Table of Content

18 November 2006, Volume 17 Issue 11

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Articles

Morphological-ecological characters and growth patterns of main tree species leaves in urban forest of Shenyang

XU Wenduo;HE Xingyuan;CHEN Wei;WEN Hua

2006, 17(11):  1999-2005 . 

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The study with statistic and multivariate analyses showed that the main meteorological factors affecting the growth and development rhythms of main tree species leaves in urban forest of Shenyang were≥5 ℃accumulated temperature, accumulated sunshine hours, and mean temperaturein the middle ten days of each phenological period. The meteorological factors needed by the tree species varied with their phenological period. Necessary low temperature and CI were required in germination period, and suitable WIand HI were needed in the growth period. The major quantitative morphological characters of 10 tree species in Shenyang urban forest were displayed in their leaf morphology and size, which decreased in the sequence of Lespedeza cyrtobotrya > Syringa oblata > Sophora japonica > Populus alba > Cornus alba > Lonicera maackii > Ligustrum obtusifolium > Fraxinus mandshurica > Prunus padus > Phellodondron amurense. As for the leaf area, it was decreased in the order of S. oblata > P. alba > P. amurense > P. padus > F. mandshurica > C. alba > L. cyrtobotrya > L. maackii > S. japonica > L. obtusifolium. The relationships of leaf length with leaf width, perimeter and area accorded with the model of y=ax^k, and the growth trend belonged to allometic type. The k value between leaf length and width of all test tree species except P. alba was lower than 1, and that between leaf length and perimeter was > 1 for P. amuresne,≈1 for P. alba, and < 1 for other tree species. As for the k value between leaf length and area, it was >1 for all the tree species, with that of P. alba being 2.1028. The increasing rate of leaf area was about 2 times higher than that of leaf length. An optimum regression assessment model of the 10 tree species leaf area was built and tested.

Genetic diversity of Sabina vulgaris populations at different succession stages

HONG Yu^1,2; WANG Linhe¹;ZHANG Guosheng¹; ENHE Bayaer²; LIANG Xiaorong¹

2006, 17(11):  2006-2010 . 

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By means of random amplified polymorphic DNA markers, a molecular ecological study was made with Sabina vulgaris populations at 4 succession stages in Maowusu sandy grassland, aimed to reveal the relationships between molecular variation and succession stages. A total of 17 random primers were selected for amplification, and 190 repetitive loci were produced, of which, 173 were polymorphic. The data were analyzed by POPGENE 3.2 Version 1.31. The results showed that the genetic diversity of S. vulgarispopulations was high, and changed with succession stages. The percentage of polymorphic loci in each S. vulgaris population ranged from 64.21% to 74.63%, with the highest in early succession stage Artemisia ordosica+S. vulgaris on semi-fixed sand dunes, and the lowest in sub-climax stage S. vulgaris on fixed dunes. The genetic differentiation among the populations was small (G_st=0.1761), and 82.39% of it was within the populations. Cluster analysis demonstrated that the populations at similar succession stage clustered together, suggesting that the genetic differentiation was closely related to succession stage. The genetic diversity indicated by Nei index ranged in 0.2163～0.2564, and the gene flow (N_m*) was 2.7972, indicating that more gene exchange occurred within the populations, which prevented the genetic differentiation among the populations at different succession stages.

Quantitative determination of the depth of edge influence on soil moisture in pepper-forest boundary of Minjiang River upper reaches

LI Liguang^1,2; HE Xingyuan¹; LI Xiuzhen¹; WEN Qingchun¹

2006, 17(11):  2011-2015 . 

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A typical pepper-forest boundary was selected in the arid valley of Minjiang River upper reaches, and the moisture content in 0.15 cm soil layer was determined by time-domain reflectometry (TDR) during drought, after rain, and different seasons. Moving split-window techniques (MSWT) was employed to detect the depth of edge influence (DEI) on soil moisture and its dynamic variation with time. The results showed that the changes of squared Euclidean distance (SED) curve on the graph tended to become stable when the window width reached 8～12 , and DEI could be detected. The seasonal variation of soil moisture could be divided into three periods, i .e ., rising period (January to April), peak period (May to October), and lessen period (November to December). DEI was smaller during drought, and increased after rain. The DEI on soil moisture ranged from 6 m in pepper field to 2 m in forest during drought and from 12 m in pepper field to 2 m in forest after rain, but ranged from 10 m in pepper field to 2 m in forest field within a year. DEI was different in different seasons, and was dynamic. Under such condition of soil moisture, the forest restoration from pepper land and the seedling planting were not ecologically reasonable. Reducing human disturbance and revegetating with natural shrubs and meadows could be more effective for vegetation conservation in the arid valley of Minjiang River upper reaches.

Effects of drought stress on photosynthesis physiology of Populus pseudo-simonii

FU Shilei^1,2; ZHOU Yongbin³; HE Xingyuan¹; CHEN Wei¹

2006, 17(11):  2016-2019 . 

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In this paper, the effects of drought stress simulated by PEG on the photosynthesis of Populus pseudo-simonii were monitored by gas exchange and chlorophyll fluorescence techniques. The results showed that in the early phase of drought stress, net photosynthetic rate (P_n), transpiration rate (T_r), stomata conductance (g_s),and intercellular CO₂ concentration (C_i) decreased with increasing stress, and the decrease of P_n was mainly related to the decreased g_s. In the late phase, C_i increased gradually, while F_v/F_m and F_v/F_o decreased significantly. POD activity increased in the early phase, but decreased in the late phase. All of these indicated that in the early phase of drought stress, stomata closure was the main factor limiting P. pseudo-simonii photosynthesis, while in the late phase, the main limiting factor was non-stomatal.A short period of drought stress to the stress resulted in the decrease of PS Ⅱ efficiency and POD activity.

Effects of color films shading on Phellodendron amurense seedlings biomass and primary nitrogen-assimilation enzyme activities

LI Xia^1,2;YAN Xiufeng¹; YU Tao¹

2006, 17(11):  2020-2023 . 

