicator of shifts from N (P) to P (N) limitation because it is easily determined and compared. However, little is known about the plant N∶P ratio in evergreen broad-leaved forests (EBLF), particularly the pattern along secondary succession. Therefore, our goal was to examine the relationship between the form of nutrient limitation and secondary successional stage by using the N∶P ratio of plant leaves (ratio of N to P concentration) as an indicator.
    Methods The research was completed in Tiantong National Forest Park (29 °52′N, 121°39′E, 200 m elevation), Zhejiang
    Province, East China. Leaf N and P concentrations of dominant tree species along a secondary succession gradient of EBLF were quantified to provide canopy N∶P ratios for different communities. Leaf N and P concentrations of common plant species in a given community were then determined to emphasize the relationships between differences in the N∶P ratios among species at each successional stage.
    Important findings Shifts in the N∶P ratios of species were consistent along the successional series, although the N∶P
    ratios of different species in a given community varied considerably. At the community level, the lowest N∶P ratio (7.38 ) was found in grassland, which was usually considered a primary stage of EBLF succession. Thereafter, the N∶P ratio increased to 19.96 in the shrub stage, declined to an average of 14-16 in the mid-stages of succession, including coniferous forest and coniferous-broadleaved mixed forest, and increased at the end stages of succession (e.g. 18.77 in the Schima superba community and 20.13 in the Castanopsis fargesii community). These results suggest that the productivity of vegetation in the Tiantong region is N-limited in the primary stages of succession, N-and P-limited in the mid-succession stages and probably P-limited in the shrub and mature EBLF stages.

    STEM RESPIRATION RATES OF DOMINANT TREE SPECIES IN A TROPICAL SEASONAL RAIN FOREST IN XISHUANGBANNA, YUNNAN, SOUTHWEST CHINA
    YAN Yu-Ping, SHA Li-Qing, CAO Min
    Chin J Plan Ecolo. 2008, 32 (1):  23-30.  doi:10.3773/j.issn.1005-264x.2008.01.003
    Abstract ( 4133 )   PDF (375KB) ( 1333 )   Save
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    Aims Forest is an important pool of carbon in terrestrial ecosystems. Woody tissues contribute much biomass, and their
    respirations influence carbon fixation. Stem respiration is an important component of the carbon budget of forest stands.
    Stem respiration has been studied in temperate and boreal zones, but seldom has been reported for tropical rain forests. Our
    objective was to investigate the characteristics of stem respiration and the response of stem respiration to temperature in
    11 common trees in Xishuangbanna tropical seasonal rainforest.
    Methods We made in situ chamber measurements of stem respiration using an Li-820 infrared CO2 gas analyzer (IRGA) from March
    2005 to February 2006. Our custom-built polyvinyl chloride (PVC) chamber sealed to the stem by thin neoprene gaskets. Stem
    respiration rates were measured on south and north sections at 1.3 m height, and stem temperatures were recorded at 1 cm
    depth.
    Important findings Stem respiration rates of all species had similar seasonal patterns and were higher in the wet season and
    lower in the dry season. There were significant differences in stem respiration rates among species, ranging from 0.823 to
    2.727μmol•m-2•s-1. Stem respiration rates on the south and north sections were similar for the same species. Significant
    exponential correlations w ere observed between stem respiration rates and stem temperatures (0.55<R2<0.9 2). Q10 values
    for stem respiration among species ranged from 1.90 to 3.03, somewhat higher than the range (1.6-2.38) reported in previous
    studies.
    COMPARISONS BETWEEN SEASONAL AND DIURNAL PATTERNS OF SOIL RESPIRATION IN A MONTANE EVERGREEN BROAD-LEAVED FOREST OF AILAO MOUNTAINS, CHINA
    FENG Wen-Ting, ZOU Xiao-Ming, SHA Li-Qing, CHEN Jian-Hui, FENG Zhi-Li, LI Jian-Zhou
    Chin J Plan Ecolo. 2008, 32 (1):  31-39.  doi:10.3773/j.issn.1005-264x.2008.01.004
    Abstract ( 5114 )   PDF (398KB) ( 1516 )   Save
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    Aims Soil respiration may have distinct dynamic patterns at different temporal scales since it is affected by diverse
    abiotic and biotic factors. Seasonal variation in soil respiration is largely controlled by abiotic factors such as
    temperature and soil moisture, whereas the regulation of diurnal variation is likely physiological rhythms of plants. Our
    objectives were to compare seasonal and diurnal patterns of soil respiration and to evaluate relationships between soil
    respiration and temperature at annual and diurnal scales. 
    Methods We examined seasonal variations of soil respiration using infrared gas analyzers at monthly or bimonthly intervals
    from April 2004 to March 2005, and diurnal variations in July, September and November 2004 as well as in January, March and
    May 2005 in a montane evergreen broad-leaved forest in Ailao Mountains, China. Soil temperature, air temperature, soil water
    content and air humidity were measured at the same time. We evaluated Q10 values of soil respiration and correlations between
    soil respiration and soil temperature. 
    Important findings Soil respiration fluctuated with distinct seasonal and diurnal patterns. Soil respiration was higher in
    the wet season (May through October) than in the dry season (November through April). Diurnal patterns of soil respiration
    varied among seasons. The mean rate of soil respiration was higher in nighttime than in daytime in July, September, January
    and March, but lower in November and May. On the whole year basis, soil respiration correlated strongly with soil temperature
    and soil water content. However, on a diurnal scale, these regressions were not significant. Q10 values were 4.48, 7.17 and
    2.34 for the whole year, dry season and wet season, and their corresponding soil temperature ranges were 5.9-16.6, 5.9-11.0
    and 10.3-16.6 ℃, respectively. Our results demonstrate that biotic and abiotic factors have distinct impacts on soil
    respiration at different temporal scales in the forest. Estimation on daily and annual car bon fluxes based on instantaneous
    measurements of soil respiration, rather than 24 hour measurements, may cause severe deviation from actual values because of
    the lack of diurnal correlation between soil respiration and temperature.
    DENSITY, STRUCTURE AND BIOMASS OF PARASHOREA CHINENSIS POPULATIONS IN DIFFER ENT PATCHES IN XISHUANGBANNA, SW CHINA
    TANG Jian-Wei, SHI Ji-Pu, ZHANG Guang-Ming, BAI Kun-Jia
    Chin J Plan Ecolo. 2008, 32 (1):  40-54.  doi:10.3773/j.issn.1005-264x.2008.01.005
    Abstract ( 4404 )   PDF (953KB) ( 1460 )   Save
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    Aims Parashorea chinensis, an endangered plant listed as the first class protected in China, now survives in local
    fragmented forests in Mengla, Hekou in Yunnan and Bama, Tianyang, Longzhou, Napo in Guangxi. We developed regression models
    for individual growth, age structure and biomass and analyzed population density, age structure, biomass dynamics and
    survivorship curves for local populations and the entire population in Mengla, Xishuangbanna, Yunnan Province, SW China. Our
    objective was to understand the population dynamics to aid protection of this endangered plant.
    Methods We established different numbers and sizes of plots (50 m × 20 m or 100 m × 20 m ) in five local patches according
    to patch size, and each plot was divided into 10 m × 10 m subplots to measure the height, diameter at breast height (DBH) or
    basal diameter and crown of each individual >0.5 m height. We also measured height, basal diameter and crown of each
    individual <0.5 m height in 2 m × 2 m quadrats in each subplot. 
    Important findings There were large differences in population density and age structure as well as mortality rate for
    different age stages of local populations in different patches. The local population density of the patch in which some trees
    were cut was 3-4 times as much as the patch which was protected and 16-18 times as much as the patch which was planted with
    Amomum villosum.Moreover, the local population of the smallest patch had no mature individuals and lacked individuals in
    some age stages. Although the biomass of local populations showed logistic increase with stand age, maximum biomass and
    biomass dynamics with time were different for local populations. The survivorship curve of the entire population was
    approximately a straight line, indicating that the age structure of entire population was stable and increasing. The
    mortality of 1-60 year-old individuals declined, mortality of 60-150 year-old individuals increased with age, and peak
    mortality occurred after 180 years. The biomass of the entire population was consistent with logistic growth before 180 years
    and was at a maximum at a bout 180 years. However, some patches had been so badly disturbed that the local populations were
    on the edge of extinction. Effective steps must be taken to protect this endangered plant population.
    SEEDLING GROWTH AND SURVIVAL OF THE ENDANGERED TREE SPECIES SHOREA WANTIANSHUEA AFTER A MAST-FRUITING EVENT
    YAN Xing-Fu, CAO Min
    Chin J Plan Ecolo. 2008, 32 (1):  55-64.  doi:10.3773/j.issn.1005-264x.2008.01.006
    Abstract ( 4352 )   PDF (401KB) ( 1024 )   Save
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    Aims Shorea wantianshuea is an endangered tree species of Dipterocarpaceae in Xishuangbanna seasonal rain forest, and is

