Table of Content

18 March 2013, Volume 24 Issue 3

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Soil aggregate stability and soil organic carbon characteristics in Quercus variabilis and Pinus tabulaeformis plantations in Beijing area.

LIU Yan1, ZHA Tong-gang1，2, WANG Yi-kun1, WANG Gao-min1

2013, 24(3):  607-613. 

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Based on the field survey and laboratory analysis, this paper studied the soil aggregate stability and soil organic carbon characteristics in  Quercus variabilis and Pinus tabulaeformis plantations in Beijing area. In the two plantations, the contents of soil macroaggregates decreased with soil depth. In P. tabulaeformis plantation, soil macroaggregates (>0.25 mm) occupied the majority, accounting for  71%-77% of the total; whereas in Q. variabilis plantation, no significant difference was observed in the contents of soil macroaggregates and microaggregates (≤0.25 mm), which accounted for 51%-58% and 42%-49%, respectively. Both the mean mass diameter and the geometrical mean mass diameter of the soil aggregates in P. tabulaeformis plantation were significantly higher than those in Q. variabilis plantation, and the fractal dimension (D) of the soil waterstable aggregates in P. tabulaeformis plantation was lower than that in Q. variabilis plantation, suggesting that P. tabulaeformis plantation was more favorable for the soil aggregate stability than Q. variabilis plantation. Also in the two plantations, the organic carbon content in soil waterstable aggregates decreased with soil depth. The organic carbon content in soil macroaggregates was significantly higher in P. tabulaeformis plantation (58%-83%) than in Q. variabilis plantation (49%-66%). It was suggested that in Beijing area, P. tabulaeformis plantation was more beneficial to the soil organic carbon protection, as compared with Q. variabilis plantation.

Effects of forest gap size and light intensity on herbaceous plants in Pinus koraiensisdominated broadleaved mixed forest.

DUAN Wen-biao, WANG Li-xia， CHEN Li-xin, DU Shan, WEI Quan-shuai, ZHAO Jian-hui

2013, 24(3):  614-620. 

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1 m×1 m fixed quadrats were parallelly arranged with a space of 2 m in each of six forest gaps in Pinus koraiensisdominated broadleaved mixed forest, taking the gap center as the starting point and along eastwest and southnorth directions. In each quadrat, the coverage and abundance of herbaceous plants at different height levels were investigated by estimation method in June and September 2011, and the matrix characteristics within the quadrats were recorded. Canopy analyzer was used to take fisheye photos in the selected overcast days in each month from June to September, 2011, and the relative light intensity was calculated by using Gap Light Analyzer 2.0 software. The differences in the relative light intensity and herbaceous plants coverage and richness between different gaps as well as the correlations between the coverage of each species and the direct light, diffuse light, and matrix were analyzed. The results showed that in opening areas and under canopy, the relative light intensity in large gaps was higher than that in small gaps, and the variation ranges of diffuse light and direct light from gap center to gap edge were bigger in large gaps than in small gaps. The direct light reaching at the ground both in large gaps and in small gaps was higher in the north than in the south direction. In the Z₁, Z₂, Z₃, and Z₄ zones, both the coverage and the richness of herbaceous plants were larger in large gaps than in small gaps, and the differences of species richness between large and small gaps reached significant level. The coverage of the majority of the herbaceous plants had significant correlations with diffuse light and matrix, and only the coverage of a few herbaceous plants was correlated with direct light.

Topographic distribution patterns of forest gap within an evergreen broad-leaved forest in Tiantong region of Zhejiang Province, Eastern China.

ZHANG Zhi-guo1,2, MA Zun-ping1,2, LIU He-ming1,2, ZHENG Ze-mei1,2, XIE Yu-bin1,2, FANG Xiao-feng1,2, WANG Xi-hua1,2

2013, 24(3):  621-625. 

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To explore the effects of multi-dimensional topographic factors on forest gap distribution, the forest gaps in a 20 hm² dynamic monitoring plot of an evergreen broad-leaved forest in Tiantong region of Zhejiang were taken as the objects to study the distribution patterns of the gap fraction, gap density, and gap area under the effects of altitude, slope degree, slope shape, slope aspect, and slope position by using a geographic information system (GIS) software. In the plot, the gap fraction was 13.1%, gap density was 9.5 ind·hm^-2, and average gap area was 137.82 m². Because of the greater intensity of typhoon disturbance at high altitudes, the gap fraction and gap density at the high altitude (≥500 m) sections were significantly larger than those at the medium and low altitude (<500 m) sections. The heavy precipitation produced by typhoon could easily cause small scale landslide, and thus, lead to the gap fraction and gap density being larger in valley area than in side-slope and ridge. It was suggested that typhoon and its produced heavy precipitation could be the main causes of the significant differences in the forest gaps along the gradients of altitude and slope position.

Fine root biomass of four main vegetation types in Daluo Mountain of Ningxia, Northwest China.

SU Ji-shuai1, CHENG Ji-min1,2, GAO Yang1, QIU Zhi-hu3, CAO Huai-qing3

2013, 24(3):  626-632. 

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By the method of soil core sampling, this paper studied the fine root biomass, soil water content, and soil bulk density in 0-40 cm soil layer of four main vegetation types (Picea crassifolia forest, Pinus tabulaeformis forest, deciduous shrubs, and desert grassland) in Daluo Mountain of Ningxia, and the fine root biomass in the 0-40 cm soil layer of P. crassifolia forests with the ages of 50-, 70-, and 100 a. The fine root biomass of the four vegetation types was mainly distributed in 0-20 cm soil layer, with the rank of P. tabulaeformis forest > P. crassifolia forest > deciduous shrubs > desert grassland, and the fine root biomass of P. tabulaeformis forest was significantly higher than that of the other three vegetation types. The fine root biomass of the P. crassifolia forests with different ages was 70 a > 100 a > 50 a, and there were no significant differences in the live fine root biomass ratio and dead fine root biomass ratio among the three P. crassifolia forests. The soil water content in the 0-40 cm soil layer of the four vegetation types was P. crassifolia forest > P. tabulaeformis forest > deciduous shrubs > desert grassland, while the soil bulk density followed an opposite pattern, and was significantly negatively correlated with the fine root biomass.

Microsite characteristics of pit and mound and their effects on the vegetation regeneration in Pinus koraiensisdominated broadleaved mixed forest.

DU Shan1, DUAN Wen-biao1, WANG Li-xia1, CHEN Li-xin1, WEI Quan-shuai1, LI Meng2, WANG Li-dong3

2013, 24(3):  633-638. 