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In this paper, greenhouse Phellodendron amurense seedlings were shaded with red, yellow, blue, and green films for 100 days, and their biomass, chlorophyll and soluble protein contents, and nitrate reductase and glutamine synthetase activities were determined. Compared with exposure under sunlight, color films shadingdecreased the seedlings biomass significantly. Plant height and stem diameter hadthe similar trend with plant biomass. Root/shoot ratio was less affected by red andyellow films shading, while root biomass was decreased significantly under blueand green films shading. Leaf chlorophyll content was increased significantly underthe shading with blue, green and red films, especially with blue film. Red filmshading increased the chlorophyll a/b ratio, while blue film shading was in adverse.Under color films shading, soluble protein content and nitrate reductase andglutamine synthetase activities were significantly higher than the control.

Influence of measurement position on calculating pear tree stem sap flow

SUN Huizhen^1,2; KANG Shaozhong^1,3; GONG Daozhi¹

2006, 17(11):  2024-2028 . 

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By the method of heat pulse, this paper studied the influence of different measurement positions on calculating the stem sap flow velocity and quantity of pear trees. The results showed that at definite depths, the directional variation of the volume fraction of water and wood was lower than the seasonal change of wood physical parameters. The directional and seasonal variation of the volumetric water and wood was 0.01～0.03 and 0～0.02, and 0.02～0.09 and 0.02～0.08, respectively.The sap flow velocity at definite depth,which was calculated by different depths wood physical parameters measured at the same time, had no significant difference, but that calculated by the same depth wood parameters measured at different time was significantly different. The sap flow quantity measured at the inner two points and four points was underestimated 1.5 and 4.9 times of that measured at the outer corresponding measurement positions, relative to the estimation obtained from a multi-point measurement. The sap flow quantity measured by four-point at the position of 0～0.6 from the cambium could represent the water consumption of whole tree.

Effects of land use change on soil organic carbon and microbial biomass carbon in Miyaluo forest area

ZHANG Yuguang¹; ZHANG Xiaoquan¹;XIAO Ye²

2006, 17(11):  2029-2033 . 

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In last century, extensive areas of native vegetation in the Miyaluo forest area of Western Sichuan were converted into agricultural land and forestland. To assess the effects of land use change on soil organic carbon (SOC) and microbial biomass carbon (MBC), soil samples were taken from Abies faxoniana wildwood, Picea likiangensis var. balfouriana plantations established in 1960s and 1980s, and cropland, and their SOC and MBC contents were determined. The results showed that A. faxoniana wildwood had the highest SOC and MBC contents, followed by the P. likiangensis var balfouriana plantations established in 1960s and 1980s, and cropland. The SOC content was 83%, 53% and 52% lower, and the MBC content was 23%, 25% and 21% lower in cropland than in wildwood and in the plantations established in 1960s and 1980s, respectively. SOC and MBC contents decreased with increasing soil depth. There existed significant correlations of these two indices with soil total N, hydrolysable N and available P, indicating that both SOC and MBC could be used as the important indicators to measure the changes of soil quality.

Genetic diversity and clonal structure of Potamogeton malaianus populations

CHEN Yuanyuan¹;LI Qi²; WU Wenying¹; LI Wei¹

2006, 17(11):  2034-2040 . 

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By using inter-simple sequence repeat (ISSR) makers, this paper studied the genetic diversity and clonal structure of two Potamogeton malaianus populations growing in different habitats of two lakes in the middle reaches of Yangtze River.With six primers selected, a total of 40 fragments, of which 30 (75.0%) were polymorphic, were obtained from 106 individuals. This species showed a high genetic diversity, with Nei’s gene diversity of H=0.2471 and Shannon’s information index of I=0.3736. A low degree of population differentiation (G_st=0.0861) was found between the two populations, and a very high clonal diversity (D=0.9917) was detected, according to the analysis based on the polymorphic loci. No common genotypes were found among the individuals from the two populations, showing a great clonal differentiation between them. The spatial distribution pattern of P. malaianus genets showed ‘guerilla’ architecture, and the clonal distance of the population in lake center (3.0～31.5 m) was significantly larger than that in lakeshore (2.4～6.7 m).

Diurnal change of photosynthetic characteristics of native Vetiveria zizanioides in Western Guangdong

LIN Baohua^1,2,3; LIU Jinxiang¹;XIAO Shenghong¹;YANG Yunfei²

2006, 17(11):  2041-2045 . 

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The determinations on the photosynthetic parameters of native Vetiveria zizanioides in Western Guangdong in autumn showed that the net photosynthetic rate (P_n) of V. zizanioides had a diurnal change with two peaks, transpiration rate (T_r) and stomatal conductance (G_s) were similar with P_n, while intercellular CO₂ concentration (C_i) was in adverse. There was a significant positive correlation between P_n and photosynthetic active radiation (PAR) (P＜0.01), T_r and PAR (P＜0.01), air temperature (T_a) and relative humidity (RH) (P＜0.01), and G_s and T_a (P＜005). Same environmental factors had different effects on P_n, T_r and G_s, and PAR had most intensive effect on the photosynthesis of V. zizanioides. Among the test photosynthetic parameters, T_r was most sensitive to the environmental factors.

Estimation of sensible and latent heat fluxes of typical steppe in Inner Mongolia based on variational method

YANG Juan¹; ZHOU Guangsheng^1,2; WANG Yunlong²; WANG Yuhui²

2006, 17(11):  2046-2051 . 

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Based on the observation data and the export data of microclimatic gradient system during growing and non-growing seasons of Stipa krylovii grassland in Inner Mongolia, this paper investigated the accuracy of variational method (VT) on estimating the surface heat fluxes of grassland. The results showed that the changes of sensible and latent heat fluxes estimated by VT were consistent with those obtained by open-path eddy covariance method (EC), and the fluxes estimated by VT could better satisfy the surface energy balance equation. The sensible heat fluxes (H) from VT were mostly higher than the corrected fluxes from EC, and the values and their difference from these two methods all got the maximum at twelve o’clock in daytime, and were close in nighttime. The variations of latent heat fluxes from VT lagged behind those from EC. VT could solve the problems that the conventional Bowen ratio energy balance method (BREB) was computationally unstable and produced spurious large values when the Bowen ratio was in vicinity of -1.Compared with EC and BREB, VT was more of rationality and stability.

Dynamics of soil microbial biomass and dissolved organic carbon and nitrogen under flooded condition

QIU Shaojun^1,2;PENG Peiqin^1,2; RONG Xiangmin²; LIU Qiang²;TANG Qi²

2006, 17(11):  2052-2058 . 