    listed in the Plant Red Book under Grade Ⅰ in China. This species regenerates exclusively from seeds. Our objective was to

    determine the fate of seedlings (including their growth and survival) following a mast fruiting event. Results will be useful

    in restoring this species and degraded natural forests dominated by it. 
    Methods In early December 2004, after mast fruiting of S. wantianshuea, we established three parallel 20 m×100 m transects

    spaced 50 m apart within an area of 100 m×200 m spanning from valley bottom to ridge top. Each transect was stratified into

    five contiguous plots of 20 m and near the center of each plot two 3 m×3 m quadrats were established. We labeled all newly

    established S. wantianshuea seedlings in each quadrat, recorded seedling height, basal stem diameter and number of leaves

    every 2-3 months over a 10-month period and calculated death rate, herbivory rate and survival rate of the seedlings. At the

    end of the survey, we destructively sampled seedlings and determined leaf areas, total dry weight, root-shoot ratio and

    specific leaf area.
    Important findings Many S. wantianshuea seedlings established after the mast-fruiting event did not recruit into its natural

    population because of high mortality rate and herbivory rate caused by seasonal drought stress, small mammals and other

    predators. The density of seedlings was as high as 2.76 plants&#8226;m-2 in December 2004 (first census), but was less than 0.26

    plants&#8226;m-2 in September 2005 when the study ended. Seedling mortality rate was high during the dry season, particularly after

    the first two months. The final seedling mortality rate on ridge-top and lower-ridge sites, 55% and 54%, respectively, were

    higher than those on other sites, with a gradually increase from valley bottom to ridge top. Herbivory rate in the first

    census was low and in 8 of 15 sites no seedlings were gnawed or pulled. At the end of the study, mean seedling height was

    17.9, 19.7, 18.4, 13.0 and 12.1 cm in valley-bottom, lower-slope, medium-slope, lower-ridge and ridge-top sites,

    respectively; however, no significant differences were observed in seedling height and other growth parameters.

    TERRESTRIAL ECOSYSTEM PRODUCTIVITY AND CARRYING CAPACITY IN NORTHEAST CHINA
    ZHOU Guang-Sheng, YUAN Wen-Ping, ZHOU Li, ZHENG Yuan-Run
    Chin J Plan Ecolo. 2008, 32 (1):  65-72.  doi:10.3773/j.issn.1005-264x.2008.01.007
    Abstract ( 4157 )   PDF (362KB) ( 1130 )   Save
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    Aims Rapidly growing population and environmental issues have been key problems for the living and sustainable development
    of humans. In order to provide policy-makers with a theoretical reference, it is urgent to know how terrestrial ecosystem
    productivity and its carrying capacity in Northeast China will respond to future climatic change. My objective was to
    simulate net primary productivity (NPP) of terrestrial ecosystems in Northeast China and their carrying capacities, as well
    as their responses to climatic change.
    Methods Values of NPP of the different terrestrial ecosystems were simulated by a natural vegetation NPP model (Zhou &
    Zhang, 1995) and an agricultural NPP model (Zheng et al., 1997), in terms of land use (forest, agriculture, grassland and
    wetland) data with a spatial resolution of 10 km×10 km and daily meteorological data from 1980 to 2002 as well as the
    projected climatic scenarios for 2020, 2050, 2070 and 2100. Ecosystem carrying capacities were given by the carrying capacity
    model (Cao, 1993) and NPP of agricultural, grassland and wetland ecosystems. 
    Important findings Mean annual temperature increased, and annual precipitation decreased in Northeast China from 1980 to
    2002. Total mean annual terrestrial ecosystem productivity during these 23 years was 3.52×1011 kg DM&#8226;a-1. Total mean annual
    terrestrial ecosystem productivities for forest, agriculture, grassland and wetland ecosystems were 1.53×1011, 4.55×1010,
    1.07×1011 and 4.63×1010 kg DM&#8226;a-1 , respectively. Mean annual terrestrial ecosystem productivities for forest,
    agriculture, grassland and wetland ecosystems were 5.73×103, 1.84×103, 5.64×103 and 5.55×103 kg DM&#8226;hm-2&#8226;a-1. Total mean
    annual carrying capacities from 1980 to 2002 were 2.61×108, 2.15×108 and 1.77×108 for well-off, comparatively well-off
    and surplus consumption levels, respectively. When 350×108 kg commercial grain export from Northeast China was considered,
    total mean annual carrying capacities from 1980 to 2002 were 1.70×108, 1.40×108 and 1.15×108 for the above three
    consumption levels, respectively. The population of Northeast China is about 1.07×108 at present. It implied that the
    population in Northeast China should be controlled in the future, in order to ensure the surplus consumption level and 350×
    108 kg commercial grain export. Simulated total mean annual carrying capacities of Northeast China in 2020, 2050, 2070 and
    2100 were 2.73×108, 2.25×108 and 1.85×108;2. 88×108, 2.38×108 and 1.95×108; 3.03×108, 2.49×108 and 2.05×108; and
    3.09×108 , 2.55×108 and 2. 09×108 for the three consumption levels, respectively, in terms of the climatic scenarios for
    the future. This study provides fundamental information for land resources and social sustainable development.
    EFFECTS OF HUMAN ACTIVITIES ON STRUCTURE AND COMPOSITION OF WOODY SPECIES OF THE NOKREK BIOSPHERE RESERVE OF MEGHALAYA, NORTHEAST INDIA
    Tripathi OP, Pandey HN, Tripathi RS
    Chin J Plan Ecolo. 2008, 32 (1):  73-79.  doi:10.3773/j.issn.1005-264x.2008.01.008
    Abstract ( 4052 )   PDF (434KB) ( 3107 )   Save
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    Aims Our study was conducted in the Nokrek Biosphere Reserve (NBR) in the Garo hills districts of Meghalaya, Northeast India. Our aim was to assess the effects of human activities on plant diversity, population structure and regeneration. 
    Methods We selected a representative 1.2 hm2 stand in both the core and buffer zones of NBR. Structure and composition were determined by randomly sampling square quadrats, population structure was assessed by determining age structure, and regeneration was assessed by measuring densities of seedling, sapling and adult trees.
    Important findings More woody species were recorded from the core zone than the buffer zone (87 vs.81 species), and there were a large number of tropical, temperate, and Sino-Himalayan, Burma-Malaysian and Malayan elements, primitive families and primitive genera. The trees were distributed in three distinct strata, canopy, subcanopy and sapling. Subcanopy and sapling layers had the highest species richness (81%-88%). Lauraceae and Euphorbiaceae were the dominant families in terms of the number of species, and a large number of families were represented by single species. Most woody species (57%-79%) were contagiously distributed and had low frequency (<20%). Although stand density was high in the buffer zone, its basal area was low compared to the stand in the core zone. Low similarity and high β-diversity indicate marked differences in species composition of the stands. Shannon diversity index was high in both the stands, while Simpson dominance index was low. The diameter-class distribution for dominant species revealed that the most had a large number of young individuals in their populations. Preponderance of tree seedlings, followed by a steep decline in population density of saplings and adult trees, indicated that the seedling to sapling stage was the most critical in the life cycle of the tree populations. Most species (42%-48%) had no regeneration, 25%-35% had good/fair regeneration, and the rest had poor regeneration or reoccurred as immigrants.