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An investigation was conducted in a 2.55 hm² plot of Pinus koraiensisdominated broadleaved mixed forest to study the microsite characteristics of pit and mound formed by 42 treefalls and the status of vegetation regeneration on the microsites. The soil water content, soil temperature, relative air humidity, and photosynthetically active radiation (PAR) on five microsites (mound top, mound face, pit wall, pit bottom, and intact forest floor) were measured. Among the five mirosites, mound top had the highest PAR (527.9 μmol·m^-2·s^-1) while intact forest floor had the lowest one (58.7 μmol·m^-2·s^-1), mound top had the highest soil temperature (16.0 ℃) but pit bottom had the lowest one (13.3 ℃), pit bottom had the highest soil water content (34.6%) but mound face had the lowest one (0.5%), and intact forest floor had the highest relative air humidity (75.9%) but mound top had the lowest one (68.0%). The frequency of forming pit/mound complex by the tree species was decreased in the order of Pinus koraiensis (42.9%)>Picea asperata (31.0%) > Betula platyphylla (16.7%) > Abies fabri (7.1%) > Prunus padus (2.4%). Among the 42 treefalls, twothirds of them were in northwest direction. The treefalls volume had significant positive correlations with pit depth, pit length, mound height, and mound width, but negative correlation with mound thickness. The treefall mean diameter at breast height had significant positive correlations with pit width (r=0.328, P=0.017) and pit length (r=0.527, P=0). The tree species richness at the microsites decreased in the order of intact forest floor > pit > mound, and the tree species coverage was in the sequence of intact forest floor > pit > mound.

Physiological responses of mycorrhizal Pinus massoniana seedlings to drought stress and drought resistance evaluation.

WANG Yi1,2, DING Gui-jie1

2013, 24(3):  639-645. 

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A greenhouse pot experiment was conducted to study the effects of inoculating Pisolithus tinctorius, Cenococcum geophilum, Cantharellus cibarius, and Suillus luteus  on the physiological characteristics of Pinus massoniana seedlings under the conditions of drought stress and re-watering, with the drought resistance of the mycorrhizal seedlings evaluated. Under drought stress, the  MDA content and membrane’s relative permeability of P. massoniana seedlings increased, but these two indices in the inoculated (mycorrhizal) seedlings  were significantly lower than these in the un=inoculated (control) seedlings. After rewatering, the MDA content and membrane’s relative permeability of  mycorrhizal seedlings  had a rapid decrease, as compared with the control. In the first 21 days of drought stress, the production rate of  superoxide radical of the seedlings increased, and the SOD, POD and NR activities of mycorrhizal seedlings  increased significantly. With the extending of drought stress, the seedlings after re-watering had different recovery ability. Under the rewatering after 14 days drought stress, the SOD, POD and NR activities recovered. The drought resistance of the mycorrhizal seedlings was in the order of Suillus luteus 1 > Suillus luteus 7 > Cantharellus cibarius > Cenococcum geophilum > Pisolithus tinctorius. The SOD and MDA activities had a greater correlation with the mycorrhizal seedlings drought resistance, being able to be used as the indicators to evaluate the drought resistance of mycorrhizal seedlings.

Relationships between nitric oxide response signal and external factors during the early interaction between Pinus thunbergii and Bursaphelenchus xylophilus.

YU Lu-zhen, WU Xiao-qin, YE Jian-ren, ZHANG Sai-nan

2013, 24(3):  646-652. 

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In the interaction between Pinus thunbergii and Bursaphelenchus xylophilus, nitric oxide (NO) is an important signaling molecule involving in the early response of P. thunbergii to the invasion of B. xylophilus. However, it is unclear that whether the NO production by P. thunbergii is triggered by the invaded B. xylophilus or its secreted metabolites. In the present study, the P. thunbergii was inoculated with living B. xylophilus, its secretion, and the suspension of grinded B. xylophilus, respectively, and the nitric oxide synthase (NOS) activity and NO content in the P. thunbergii were detected at the early stage. In all treatments, the inoculated P. thunbergii appeared disease symptoms, and the NOS activity and NO content in the P. thunbergii inoculated with B. xylophilus secretion and grinded B. xylophilus suspension increased, suggesting that besides living B. xylophilus, its contents or secretion could also trigger the expression of NO response signal in P. thunbergii, inducing the downstream response and causing the disease development of P. thunbergi. With the increasing temperature at 15-25 ℃, both the NOS activity and the NO content in inoculated P. thunbergii increased, and the disease symptoms appeared earlier. The same patterns of NOS activity, NO content, and disease symptoms were also observed under increasing drought stress. It was suggested that within a definite range, increased temperature and drought stress could enhance the NO signal expression in inoculated P. thunbergii and accelerate its disease development, and thus, the disease development of inoculated P. thunbergii under high temperature and drought condition could be related to the enhancement of the NO response signal in the host.

Ecological effect of hygroscopic and condensate water on biological soil crusts in Shapotou region of China.

PAN Yan-xia, WANG Xin-ping, ZHANG Ya-feng, HU Rui

2013, 24(3):  653-658. 

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By the method of field experiment combined with laboratory analysis, this paper studied the ecological significance of hygroscopic and condensate water on the biological soil crusts in the vegetation sandfixing area in Shapotou region of China. In the study area, 90% of hygroscopic and condensate water was within the 3 cm soil depth, which didn’t affect the surface soil water content. The hygroscopic and condensate water generated at night involved in the exchange process of soil surface water and atmosphere water vapor, made up the loss of soil water due to the evaporation during the day, and made the surface soil water not reduced rapidly. The amount of the generated hygroscopic and condensate water had a positive correlation with the chlorophyll content of biological soil crusts, indicating that the hygroscopic and condensate water could improve the growth activity of the biological soil crusts, and thus, benefit the biomass accumulation of the crusts.

Effects of biological soil crust at different succession stages in hilly region of Loess Plateau on soil CO₂ flux.

WANG Ai-guo1,2, ZHAO Yun-ge2, XU Ming-xiang1,2, YANG Li-na2,3, MING Jiao2,3

2013, 24(3):  659-666. 

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Biological soil crust (biocrust) is a compact complex layer of soil, which has photosynthetic activity and is one of the factors affecting the CO₂ flux of soilatmosphere interface. In this paper, the soil CO₂ flux under the effects of biocrust at different succession stages on the re-vegetated grassland in the hilly region of Loess Plateau was measured by a modified LI-8100 automated CO₂ flux system. Under light condition, the soil CO₂ flux under effects of cyanobacteria crust and moss crust was significantly decreased by 92% and 305%, respectively, as compared with the flux without the effects of the biocrusts. The decrement of the soil CO₂ flux by the biocrusts was related to the biocrusts components and their biomass. Under the effects of dark colored cyanobacteria crust and moss crust, the soil CO₂ flux was decreased by 141% and 484%, respectively, as compared with that in bare land. The diurnal curve of soil CO₂ flux under effects of biocrusts presented a trend of ‘droprisedrop’, with the maximum carbon uptake under effects of cyanobacteria crust and moss crust being 0.13and -1.02 μmol CO₂·m^-2·s^-1 and occurred at about 8:00 and 9:00 am, respectively, while that in bare land was unimodal. In a day (24 h), the total CO₂ flux under effects of cyanobacteria crust was increased by 7.7%, while that under effects of moss crust was decreased by 29.6%, as compared with the total CO₂ flux in bare land. This study suggested that in the hilly region of Loess Plateau, biocrust had significant effects on soil CO₂ flux, which should be taken into consideration when assessing the carbon budget of the ‘Grain for Green’ eco-project.

Effects of exogenous phenolic acid on soil nutrient availability and enzyme activities in a poplar plantation.

WANG Yan-ping1,2, WANG Hua-tian1,2， XU Tan1, NI Gui-ping1, JIANG Yue-zhong3

2013, 24(3):  667-674. 