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With reddish yellow soil (RYS) and alluvial purple soil (APS), the two typical paddy soils in the Dongting Lake floodplain of China as test soils, an incubation test was conducted at 25 ℃ to study the dynamic changes of soil microbial biomass and dissolved organic carbon and nitrogen under flooded condition. Three treatments were installed,i . e . , control (CK), ammonium sulfate (N), and rice straw powder plus ammonium sulfate (S-N). The results showed that during incubation , soil microbial biomass carbon (SMBC), soil microbial biomass nitrogen (SMBN), soil dissolved organic carbon (SDOC), and soil dissolved organic nitrogen (SDON) reached their maximum initially, decreased thereafter, and tended to be stable. After amending the substrates to the two soils, the averages of SMBC to soil total carbon,SMBN to soil total nitrogen, SDOC to soil total carbon, and SDON to soil total nitrogen were 2%～3%, 2%～3%, 1% or so, and 5%～6%,respectively.In the two soils, the peak values of SMBC in treatment N and those of SMBN, SDOC and SDON in treatment S-N were the highest, while thaose of SMBC in treatments N and S-N had no significant difference. The peak values of SMBN, SDOC and SDON in RYS were significantly different between treatments N and S-N,while significant difference was observed between the peak values of SMBN and SDOC in APS, because the fertility of RYS was lower than that of APS. In the first 7 days of incubation, SMBC/SMBN ratio was ＜10, while after 14 days of incubation, this ratio was higher in treatment N than in treatment S-N at the same time in the same soil. The SDOC/SDON ratio in all treatments was the highest at the 3rd d, and the lowest at the 28th d of incubation.

Optimal chemical fertilizer application rate accorded with local economic and ecological benefits

XIANG Ping'an¹; ZHOU Yan²; ZHENG Hua³; YAN Huimin⁴; HUANG Huang¹;HUANG Qingyun¹

2006, 17(11):  2059-2063 . 

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This paper studied the exterior cost of applying chemical fertilizer on the farmland in Dongting Lake area, one of the main foodstuff production regions in China, aimed to search for an optimal chemical fertilizer application rate accorded with local economic and ecological benefits. The exterior cost was estimated by the method of economic and environmental evaluation, while the optimal application rate was calculated based on Exterior Diseconomy Theory and by using production function model, with both ecological and farmers’ economic benefits considered. The results showed that in 2002, the exterior cost of inappropriately applying chemical fertilizer was about 1.35×10⁸ yuan, equivalent to 0.3 yuan·kg^-1 fertilizer N.Under current situation of test area, the optimal application rate of chemical fertilizer should be 208.26～210.65 kg·hm^-2, and the corresponding foodstuff supply would be 5528～5539 kg·hm^-2.However,the actual fertilizer application rate in 2002 exceeded the optimal one. A suggestion was made to impose tax for the environmental pollution of over-using chemical fertilizer.

Effects of nitrogen fertilization on leaf photosynthesis and respiration of different drought-resistance winter wheat varieties

ZHANG Xucheng^1,2; SHANGGUAN Zhouping¹

2006, 17(11):  2064-2069 . 

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Under field condition, this paper measured the leaf gas exchange parameters and photosynthetic pigments content of different drought-resistance wheat varieties at all growth stages, with their responses to different nitrogen fertilization levels studied. The results showed that in treatment N₁₈₀, the leaf G_s, P_n, and total photosynthetic pigments content of dry land varieties increased by 43.75%, 18.54% and 49.66%, while those of watered land varieties increased by 12.12%, 20.88% and 29.25%, respectively, compared with control. On the contrary, the respiration rate of dry land and watered land varieties decreased by 4.8% and 4.5%, respectively. Nitrogen supply accelerated the photosynthetic carbon assimilation, because the gas exchange capacity and photosynthetic pigments content increased while the respiration rate decreased with increasing nitrogen supply. The difference in photosynthetic capacity between different winter varieties was mainly dependent on non--stomatal factors. The dry land varieties had higher capacities of light energy absorption and photosynthetic carbon assimilation, because they had higher leaf photosynthetic pigments content but lower respiration rate. Compared with watered land varieties, dry land varieties had an 8.9% decrease of respiration rate and a 14.12% increase of P_n. At the same growth stage, the photosynthetic and respiration rates in the control varied consistently, while in treatments N₁₈₀ and N₃₆₀, the photosynthetic rate increased but the respiration rate decreased. Nitrogen fertilization promoted the absorbed light energy allocating to the process of photosynthetic carbon assimilation. It could be concluded that nitrogen supply was favorable to the improvement of winter wheat drought-resistance, because it could improve leaf gas exchange capacity, increase leaf photosynthetic pigments content, and optimize the allocation of absorbed light energy.

Allelopathic potential and physiological mechanism of Oryza sativa L. under phosphorus deficiency stress

HE Huaqin; LIANG Yiyuan; CHEN Lujie; ZHUANG Chongguang; KE Yuqin; LIANG Kangjing; LIN Wenxiong

2006, 17(11):  2070-2074 . 

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In this paper, allelopathic rice PI312777 (PI) and non-allelopahtic rice Lemont(Le) were grown in the nutrient solution with two levels of phosphorus (P) supply, and their allelopathic effects on Echinochloa crus-galli L. were studied. The results showed that under phosphorous deficiency stress, the inhibitory effect of PI on E. crus-galli root growth had an obvious increase. After growing in the nutrient solution with low P supply (0.5 mg·L^-1) for 5, 10 and 15 days, the inhibitory rate of PI on E. crus-galli root dry matter increased by 5.64%, 3.89% and 12.13%, respectively, while that of Le did not show the same trend, compared with normal P supply. With low P supply for 5, 10 and 15 days, PI allelopathic effect on the leaf POD activity of E. crus-galli increased by20.19%, 15.47and 6.68%, IAAoase activity increased by 18.08%, 17.71% and 12.50%, while NR activity increased by 13.89%, 18.60% and 2.10%, respectively, suggesting that under P deficiency, PI enhanced its allelopathic potential through two pathways, i . e ., to increase the weed POD and IAAoase activities to slow down its growth rate, and to decrease the weed NR activity to affect its N uptake.

Effects of different mulches on rhizosphere temperature, growth, and physiological properties of flue-cured tobacco

JIA Zhihong^1,2; YI Jianhua²;SUN Zaijun²

2006, 17(11):  2075-2078 . 