    SENSITIVITY OF CONIFEROUS TREES TO ENVIRONMENTAL FACTORS AT DIFFERENT SCALES IN THE SMALL XING’AN MOUNTAINS, CHINA
    BU Ren-Cang, CHANG Yu, HU Yuan-Man, LI Xiu-Zhen, HE Hong-Shi
    Chin J Plan Ecolo. 2008, 32 (1):  80-87.  doi:10.3773/j.issn.1005-264x.2008.01.009
    Abstract ( 3690 )   PDF (342KB) ( 1012 )   Save
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    Aims Our objective is to predict the distribution of coniferous species and determine species' sensitivity to environmental

    factors in the Small Xing'an Mountains, China. This information is important for forest regeneration and biodiversity

    conservation and is useful to policy makers for forest management at different scales.
    Methods Slope, aspect, compound topographic index, elevation, topographic position index and average annual temperature and

    precipitation were selected for use in Logistic regression to predict the occurrence of Korean pine (Pinus koraiensis), larch

    (Larix gmelinii), fir (Abies nephrolepis), spruces (Picea koraiensis and P. jezoensis) and Mongol scotch pine's (Pinus

    sylvestris var. mongolica). Relative operating characteristic (ROC) was used to evaluate the Logistic models. Because

    Logistic regression is difficult to explain, we used the correlation coefficient between species distribution and

    environmental factors to explore the sensitivity of species to environmental factors.
    Important findings The fir model had best fitness (ROC >80%), and Korean pine, spruces and larch had good fitness (ROC =

    60%-80%). The predictions of Mongol Scotch pine, a rare species, had low accuracy. At the regional scale, Korean pine, fir,

    spruces and Mongol Scotch pine were the most sensitive to average annual precipitation, and larch was the most sensitive to

    slope. At local scale, Korean pine was the most sensitive to slope, fir and spruces to elevation and larch to slope position.

    In addition, this shift of the most important factor in species occurrence at different scale was accompanied by a change of

    distribution type. Korean pine w as more clustered at regional scale (ROC=78.6%) than at local scale (74.4%), and its

    proportion increased in Fenglin Natural Reserve. Fir and spruces clustered at regional scale, but approached random

    distribution at local scale (ROC<60 %), i.e., they occurred everywhere. Larch, the dominant species in the north, became more

    clustered at local scale (ROC increased from 71.7 to 82.0%) and was restricted to sites such as valleys. Scaling down from

    regional to local scale resulted in the changes of the most important factors affecting species distribution. Most species

    were sensitive to climatic factors at regional scale and geographic factors at local scale; however, larch was always the

    most sensitive to geographic factors due to the temperature inversion in the region.

    A PRELIMINARY STUDY ON BIOMASS OF WOODWARDIA JAPONICA COMMUNITY UNDER A CONIFEROUS PLANTATION IN SUBTROPICAL CHINA
    MA Ze-Qing, LIU Qi-Jing, XU Wen-Jia, LI Xuan-Ran, LIU Ying-Chun
    Chin J Plan Ecolo. 2008, 32 (1):  88-94.  doi:10.3773/j.issn.1005-264x.2008.01.010
    Abstract ( 3460 )   PDF (318KB) ( 974 )   Save
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    Aims The purpose of the study was to determine the biomass (including fine roots), NPP, specific leaf area (SLA), leaf area
    index (LAI), and soil nutrients of Woodwardia japonica community under artificial coniferous forest in Jiangxi Province in
    subtropical China.
    Methods Plants in quadrats were harvested and dry weight was measured. Leaf area was measured by scanning, and SLA was
    represented by the ratio of dry matter to leaf area. LAI of the population was estimated by SLA and leaf biomass. 
    Important findings The relationships between aboveground biomass (W1) and geometric parameters of W. japonica were
    established (W1=0.021H1.545R2=0.790)and W1=2.518(D2H0.616R2=0.894), H: height; D: diameter ). The biomass of
    herbage and shrub under coniferous plantation was 367.8 g&#8226;m-2(52-932 g&#8226;m-2), 4.7% of canopy layer. The accumulated
    litter under forest was 1 631 g&#8226;m-2(672-2 763 g&#8226;m-2 ). The above-and under-ground biomass of W. japonica community were
    266.6 g&#8226;m-2 and 212.6 g&#8226;m-2, respectively. In total, the biomass of W. japonica population approximately accounted for
    73.7% of the whole herbaceous layer. There was a significant negative-correlation between SLA and leaves dry matter content 
    LDMC ). A leaf area (S) model was established in the form of S=21.922 6-0.152 L2+0.000 9L3(9.0≤L: max length of leaf ≤
    23.5;1.4 ≤ W: max width of leaf ≤5.9).LAI ofW. japonica population was estimated as 1.8 m2&#8226;m-2. Soil water content
    affected biomass of the community. A positive correlation between biomass and soil nitrogen concentration or soil organic
    matter (SOC) was identified.
    QUANTITATIVE FEATURES OF POPULATIONS OF PINUS TABULAEFORMIS AND P. ARMANDII REGENERATED FOLLOWING WATER DAMAGE AT QINLING MOUNTAIN, CHINA
    FEI Shi-Min, HE Ya-Ping, CHEN Xiu-Ming, JIANG Jun-Ming, GUO Zhi-Hua
    Chin J Plan Ecolo. 2008, 32 (1):  95-105.  doi:10.3773/j.issn.1005-264x.2008.01.011
    Abstract ( 3904 )   PDF (653KB) ( 1276 )   Save
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    Aims Comparison of populations of different plant species can reveal the formation mechanism and the influencing factors of the populations. We compared quantitative features of populations of Pinus tabulaeformis and P. armandii, which are the dominants in naturally regenerating communities, following water damage 17 years ago in part of the Fanjiazhuang section of the Caiyuhe Watershed of Qinling Mountain. We asked whether biological features of P. tabulaeformis and P. armandii influence the population size, age structure and population survival dynamics.
    Methods We measured the height, basal diameter and age (number of whorled branches) of two individuals in a total plot area of 11 900 m2 in 2005.
    Important findings As a result of faster height and lateral growth, P . tabulaeformis had greater mean height and basal diameter than P. armandii, and individuals occupied larger vertical and horizontal space. The two populations had different height, diameter and age structures, and no consistenay, which indicated that size structure did not always reflect the age structure. The populations had different age structures, with that of P. tabulaeformis skewed to older trees and that of P. armandii in a near normal distribution. The age structure of P. armandii population was influenced by slope aspect, but that of P. tabulaeformis population was not. Both survivorship curves were the type Ⅱ, which indicated that both populations had similar survival dynamics. Therefore, the different biological characteristics of P. tabulaeformis and P. armandii led to different population size and age structure features, but not survival processes. This implied that environmental factors were the main determinants of population survival dynamics.
    VALLISNERIASPECIES IN LAKES OF THE MIDDLE-LOWER REACHES OF THE YANGTZE RIVER OF CHINA
    CHEN Lei, YE Qi-Gang, PAN Li-Zhu, XU Li-Ming, HUANG Hong-Wen
    Chin J Plan Ecolo. 2008, 32 (1):  106-113.  doi:10.3773/j.issn.1005-264x.2008.01.012
    Abstract ( 3217 )   PDF (315KB) ( 1306 )   Save
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    Aims Vallisneria species are very common and important in shallow lakes of the middle-lower reaches of the Yangtze River of
    China. Our objectives were to: 1) examine whether these co-existing Vallisneria species differ in sexual and clonal life-
    history traits, and 2) determine whether life-history traits explain the interspecific distribution pattern of these species.

