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Table of Content

    16 July 2007, Volume 18 Issue 07
    Articles
    Growth and reproduction of Rosa multibracteata population in Minjiang River dry valley.
    ZHOU Zhi-qiong1,2; BAO Wei-kai1; WU Fu-zhong1,2; PANG Xue-yong1; HE Xiao1; WU Ning1
    2007, 18(07):  1407-1413 . 
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    Based on large area field survey and sampling plots investigation, this paper analyzed the distribution, growth and reproduction, and spatial differentiation of native Rosa multibracteata population in the dry valley of Minjiang River. The results showed that this shrub was widely distributed within the area about 170 km long and across the altitude between 1 200 m and 2 600 m from Mianchi Town of Wenchuan County to Zhenjiangguan of Songpan Town. The plant height, base diameter, age, canopy area, sprout number per clump, and hip number each cluster of the shrub were averagely (123.33±3.13) cm, (12.49±0.40) mm, (3.34±0.16) a, (1.30±0.13) m2, (5.07±.39) stem/cluster, and (171.47±25.90) hip/cluster, respectively. Except the sprout number per cluster, all test parameters showed significantly higher values with increasing altitude and latitude, being most likely related to the improvement of water condition. The increasing fruit output and sprouting number with increasing altitude and latitude was closely related to the better growth, and possibly, to the trade-off of sexual and asexual capability of R. multibracteata across the changing environment. The lack of younger clusters in age structure indicated the instability of the population development, but the fact that the population had bigger ratio of older sprouts and bigger age structure with increasing altitude showed the sustainable development of the population. The stronger capability of R. multibracteata in growth, sprouting, and sexual reproduction in the dry valley of Minjiang River provided reliable guarantee for the sustainable development of the population.
    Antioxidase activities and photosynthetic pigment contents in Larix principis-rupprechtii leaves along an altitudinal gradient.
    LIANG Jian-ping; NIU Yuan; XIE Jing-si; ZHANG Jian-da
    2007, 18(07):  1414-1419 . 
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    To study the physiological mechanisms in environment adaptation of alpine trees, the antioxidase activities and photosynthetic pigment contents in Larix principis-rupprechtii leaves along an altitudinal gradient from 1 600 m to 2 800 m at Pangquangou National Nature Reserve were investigated. The results showed that the superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) activities in L. principis-rupprechtii leaves had the same change pattern along the altitudinal gradient, i. e. , relatively lower at middle altitude (1900-2400 m) and relatively higher at lower (1 600-1 800 m) and higher altitudes (2 500-2 800 m). Comparing with those at middle altitude, the SOD, POD and CAT activities were 62.79%, 42.13% and 7.87% higher at lower altitude and 75.20%, 14.49% and 63.38% higher at higher altitude, respectively, but decreased at the altitude near the upper limit of forest vertical distribution. At lower and higher altitudes, malondialdehyde (MDA) content was up to 9.27 and 14.06 μmol·g-1 FM, respectively, while at middle altitude, it was 5.58 μmol·g-1FM on average. Chlorophyll and carotinoid contents tended to decrease with increasing altitude, while chlorophyll a/b ratio and relative carotinoid content (Car/Chl) were in adverse, with the relative coefficients being -0.969 and -0.986, and 0.962 and 0.877, respectively.
    Effects of elevated atmospheric CO2 concentration on endogenous hormones in gingko leaves.
    LI Xue-mei1,2; HE Xing-yuan1; CHEN Wei1; FU Shi-lei1; ZHANG Li-hong3
    2007, 18(07):  1420-1424 . 