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By using ion exchange resin membrane as a plant root simulator, this paper studied the variations of soil nutrient availability and enzyme activities in a poplar plantation after applying phenolic acid. The exogenous phenolic acid had significant effects on the soil nutrient availability and enzyme activities, and the effects were concentration and time dependent. With increasing phenolic acid concentration, the extraction mass of soil NH₄⁺-N and NO₃^--N decreased significantly. At high concentration phenolic acid, soil PO₄^3- and Mn²⁺ availability increased significantly while soil K⁺ and Fe³⁺ availability was in adverse, and soil urease and phosphatase activities had a significant decrease while soil catalase and polyphenol oxidase activities increased significantly. With the elongation of incubation time, the availability of soil NH₄⁺-N, PO₄^3-, and Mn²⁺ increased gradually, while that of soil NO₃^--N, K⁺, Fe³⁺, and Zn²⁺ decreased significantly. The correlation analysis showed that the availability of soil NO₃^--N, K⁺, Fe²⁺, and Mn^2+ had close correlations with the activities of soil urease, polyphenol oxidase, and phosphatase.

Effects of flooding on the photosynthetic physiology characteristics of Pterocarya stenoptera seedlings.

WANG Chao-ying1,2, LI Chang-xiao1,2, ZHANG Ye1,2

2013, 24(3):  675-682. 

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Three water treatments (control, CK; continuous flooding, CF; and periodic flooding, PF) were installed to simulate the soil moisture change of the riparian zone in the Three Gorges Reservoir (TGR) region of China to study the physiological and ecological adaptation mechanisms of the native plant species Pterocarya stenoptera seedlings to the soil moisture change. All the water treatments had significant effects on the photosynthesis, biomass accumulation, and growth of the P. stenoptera seedlings. As compared with those in CK, the seedling’s net photosynthetic rate (P_n) and stomatal conductance (g_s) in treatments CF and PF were significantly lower while the intercellular carbon dioxide concentration  was significantly higher, and the P_n and g_s in CF and PF declined initially followed by a gradual recovery or tended to be stable. With the extension of treatment time, the total biomass and root, stem, and leaf biomass, plant height, and basal diameter in CF and PF all presented an increasing trend. Throughout the experimental period, the total biomass, root and leaf biomass, and plant height in CF and PF and the stem biomass in PF were significantly lower than those in CK, whereas the stem biomass in CF had no significant difference with that in CK, though the basal diameter in CF was significantly higher than that in CK. It was suggested that the P. stenoptera seedlings had the physiological and ecological characteristics of tolerating flooding rather than flooding-drought alteration.

Estimation of soil organic carbon density and storage in Zhejiang Province of East China by using 1：50000 soil database.

ZHI Jun-jun1, JING Chang-wei1, ZHANG Cao1, WU Jia-ping1, NI Zhi-hua2, CHEN Hong-jin2, XU Jin2

2013, 24(3):  683-689. 

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As an important component of the carbon pool of terrestrial ecosystem, soil carbon pool plays a key role in the studies of greenhouse effect and global change. By using a 1:50000 soil database, the organic carbon density in the 0-100 cm layer of 277 soil species in Zhejiang Province was estimated, and the soil organic carbon (SOC) density and storage in the whole Province as well as the spatial distribution of the SOC density and storage in the main soil types of the Province were analyzed. In the whole Province, the SOC density ranged from 5 kg·m^-2 to 10 kg·m^-2. Among the main soil types in the Province, humic mountain yellow soil had the highest SOC density (52.80 kg·m^-2), whereas fluvio-sand ridge soil had the lowest one (1.82 kg·m^-2). Red soil and paddy soil had the largest SOC storages, with the sum accounting for 63.8% of the total SOC storage in the Province. The total area of the soils in the Province was 100784.19 km², the estimated SOC storage was 875.42×10⁶ t, and the estimated SOC density was averagely 8.69 kg·m^-2. The analysis with the superposition digital elevation model showed that the SOC density presented an obvious variation trend with the changes of elevation, slope gradient, and aspect.

Effects of farming managements on the global warming potentials of CH₄ and N₂O from a rice-wheat rotation system based on the analysis of DNDC modeling.

ZHANG Xiao-lin1, PAN Xiao-jian1, XIONG Zheng-qin1, WANG Jin-yang1, YANG Bo1, LIU Ying-lie1, LIU Ping-li1,2

2013, 24(3):  690-696. 

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Taking a rice-wheat rotation system in the suburb of Nanjing, Jiangsu Province of East China as test object, this paper studied the fluxes of CH₄ and N₂O and their annual dynamics under different farming managements in 2010-2011, and the field observation data were applied to validate the processbased model, denitrificationdecomposition (DNDC) model, aimed to approach the applicability of the model to this rotation system, and to use this model to simulate the effects of different environmental factors and farming managements on the global warming potentials (GWPs) of CH₄ and N₂O. The results showed that except in the treatment control and during wheat growth season, the simulated cumulative emissions of CH₄ and N₂O from the rotation system in all treatments were basically in coincide with the observed data, the relative deviations being from 7.1% to 26.3%, and thus, the DNDC model could be applied to simulate the GWPs of cumulative emissions of CH₄ and N₂O as affected by various environmental factors or management practices. The sensitivity test showed that the GWPs of CH₄ and N₂O varied significantly with the changes of environmental factors such as the mean annual air temperature, soil bulk density, soil organic carbon, soil texture, and soil pH. Farming managements such as N fertilization, straw returning, and duration of mid-season drainage also had significant effects on the GWPs of CH₄ and N₂O. Therefore, the above-mentioned environmental factors and farming managements should be taken into account to estimate the greenhouse gases emission from the rice-wheat cropping system on site-specific or regional scale.

Multi-scenario simulation and prediction of ecosystem services as affected by urban expansion: A case study in coastal area of Tianjin, North China.

HUANG Huan-chun1, YUN Ying-xia1, MIAO Zhan-tang1, HAO Cui2, LI Hong-yuan2

2013, 24(3):  697-704. 

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Based on the modified Logistic-CA model, and taking the coastal area of Tianjin as a case, this paper simulated the spatial evolution patterns of ecosystem services as affected by the urban expansion in 2011-2020 under the scenarios of historical extrapolation, endogenous development, and exogenous development. Overall, the total ecosystem services of the study area under the three scenarios were generally the same, and the functional region with the lowest level ecosystem services had the identical spatial pattern. However, the spatial evolution patterns of the ecosystem services of the study area under the three scenarios had a great difference. The functional regions with lowerlevel ecosystem services grew in a cross-shaped pattern, with the Tanggu downtown as a center, and finally formed a full connectivity area along the Haihe River and coastal zone.

Ecological risk assessment of rural-urban ecotone based on landscape pattern: A case study in Daiyue District of Tai’an City, Shandong Province of East China.

SHI Hao-peng, YU Kai-qin, FENG Yong-jun

2013, 24(3):  705-712. 