    Methods Field investigations were carried out to determine the distribution and coexistence pattern of the three
    Vallisneria species (V. spinulosa, V. natans and V. denseserrulata) in lakes of the middle-lower reaches of the Yangtze
    River. Life-history traits of sexual reproduction and clonal propagation of V. spinulosa and V. natans were determined and
    compared under field condition and uniform glasshouse environment.
    Important findings V. spinulosa was the dominant species in these lakes, V. natans was very common and V. denseserrulata was
    rare in this region. V. spinulosa and V. natans widely coexisted in these lakes; they frequently displayed a clear
    interspecific zonation pattern, or V. natans individuals scarcely occurred in V. spinulosa communities. Field investigations
    and glasshouse experiments suggested great differences of sexual and clonal life-history traits between V. spinulosa and V.
    natans
    . V. spinulosa is perennial, and capable of extensive clonal propagation, while V. natans is annual and reproduces
    mainly by sexual seedling as well as limited clonal growth. Differences of resource-acquisition and competitive abilities,
    caused by trade-offs of resource allocation between sexual reproduction and clonal propagation, might determine the pattern
    of competitive coexistence of V. spinulosa and V. natans.
    RELATIONSHIPS OF PLANT COMPOSITION,WATER LEVEL AND SOLAR RADIATION IN XIXI WETLAND, HANGZHOU, CHINA
    SHEN Qi, LIU Ke, LI Shi-Yu, ZHANG Jun, JIANG Yue-Ping, GE Ying, CHANG Jie
    Chin J Plan Ecolo. 2008, 32 (1):  114-122.  doi:10.3773/j.issn.1005-264x.2008.01.013
    Abstract ( 3458 )   PDF (427KB) ( 1286 )   Save
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    Aims Xixi wetland is located at the outskirt of Hangzhou, eastern China. Under the influences of human residents, farming
    and fishing activities for more than one thousand years, Xixi has changed to secondary farming wetland with 70% of the area
    covered by open water interfaced by narrow dikes and large islets. Urbanization and industrialization during the last 20
    years has rapidly shrunken Xixi. We investigated species composition of vascular plants in Xixi to explore: 1) relationships
    between species composition and habitats, 2) species which should be protected in the restoration of Xixi and methods for
    their protection, 3) favorable habitats for native and wetland species, and 4) occurrence and effects of invasive exotic
    species in different habitats and methods for their control. 
    Methods The herbaceous habitats of Xixi were classified into five types based on plant composition, water level, and solar
    radiation: blazing high dike (BHD), shading high dike (SHD), blazing low dike (BLD), blazing high islet (BHI), and blazing
    low islet (BLI). Community composition of the five habitats was studied by quadrat sampling method. Important values (IV)
    were used to calculate diversity indices and DCA ordination. A total of 26 sites with 234 m2 quadrats were sampled in this
    study.
    Important findings There were 119 vascular species belonging to 103 genera and 44 families. Among them, 108 species were
    native, 11 were invasive exotic; 50 were wetland plants; 6 were legumes, and 35 were grasses or grasses relatives. Results
    showed that BHD, SHD, BLD, BHI had greater plant species richness than BLI, and BHD had the greatest native species and woody
    species richness. Invasive exotic species and wetland plant species were prevalent in BLI, and common in BHD, SHD, BLD and
    BHI. BHD may be in favor of the protection of native species, and may be good for resisting the invasion of exotic species,
    but may be an unfavorable habitat for wetland plants, BLI was reversed. BLD could maintain moderately native plant species
    richness and had higher proportions of herbs and wetland plant species. Therefore, well-managed BLD should be emphasized in
    Xixi for protection and enhancement of native vegetation diversity and wetland plant species richness. The invasive exotic
    species, such as Alternanthera philoxeroides, which were harmful to the landscape or harmful to maintain native species
    diversity, must be removed periodically.
    ACTUAL EVAPORATION OF BARE SAND DUNES IN MAOWUSU, CHINA AND ITS RESPONSE TO PRECIPITATION PATTERN
    LIU Jun-Shan, GAO Qiong, GUO Ke, LIU Xin-Ping, SHAO Zhen-Yan, ZHANG Zhi-Cai
    Chin J Plan Ecolo. 2008, 32 (1):  123-132.  doi:10.3773/j.issn.1005-264x.2008.01.014
    Abstract ( 3017 )   PDF (622KB) ( 1167 )   Save
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    Aims Annual or long-term actual evaporation and its response to precipitation pattern are poorly known. Our aims are to
    estimate average annual surface evaporation of bare sand dunes and explore the relationship between precipitation pattern and
    annual evaporation variance. 
    Methods Based on a meta-analysis of previous experiments, we used a process-based model to calculate the evaporation (EV) of
    bare sand dunes in Maowusu from day to multiyear scales. We also developed a simple Rainfall-EV model driven by amount and
    frequency of rainfalls, by which we explored the relationship between intensify of rainfall events and variance of annual
    evaporation. 
    Important findings The process-based model yielded reasonable short-term evaporation pattern after rainfalls and
    accumulative evaporation. The long-term average of evaporation from 1959 to 1992 is 166 mm, accounting for 56% of annual
    precipitation. Although there is no significant change of annual precipitation, the actual evaporation increased
    significantly with a tendency of 1.30 mm&#8226;a-1. We suggested the significant increase (0.69 mm&#8226;a-1) of small rainfall events
    (<5 mm) was the dominant reason of the increase of annual actual evaporation. The frequencies and amounts of strong rainfall
    contributed more to annual precipitation than annual evaporation, while weak rainfall events (<12 mm) kept relatively
    constant among years, providing about 100 mm evaporation. These resulted in less variance of annual evaporation than
    precipitation. Since the precipitation pattern among years apparently will influence annual evaporation, the simple Rainfall
    -EV model is able to predict annual evaporation effectively.
    SEED DISPERSAL AND SPATIAL-TEMPORAL VARIATION OF SEED PREDATION OF MUSA ACUMINATA IN XISHUANGBANNA, SOUTHWEST CHINA
    MENG Ling-Zeng, GAO Xiu-Xia, CHEN Jin
    Chin J Plan Ecolo. 2008, 32 (1):  133-142.  doi:10.3773/j.issn.1005-264x.2008.01.015
    Abstract ( 3062 )   PDF (556KB) ( 1096 )   Save
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    Aims Seed dispersal and seed predation are important on mechanisms of forest maintenance and degeneration. Understanding
    them can enable effective conservation measures, especially in Xishuangbanna tropical rainforest in China which is suffering
    severe pressures.
    Methods Musa acuminata is a large herbaceous plant in Xishuangbanna , Yunnan Province. We investigated seed dispersal and
    spatial-temporal variation of seed predation in three habitats (wild banana communities, virgin rainforest and open habitat)
    in three different sites of Xishuangbanna (XTBG, Xinshan and Bubeng). We used two treatments excluding ants and rodents and
    surveyed community structure of ants and rodents to explore the relationship between abundance of predators and intensity of
    seed predation.
    Important findings Bats were the most important, effective seed disperser, and birds also played an important role in seed
    dispersal, with approximately 75% of the mature fruits of M. acuminata dispersed at night and about 25% during daytime. After
    primary dispersal, seeds of M. acuminata were mainly removed by small rodents and ants. This seed predation was significantly