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    With top-opened chamber system, this paper studied the responses of endogenous hormones abscisic acid (ABA), indoleacetic acid (IAA), zeatin riboside (ZR) and gibberellins (GA3) in gingko leaves to elevated atmospheric CO2 concentration (ambient+350 μmol·mol-1, EC). The results showed that EC could decrease the ABA content. After treated with EC for 120 days, the ABA content could be decreased by 63.0%, in comparing with the control. EC could also decrease the contents of IAA and ZR, and the decrement could reach significant with the extension of the treatment. The IAA content was 2 times higher after 100 days treatment, and ZR content was 2.5 times higher after 80 days treatment than those of CK. Under EC, the peak of GA3 appeared earlier. The (IAA+GA3+ZR)/ABA ratio decreased gradually with the growth of gingko, and was obviously higher than the control at later stage (after 40-60 days treatment), indicating that elevated atmospheric CO2 concentration could promote the growth and development of gingko.
    Profile distribution and accumulation characteristics of organic carbon and total nitrogen in typical marshes in Sanjiang Plain.
    SHI Fu-chen1; LI Rui-li1; WANG Shao-qiang2; Sasa Kaichiro3
    2007, 18(07):  1425-1431 . 
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    The study on the profile distribution and accumulation characteristics of organic carbon (C) and total nitrogen (N) in two typical marshes in Sanjiang Plain showed that on the sediment profiles of Carex lasiocarpa marsh and Phragmites communis marsh, there existed distinct deposition horizon and illuviation horizon. In deposition horizon (0-60 cm), the average contents of organic C and total N were about 96 and 184 g·kg-1, and 7.4 and 17.6 g·kg-1, respectively, while in illuviation horizon, they were at low level. The contents of organic C and total N were exponentially decreased with increasing depth, and had significant correlations with bulk density (P<0.01). The organic C density was the highest at the depth of 20-40 cm. In the deposition horizon of the two marshes, the stocks of organic C and total N were 1.83×104 and 1.73×104 t·km-2, and 1.45×103 and 1.67×103 t·km-2, respectively, and at the depth of 0-100 cm, they were 2.86×104 and 2.62×104 t·km-2, and 2.18×103 and 2.49×103 t·km-2, respectively. Vegetation type had definite effects on the content and stock of organic C and total N in the marsh profiles.
    Effects of NO3- stress on photosynthetic rate, photochemical efficiency of PSⅡ and light energy allocation in cucumber seedling leaves.
    SU Xiu-rong1; WANG Xiu-feng2; YANG Feng-juan2; WEI Min2
    2007, 18(07):  1441-1446 . 
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    This paper studied the effects of different NO3- concentration on the photosynthetic rate, photochemical efficiency, and absorbed light energy allocation in cucumber seedling leaves. The results indicated that when the available NO3- concentration in the medium was low (14-98 mmol NO3-·L-1),an appropriate supplement of NO3- could enhance the capability of cucumber leaves in capturing light energy, and promote the photosynthesis. However, with further increase of NO3-, the photochemical efficiency of PSⅡ decreased, electron transfer restrained, and net photosynthetic rate as well as the absorbed light energy used in photochemical reaction of PSⅡ decreased. At the same time, the light energy used in antenna heat dissipation increased, while the photochemical efficiency decreased. After treated with 140 and 182 mmol NO3-·L-1 for 6 days, the photosynthetic rate (Pn) was decreased by 35% and 78%, respectively, maximal PSⅡ efficiency at open centers in the absence of NPQ (Fv/Fm), antenna efficiency at open centers in the presence of NPQ(Fv’/Fm’), actual PSⅡ efficiency (ΦPSⅡ) and photochemical quenching (qP) were lower, non-photochemical quenching (NPQ) was higher, and the deviation from full balance between PSⅠ and PSⅡ (β/α-1) was improved significantly, compared with the control. The fluctuant ranges of these chlorophyll fluorescence parameters were increased at higher NO3- concentration, compared with those at lower NO3-concentration. The absorbed light energy allocated to the photochemical reaction of PSⅡ (P) was reduced by high light intensity and high NO3-concentration. Meanwhile, the proportion allocated in antenna heat dissipation (D) increased significantly. Antenna heat dissipation was the main way for excessive energy dissipation.