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With greenhouse plastic film, rice straw plus greenhouse plastic film, soil-mulching plastic film, rice straw, rice straw plus sun-shading net, and sun-shading net as test mulches, this paper studied their effects on the rhizosphere temperature, growth, and physiological properties of flue-cured tobacco. The results showed that after mulching for 22 days, the accumulative rhizosphere temperature at the depth of 5 cm was the highest (424.75 ℃) for greenhouse plastic film and the lowest (378.75 ℃) for rice straw plus sun-shading net, while that at the depth of 15 cm was the highest (396.75 ℃) for greenhouse plastic film and the lowest (368.31 ℃) for sun-shading net. With the increase of accumulative rhizosphere temperature, the dry weight of above- and underground parts, photosynthesis, and root vigor of flue-cured tobacco tended to increase, and at the 10th day after mulches removal, root biomass had the largest increment in the treatment of soil-mulching plastic film and the smallest increment in the treatment of rice straw plus sun-shading net.

Seasonal fluctuation of macrobenthos community in Jiuduansha intertidal wetland of Yangtze River Estuary

ZHOU Xiao;GE Zhenming; SHI Wenyu; WANG Tianhou;CAO Dan;ZHOU Lichen

2006, 17(11):  2079-2083 . 

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From November 2004 to October 2005, an investigation was made on the seasonal fluctuation of macrobenthos community in the Jiuduansha intertidal wetland of Yangtze River Estuary, with the correlations between this fluctuation and sediment factors studied. 864 samples were collected seasonally from 216 sites in 7 sampling transects. A total of 30 species were identified, mainly belonging to Mollusca, Annelida, Crustacea and insect. The dominant species were Stenothyra glabra, Assiminea violacea, Potamocorbula ustulata, Glaucomya chinensis, and Ilyrplax deschampsi. In spring, macrobenthos had the highest density and biomass and the richest diversity, but in summer, the density and biomass were the lowest, the diversity was on a lower level, and the distribution was uneven. There were no significant differences in the species number and biomass between autumn and winter, but the density was higher in winter than in autumn. In spring, summer and autumn, the species number, density, and biomass of macrobenthos had no significant correlations with sediment factors, but in winter, macrobenthos density had significant correlations with the humidity and organic matter content of sediment.

Behavioral patterns of wild-caught and captive-bred male musk deer

MENG Xiuxiang^1,2; FENG Jinchao¹;ZHOU Yijun¹; YANG Qisen²; FENG Zuojian²;XIA Lin²;MENG Zhibin²;HUA Xing³

2006, 17(11):  2084-2087 . 

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By the method of focal sampling and continuous recording, a comparative study was made on the behavioral patterns of 23 captive alpine musk deer (Moschus sifanicus), among which, 17 deer were wild-caught (WC), and 6 deer were captive-bred (CB). The results showed that owing to the same enclosure facilities and managing system, there was no essential difference in the behavioral modes between WC and CB, but WC exhibited more collision behavior than CB (P<0.05) because of the differences in capture, lactation, and contact with other baby deer. Male deer showed lower bedding (P<0.05), ingestion (P<0.05) and ruminating (P<0.05), but more moving (P<0.05) at mating season, compared with those at non-mating season. Furthermore, male deer expressed more scent marking through intensive tail-rubbing and urination-defecation, and accordingly, the behaviors of scent collecting such as environment sniffing and anogenital exploring were expressed more stronger, though the differences were not significant (P>0.05).

Community structure and its dynamics of predatory arthropod in jujube orchards intercropped with different herbage species

SHI Guanglu¹; WANG Younian¹; MIAO Zhenwang²; LI Dengke³; ZHANG Tieqiang¹; YU Tongquan¹;JI Qianlong¹; DONG Hui⁴

2006, 17(11):  2088-2092 . 

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By using community structural characteristic indices and principal component analysis, this paper studied the community structure and its dynamics of predatory arthropod in the jujube orchards intercropped with Astrugalus complanatus, Trifolium repen, Lotus comiculotus, and Medicago sativa. The results showed that in all test jujube orchards, spider and predatory insects were the predominant components of the predatory arthropod community, and their relative abundances were 48.3%~52.7% and 38.8%~44.4%, respectively. There were significant differences (P<0.05) in the mean density, diversity, and evenness of the most common predatory arthropod groups in the jujube orchards intercropped with different herbage species, with the sequence of intercropped with Lotus comiculotus> Medicago sativa>Astrugalus complanatu> Trifolium repens, but for dominant concentration index, the sequence was intercropped with Trifolium repens>Astrugalus complanatu>Medicago sativa>Lotus comiculotus. The average density of predatory spiders was significant higher (P<0.05) than that of predatory insects in all test jujube orchards. The individuals of Coccinellidae, Pentatomidae, inoccllidae, Chrysopidae, Thomisidae, Araneidae and Phytoseiidae played the dominant role in the community.

Potential establishment areas of Solenopsis invicta in China：A prediction based on GIS

CHEN Chen¹; GONG Weirong²; HU Baishi¹; ZHOU Guoliang³;BAO Yunxuan¹; LIU Fengquan¹

2006, 17(11):  2093-2097 . 

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Based on geographic information system (GIS), the potential establishment areas of Solenopsis invicta Buren in China were predicted. The days above threshold temperature and the number of degree-days were used as main determining factors, while annual precipitation and altitude were used as limiting factors. By using the Kriging spatial interpolation function in GIS software, the potential establishment area was divided into four categories, i . e ., most suitable, suitable, mildly suitable, and unsuitable. The most suitable area was in the greater part of Guangdong, central and southern Guangxi, small part of southern Yunnan, Hainan, Taiwan, Hong Kong, and Macao, suitable area was in southern Yunnan, northern Guangxi and Guangdong, southern Henan, western Anhui, greater part of Zhejiang, central and eastern Hubei, Chongqing, Hunan, Jiangxi, and Fujian, mildly suitable area was in the greater parts of Anhui and Henan, central and eastern Hebei and Shandong, Beijing, Tianjian, central and northern Jiangsu, northwestern Zhejiang and Hubei, southern Shanxi, eastern Sichuan, central and western Guizhou, and small part of central Yunnan, and unsuitable area was in the greater parts of northwest, northeast, and north China.

Aromatic constituents in fresh leaves of Lingtou Dancong tea under Basilepta melanopus Lefevre stress

CAO Panrong¹; LIU Kebin²; LIU Chunyan³; LEI jianjun¹

2006, 17(11):  2098-2101 . 