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Based on the remote sensing data in 2000, 2005, and 2010, this paper analyzed the variation trends of the land use type and landscape pattern in Daiyue District of Tai’an City from 2000 to 2010. The ecological risk index was built, that of the District was re-sampled and spatially interpolated, and the spatiotemporal pattern of the ecological risk in the ruralurban ecotone of the District was analyzed. In 2000-2010, the main variation trend of the land use type in the District was the shift from natural landscape to artificial landscape. The intensity of human disturbance was larger in cultivated land, garden plot, and forestland than in other landscape types, while the human disturbance in water area was smaller. The ecological loss degree of cultivated land and water area decreased somewhat, while that of the other land use types presented an increasing trend. The ecological risk distribution in the District was discrete in 2000 and 2010, but most centralized in 2005. The ecological risk of each ecological risk sub-area had an increasing trend in 2000-2005, but was in adverse in 2005-2010. In 2000-2010, the ecological risk of the District was mainly at medium level. Spatially, the distribution of the ecological risk in the District had an obvious differentiation, with an overall diffusive increasing from forestland as the center to the surrounding areas. In the District, the ecological risk was mainly at medium and higher levels, the area with lower ecological risk had an obvious dynamic change, while that with the lowest and highest ecological risk had less change.

Simulation model of the development stages of flue-cured tobacco based on physiological development period and growing degree days.

ZHANG Ming-da1, ZHU Yong1, HU Xue-qiong1, LI Meng1, LI Xiao-yan2

2013, 24(3):  713-718. 

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Based on the 2010-2011 experimental data of planting flue-cured tobacco in its representative production counties of Yunnan Province, Southwest China, the models of the tobacco plant physiological development period and growing degree days were established, and validated by the observation data from local agro-meteorological stations. The two models had good performance at pre-transplanting stage, and the errors of the estimated dates were smaller. After transplanting stage, the errors of the estimated dates were larger, because of the disturbances from farming activities such as transplanting and topping. The simulated values based on the tobacco plant physiological development period had a higher coincidence with the observed values, especially at the pretransplanting stage, with the errors of the estimated dates being smaller than two days. As affected by the photoperiod effect, the model of tobacco plant physiological development period fitted better in high latitude regions than in low latitude regions.

Distribution characteristics of aggregates organic carbon in a paddy soil chronosequence.

WANG Xin-xin1,2, FU Jian-rong2, ZOU Ping2, CHEN Wei2, YE Jing2, YU Qiao-gang2, JIANG Li-na2, WANG Qiang2

2013, 24(3):  719-724. 

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By the method of physical fractionation of organic matter, this paper studied the  distribution characteristics of organic carbon in different particle size aggregates in a paddy soil chronosequence on the south bank of Hangzhou Bay, East China. In the plow layers of the paddy soil chronosequence, micro-aggregates (<0.25 mm) dominated, and the proportion of large micro-aggregates (0.053-0.25 mm) decreased with increasing rice cultivation year. In the micro-aggregates (<0.053 mm and 0.053-0.25 mm), the organic carbon content increased with increasing rice cultivation time; and in the aggregates (0.053-2 mm), the ratio of the organic carbon in different particle size fractions to the bulk soil organic carbon increased with decreasing particle size, and the organic carbon mainly distributed in large micro-aggregates (0.053-0.25 mm). With increasing rice cultivation time, soil particulate organic carbon decreased, indicating that the paddy soil with a longer rice cultivation history had a stronger capability of carbon sequestration than the soil with a shorter rice cultivation history, and the early cultivated paddy soil still had great potential for carbon sequestration.

 

Effects of different planting modes on the soil permeability of sloping farmlands in purple soil area.

LI Jian-xing, HE Bing-hui, MEI Xue-mei, LIANG Yan-ling, XIONG Jian

2013, 24(3):  725-731. 

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Taking bare land as the control, this paper studied the effects of different planting modes on the soil permeability of sloping farmlands in purple soil area. For the test six planting modes, the soil permeability was in the order of Eriobotrya japonica＞Citrus limon＞Vetiveria zizanioides hedgerows+corn＞Leucaena leucocephala hedgerows+corn＞Hemerocallis fulva＞corn＞bare land, and decreased with increasing depth. The eigenvalues of soil infiltration were in the order of initial infiltration rate＞average infiltration rate＞stable infiltration rate. The soil permeability had significant positive linear correlations with soil total porosity, non-capillary porosity, initial moisture content, water holding capacity, and organic matter content, and significant negative linear correlation with soil bulk density. The common empirical infiltration model could well fit the soil moisture infiltration processes under the six planting modes, while the Kostiakov equation could not.

Effects of long-term fertilization on soil organic carbon pool and carbon sequestration under double rice cropping.

SUN Yu-tao1, 2, LIAO Yu-lin1, 2, ZHENG Sheng-xian1, 2, NIE Jun1,2, LU Yan-hong1,2, XIE Jian1,2

2013, 24(3):  732-740. 

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This paper studied the effects of 30 years (1981-2010) fertilization with chemical N, P, and K, pig manure (PM), and rice straw (RS) on the soil organic carbon (SOC) and its components contents under intensive double rice cropping. The experiment was established on a typic Hapli-Stagnic Anthrosols in Hunan in 1981, and the soil samples were collected in November 2010. In treatment NPK, the contents of SOC, particulate organic C (POC), and KMnO₄oxidizable C (KMnO₄C) were higher than those in treatments NP and NK. The combined application of chemical and organic fertilizers (treatments NK+PM, NP+RS, and NPK+RS) made the contents of SOC, POC, and KMnO₄C have a significant increase, as compared with chemical fertilizations. Treatment NK+PM had the highest contents of SOC (84.71 t C·hm^-2), POC (8.94 t C·hm^-2), and KMnO₄C (21.09 t C·hm^-2) in top soil (0-45 cm), followed by treatment NPK+RS. Treatment NK+PM had the highest C sequestration (485 kg C·hm^-2·a^-1), followed by treatment NPK+RS (375 kg C·hm^-2·a^-1). The C sequestration efficiency (CSE) of SOC in the treatments of chemical fertilizers plus pig manure or rice straw was obviously higher than that in the treatments of chemical fertilizations, and the CSE of the POC in fertilization treatments (ranging from 0.4% and 1.2%) was lower than that of the KMnO₄C (ranging from 3.0% to 8.3%). By using the values of humification constant (h) and the decay constant (k) in Jenkinson’s equation, it was possible to predict the SOC storages in different treatments in the year 2010; and by using Jenkinson’s equation, it was possible to calculate the C input required to maintain the SOC storages in the year 1981 (A_E). The increase of the SOC in treatments NK+PM, NP+RS, and NPK+RS was due to the annual C input being higher than the A_E. It was considered that in the double rice cropping areas in subtropical region of China, long-term application of chemical fertilizers combined with pig manure or rice straw could promote the organic carbon sequestration in paddy soils.

 

Effects of soil compaction stress on respiratory metabolism of cucumber root.

ZHENG Jun-xian, SUN Yan, HAN Shou-kun, ZHANG Hao

2013, 24(3):  741-746. 