    Effects of nitrogen application rate on nitrate reductase activity, nitric oxide content and gas exchange in winter wheat leaves.
    ZHANG Xu-cheng1,2; SHANGGUAN Zhou-ping2
    2007, 18(07):  1447-1452 . 
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    In this paper, the effects of different nitrogen application rates on the nitrate reductase (NR) activity, nitric oxide (NO) content and gas exchange parameters in winter wheat (Triticum aestivum L.) leaves from tillering stage to heading stage and on grain yield were studied. The results showed that the photosynthetic rate (Pn), transpiration rate (Tr) and instantaneous water use efficiency (IWUE) of leaves as well as the grain yield were increased with increasing nitrogen application rate first but decreased then, with the values of all these parameters reached the highest in treatment N180. The NR activity increased with increasing nitrogen application rate, and there was a significant linear correlation between NR activity and NO content at tillering and jointing stages (R2≥0.68, n=15). NO content had a quadratic positive correlation with stomatal conductance (Gs) (R2≥0.43, n=15). The lower NO content produced by lower NR activity under lower nitrogen application rate promoted the stoma opened, while the higher NO content produced by higher NR activity under higher nitrogen application rate induced the stoma closed. Although the leaf NO content had a quadratic positive correlation with stomatal conductance (R2≥0.36, n=15), no remarkable correlation was observed between NR activity and NO content at heading stage, suggesting that nitrogen fertilization could not affect leaf NO content through promoting NR activity, and further more, regulate the stomatal action. Under appropriate nitrogen application the leaf NR activity and NO content were lower,Gs,Tr and IWUE were higher, and thus, the crop had a better drought-resistant ability, higher Pn, and higher grain yield.
    Effects of sulfur on chemical properties of calcareous soil
    ZHANG Chang-ai; ZHANG Min; ZENG Yue-chun
    2007, 18(07):  1453-1458 . 
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    A pot trial with two continuous crops of rape was conducted to study the effects of sulfur on the chemical properties of calcareous soil. The results indicated that sulfur could decrease soil pH, while increase the electrical conductivity of soil solution markedly. Applying sulfur could enhance the contents of soil exchangeable Na+ and K+and the accumulation of soil water-soluble anions, but had less effect on soil exchangeable Ca2+and Mg2+, CEC, and alkalization degree. Comparing with urea, sulfur-coated urea (SCU) had less effect on soil pH and electrical conductivity, but markedly affected soil exchangeable cations and water-soluble anions. Sulfur application had no obvious yield-increasing effect, and higher application rate of sulfur could decrease the rape yield significantly.
    Effects of planting pattern and bare rock ratio on spatial distribution of soil nutrients in Karst depression area.
    ZHANG Wei1,2; CHEN Hong-song1,2; WANG Ke-lin1,2; ZHANG Ji-guang1; HOU Ya1,2
    2007, 18(07):  1459-1463 . 
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    This paper studied the effects of planting pattern and bare rock ratio on the spatial distribution of soil nutrients in Karst depression area of northwest Guangxi. The results showed that planting pattern had significant effects on soil organic carbon (SOC), total nitrogen (TN), total phosphorus (TP), total potassium (TK), available nitrogen (AN), available phosphorus (AP), available potassium (AK), and C/N. Bare rock ratio also had significant effects on SOC, TN, TP, TK, AN, AK and C/N, and was the crucial factor in determining the spatial variability of SOC, TN, TP and AN, which was mainly due to the higher intensity of cultivation in the places covered with less bare rock. Fields planted with Cajanus cajan-Castanca mollissima had significantly higher contents of SOC, TN, TN, TK, AN, and AK than those with other planting patterns, suggesting that converting farmland into forestland had positive effects on the accumulation of soil nutrients. Due to the effects of local topography and land use structure, foot slope had a higher content of SOC than depression, while fertilization made the depression have a higher content of AP than foot slope.
    Spatiotemporal variability of soil fertility parameters in Xinhui District of Guangdong Province.