    influenced by season, site and habitat. Seed predation was significantly stronger in rainy than dry seasons (p<0.001). Seed
    predation in M. acuminata communities was the highest among the three habitats (p<0.001), and seed predation in Bubeng Nature
    Reserve, which had the least disturbance, was significantly lower than the other two sites (which were not significantly
    different at p>0.05). Seed removal was generally consistent with the abundance of rodents and ants in different seasons,
    habitats and sites. The interaction between sites and habitats and the interaction among seasons, sites and habitats had
    significant effects on seed predation. Compared to near by forest and open habitats,Musa communities had the most abundant
    rodents and the highest seed predation and the lowest proportion of secondary seed dispersal by ants. In contrast, seed
    predation by rodents in forest and open habitat was relatively weak and a large proportion of post dispersal seed was removed
    by ants. Therefore, primary seed dispersal mostly by bats and birds is essential for M. acuminata seeds to escape seed
    predation.
    GENETIC DIFFERENTIATION OF QUANTITATIVE TRAITS AND LOCAL ADAPTABILITY OF REMNANT POPULATIONS OF ISOETES SINENSIS AND IMPLICATIONS FOR CONSERVATION AND GENETIC REINFORCEMENT
    YANG Wei, YE Qi-Gang, LI Zuo-Zhou, HUANG Hong-Wen
    Chin J Plan Ecolo. 2008, 32 (1):  143-151.  doi:10.3773/j.issn.1005-264x.2008.01.016
    Abstract ( 2870 )   PDF (340KB) ( 1299 )   Save
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    Aims Isoetes sinensis (Isoeteaceae) is a critically endangered aquatic fern ally in China. Understanding the genetic
    differentiation of quantitative traits and local adaptation of the remnant populations should provide insight into the
    adaptation of different populations to their local environment and useful information for formulating appropriate
    conservation strategy. 
    Methods The quantitative traits of nine isozyme multilocus genotypes from three remnant populations of I. sinensis were
    investigated using nested analysis based on random block design in common-garden experiments. Population differentiation of
    allozyme (FST) and quantitative traits (QST) were estimated using the Bayesian approach.
    Important findings Of 14 quantitative traits examined, ten were found to be significantly different among populations and
    three were significantly different within populations. Multiple comparison by Turkey tests indicated that the mean values of
    five traits were the highest for the Songyang population and lowest for the Xiuning population, whereas the mean values of
    the macrosporangium characteristics and plant height were highest for the Jiande population and lowest for the Xiuning
    population. This result probably reflected different scenarios of founder effect, habitat competition ability and trade-off
    between vegetative and reproductive growth. Local adaptation was evaluated as a difference of QST vs. FST value, and eight
    important reproductive fitness traits were found to be significant (QST>FST, p≤0.05 ) under the selfing assumption,
    suggesting local adaptability in the remnant populations. It is more likely that there is a potential risk of outbreeding
    depression if genetic enhancement is implemented by translocation of individuals from different populations. Therefore,
    translocation among these remnant populations is not recommended. Instead, we recommend increasing gene flow within each
    population and improving habitat management by reducing competition with companion species in in situ conservation for
    Xiuning and Songyang populations. In the case of Jiande population, minimizing human disturbance should be considered as a
    top priority and an in situ conservation plot should be designated for the population.
    SOYBEAN CHLOROPHYLL A CONCENTRATION ESTIMATION MODELS BASED ON WAVELET-TRANSFORMED, IN SITU COLLECTED, CANOPY HYPERSPECTRAL DATA
    SONG Kai-Shan, ZHANG Bai, WANG Zong-Ming, LIU Dian-Wei, LIU Huan-Jun
    Chin J Plan Ecolo. 2008, 32 (1):  152-160.  doi:10.3773/j.issn.1005-264x.2008.01.017
    Abstract ( 2994 )   PDF (393KB) ( 1138 )   Save
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    Aims A growing number of studies have focused on evaluating spectral indices in terms of their sensitivity to vegetation
    biophysical parameters. We use a regression model, based on wavelet-transformed reflectance, and vegetation indices (VI) to
    estimate a wide range of soybean (Glycine max) canopy reflectances to study the sensitivity of wavelet-transformed
    reflectance and vegetation in dices to soybean chlorophyll a concentration. We modify some VI to enhance their sensitivity to
    variations in chlorophyll a concentration. 
    Methods We collected soybean canopy hyperspectral reflectance and chlorophyll a concentration data in 2003 and 2004 at two
    sites in the black soil belt of China. We correlated reflectance, derivative reflectance and soybean chlorophyll a
    concentration and regressed vegetation indices (NDVI, SAVI, RDVI andMSRI) and soybean chlorophyll a concentration. We
    transformed soybean canopy reflectance with wavelet analysis and applied extracted wavelet energy coefficient in a regression
    model for estimation of chlorophyll a concentration.
    Important findings Soybean canopy reflectance shows a negative correlation with chlorophyll a concentration in the visible
    spectral region, while it shows a positive correlation with soybean chlorophyll a concentration in the near-infrared region.
    Reflectance derivative has a strong relationship with soybean chlorophyll a concentration in the blue, green and red edge
    spectral region, with maximum correlation coefficient in the red-edge region. Four vegetation indices have strong
    correlations with soybean chlorophyll a concentration, with R2 >0.75. The s ingle variable regression model based upon
    wavelet-extracted reflectance energy can accurately estimate soybean chlorophyll a concentration, with R2 about 0.75, while
    R2 was 0.85 with the multivariate regression model. Our study indicated that wavelet analysis can be applied to in situ
    collected hyperspectral data for soybean chlorophyll a concentration estimation with accurate prediction and in the future
    wavelet analysis methods should be applied to hyperspectral data for estimation of other vegetation biophysical and
    biochemical parameters.
    EFFECTS OF NaCl AND Na2CO3 STRESSES ON PHOTOSYNTHESIS AND PARAMETERS OF CHLOROPHYLL FLUORESCENCE IN HELIANTHUS TUBEROSUS SEEDLINGS
    XUE Yan-Feng, LIU Zhao-Pu
    Chin J Plan Ecolo. 2008, 32 (1):  161-167.  doi:10.3773/j.issn.1005-264x.2008.01.018
    Abstract ( 2957 )   PDF (357KB) ( 1235 )   Save
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    Aims Our objective was to explore the effects of saline-alkali stress on photosynthetic apparatus of Helianthus tuberosus
    seedlings. 
    Methods H. tuberosus seedlings were treated with NaCl (50, 100, 150 , 200, 250 mmol&#8226;L-1) and Na2CO3 (25, 50, 75, 100, 125
    mmol&#8226;L-1) in plastic pots with sand. Others were cultured in modulated half-strength Hoagland solution as a control. We
    studied the effects of NaCl and Na2CO3 on net photosynthetic rate (Pn) and parameters of chlorophyll fluorescence by
    measuring chlorophyll content,Pn, stomatal conductivity (Gs) and fluorescence parameters after 7 days.
    Important findings Significant increases of chlorophyll content, Pn and Gs compared with the control were observed under the
    150 mmol&#8226;L-1 NaCl treatment, whereas there were no effects on fluorescence parameters, Fv/Fm (maximal photochemical
    efficiency of photosystem Ⅱ (PSⅡ) while all PSⅡ reaction centers are open), Fm/Fo(another expression for the maximal
    photochemical efficiency of PSⅡ), φPSⅡ(actual quantum yield of PSⅡ under actinic irradiation), qP (photochemical