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A pot experiment with cucumber cultivar “Jingchun 4” was conducted to study the effects of soil compaction stress on the respiratory metabolism of cucumber root. Two treatments were installed, i.e., soil bulk densities 1.20 and 1.55 g·cm^-3. Under soil compaction stress, the activities of root pyruvate decarboxylase, alcohol dehydrogenase, and lactate dehydrogenase and the contents of root anaerobic respiration products alcohol, acetaldehyde, and lactate increased significantly, while the activities of the key enzymes involved in root aerobic respiration, including malate dehydrogenase, succinate dehydrogenase, and isocitrate dehydrogenase, decreased significantly, root pyruvate and succinate contents had significant increase, whereas root malate content decreased significantly. All the results illustrated that under soil compaction stress, the aerobic respiration of cucumber root was inhibited, while its anaerobic respiration was promoted.

Effects of different cultivation modes on the leaf photosynthetic characteristics and yield of summer-sowing peanut.

YANG Fu-jun, ZHAO Chang-xing, YAN Meng-meng, WANG Yue-fu, WANG Ming-lun

2013, 24(3):  747-752. 

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Taking the Arachis hypogaea cv. ‘Qinghua 7’ as test material, a field experiment was conducted to study the effects of different cultivation modes on the leaf photosynthetic characteristics and yield of summer-sowing peanut after wheat harvest. As compared with conventional cultivation mode, high-yield protective cultivation mode promoted the leaf growth, significantly improved the leaf area index (LAI), and maintained a longer time of high LAI and chlorophyll content. Meanwhile, the net photosynthetic rate, stomatal conductance, and transpiration rate of functional leaves under highyield protective cultivation mode were higher while the intercellular CO₂ concentration was lower, which induced the photosynthetic efficiency of functional leaves being significantly improved. Therefore, under high-yield protective cultivation mode, the yield per peanut plant was higher, the pod yield increased significantly, and the economic coefficient improved obviously. Both film mulching and straw returning could also improve the leaf photosynthesis of summer-sowing peanut, and increase the peanut yield. It was suggested that high-yield protective cultivation mode could effectively alleviate the adverse factors of summer-sowing peanut, such as the short growth period and lower productivity per plant, being a practical high-yield cultivation mode of summer-sowing peanut.

Effects of outer type and built-in type straw bio-reactors on tomato growth and photosynthetic performance.

BIAN Zhong-hua1,2，3, WANG Yu1, HU Xiao-hui1, ZOU Zhi-rong1, ZHANG Jing1, YAN Fei1

2013, 24(3):  753-758. 

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Taking the tomato (Solanum lycopersicum) cultivar “Kuiguan108” as test object, a comparative study was made on the effects of outer type and built-in type straw bio-reactors on the CO₂ concentration, air relative humidity , air vapor pressure deficit in the solar greenhouse during the tomato growth over autumn-delayed cultivation as well as the effects of the bio-reactors on the tomato growth and photosynthetic performance. As compared with that in CK, the average CO₂ concentration in the greenhouse with outer type straw bio-reactor at 9:30-11:30 and 14:30-15:00 on sunny days was increased significantly by 207.3 and 103 μmol·mol^-1, respectively, and the average CO₂ concentration in the greenhouse with built-in straw bio-reactor at 9:30-11:30 on sunny days was raised by 19.0 μmol·mol^-1. Both the outer type and the built-in type straw bio-reactors promoted the tomato plant height growth and early flowering, enhanced the plant net photosynthetic rate  and the yield per plant and per unit area significantly, and decreased the plant transpiration rate at the stages of vegetative growth and fruit bearing significantly. Nevertheless, as compared with built-in type straw bio-reactor, outer type straw bio-reactor was more suitable for the autumn- delayed cultivation of tomato in solar greenhouse.

Effects of potassium fertilization period on photosynthetic characteristics and storage root starch accumulation of edible sweetpotato.

CHEN Xiao-guang1, SHI Chun-yu2, LI Hong-min1, ZHANG Ai-jun1, SHI Xin-min1, TANG Zhong-hou1, WEI Meng1

2013, 24(3):  759-763. 

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In this study, same amount of potassium (240 kg·hm^-2) was applied as basal dressing (treatment 1) and as 1/2 basal dressing + 1/2 topdressing at day 75 after planting (treatment 2), aimed to investigate the effects of potassium fertilization period on the photosynthetic characteristics of edible sweetpotato and the starch accumulation in storage root. As compared with treatment 1, treatment 2 improved the leaf photosynthetic rate and sucrosephosphate synthase activity and the storage root’s adenosine diphosphate glucose pyrophosphortlase  activity, enhanced the starch accumulation rate in storage root (with an average increment of 6.7%), and increased the root tuber yield significantly by 8.2%. Both of the potassium fertilization treatments improved the synthesis of sucrose in leaf and the transformation from sucrose to starch in storage root, as compared with no potassium fertilization.

 

Characteristics of DNA adsorption on different sizes red soil colloidal particles.

LIAO Min1,2, XIE Xiao-mei1,2, FANG Shu1,2, QIU Xiao-bai1,2, CHEN Na1,2, XU Ya-qian1,2, JIANG Chun-yan3, CHEN Xue-fang3

2013, 24(3):  764-770. 

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By using balance reaction method, this paper studied the adsorption characteristics and thermodynamic properties of DNA on four kinds of red soil colloids (organic matter-contained coarse clay, organic matterremoved coarse clay, organic matter-contained fine clay, and organic matter-removed fine clay). The DNA adsorption on the four red soil colloids was a process of fast reaction, and the adsorption isotherms were conformed to the Langmuir equation, with the corresponding correlation coefficient (r²) being 0.974, 0.991, 0.958, and 0.975, respectively. The maximum adsorption amount of DNA on the colloidal particles followed the order of organic mattercontained fine clay > organic matterremoved fine clay ＞ organic matter-contained coarse clay ＞ organic matterremoved coarse clay, implying that the size and organic matter content of colloidal particles played an important role in DNA adsorption. Electrolyte concentration and type and adsorption system pH were the main factors affecting the DNA adsorption on the four soil colloids. Within a definite electrolyte concentration range (NaCl < 60 mmol·L^-1 and CaCl2 <10 mmol·L^-1), the adsorption amount of DNA on the red soil colloids increased significantly with the increase of electrolyte concentration. As compared with sodium ion, calcium ion had a greater promotion effect on the DNA adsorption, but the effect decreased significantly with the increase of adsorption system pH. The DNA adsorption on the organic matter-contained red soil colloids was an endothermic reaction, while the DNA adsorption on the organic matter-removed red soil colloids was an exothermic reaction. The DNA adsorption on the red soil colloids was a process of entropy increase.

Ecological regionalization of cotton varieties based on GGE biplot.

XU Nai-yin1,2, ZHANG Guo-wei2, LI Jian2, ZHOU Zhi-guo1

2013, 24(3):  771-776. 

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By using the heritability-adjusted GGE biplot analysis method, and taking the trial sites Anqing, Nanyang, Huanggang, Jingzhou, Wuhan, Xiangyang, Changde, Yueyang, Nanjing, Nantong, Yancheng, Jiujiang, Jianyang, Shehong, and Cixi as the representative cotton-planting areas in the Yangtze River basin, the ecological regionalization of cotton varieties in the basin was made based on the lint cotton yield, and the regionalization results were adjusted by the information ratio (IR) method, aimed to provide scientific basis for the selection of cotton varieties in the cottonplanting areas of the basin. The cottonplanting areas in the Yangtze River basin could be divided into three ecological regions, i.e., the “Sichuan basin cotton region” with Jianyang and Shehong as the representative, the “NanXiang basin cotton region” with Xiangyang and Nanyang as the representative, and the “majority complex cotton region in the Yangtze River basin” including all the other sites in the basin.