    GAN Hai-hua; PENG Ling-yun;LU Ying;WU Jing-yu;LAI Xue-mei
    2007, 18(07):  1464-1470 . 
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    By the methods of geostatistics and GIS, this paper studied the spatial distribution patterns of pH, organic matter, total nitrogen (N) and total phosphorus (P) in cultivated soils of Xinhui District, Guangdong Province from 1982 to 2003. The paired samples t test and Kriging results showed that soil pH and organic matter content were significantly lower in 2003 than in 1982, while the contents of soil total N and total P were in adverse. The spatial distribution of test parameters changed to different degrees over the past 20 years. Soil pH tended to decrease in most areas of the study district, soil organic matter decreased except at the banks of Yinzhou Lake and parts of south and northwest, soil total N increased in most areas except the parts of east and northwest, and soil total P increased in most areas.
    Distribution characteristics of soil organic carbon, nitrogen and phosphorus in densely populated village landscapes of different hilly regions of China.
    JIAO Jia-guo1,2; YANG Lin-zhang2; WU Jun-xi3; LI Hui-xin1; E. C. Ellis4
    2007, 18(07):  1471-1478 . 
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    Based on high spatial resolution remote sensing map (1 m) and sampling with a stratified design on different site types, the effects of fine-scale land use patterns in villages on top soil (0-30 cm) organic carbon (OC), total nitrogen (TN) and total phosphorus (TP) within and across the densely populated hilly landscapes, i. e. , Sichuan Hilly Region (SIHR; Jintang County, Sichuan Province), Subtropical Hilly Region (SUHR; Yiyang County, Hunan Province), and Tropical Hilly Region (THR; Dianbai County, Guangdong Province), were investigated. The results showed that soil OC density was decreased in the order of SUHR (2.72±0.76 kg·m-2)>THR (2.65±0.73 kg·m-2)> SIHR (2.15±0.57 kg·m-2), TN density was in the order of SUHR (0.28±0.06 kg·m-2)>SIHR (0.27±0.06 kg·m-2)>THR (0.21±0.06 kg·m-2), and TP density was in the order of SIHR (0.19±0.04 kg·m-2)> SUHR (0.11±0.03 kg·m-2)> THR (0.08±0.04 kg·m-2). The fine-scale landscape units (ecotopes) with the highest soil OC, TN and/or TP stocks were rainfed annual crops in SIHR, paddy rice in SUHR, and open canopy trees and brush in THR, respectively. In all hilly regions, paddy and forest land use classes had the highest soil OC and TN density, while mined areas had the lowest soil OC and TN density, with the distribution of TP density showing a more complicated pattern than that of OC and TN. Ecotope level analysis could reflect the soil organic carbon, nitrogen and phosphorus distribution in densely populated village landscape of hilly regions more comprehensively than land use or land cover analysis.
    Impact of heavy metals pollution on soil organic matter accumulation.
    ZHANG Ming-kui; WANG Li-ping
    2007, 18(07):  1479-1483 . 
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    By the methods of field sampling and indoor incubation, this paper studied the accumulation and mineralization of soil organic matter under impact of heavy metals pollution. The results showed that high amount of heavy metals in polluted soil could slow down the mineralization rate of soil organic C, and increase the amount of hardly biodegradable organic C. With increasing soil heavy metals pollution, the particulate organic matter and its proportion in total soil organic C increased, while the microbial biomass C and its proportion in total organic C decreased. Heavy metals were largely enriched in particulate organic matter, which could impact the further mineralization of soil organic matter. In a word, soil heave metals pollution could change the mineralization rate of soil organic matter, and affect its accumulation and distribution.
    Impact of Cu and Zn pollution on rape growth and soil enzyme activity.
    YANG Hong-fei; YAN Mi; YAO Jing; WANG You-bao; LIU Deng-yi
    2007, 18(07):  1484-1490 . 