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The study showed that under different degrees of Basilepta melanopus Lefevre stress, the kinds of aromatic constituents in the fresh leaves of Lingtou Dancong tea plant increased evidently, being the most (36 kinds) under medium stress. With the increase of the stress, the contents of 9 aromatic constituents like 1,6-methylene annulene increased, whereas those of 8 constituents as linalool decreased. Light stress induced the appearance of 4 aromatic constituents like 2-methyl hexadecane, while medium stress induced that of 6 constituents as H1-docosanol. Different degrees of B. melanopus stress could induce the synthesis of 23 aromatic constituents like 1,6-methylene annulene, but inhibit the formation of 6 constituents as nonanal.

Genetic diversity of Melampsora larici-populina

YU Zhongdong;CAO Zhimin; YUAN Benben

2006, 17(11):  2102-2106 . 

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By using ITS-nrDNA-RELP, ITS sequencing, and RAPD molecular marker, this paper studied the genetic diversity of 11 isolates in 5 races of Melampsora larici-populina from different regions. The results indicated that the genetic differentiation of M. larici-populina was correlated to its geographical distribution,which could be grouped into northern and western geographic populations, and the latter could be grouped into high-mountain forest ecologic type (HMF) and western plain ecologic type (WPL). The genetic differentiation of the race was not always corresponded with the pathogenic one. T test manifested that the genetic diversity of the 5 races had no statistic difference in RAPD markers, and the diversity index of HMF was 0.5172, being slightly higher than that of WPL (0.5089). The ITS sequence of ribosome DNA was strictly conservative, and not suitable for the genetic diversity study of M. larici-populina intra-species populations.

A highly effective extraction method for PCR analysis of soil microbial DNA

LI Junmin; JIN Zexin

2006, 17(11):  2107-2111 . 

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In this paper, soil microbial DNA was extracted by cetyltrimethyl ammonium bromide (CTAB)-lysosome-protease K-freezing thaw lysing, and precipitated and purified with PEG 8000. The results showed that this method was simple and effective for the PCR analysis of soil microbial DNA. To effectively remove humid acid, test soil was pre-washed by polyvinylpyrrolidone (PVP) buffer and added with CaCl₂ and bovine serum albumin (BSA). The precipitation with PEG8000 could obtain high quality DNA, and the lysing with (CTAB)-lysosome-protease K-freezing thaw could get large fragment DNA. Using this method, the yield of soil microbial DNA under Heptacodium miconioides forest was 9.22 μg·g^-1, with A₂₆₀/A₂₈₀ being 1.65. The extracted DNA was proved to be successfully used for further PCR amplification and amplified ribosomal DNA restriction analysis (ARDRA). The optimal template DNA concentration in PCR amplification was 0.67 ng·μl^-1. The establishment of this simple, rapid and effective method made it possible to study the molecular ecology of soil microbes in a large scale.

Isolation, purification, and phosphate-solubilizing capability of phosphorous bacteria in West Lake sediment

LI Wenhong;SHI Jiyan

2006, 17(11):  2112-2116 . 

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By using solid culture media containing organic and inorganic phosphorus, six strains of phosphorous bacteria in West Lake sediment were isolated and purified,among which, two strains coded as OP₁ and OP₂ could decompose lecithin, and the other four coded as NOP₁, NOP₂, NOP₃ and NOP₄ could dissolve inorganic phosphate. OP₁, OP₂ and NOP₃ had a stronger phosphate-solubilizing capability, followed by NOP₄, while NOP₁ and NOP₂ lost this capability after isolation and purification. The water-soluble P concentration in the culture media inoculated with OP₁,OP₂ and NOP₃ increased 38.53, 64.53 and 54.06 fold, respectively, compared with the control.

Isolation and identification of a phenanthrene-degrading bacterial strain

ZHU Rugang¹; ZHONG Ming¹; ZHOU Qixing²; LIU Haining¹;LI Yushuang¹

2006, 17(11):  2117-2120 . 

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Through selective enriched culture, a phenanthrene-degrading bacterial strain was isolated from the oil-contaminated soil in Shenfu irrigation area of Shenyang, Northeast China. The morphological and physiological-biochemical identification, 16S rDNA sequence analysis, and phylogenetic study showed that this strain was belonged to genus Acinetobacter and named as Acinetobacter sp. L2, and closest to Acinetobacter sp. DG880［AY258108］. It could use phenanthrene as the sole carbon source. After 7 days culture, the degradation rate of phenanthrene was 96.3%. According to the activity of catechol 2,3-dioxygenase, the strain probably had phenanthrene-degrading genes.

Field inoculation effect of AM fungi on Tibet plateau Stipa bungeana grassland

CAI Xiaobu¹;GAI Jingping²; QIAN Cheng¹; FENG Gu²

2006, 17(11):  2121-2126 . 

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A field experiment was conducted on the Tibet plateau Stipa bungeana grassland to investigate the effects of arbuscular mycorrhizal fungi (AMF) inoculation on S. bungeana growth and its phosphorus uptake, and on soil microbial communities under unsterilized condition. The results showed that AMF inoculation increased the AMF spore density, infection rate and infection intensity in rhizosphere soil significantly, but had less effect on arbuscule richness. The infection rate of AMF increased with its increasing spore density, and the plant dry weight and P uptake of S. bungeana increased significantly with AMF infection rate. Similar results were observed in S. bungeana root dry weight and its P content. AMF inoculation increased the acid and alkaline phosphatase activities and bacterial biomass in rhizosphere soil, but had less effect on fungal and actinomyces communities. The infection effect of AMF varied with inoculation treatments , being in the sequence of Glomus mosseae+G. intraradices+Scutellospora calospora＞G. mosseae+G. aggregatum＞Glomus sp.＞G. mosseae＞G. mosseae+ G. etunicatum+G. intraradices+S. erythropa＞G. geosporum.

Electrical conductivity as an indicator of hydrological characteristics in catchment scale

FAN Ningjiang¹; LIU Yuhong¹; AN Shuqing¹;WANG Zhongsheng¹;YANG Haibo¹;WU Chun²; ZHAN Jihua²

2006, 17(11):  2127-2131 . 