Effects of different soil and water loss control measures on the dung beetle assemblages in Huangfuchuan watershed, Inner Mongolia of North China.

LIU Wei1,2, WANG Run-run3, LIU Xin-min3

2013, 24(3):  777-787. 

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By using pitfall trap method, and taking the croplands and natural grasslands under different soil and water loss control measures as sampling plots, an investigation was conducted on the dung beetle assemblages in the Huangfuchuan watershed of Inner Mongolia from September 2007 to September 2008, aimed to understand the effects of different soil and water loss control measures on the dung beetle assemblages in the watershed. A total of 6169 dung beetles were captured, belonging to 15 species, 5 genus, and 2 families. The dominant species were Aphodius rectus and Onthophagus gibbulus, accounting for 66.54% and 13.26% of the total captured beetles, respectively. A lack of the species suitable for living in woodland habitats was the basic feature of the dung beetle assemblages. As compared with the control, all test soil and water loss control measures did not cause an obvious increase of species richness, biomass, and abundance of the dung beetle assemblages. The biomass and species richness of the assemblages as well as the abundance of the functional groups Ⅱ and Ⅲ had a significant negative correlation with the average tree (grass) height. Under the effects of long-term agricultural cultivation and the lack of large herbivores, the species richness and abundance of the functional group I (larger paracoprids and telocoprids) were lower than those of the functional groups Ⅱ (relatively smaller paracoprids) and Ⅲ (endocoprids), the main components of the dung beetle assemblages in the watershed. The faeces of the residents and livestock in the study region provided abundant foods for the dung beetle assemblages, inducing the relatively high abundance and spices richness of the assemblages occurred in the croplands nearby the villages. Our results suggested that natural grasslands were the suitable habitats for the dung beetles in Huangfuchuan watershed. At regional scale, to popularize the successful experiences of comprehensive soil and water loss control, preserve natural grasslands, and feed appropriate number of livestock (especially larger herbivores) could be the effective approaches for maintaining the diversity of dung beetles and the ecosystem functions.

CaCl₂heat shock preparation of  competent cells of three Pseudomonas strains and related transformation conditions.

ZHAO Feng1,2, ZHANG Ying1, LI Hui1, SHI Rong-jiu1, HAN Si-qin1

2013, 24(3):  788-794. 

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Pseudomonas, due to its diversity in habitat and metabolic type, makes it have broad prospects applying in bioremediation, bioconversion, and biocontrol, while the introduction of exogenous gene is the key link to genetically modified Pseudomonas. The preparation and transformation of competent cells are the important methodological basis of the introduction of exogenous gene. In this paper, three Pseudomonas strains (P. putida TS11, P. stutzeri DNB, and P. mendocina JJ12) isolated from a petroleum-contaminated soil were taken as the recipient strains, and a three-factor and four-level orthogonal experiment was conducted to investigate the effects of CaCl₂ concentration, heat shock duration, and recovery duration on the preparation and transformation efficiency of the strains competent cells. The results showed that CaCl₂ concentration was the most important factor affecting the transformation efficiency (P<0.05), and the transformation efficiency was improved markedly when the Pseudomonas cells were repeatedly washed with sterile distilled water before the preparation of competent cells. When the P. putida TS11 cells were treated with 100 mmol·L^-1 of CaCl₂, heatshocked for 3 minutes at 42 ℃, and incubated for 1.5 hours at 30 ℃, the P. stutzeri DNB cells were treated with 50 mmol·L^-1 of CaCl_2, heatshocked for 6 minutes, and incubated for 1.5 hours, and the P. mendocina JJ12 cells were treated with 75 mmol·L^-1 of CaCl₂, heat shocked for 4.5 minutes, and incubated for 0.5 hours, the transformation efficiency of exogenous plasmids in the three strains all achieved 10.5 cells·μg^-1 DNA.

 

Effects of different treatment methods of housefly pupae for the reproduction of Pachycrepoideus vindemmiae Rondani.

HE Zhang, LIU Ji-bing, CHEN Yong-ling, CHEN Zhong-zheng, DUAN Bi-sheng, HU Hao-yuan

2013, 24(3):  795-800. 

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It is an important way to massively rear parasitoid wasps by using appropriate methods to treat the wasps’ hosts and preserve them for a long duration. Pachycrepoideus vindemmiae Rondani is a pupal parasitoid of several dipteral pests, being of significance for the biological control of the pests. In this paper, housefly pupae were frozen at -20 ℃, cold storagepreserved at 6 ℃, and CO₂asphyxiated for 1-, 3-, and 30 days, respectively, and some pupae were heatkilled and cold storagepreserved for 30 days, aimed to approach the effects of these treatment methods on the reproduction of P. vindemmiae on the pupae. The results showed that P. vindemmiae could reproduce on the pupae treated with the abovementioned methods, and the tibia length of the offspring had less difference with that on the fresh pupae. However, the reproduction of P. vindemmiae on the pupae treated with the abovementioned methods except frozen decreased with the increasing preserving duration of the pupae. At the prerequisite of preserving for 30 days, frozen pupae had the highest P. vindemmiae offspring reproduction, suggesting that P. vindemmiae could be massively reared when the housefly pupae were treated by frozen and cold storagepreserved.

Soil seed bank and its correlations with aboveground vegetation and environmental factors in water level fluctuating zone of Danjiangkou Reservoir, Central China.

LIU Rui-xue1, ZHAN Juan1, SHI Zhi-hua2, CHEN Long-qing1

2013, 24(3):  801-808. 

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Taking the water level fluctuating zone of the Danjiangkou Reservoir as a case, and by the method of hierarchical cluster analysis, the soil seed banks at 37 sampling plots within the areas of 140-145 m elevation were divided into 6 groups, and the species composition, density, and diversity of the soil seed banks among the groups were compared. The differences between the soil seed banks and the aboveground vegetations were analyzed by S-rensen similarity coefficient, and the correlations among the soil seed banks, aboveground vegetations, and environmental factors were explored by principal component analysis (PCA) and multivariable regression analysis. At the same altitudes of the water level fluctuating zone, the species composition of the soil seed banks had obvious heterogeneity, and the density and diversity indices of the soil seed banks among different groups were great. The similarity coefficient between the soil seed banks and aboveground vegetations was low, and the species number in the soil seed banks was obviously lesser than that in the aboveground vegetations. The density of the soil seed banks was highly positively correlated with the aboveground vegetations coverage and species number and the soil texture, but highly negatively correlated with the soil water-holding capacity and soil porosity.

Effects of Three Gorges Reservoir impoundment on the wetland ecosystem service value of Dongting Lake, South-central China.

LI Jing-bao, DAI Yong, YIN Ri-xin, YANG Yan, LI Yu-dan, WANG Ke-ying

2013, 24(3):  809-817. 