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    A pot experiment was conducted to study the impact of Cu and Zn pollution on soil enzyme activities and rape seedlings growth. The results showed that Cu had a stronger inhibitory effect than Zn on soil urease activity, while Zn had more obvious impact on soil calatase activity. The damage on the growth and dry mass of rape was more serious under Cu than under Zn pollution. The inhibition of rape seedlings growth was mainly due to the inhibition of root growth and its material accumulation. Factor analysis indicated that root dry mass was more sensitive than other indices, which could be adopted to monitor soil Cu and Zn pollution.
    Effects of longterm heavy metals stress on farmland soil microbial population, biomass and activity.
    ZHANG Yan1,2; ZHANG Hui-wen1; SU Zhen-cheng1; ZHANG Cheng-gang1
    2007, 18(07):  1491-1497 . 
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    An in situ investigation on the farmland soil heavy metals pollution caused by long-term irrigation with heavy metals containing wastewater was carried out in the Zhangshi Irrigation Area of Shenyang. The indices soil microbial population, biomass, and activity were used to evaluate the effects of long-term heavy metals pollution on farmland soil ecosystem. The results showed that in Zhangshi Irrigation Area, soils were heavily polluted by cadmium, with the cadmium content ranged from 1.75 to 3.89 mg·kg-1, and parts of them were co-contaminated by cadmium, copper and zinc. At the present pollution level, the increased soil heavy metals content resulted in a substantial decrease in soil free-living nitrogen fixing bacteria, microbial biomass carbon (Cmic), microbial quotient (qM) and dehydrogenase activity, and a significant increase of metabolic quotient (qCO2). No significant changes were observed in soil bacteria, actinomyces, fungi, and substrate-induced respiration (SIR).Correlation analysis showed that the changes of soil microbial parameters were mainly caused by soil cadmium pollution. Comparing with other test microbial parameters, microbial quotient and metabolic quotient were more sensitive to soil heavy metals pollution.
    Changes of Cd forms on wheat root-soil interface under stress of combined Cd and chlorimuron-ethyl.
    JIN Cai-xia1,2; ZHOU Qi-xing1; FAN Jing2; WANG Jian-ling1
    2007, 18(07):  1498-1504 . 
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    With rhizobox experiment, this paper studied the changes of Cd forms on wheat root-soil interface under the stress of combined cadmium (Cd) and chlorimuron-ethyl. The root-soil interface (0-5 mm) was separated into 6 parts every other 1 mm, and the sampling time was 14, 21, 28, 35 and 42 days after treatment. The correlativity between Cd forms and Cd absorption by wheat was made to assess the availability of each Cd form. The results showed that exchangeable Cd showed different spatial effect during various growth periods. The trend of carbonate-bound Cd and Fe-Mn oxide-bound Cd transforming to exchangeable Cd was weaken, but the trend of the two Cd forms transforming to residual Cd was strengthened from root-center zone to non-rhizosphere. The concentration of organic-bound Cd varied significantly in neighboring root zone. During the whole experiment period, the concentrations of carbonate-bound Cd, Fe-Mn oxide-bound Cd and organic-bound Cd decreased, while that of residual Cd increased. Correlation analysis suggested that exchangeable Cd and organic-bound Cd nearby the root were the main Cd forms that could be absorbed by wheat. It could be concluded that the transformation of carbonate-bound Cd and Fe-Mn oxide-bound Cd and the concentration of exchangeable Cd were affected by chlorimuron-ethyl significantly.
    Distribution and migration of zinc in Avicennia marina plant;soil system.
    CHEN Gui-kui1;CHEN Gui-zhu2
    2007, 18(07):  1505-1509 . 