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In this paper, the hydrological characteristics of Heishui River in Sichuan Province were studied, with electrical conductance (EC) as the main indicator. A total of 10 sites were selected on the branch and main streams, and the EC determinations were made at low-flow and level-flow periods. The results showed that EC value was significantly different among test sites, but had no significant difference between the two sampling times. The t test on the EC values of different sites at two sampling times also showed the similar pattern, indicating that the index EC could be helpful for distinguishing hydrological period and indexing river characteristics, and the contribution of branch stream to its neighboring main stream could be estimated by the EC. Using EC as a characteristic index of hydrological temporal-spatial changes could provide a convenient way for the further studies of catchment hydrology.

Statistical self-similarity of channel networks in Zagunao River catchments

ZHONG Ye^1,2;JIN Changjie¹; PEI Tiefan¹

2006, 17(11):  2132-2135 . 

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Self-similarity of channel networks is an important field in hydrologic scaling research, while the statistical self-similarity of channel networks is to study the similarity of the probabilistic distribution functions of network parameters at different scales. In this paper, the relationships between the entire network and the streams of the same Horton-Strahler order were derived in terms of the probabilistic distribution of network parameters, and empirical tests were performed by using the DEM data of Zagunao River catchments. The results of Kolmogorov-Smirnov Two-Sample test showed that the derived equations fitted the empirical data well, suggesting that the relationships between the entire network and the streams of the same Horton-Strahler order were of complicated cascade rather than “simple scaling”.

Effects of human engineering activities on permafrost active layer and its environment in northern Qinghai-Tibetan plateau

GUO Zhenggang^1,2;WU Qingbo²; NIU Fujun² 

2006, 17(11):  2136-2140 . 

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With disturbed and undisturbed belts during the construction of Qinghai-Tibet highway as test objectives, this paper studied the effects of human engineering activities on the permafrost ecosystem in northern Qinghai-Tibetan plateau. The results showed that the thickness of permafrost active layer was smaller in disturbed than in undisturbed belt, and decreased with increasing altitude in undisturbed belt while no definite pattern was observed in disturbed belt. Different vegetation types had different effects on the thickness of permafrost active layer, being decreased in the order of steppe>shrub>meadow. In the two belts, altitude was the main factor affecting the vertical distribution of soil moisture, but vegetation type was also an important affecting factor if the altitude was similar. Due to the human engineering activities, soil temperature in summer was lower in disturbed than in undisturbed belt.

Remote sensing information model for desertification evaluation of Keerqin sandy land

FAN Wenyi;ZHANG Wenhua

2006, 17(11):  2141-2146 . 

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By using remote sensing information model, this paper quantitatively retrieved the main factors for desertification evaluation of Keerqin sandy land, which included vegetation cover, biomass, and soil moisture content. The occupation ratio of bare sandy land was obtained by using linear mixed spectrum model. Every image pixel could be used to acquire the indices of all evaluation factors. Based on the current methods of desertification assessment, the quantitative remote sensing information model on the basis of the pixel was built, and the distribution map of desertification degree was plotted. The precision of the model calculated by selecting 60 in situ sample data reached 91.7%, suggesting that it was reliable and scientific to evaluate the desertification degree by using this model.

Integrative study of Guangdong ecological-economic system based on emergy analysis

SUI Chunhua¹; LU Hongfang² ;ZHENG Fengying³

2006, 17(11):  2147-2152 . 

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Based on the theories and methodologies of emergy, a quantitative analysis on the development sustainability of Guangdong Province in 1990～2003 was made from the aspects of environment, society, and economy at system and subsystem levels. The results showed that Guangdong Province was of developed provinces in China, and highly depended on the input of feedback emergy. Though the pollution control was fruitful, the increasing environmental loading was still not relieved on the whole, and the development sustainability was relatively low. This Province was increasingly relied on international market, and actually, under the status to the bad in exporting primary products and importing high-tech products. To improve the development sustainability of this Province, more concerns should be paid on improving the added values of products, making full use of the natural and labor resources in its underdeveloped area, and further bringing the economic superiority of its developed area into play.

Dynamic changes of ecological footprint and ecological capacity in Fujian Province

WENG Boqi; WANG Yixiang;HUANG Yibin; YING Zhaoyang;HUANG Qinlou

2006, 17(11):  2153-2157 . 

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The analysis on the dynamic changes of ecological footprint and ecological capacity in Fujian Province showed that in 1999～2003, the ecological footprint per capita in the Province increased from 1.428 hm² to 1.658 hm², while the ecological capacity per capita decreased from 0.683 hm² to 0.607 hm², with an increased ecological deficit year after year. The contradiction between the ecological footprint and ecological capacity pricked up gradually, and the ecological environment was at risk. There existed a severe imbalance in the supply and demand of ecological footprint per capita. The main body of the demands was grassland and fossil fuel, accouting for 55.74%～63.43% of the total, while their supply only occupied 0.77%～0.82% and next to nothing of the eological capacity per capita, respectively. As a whole, the ecological footprint per ten thousand yuan GDP declined in the five years, indicating that the resources use efficiency in the Province was improved gradually. Based on the analysis of the present situation of the economic development and resources distribution in the Province, the strategies on reducing ecological deficit were put forward.

Air negative charge ion concentration and its relationships with meteorological factors in different ecological functional zones of Hefei City.

WEI Chaoling;WANG Jingtao;JIANG Yuelin;ZHANG Qingguo

2006, 17(11):  2158-2162 . 

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Air negative charge ion concentration (ANCIC) has a close relationship with air quality. The observations on the ANCIC, sunlight intensity, air temperature, and air relative humidity in different ecological functional zones of Hefei City from 2003 to 2004 showed that the diurnal change pattern of ANCIC was of single peak in sightseeing and habitation zones, dual peak in industrial zone, and complicated in commercial zone. Different ecological functional zones had different appearance time of their daily ANCIC extremum. The diurnal fluctuation of ANCIC was in the order of commercial zone > industrial zone > habitation zone and sightseeing zone. The annual change pattern of ANCIC in these zones was similar, being the highest in summer and lowest in winter, and the mean annual ANCIC was 819, 340, 149 and 126 ions·cm^-3, respectively. The most important meteorological factor affecting the ANCIC in Hefei City was air relative humidity, followed by sunlight intensity and air temperature. There was an exponential relationship between ANCIC and air relative humidity.