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Based on the field investigation and measurement, and by using the monetary method, this paper estimated the wetland ecosystem service value of Dongting Lake before and after the impoundment of Three Gorges Reservoir (in 1996 and 2010, respectively). After the impoundment, the total ecosystem service value increased from 156.69×10⁸ yuan in 1996 to 177.11×10⁸ yuan in 2010. The main services value in 1996 was in the order of flood storage and regulation > water storage and supply > air regulation > scientific research and education, while that in 2010 was leisure tourism > shipping transportation > air regulation > water storage and supply. In the total service value of the wetland ecosystem, the direct value associated with water decreased from 110.85×10⁸ in 1996 to 27.47×10⁸ in 2010, with a decrement of 75.2%. Though the proportion of the direct value in the production and supply of material products had somewhat increase, the indirect value in ecological environment regulation and maintenance and in culture and society still maintained at about 80% of the total value. In addition to climate factors, the impoundment of Three Gorges Reservoir and the reduction of water and sediment from Yangtze River to the Lake were the crucial reasons leading to the changes of the wetland ecosystem service value of Dongting Lake.

Spatial niches of dominant zooplankton species in Sanmen Bay, Zhejiang Province of East China.

XU Xiao-qun1,2, ZENG Jiang-ning2, CHEN Quan-zhen2, LIU Jing-jing2, DU Ping2, WANG Gui-zhong1

2013, 24(3):  818-824. 

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Ecological niche has close relations with inter-species competition and resources utilization, and thus, can be used as an indicator to symbolize the resources utilization capability of certain groups of related species. In this paper, the niche breadth and overlap of the dominant zooplankton species in the Sanmen Bay of Zhejiang were determined by Shannon’〖KG-*3〗s formula and Petraitis index, respectively, and the differentiation of the niche was studied by canonical correspondence analysis (CCA), aiming to approach the distribution features of coastal zooplankton and related affecting factors in the Bay. In the study area, some coastal species such as Zonosagitta bedoti, Centropages dorsispinatus, and brachyuran larvae had wider niche breadth than the pelagic species such as Flaccisagitta enflata and Pseudeuphausia sinica, and the species of different groups with prey-predator relation had a greater niche overlap than those of the same groups without this relation. The CCA analysis showed that the spatial distribution of the zooplankton was more affected by water temperature, salinity, and chlorophyll a content rather than nutrients. The spatial niche of the zooplankton species was correlated with their living habit, interspecies competition, and prey- predator relationship.

Eco-environmental quality assessment of Luoyuan Bay, Fujian Province of East China based on biotic indices.

WU Hai-yan, CHEN Ke-liang, ZHANG Ping, FU Shi-feng, HOU Jian-ping, CHEN Qing-hui

2013, 24(3):  825-831. 

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In this paper, two types of eco-environmental quality assessment indices that have been successively applied abroad, i.e., the AZTI marine biotic index (AMBI) and BENTIX index based on the ecological sensitivity of benthos and the multivariateAMBI (MAMBI), a multivariate index integrating AMBI, Shannon Index H′, and species richness, were applied to assess the ecoenvironmental quality of Luoyuan Bay, Fujian Province of East China, and the assessment results were compared with those by the H′, an index based on community structure, which is often applied in China, aimed to test the applicability of these indices to the Bay, and to provide reference in selecting the indices for assessing our coastal eco-environment quality. Similar assessment results were obtained by applying AMBI and BENTIX index, and M-AMBI and H′. At most stations (13 of 16), the assessment results by applying AMBI and BENTIX index, M-AMBI and H′ were coincident, respectively; while at the other 3 stations, the assessment grade was high or good based on AMBI and BENTIX index, but moderate based on M-AMBI and H′. Taking account of the richness, individual abundance, and ecological group composition of the benthos in Luoyuan Bay, the assessment results based on M-AMBI and H′ could be more reasonable. It was suggested that for the Luoyuan Bay which has a high level of eutrophication and low organic matter enrichment in sediment and is dominated by sensitive benthos species, M-AMBI and H′ could be more applicative and objective than AMBI and BENTIX index in assessing
its ecoenvironmental quality.

Using kenaf (Hibiscus cannabinus) to reclaim multi-metal contaminated acidic soil.

YANG Yu-xi1,2, LU Huan-liang1,3, ZHAN Shu-shun1,2, DENG Teng-hao-bo1,2-, LIN Qing-qi1,2, WANG Shi-zhong1,2, YANG Xiu-hong1,2,QIU Rong-liang1,2

2013, 24(3):  832-838. 

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A five-year field trial was conducted at the surrounding area of Dabao Mountain Mine to explore the feasibility and availability of using kenaf (Hibiscus cannabinus), a fiber crop with strong heavy metals tolerance and potential economic value, to reclaim the multimetal contaminated acidic farmland soil. Different amendments were applied prior to the kenaf planting to evaluate their effects on the soil properties and kenaf growth. After the amendments application, the kenaf could grow well on the heavy metals contaminated soil with the Pb, Zn, Cu, Cd, and As concentrations being 1600, 440, 640, 7.6, and 850 mg·kg^-1, respectively. Among the amendments, dolomite and fly ash had better effects than limestone and organic fertilizer. With the application of dolomite and fly ash, the aboveground dry mass production of kenaf reached 14-15 t·hm^-2, which was similar to that on normal soils, and the heavy metal concentrations in the bast fiber and stem of kenaf decreased significantly, as compared with the control. The mass of the bast fiber accounted for 32%-38% of the shoot production, and the extractable heavy metal concentrations in the bast fiber could meet the standard of ‘technical specifications of ecological textiles’in China, suggesting that the bast fiber had potential economic value. It was suggested that planting kenaf combining with dolomite/fly ash application could be an effective measure to reclaim the multi-metal contaminated acidic farmland soil.

Effects of enhanced CO₂ fertilization on phytoremediation of DEHPpolluted soil.

DIAO Xiao-jun1,2, WANG Shu-guang2, MU Nan2

2013, 24(3):  839-846. 

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Low efficiency of remediation is one of the key issues to be solved in phytoremediation technology. Based on the necessity of reducing CO₂ emission in China and the significance of CO₂ in plant photosynthesis, this paper studied the effects of enhanced CO₂ fertilization on the phytoremediation of polluted soil, selecting the C3 plant mung bean (Vigna radiate) and the C4 plant maize (Zea mays) as test plants for phytoremediation and the DEHP as the target pollutant. DEHP pollution had negative effects on the growth and rhizosphere microenvironment of the two plants. After enhanced CO₂ fertilization, the aboveground dry mass of the two plants and the alkaline phosphatase activity in the rhizosphere soils of the two plants increased, the COD activity in the leaves of the two plants decreased, the microbial community in the rhizosphere soils shifted, and the numbers of the microbes with DEHPtolerance in the rhizosphere soils increased. These changes indicated that enhanced CO₂ fertilization could promote the plant growth and the plant tolerance to DEHP stress, and improve the rhizosphere micro-environment. Enhanced CO₂ fertilization also increased the DEHP uptake by the two plants, especially their underground parts. All these effects induced the residual DEHP concentration in the rhizospheres of the two plants, especially that of mung bean, decreased obviously, and the phytoremediation efficiency increased. Overall, enhanced CO₂ fertilization produced greater effects on C3 plant than on C4 plant. It was suggested that enhanced CO₂ fertilization could be a useful measure to enhance the efficiency of phytoremediation.