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    Zinc is a major anthropogenic contaminant in estuarine ecosystem, and has potential ecotoxicological consequences for aquatic animals and plants. An artificial mangrove wetland was set up in greenhouse to study the distribution and migration of zinc in synthetic wastewater in Avicennia marina plant-soil system. Different concentration synthetic wastewater and 1.5% salinity artificial seawater (control) were discharged into the system in fixed quantity twice a week for a year. The results showed that most part (>67%) of zinc in the artificial wastewater discharged into the system was remained in the soil, and only a small portion (1.24%-10.4%) of it was entered into plant and litter,indicating that this artificial plant-soil system had a stronger purifying effect on the zinc in synthetic wastewater. The calculation with matter balance model indicated that soil subsystem had a higher environmental capacity of bearing zinc.
    Contents and spatial distribution patterns of heavy metals in farmland soils of Fuxin City.
    XU Li-chao1,2; LI Yan-xia1; SU Qiu-hong1,3; WU Juan1,4; XIONG Xiong1; SONG Bo1; ZHENG Guo-di1; CHEN Yu-cheng2
    2007, 18(07):  1510-1517 . 
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    A total of 180 farmland soil samples were collected from the suburbs of Fuxin City, Liaoning Province, to investigate the contents and spatial distribution patterns of Cu, Zn, As and Ni, with the effects of mining on their accumulation and spatial distribution in test farmland soils discussed. The results indicated that in study area, farmland soils had an accumulation of Cu, Zn and Ni, with the geometric mean concentrations higher than the background values. Among the soils planted with different crops, vegetable soil had significantly higher contents of Cu, Zn and As than grain crop soil. The spatial distribution of four test metals showed the same pattern of urban>suburban, and the regions with high concentrations of heavy metals were well overlapped with mining areas, suggesting that mining activities might be one of the most important source of heavy metals in the farmland soils. The rapid increase of animal manure also contributed to the import of pollutants to farmland soils to some degree. The potential risks of soil heavy metals pollution should be considered in the arrangement of local agricultural and animal husbandry productions.
    Heavy metals accumulation in river sediments of Chongming Island, Shanghai City, and its environmental risk.
    WANG Jun; CHEN Zhen-lou; WANG Chu; YE Ming-wu; SHEN Jing; NIE Zhi-ling
    2007, 18(07):  1518-1522 . 
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    Heavy metals accumulation in river sediments can reflect the environmental quality of river waters. It’s of practical significance to study the accumulation level of heavy metals in river sediments and its environmental risk. In this paper, the heavy metals accumulation in river sediments of three typical towns of Chongming Island was studied, and the results showed that the average accumulation of Zn, Cr, Cu, Pb and Cd in Chengqiao Town, Baozhen Town and Chenjia Town was 103.1, 79.2, 39.0, 29.7 and 0.300 mg·kg-1, 99.0, 104.0, 50.5, 32.7 and 0.308 mg·kg-1, and 86.7, 79.5, 32.2, 30.5 and 0.274 mg·kg-1, respectively. In South Chongming, the average accumulation of Zn, Cr, Cu, Pb and Cd was 94.72, 81.35, 38.52, 30.78 and 0.297 mg·kg-1, respectively. The environmental risk assessment by using geoaccumulation index (Igeo) indicated that these three towns had a low-medium rank environmental risk of heavy metals accumulation in river sediments, and the probability of achieving medium rank risk was in the order of Chengqiao>Baozhen>Chenjia.
    Distribution characteristics of organochlorine pesticides in river surface sedim ents in Song-Liao Watershed.
    WANG Hao-zheng; HE Meng-chang; LIN Chun-ye; QUAN Xiang-chun; GUO Wei
    2007, 18(07):  1523-1527 . 
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    With gas chromatography-electron capture detector (GC-ECD), this paper analyzed 13 kinds of organochlorinae pesticides (OCP) in surface sediments collected from 22 sites of Song-Liao water system. The results showed that the total concentration of OCP varied from 3.06 to 23.24 ng·g-1 in Daliao River system and from 4.26 to 18.45 ng·g-1 in Songhuajiang River system. The most dominant OCP pollutant in the sediments in Song-Liao Watershed was HCH, but there existed different pollution tendency in the two subsystems. In Songhuajiang River, there were also relatively high concentrations of DDT. High concentration γ-HCH was observed among the isomers of HCH in the whole watershed, which exceeded the initial affecting concentration and could potentially do toxic effect on the water creatures.