    quenching coefficient), and NPQ (non-photochemical quenching coefficient). But with greater NaCl concentration, the
    chlorophyll content, Pn, Gs and fluorescence parameters significantly decreased except for an increase of NPQ compared with
    the control. When H. tuberosus seedlings were treated with Na2CO3, chlorophyll content, Pn, Gs, Fv/Fm, Fm/Fo, φPSⅡ and qP
    significantly decreased and NPQ increased compared with the control. At the same concentration of Na+, the decrease of
    chlorophyll content, Pn, Gs, Fv/Fm, Fm/Fo, φPSⅡ,qP and the increase of NPQ were higher in Na2CO3 stress than in NaCl
    stress. All results suggested that the tolerance of H. tuberosus seedlings to saline stress was higher than to alkaline
    stress.
    GROWTH RESPONSE AND UPTAKE DIFFERENCES BETWEEN TWO ECOTYPES OF SEDUM ALFREDII TO SOILS Cd
    LONG Xin-Xian, WANG Yan-Hong, LIU Hong-Yan
    Chin J Plan Ecolo. 2008, 32 (1):  168-175.  doi:10.3773/j.issn.1005-264x.2008.01.019
    Abstract ( 2600 )   PDF (355KB) ( 1038 )   Save
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    Aims Our objective was to compare growth responses to soil Cd, as well as Cd uptake and accumulation in two ecotypes of
    Sedum alfredii. 
    Methods In a pot experiment, we planted one mining ecotype of S. alfredii and one non-mining ecotype in eight soils with
    different Cd levels (control, 12.5, 25 , 50, 100, 200, 300, 400 mg&#8226;kg-1) for two successive croppings.
    Important findings The mining ecotype of S. alfredii grew healthy at all Cd supply levels. Its Cd concentrations in shoots
    and roots linearly increased with increasing soil Cd levels and reached a maximum of approximately 2 900 mg&#8226;kg-1 (DW) and
    500 mg&#8226;kg-1 at 400 mg&#8226;kg-1 treatment, respectively. Its Cd concentration in shoots was far higher than roots. In contrast,
    the growth of the non-mining ecotype was severely inhibited by soil Cd supply, as its shoot and root biomass significantly
    decreased compared with the control treatment. Cd concentrations in shoots an d roots of the non-mining ecotype also
    increased with increasing soil Cd levels, but its Cd concentration in roots was higher than in shoots. At low soil Cd levels
    (≤50 mg&#8226;kg-1), Cd concentration in roots of the mining ecotype was higher than the non-mining ecotype, while there were no
    significant differences between the two ecotypes at high Cd levels (100 and 200 mg&#8226;kg-1). Increasing soil Cd levels from 0
    to 400 mg&#8226;kg-1 enhanced Cd concentration in shoots of the two ecotypes, and Cd concentration in shoots of the mining ecotype
    was always far higher than the non-mining ecotype at all Cd supply levels. These results indicate that the mining ecotype of
    S. alfredii has an extraordinary ability to tolerate and uptake Cd from soil and is proved to be a Cd hyper-accumulator.
    BIOLOGICAL PROPERTIES AND ENZYMATIC ACTIVITY OF ARABLE SOILS AFFECTED BY LONG-TERM DIFFERENT FERTILIZATION SYSTEMS
    LIU En-Ke, ZHAO Bing-Qiang, LI Xiu-Ying, JIANG Rui-Bo, LI Yan-Ting, HWAT Bing So
    Chin J Plan Ecolo. 2008, 32 (1):  176-182.  doi:10.3773/j.issn.1005-264x.2008.01.020
    Abstract ( 4394 )   PDF (371KB) ( 4140 )   Save
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    Aims Cropping practices and fertilizer/organic matter application affects the soil microbial growth and activity. In china, only few studies have been conducted on the influence of long-term fertilizer and organic matter with fertilizer application on the soil biological properties. Our objective was to study the changes in soil biological and biochemical characteristics under a long-term (15 years) field experiment involving fertility treatments (inorganic fertilizers and organic matter with fertilizers) and two crop rotation systems.
    Methods In 1990, thirteen different treatments were established in the Drab Fluvo-aquic soil in Beijing for the long-term experiment. Six treatments werechosen in this study. Four were in a wheat-maize rotation receiving no fertilizer (CK), mineral fertilizers (NPK), mineral fertilizers plus farmyard manure (NPKM) and mineral fertilizers with maize straw incorporated (NPKS). One was in a wheat-maize/wheat-soybean rotation receiving NPK (NPKF). The other was abandoned arable land (CK0) growing weeds. The amount of chemical fertilizer per year was N 150 kg&#8226;hm-2, P2O5 75 kg&#8226;hm-2, K2O 45 kg&#8226;hm-2, manure 22.5 Mg&#8226;hm-2 and maize straw 2.25 Mg&#8226;hm-2. Established methods were used to analyze soil enzymes and soil physical and chemical characteristics. Analysis was done using an integrative method combining correlation and component analyses in SPSS. Important findings The soil organic C (SOC) and total N (STN) content, microbial biomass C (SMB-C) & N (SMB-N), activities of soil invertase, phosphatase and urease, and the ratio of SMB-C/SOC and SMB-N/STN were found higher in long-term (15 years) abandoned arable land than those in cultivated arable land soils. However, the soil metabolic quotient, pH value and bulk density of fallow soil were lower than those in cultivated arable land soils. The soil nutrient concentration, microbial biomass C & N, activities of soil invertase, phosphatase and urease, were higher in treatments with fertilizer application
    (NPK, NPKM, NPKS and NPKF) compared to no fertilizer application treatment (CK). The above soil parameters were also found higher in wheat-maize/wheat-soybean rotation cropping system compared to continuous wheat-maize cropping system. Among the fertilizer application treatments (NPK, NPKM, NPKS and NPKF), NPKM had relative higher soil nutrient concentration, microbial biomass C & N, and enzyme activities compared to other fertilizer application treatments. However, the soil metabolic quotient, pH value and bulk density of NPKM were lower than them.
    RESPONSE OF XYLEM EMBOLISM TO PHOSPHORUS ADDITION UNDER DIFFERENT WATER REGIMES IN TWO TREE SPECIES
    HUANG Ju-Ying, CAI Jing, JIANG Zai-Min, ZHANG Shuo-Xin, YU Hai-Long
    Chin J Plan Ecolo. 2008, 32 (1):  183-188.  doi:10.3773/j.issn.1005-264x.2008.01.021
    Abstract ( 2515 )   PDF (360KB) ( 1016 )   Save
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    Aims Xylem embolism is a physiological response of tree species to adverse environmental factors, such as water deficit.
    However there is little research on relationships between phosphorus and xylem embolism. Our objectives were to 1) explore
    whether phosphorus could increase xylem embolism occurrence and 2) test the hypothesis of “drought tolerance by restricting
    sap flow in xylem". 
    Methods The tree species Acer truncatum and Ligustrum lucidum were chosen to study the response of xylem embolism (measured
    as percentage loss of hydraulic conductivity, PLC) to phosphorus addition under drought-stressed and well-watered treatments
    (soil water content of about 30%-40% and 70%-80% of field moisture capacity, respectively).
    Important findings Daily PLC ranged from 60.7% to 70.7% in A. truncatum and 43.9%-72.3% in L. lucidum, indicating that
    occurrence and refilling of xylem embolism was a usual event in these woody plants. Phosphorus addition raised PLC
    significantly forA. truncatum at each water status and L. lucidum was subjected to drought. A. truncatum had more xylem
    embolism occurrence with drought than when well-watered, but there was no significant difference within two water statuses in
    L. lucidum. Drought could increase the embolism vulnerability of A. truncatum, causing higher percentage loss of hydraulic
    conductivity than in L. lucidum under the same water stress. Consequently, drought-resistant trees are not always
    invulnerable to water deficit. This might be a strategy for a water-limited environment. This study suggests that xylem
    embolism might be a “hydraulic signal" in plants. Once a plant is under water stress, its xylem conduits become cavited or