Molecular identification and detection of moon jellyfish (Aurelia sp.) based on partial sequencing of mitochondrial 16S rDNA and COI.

WANG Jian-yan1, ZHEN Yu2, WANG Guo-shan1, MI Tie-zhu2, YU Zhi-gang3

2013, 24(3):  847-852. 

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Taking the moon jellyfish Aurelia sp. commonly found in our coastal sea areas as test object, its genome DNA was extracted, the partial sequences of mt-16S rDNA (650 bp) and mt-COI (709 bp) were PCR-amplified, and, after purification, cloning, and sequencing, the sequences obtained were BLASTnanalyzed. The sequences of greater difference with those of the other jellyfish were chosen, and eight specific primers for the mt-6S rDNA and mt-COI of Aurelia sp. were designed, respectively. The specificity test indicated that the primer AS3 for the mt16S rDNA and the primer AC3 for the mtCOI were excellent in rapidly detecting the target jellyfish from Rhopilema esculentum, Nemopilema nomurai, Cyanea nozakii, Acromitus sp., and Aurelia sp., and thus, the techniques for the molecular identification and detection of moon jellyfish were preliminarily established, which could get rid of the limitations in classical morphological identification of Aurelia sp., being able to find the Aurelia sp. in the samples more quickly and accurately.

Factors affecting the vegetation restoration after fires in cold temperate wetlands: A review.

ZHAO Feng-jun1, WANG Li-zhong2, SHU Li-fu1, CHEN Peng-yu1, CHEN Li-guang1

2013, 24(3):  853-860. 

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Cold temperate wetland plays an important role in maintaining regional ecological balance. Fire is an important disturbance factor in wetland ecosystem. Severe burning can induce the marked degradation of the ecological functions of wetland ecosystem. The vegetation restoration, especially the early vegetation restoration, after fires, is the premise and basis for the recovery of the ecological functions of the ecosystem. This paper reviewed the research progress  on the factors affecting the vegetation restoration after fires in wetlands. The vegetation restoration after fires in cold temperate wetlands was controlled by the fire intensity, fire size, vegetation types before fires, regeneration characteristics of plant species, and site conditions. It was considered that the long-term monitoring on the post-fire vegetation restoration in cold temperate wetland, the key factors affecting the vegetation restoration, the roles of frozen soil layer on the post-fire vegetation restoration, and the theories and technologies on the vegetation restoration would be the main research directions in the future.

Nitrogen metabolism and translocation in arbuscular mycorrhizal symbiote and its ecological implications.

LI Yuan-jing, LIU Zhi-lei, HE Xing-yuan, TIAN Chun-jie

2013, 24(3):  861-868. 

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Arbuscular mycorrhizal fungi (AMF) can form mutually beneficial relations with more than 80% of vascular plants, and the existence of the symbiote is of significance in promoting the growth and stress tolerance of host plants. AMF can obtain the photosynthate carbohydrates from host plants, and in the meantime, effectively promote the nitrogen (N) uptake by host plants via the absorption of various N sources by mycorrhiza mycelia, resulting in the N exchange at population or community level, the improvement of host plants nutrition and metabolism, and the strengthening of the stress tolerance of host plants. However, there are still in debates in which ways the symbiote absorbs and transfers N and what the mechanisms the N metabolism and translocation from AMF to host plants. This paper reviewed the mechanisms of N metabolism and translocation in the symbiote and the effects of carbon and phosphorous on the N metabolism and translocation. The roles of AMF in the N allocation in host plants and the related ecological significance at community and ecosystem levels were briefly elucidated, and some issues to be further studied on the N metabolism in the symbiote were addressed.


 

Inhalable particulate matter and fine particulate matter: Their basic characteristics, monitoring methods, and forest regulation functions.

WANG Hua, LU Shao-wei, LI Shao-ning, PAN Qing-hua, ZHANG Yu-ping

2013, 24(3):  869-877. 

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Both inhalable particulate matter (PM₁₀) and fine particulate matter (PM_2.5) are not only one of the main causes of air pollution, but also the primary pollutants in most cities. Based on the analysis of the impacts of PM₁₀ and PM_2.5 on the environment and human health, this paper summarized the components, sources, and mass concentration variations of PM₁₀ and PM_2.5 and related affecting factors, and introduced the network layout of PM_10 and PM_2.5 monitoring and its principles and features. The research methods on the removal of PM_10 and PM_2.5 by forests, the removal rates of PM_10 and PM_2.5 by different forests, and the related affecting mechanisms were summed up at regional and individual scales, and the existed problems in this research field were discussed. Due to the lack of the comparable observation studies on the atmospheric PM_10 and PM_2.5 along different gradients and in background areas, the joint effects of multiple factors on the PM₁₀ and PM_2.5 concentrations are not revealed. It was suggested that to make a rational network layout of PM_10 and PM_2.5 monitoring, to correctly select proper monitoring methods, and to compare and calibrate the observed results from classical manual methods would be the bases to guarantee the validity of PM_10 and PM_2.5 monitoring data. At present, there are few reports about the PM_2.5 removal by forests, and it’s not clear about the physiological processes and ecological mechanisms of PM_10 and PM_2.5 removal at cell, tissue, organ, and individual level.

Effects of extracellular protein on the formation and properties of microbial assemblages: A review.

LU Mei-le1, ZHU Liang1, DAI Xin1, ZHOU Jia-heng1, XU Xiang-yang1,2

2013, 24(3):  878-884. 

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Extracellular polymeric substance (EPS), as a major component of microbial assemblages, e.g., activated sludge, biofilm and particulate sludge, etc., plays a crucial role in the formation and structural maintenance of microbial assemblages. Extracellular protein is a main constituent of EPS, and its functioning in microbial flocculation and aggregation has being paid more and more attention. The development and application of protein analytical techniques provide a good platform for the further study of extracellular protein. The paper reviewed the kind and distribution of extracellular protein in microbial assemblages and the roles of the extracellular protein in flocculation, sedimentation, adsorption, mass transferring, and dewatering. The prospects of the future study and applications of extracellular protein were also put forward.

 

Eco-toxicological effect of metal-based nanoparticles on plants: Research progress.

ZHANG Hai, PENG Cheng, YANG Jian-jun, SHI Ji-yan

2013, 24(3):  885-892. 

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The rapid development of nanotechnology and the potential environmental risk of wide application of artificial nanoparticles (NPs) have raised considerable concerns. Metal-based nanoparticles (MB NPs) have dual-toxicity of metal and NPs, and thus, their biotoxicity and ecological risk are the hotspots in the studies of nanotoxicology. Plant, as a main component of ecosystem, is a potential pathway for NPs bioaccumulation and entering into food chain. This paper discussed the MB NPs absorption, translocation, and accumulation by plants, and summarized the eco-toxicological effect of MB NPs on plants and related mechanisms. The factors affecting the phytotoxicity of MB NPs were approached, and the research progress on the eco-toxicological effect of MB NPs on plants, especially on food crops, was reviewed. Also, the existing problems in present MB NPs phytotoxicity studies were analyzed, and the future research directions were proposed.