Comprehensive evaluation of eco-tourism resources in Yichun forest region of Northeast China

HUANG Maozhu; HU Haiqing; ZHANG Jie; CHEN Lijun

2006, 17(11):  2163-2169 . 

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By using analytical hierarchy process (AHP) and Delphi method, a total of 30 representative evaluation factors in the aspects of tourism resources quantity, environmental quantity, tourism conditions, and tourism functions were chosen to build up a comprehensive quantitative evaluation model to evaluate the eco-tourism resources of Yichun forest region in Northeast China. The results showed that in Yichun forest region, the natural eco-tourism resources were superior to the humanity resources. On the regional distribution of favorable level eco-tourism resources quantity, 4 sites were very prominent,i.e., north (Jiayin)-center (Yichun)-east (Jinshantun)-south (Tieli). As for the distribution of eco-tourism resources type, it was basically in the sequence of north (Jiayin, Tangwang River, Wuying)-center (Yichun, Shangganling)-east (Jinshantun, Meixi)-south (Teli, Dailing). Based on the above analyses, Yichun forest region could be divided into four tourism areas,i.e., the south, the east, the central, and the north. Aimed at the special features of each area, the initial development directions were introduced.

Effects of soil moisture and temperature on N₂O production rate of meadow grassland soil

DU Rui

2006, 17(11):  2170-2174 . 

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With incubation test, this paper studied the effects of soil moisture and temperature on the N₂O production rate of meadow grassland chernozem in nner Mongolia. The results showed that soil moisture had a significant effect on the N₂O production rate, with a non-linear relationship between them. Soil temperature had less effect than soil moisture. Their effects on the test soil N₂O production rate at different growth stages could be described as a multi-rder polynomial relationship y=ax³+bx²+cx+d, where a, b, c and d were the constants.

Effects of soil moisture and temperature on N₂O production rate of meadow grassland soil

DU Rui

2006, 17(11):  2170-2174 . 

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With incubation test, this paper studied the effects of soil moisture and temperature on the N₂O production rate of meadow grassland chernozem in nner Mongolia. The results showed that soil moisture had a significant effect on the N₂O production rate, with a non-linear relationship between them. Soil temperature had less effect than soil moisture. Their effects on the test soil N₂O production rate at different growth stages could be described as a multi-rder polynomial relationship y=ax³+bx²+cx+d, where a, b, c and d were the constants.

Responses of Onobrychis viciaefolia Scop and soil nitrogen contents to elevated atmospheric CO₂ concentration

ZHOU Zhengchao¹; SHANGGUAN Zhouping^1,2

2006, 17(11):  2175-2178 . 

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The effects of elevated CO₂ on terrestrial ecosystem processes are highly related to the N cycling in the ecosystem. In two closed chambers with different CO₂ concentration (ambient CO₂ 355～370 μmol·mol^-1, and elevated CO₂ 700 μmol·mol^-1), pot experiments were conducted to study the responses of Onobrychis viciaefolia Scop and soil nitrogen contents to elevated CO₂. The results showed that compared with ambient CO₂, elevated CO₂ increased the plant dry biomass by 25.1% (P<0.01), but decreased the plant N concentration by 25.3% (P<0.001), resulting in little change of total plant N. After three months experiment, soil total N, NO₃^--N and NH₄⁺-N under both ambient and elevated CO₂ conditions decreased, while soil microbial biomass N increased significantly. Soil NH₄⁺-N concentration had little difference under ambient and elevated CO₂ conditions, but under elevated CO₂ condition, soil NO₃^--N concentration decreased significantly, while microbial biomass N increased significantly. By the end of the experiment, the total N content of whole soil-plant ecosystem had a slight increase, especially under elevated CO₂ condition, which was probably due to the higher N-fixation capability of O. viciaefolia Scop under CO₂ enrichment.

Effect of free-air CO₂ enrichment (FACE) on leaf nitrate reductase activity of Oryza sativa L. cultivar Wuxianjing 14

HU Jian^1,2; WANG Yulong¹; YANG Lianxin¹;ZHOU Juan¹; ZHU Jianguo³

2006, 17(11):  2179-2184 . 

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With the target CO₂ concentration of FACE plots being 200 μmol·mol^-1 above that in ambient air, this paper studied the effect of free-air CO₂ enrichment (FACE) on leaf nitrate reductase activity (NRA) of Oryza sativa L. cultivar Wuxianjing 14. The results showed that FACE obviously increased the NRA of functional leaves at all growth stages, with an average increment of 50%, 20%, 60%, 80% and 30% at the stages of jointing, booting, heading, 10 after heading, and 20 days after heading, respectively, showing a pronounced effect at jointing,heading and 10 days after heading. Nitrogen application rate also had an obvious effect on the absolute value of NRA in functional leaves under FACE condition. The magnitude of NRA in three nitrogen treatments was in the order of normal nitrogen (NN)＞low nitrogen (LN)＞high nitrogen (HN) at jointing stage, HN＞NN＞LN at both booting and heading stages, and NN＞HN＞LN at both 10 days and 20 days after heading, respectively. The interactive effect of FACE and N supply on NAR varied with the growth stage of Wuxianjing 14, being very significant or significant at the stages of jointing and 20 and 10 days after heading, but not significant at booting and heading stages.

Toxic effects of 1,2,4-trichlorobenzene on rice seed germination and seedling growth

DU Qingping^1,2; JIA Xiaoshan¹; YUAN Baohong³

2006, 17(11):  2185-2188 . 

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By the method of water culture, this paper studied the effects of 1,2,4-trichlorobenzene (1,2,4-TCB) on the seed germination and seedling growth of rice, with the chlorophyll, protein and proline contents and cytomembrane permeability of seedling leaf measured. The results showed the seed germination rate and vigor index were decreased with increasing concentration of 1,2,4-TCB, showing a definite dose-response relationship, and the seedling growth and root length were inhibited, showing definite time-response and dose-response relationships. The chlorophyll a, chlorophyll b, total chlorophyll, and protein contents in seedling leaf decreased with increasing concentration of 1,2,4-TCB, while the free proline content and cytomembrane permeability had a sharp increase when the concentration of 1,2,4-TCB was higher than 15 mg·L^-1. All of these suggested that the damage of rice seedling was a complicated process, which might be related to the structural and functional damage of cellular membrane, protein, and organelles.

Modeling of carbon cycling in terrestrial ecosystem: A review

MAO Liuxi¹; SUN Yanling^2,3; YAN Xiaodong²

2006, 17(11):  2189-2195 . 