    embolized, resulting in decreased hydraulic conductivity and closure of stomata to maintain water balance by reducing water
    transportation and consumption. This study supports the hypothesis of “drought tolerance by restricting sap flow in xylem ".
    DIFFERENCES OF ADAPTABILITY AMONG CUNNINGHAMIA LANCEOLATA VARIETIES TO HETER OGENEOUS NUTRIENT ENVIRONMENT
    MA Xue-Hong, ZHOU Zhi-Chun, ZHANG Yi, JIN Guo-Qing
    Chin J Plan Ecolo. 2008, 32 (1):  189-196.  doi:10.3773/j.issn.1005-264x.2008.01.022
    Abstract ( 2628 )   PDF (286KB) ( 842 )   Save
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    Aims Chinese fir (Cunninghamia lanceolata), an important tree of timber plantations in South China, is a fast-growing
    coniferous species with high yield and quality of wood. Since the forest soil in South China is highly heterogeneous in
    nutrients, our objective is to study responses of Chinese fir to soil heterogeneity.
    Methods We used pot experiments under heterogeous and homogeneous environments to study tree growth, dry matter
    accumulation and allocation, root morphology and nutrient absorption efficiency of three open-pollinated varieties of C.
    lanceolata
    (`Long 15’, `Jinping 45’ and `Jing 398’) to detect the differences in their adaptability to the heterogenous
    nutrient environment. 
    Important findings The three varieties were significantly different in their adaptability to the heterogenous nutrient
    environment and in their response to soil patches. `Jinpin 45’ exhibited higher plant height, higher biomass accumulation and
    more developed roots in the heterogeneous environment than homogeneous environment, but `Long 15’ and `Jing 398’ grew better
    in the homogeneous environment. Al though the responses of the three varieties were different, roots proliferated mainly in
    poor patches. `Jinping 45’ showed high root physiological plasticity in the heterogeneous environment, but `Long 15’ and
    `Jing 398’ were low and average, respectively, in the hererogeous environment. The root concentration of N, P and K in the
    heterogeous environment (poor-patch) was lower than in the homogeneous environment (rich-patch); this is different from Pinus
    massoniana, which had high nutrient absorption. However, concentration of nutrients was not lower in rich-patch than poor-
    patch. Further more, it can be inferred that `J inping 45’ grew better in the heterogeneous environment than the homogeneous
    environment not only because of physiological plasticity but also because of a larger portion of biomass and nutrients
    distributed to leaves.
    EFFECTS OF Bt TRANSGENIC COTTONS PLANTING ON RHIZOSPHERE SOIL MICROORGANISMS AT DIFFERENT GROWTH STAGES
    ZHANG Mei-Jun, YANG Wu-De, LI Yan-E
    Chin J Plan Ecolo. 2008, 32 (1):  197-203.  doi:10.3773/j.issn.1005-264x.2008.01.023
    Abstract ( 2482 )   PDF (270KB) ( 1189 )   Save
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    Aims Ecological risk assessments have paid increasing attention to the field release of transgenic Bt crops. Some studies
    have reported that Bt protein could enter the soil ecosystem through root exudates, crop residues, crop decomposition and
    pollen. Protein from transgenic Bt crops is a potential hazard for soil non-target organisms and biodiversity, and this may
    affect soil ecological function and soil nutrients. This study aims to evaluate the soil ecological risk of transgenic Bt
    cotton. 
    Methods A pot experiment with two types of transgenic Bt cotton, ‘BtXincai1’ and ‘BtJi668’, was conducted to study the
    effects of transgenic Bt cotton planting on rhizosphere soil microorganisms. The plant was carefully removed from the pot at
    seedling, budding, flowering, bolling and boll-opening stages. Rhizosphere soil approximately 0-5 mm in diameter was
    separated from bulk soil by gently shaking the root system. Samples were frozen at -20 ℃ after sieving for subsequent Bt
    protein analyses, or stored at 4 ℃ for microorganism analyses, which were begun within a day of sampling. Bt protein was
    analyzed by ELISA BOX. The populations of three main microorganism groups and some functional groups were measured by
    cultivation.
    Important findings The content of Bt protein exuded by different transgenic Bt cottons and the degradation rate of Bt
    protein in different rhizosphere soils were different. Compared with the controls, transgenic Bt cottons seemed to stimulate
    the reproduction of rhizosphere soil bacteria and fungi. However, no significant effects on the populations of actinomycete,
    aerobic nitrogen fixing bacteria and kalium-solubilizing bacteria were observed. Transgenic Bt cottons increased the
    population of ammonifying bacteria and decreased that of inorganic phosphorus-solubilizing bacteria significantly at seedling
    and flowering stages, whereas they increased the population of aerobic cellulose-decomposing bacteria and decreased that of
    organic phosphorus-solubilizing bacteria significantly only at the flowering stage. ‘BtJi668’ also enhanced the population
    of aerobic cellulose-decomposing bacteria significantly at the seedling stage. The abundance of aerobic cellulose-decomposing
    bacteria and organic and inorganic phosphorus-solubilizing bacteria in transgenic Bt cottons rhizosphere soils changed.
    Although the total population of functional groups in transgenic Bt cottons rhizosphere soils was higher than in control
    cultivars, community diversity (H) and evenness (J) decrease d and dominance concentration (C) increased. The change range of
    diversity indexes and population of functional groups in transgenic Bt cottons rhizosphere soils at the flowering stage was
    higher than at the seedling stage.
    INFLUENCE OF INCREASED ATMOSPHERIC NH3 ON PHYSIOLOGY INDEX AND BIOMASS OF MAIZE WITH DIFFERENT N EFFICIENCY
    CHEN Xiao-Li, LI Shi-Qing, REN Xiao-Long, QIANG Hong, JI Chun-Rong, YAN Deng-Ming
    Chin J Plan Ecolo. 2008, 32 (1):  204-211.  doi:10.3773/j.issn.1005-264x.2008.01.024
    Abstract ( 2336 )   PDF (329KB) ( 711 )   Save
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    Aims The main aim of this study was to investigate the response of various physiology indexes, e.g., chlorophyll index value
    (stand for the relative content of chlorophyll, SPAD value), net photosynthetic rate (Pn), stomatal conductance (Gs), and
    root shoot ratio (R/S) in two genotypes of maize (Zea mays) to NH3 concentration enrichment.
    Methods We grew maize on Hoagland solution in PVC pots in open top chambers (OTCs). The experiment was a split-split plot
    design, which main treatments were two NH3 concentrations (10 and 1 000 nl&#8226;L-1). The sub-plot treatments of the experiment
    were two levels of nitrogen (high and low), and sub-sub-plot treatments were two N efficiency genotypes (high N efficiency,
    ‘NE5’, and low N efficiency, ‘SD19’). Air flow in OTCs was controlled by small fans and atmospheric NH3 concentration was
    measured accurately by two methods (NH3 determination tubes and GTL_C atmosphere detecting apparatus).
    Important findings Under elevated atmospheric NH3, there were significant differences (p<0. 05) for physiology indexes
    between the two varieties, ‘NE5’ and ‘SD19’. Under high N medium, compared with 10 nl&#8226;L-1 atmospheric NH3 concentration,
    the SPAD value, Pn and Gs of ‘NE5’ treated with 1 000 nl&#8226;L-1 decreased 7.0%, 14.0% and 6 .5%, respectively, and the
    corresponding targets of ‘SD19’ decreased 9.0%, 11.0% and 6.9%, respectively. Under low N medium, various physiology
    indexes of the two varieties significantly increased, i.e., the SPAD value, Pn and Gs of ‘NE5’ increased 5.7%, 7.1% and
    17%, respectively, and the relative value of ‘SD19’ increased 7.0%, 11.0% and 22.0%, respectively. The results also
    demonstrated that under high N medium, the inhibition effect of increased atmospheric NH3 on ‘SD19’ shoot biomass was
    obviously lower than that of ‘NE5’, while under low N medium, NH3 concentration enrichment had more positive influence on
    ‘NE5’ (p<0. 05) than ‘SD19’. Moreover, the ratio of roots to shoots of ‘NE5’ and ‘SD19’ in the two atmospheric NH3
    concentrations was related to maize growth periods, i.e., there were different changes for their root and shoot biomass in
    three sampling time, but still obeying certain laws. All these results indicated that the absorbed atmospheric NH3 by plants
    can improve crop nitrogen nutrition growing in low N medium, and there may be m ore significantly positive effect on low
    nitrogen efficiency genotypes.
    RESPONSE OF PHOTOSYNTHESIS, GROWTH AND YIELD OF FIELD-GROWN WINTER WHEAT TO OZON EEXPOSURE
    YAO Fang-Fang, WANG Xiao-Ke, CHEN Zhan, FENG Zhao-Zhong, ZHENG Qi-Wei, DUAN Xiao-Nan, OUYANG Zhi-Yun, FENG Zong-Wei
    Chin J Plan Ecolo. 2008, 32 (1):  212-219.  doi:10.3773/j.issn.1005-264x.2008.01.025
    Abstract ( 2822 )   PDF (386KB) ( 941 )   Save
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    Aims Ozone is a prominent gas pollutant that adversely affects vegetation, including visible leaf injury, growth and yield
    reduction. Our objective was to assess photosynthesis, growth and yield responses of field-grown wheat to increased ozone. 
    Methods We planted winter wheat (Triticum aestivum cv. Jia 403) in 12 plots of 2 m×2 m on 7 November 2005. After the wheat
    greened, we established 12 open-top octagonal (2.2 m high, 2 m diameter) chambers on 1 March 2006. Except rainy days, wheat
    was exposed to charcoal-filtered air, unfiltered air, and two treatments with ozone addition (DO100, DO150) from 13 March to
    28 April 2006, for 8 h per day, for a total of 30 days. We measured diurnal gas exchange and Pn-PAR response curves of flag
    leaves at the early grain filling stage (after 25 days exposure to ozone) and components of yield at harvest.
    Important findings High concentration of ozone altered gas exchange parameters, including stomatal conductance (Gs), leaf
    photosynthetic rate (Pn), transpiration rate (Tr) and intercellular CO2 concentration (Ci). Apparent quantum yield (AQY),
    light saturation point (LSP) and light compensation point (LCP) were significantly decreased, suggesting photosynthetic
    capacity could also be changed, characterized as reduced photon-saturated photosynthetic rate (Pmax). The decrease of
    photosynthetic activity was probably dominated by non-stomatal factors in combination with stomatal closure. In addition,
    ozone exposure caused leaf aging and decreases in plant height, ear length and number of grains per ear. Although similar
    responses were observed in plants exposed to ambient ozone concentration, we found no statistically significant differences
    at current concentration. We concluded that dynamic ozone exposure detrimentally affects photosynthesis, growth and yield of
    winter wheat.
    ANALYSIS OF PROTEIN RESPONSE TO MECHANICAL WOUNDING IN LEAVES OF BRASSICA NAPUSCV. WESTAR
    LE Yin-Ting, LI Mei, CHEN Qian, WEI Wei
    Chin J Plan Ecolo. 2008, 32 (1):  220-225.  doi:10.3773/j.issn.1005-264x.2008.01.026
    Abstract ( 2535 )   PDF (246KB) ( 1035 )   Save
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    Aims Plants have evolved self-defense mechanisms against insects and can produce insecticidal protein and other compounds.
    The development of proteomics has enabled study of the molecular mechanism of this defense. Oilseed rape ( Brassica napus cv.
    Westar) is an important oil crop in China and suffers from damage caused by insect pests and disturbances such as hail. Our
    objective is to investigate changes of total soluble protein and induced individual protein in B. napus using mechanical
    damage to mimic insect feeding. 
    Methods We took two leaf samples from the same leaf of each plant 4 h apart and treated the first sample as mechanical
    damage. Total soluble protein (TP) of samples was measured by Bio-rad Protein Assay and separated by two-dimensional (2-D)
    polyacrylamide gel electrophoresis. Up-regulated proteins and new proteins we re discriminated on the gel after staining. Two
    of eight different protein spots were analyzed by matrix-assisted laser desorption/ionization-time of flight mass
    spectrometry and identified by Mascot in database of Matrix Science. 
    Important findings TP concentration in leaves increased when measured after wounding. The two proteins discriminated on the
    2-D gel were the small subunit (SSU ) precursor of ribulose-1,5-bisphosphate carboxylase (rubisco) and a mixture containing
    fructose-bisphosphate aldolase and coproporphyrinogen Ⅲ oxidase (COP). The sequence of rubisco SSU was first reported in B.
    napus
    ,and the other two enzymes were reported in Arabidopsis thaliana, a relative of B. napus.All of these proteins have
    been shown to be involved in plant responses to stress. Thus we assume that these three proteins are important in maintaining
    plant physiological functions during wound-response in leaves of B. napus.This finding could be useful in understanding the
    relationship between plants and phytophagous insects at the proteomic level.
    EVALUATION OF ECOLOGICAL FACTORS AND FLUE-CURED TOBACCO QUALITY IN TOBACCO-GROWING AREAS IN SOUTHERN HUNAN, CHINA
    XU Zi-Cheng, LI Yan-Yan, XIAO Han-Qian, WANG Lin
    Chin J Plan Ecolo. 2008, 32 (1):  226-234.  doi:10.3773/j.issn.1005-264x.2008.01.027
    Abstract ( 2504 )   PDF (352KB) ( 1125 )   Save
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    Aims Southern Hunan is the largest flue-cured tobacco-growing area in Hunan, China, aided by climate and soil conducive to the growth and development of tobacco. Our objectives were to evaluate climate feasibility, soil fertility and tobacco quality, and provide a scientific basis for classifying southern Hunan tobacco-growing areas.
    Methods We obtained climate data for 30 years, including different growth and development periods and total sunlight hours during the field period, for the counties of Xintian, Yongxing, Jianghua, Jiangyong, Daoxian, Ningyuan, Guiyang, Jiahe, Hengnan and Lanshan from the Hunan Meteorology Bureau. We collected 1 225 soil samples from 2002 to 2003 and determined soil parameters, including pH, organic matter, nutrient elements and cation exchange capacity (CEC). We selected three or four flue-cured tobacco varieties from southern Hunan in 2004 and determined six appearance quality indexes and nine sensory quality indexes of 15 tobacco samples of C3F grades. We estimated climate feasibility index (CFI), soil feasibility index (SFI), appearance quality index (AQI) and sensory quality index (SQI) for tobacco by applying membership function and estimating weight values for each index by using principal components analysis. 
    Important findings The CFI was (79.59%±3.96%) and ranged from 74.71% to 83.98%. The areas had feasible temperature, a long period with average daily temperature ≥20 ℃, high accumulated temperature of ≥10 ℃, small day-and-night temperature differences, abundant precipitation, high humidity, and low sunlight percentage during field periods. The SFI was (43.92%± 15.49%) and ranged from 13.32% to 82.82%. The soil had high nutrient storage capability and was rich in organic matter, total N, hydrolytic N, available P and most micro elements; however, pH was neutral to slightly alkaline and total P, total K and available K were insufficient for tobacco. Furthermore, the ratio of exchangeable Ca to Mg was unbalanced, available S was high and available B was lacking. The AQI and SQI were (86.65%±3.29%) and (63.08%±0.74%), respectively. Tobacco leaves had good maturity, open configuration and high quality of aroma; undesirable taste and biting taste were small.


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