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Terrestrial carbon cycling is one of the important issues in global change research, while carbon cycling modeling has become a necessary method and tool in understanding this cycling. This paper reviewed the research progress in terrestrial carbon cycling, with the focus on the basic framework of simulation modeling, two essential models of carbon cycling, and the classes of terrestrial carbon cycling modeling, and analyzed the present situation of terrestrial carbon cycling modeling. It was pointed out that the future research direction could be based on the biophysical modeling of dynamic vegetation, and this modeling could be an important component in the earth system modeling.

Connotation of ecological integrity and its assessment methods: A review

HUANG Baorong;OUYANG Zhiyun;ZHENG Hua; WANG Xiaoke; MIAO Hong

2006, 17(11):  2196-2202 . 

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Ecological integrity is the capability to support and maintain a balanced, integrative and adaptive biologic system, having the full range of elements and processes expected in the natural habitats of a region. Assessment of ecological integrity has great significance for preventing sensitive nature habitats from human disturbance. The theory of dissipative structures suggests that the stressors from human activities, as well as the biological, physical and chemical integrity and ecosystem function that reflect the ability of self-organizing, can well indicate the integrity of an ecosystem. This paper summarized the experiential indicators for assessing the integrity of aquatic and terrestrial ecosystems and the stressors from human disturbance, and discussed the methods for selecting priority indicators and comprehensive assessment in actual assessment programs. The prospects of further study were discussed, according to some issues existed in published researches.

Research advances in soil organic carbon and its fractions under different management patterns

ZHAO Xin^1,2; YU Wantai²; LI Jiandong¹;JIANG Zishao²

2006, 17(11):  2203-2209 . 

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Soil organic carbon can reflect soil quality and soil health, and is one of the hotspots in related researches at home and abroad. This paper reviewed the research results on the fractionation of soil organic carbon, with the focus on the dynamics of soil organic carbon and its fractions in their decomposition, accumulation, content, storage, and allocation proportion under different land use type and management pattern. Some related issues and further research directions were discussed.

Roles of organic acid metabolism in plant adaptation to nutrient deficiency and aluminum toxicity stress

WANG Jianfei^1,2; SHEN Qirong²

2006, 17(11):  2210-2216 . 

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Organic acids not only act as the intermediates in carbon metabolism, but also exert key roles in the plant adaptation to nutrient deficiency and metal stress and in the plant-microbe interactions at root-soil interface. From the viewpoint of plant nutrition,this paper reviewed the research progress on the formation and physiology of organic acids in plant, and their functions in nitrogen metabolism, phosphorus and iron uptake, aluminum tolerance, and soil ecology. New findings in the membrane transport of organic acids and the biotechnological manipulation of organic acids in transgenic model were also discussed. This novel perspectives of organic acid metabolism and its potential manipulation might present a possibility to understand the fundamental aspects of plant physiology, and lead to the new strategies to obtain crop varieties better adapted to environmental and metal stress.

Arbuscular mycorrhizal bioremediation and its mechanisms of organic pollutants-contaminated soils

LI Qiuling;LING Wanting;GAO Yanzheng;LI Fuchun; XIONG Wei

2006, 17(11):  2217-2221 . 

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Arbuscular mycorrhiza (AM), the symbiont of arbuscular mycorrhizal fungi (AMF) and host plant root, has been proved to be able to improve soil structure and enhance the plant resistance to environmental stress. There are more than 170 kinds of AMF worldwide. Recently, the promoted degradation of organic pollutants in soils in the presence of AM was observed, and AM bioremediation (AMB) is becoming a promising and perspective remediation technique for organic pollutants-contaminated soils. This paper reviewed the research progress on the AMB of soils contaminated by typical organic pollutants such as polycyclic aromatic hydrocarbons, PAEs, petroleum, and pesticides. The mechanisms of AMB mainly include the metabolism of organic pollutants by AM fungi, the degradation of these pollutants by the enzymes derived from AM exudation and by the enhanced root exudation and rhizospheric microbial activity in the presence of AM, and the removal of the pollutants by plant uptake and accumulation. As a new approach for the remediation of contaminated soils, some aspects involved in AMB, e.g., the screening of high efficient AM fungi, efficacy of co-existing AM fungi, soil ageing, and plant up take of organic pollutants from soils in the presence of AM, still need to be further investigated.

Effects of elevated CO₂ on soil hydrolase activities associated with Pinus koraiensis seedlings

JIA Xia^1,2;HAN Shijie²;ZHAO Yonghua³;ZHOU Yumei²

2006, 17(11):  2222-2225 . 

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In this study, Pinus koraiensis seedlings were grown under elevated CO₂ (500 and 700 μmol·mol^-1), and the hydrolase activities in 0～10 cm soil layer were determined. The results showed that compared with those under ambient condition, the activities of soil protease, urease, amylase and phosphatase under elevated CO₂ increased significantly, while invertase activity decreased significantly. Different concentration of elevated CO₂ had different effects on soil hydrolase activities. 500 μmol CO₂·mol^-1 had more significant effect on soil protease and phosphatase activities, while 700 μmol CO₂·mol^-1 had more significant effect on soil urease, amylase, and invertase activities.

Immobilization of introduced bacteria and degradation of pyrene and benzo(α)pyrene in soil by immobilized bacteria

WANG Xin^1,2; LI Peijun³;SONG Shouzhi¹;ZHONG Yong¹;ZHANG Hui¹;E.V.Verkhozina⁴

2006, 17(11):  2226-2228 . 

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In this study, introduced bacteria were applied in the bioremediation of pyrene and benzo(α)pyrene in organic pollutants-contaminated soils, aimed to test whether it was feasible to introduce bacteria to environmental engineering. Three introduced bacteria were immobilized separately or together to degrade the pyrene and benzo(α)pyrene in soil, taking dissociated bacteria as the control, and comparing with three indigenous bacteria. The results showed that immobilized introduced bacteria, either single or mixed, had higher degradation efficiency than dissociated bacteria. Compared with indigenous bacteria, some introduced bacteria had predominance to some degree. The introduced bacteria-mixture had better degradation efficiency after being immobilized. The degradation rate of pyrene and benzo(α)pyrene after treated with immobilized bacteria-(B61-B67)-mixture for 96 hours was 43.49% and 38.55%, respectively.