    Bio-toxic effect of pyrene on Vallisneria spiralis.
    YIN Ying1; SUN Yuan-yuan2; GUO Hong-yan1; WANG Xiao-rong1
    2007, 18(07):  1528-1533 . 
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    With indoor static simulation test, this paper studied the effects of different concentrations (0.01, 0.02, 0.05, 0.07 and 0.1 mg·L-1) pyrene on the pyrene accumulation, free radical, antioxidant defenses, and the contents of chlorophyll and soluble sugar in Vallisneria spiralis. The results showed that after 10 days exposure to pyrene, V. spiralis leaf could accumulate large amount of pyrene. The free radical generation, peroxidase (POD) activity and malondialdehyde (MDA) content had a persistent increase, but the increment decreased when exposed to higher concentrations (>0.05 mg·L-1) pyrene. Glutathione S-transferase (GST) activity and oxidized glutathione (GSSG) and soluble sugar contents increased with increasing concentration of pyrene, while reduced glutathione (GSH) and chlorophyll contents were in adverse. It was concluded that V. spiralis was sensitive to pyrene, and the stress effect would happen at 0.01 mg·L-1 of pyrene.
    Contamination characters of polycyclic aromatic hydrocarbons in Daliao River system of China.
    GUO Wei; HE Meng-chang; YANG Zhi-feng; LIN Chun-ye; QUAN Xiang-chun; WANG Hao-zheng
    2007, 18(07):  1534-1538 . 
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    With GC/MS, a quantitative study was made on the polycyclic aromatic hydrocarbons (PAHs) in the surface water and suspended particulates in Daliao River system, with their spatial distribution and sources investigated. The results showed that the total PAHs concentration ranged from 946.1 to 13448.5 ng·L -1 in surface water, and from 317.5 to 238 518.7 ng·g-1 in suspended particulates. The PAHs concentration was decreased in the order of Taizi River>Daliao River>Hunhe River. The PAHs in surface water were dominated by 3-5 rings, while those in suspended particulates were dominated by 2 rings. The calculated ratios of selected PAHs suggested that the discharges from municipal, petrochemical and steel industrial wastewater, and the atmospheric fallout might be the important PAHs sources, and the contamination sources of PAHs were the mixture of petrogenic and pyrolytic inputs. In comparing with other river and marine systems in the world, Daliao River system had higher concentrations of PAHs in its surface water and suspended particulates, and thus, presented certain ecological risk.
    Estimation of chemical fertilizer N-induced direct N2O emission from China agricultural fields in 1991-2000 based on GIS technology.
    LU Yan-yu1;HUANG Yao1,2;ZHANG Wen2;ZHENG Xun-hua2
    2007, 18(07):  1539-1545 . 
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    Referring to the definition of agricultural field N2O emission factor by the Intergovernmental Panel on Climate Change, the main controlling factors climate and cropping system were introduced to estimate the chemical fertilizer N-induced direct N2O emission from China agricultural fields in 1991-2000, and a spatial inventory with 10 km×10 km resolution was developed by dint of GIS framework. The results indicated that there was an increasing trend in the annual direct N2O emission, due to the increasing input of chemical fertilizer N. The mean annual emission in 1990s was estimated to be 204 Gg N2O-N, ranging from 159 to 269 Gg N2O-N, and the lowest and the highest emission occurred in 1992 and 1998, respectively. The uncertainty of the estimation was quantified to be about 23%. The spatial distribution of N2O emission was characterized by higher flux in eastern China and lower flux in western China, which was mainly attributed to the application rate of chemical fertilizer N and precipitation.
    Variation trends of China terrestrial vegetation net primary productivity and its responses to climate factors in 1982-2000.
    HOU Ying-Yu1,2,3; LIU Qin-Huo1; YAN Hao2; TIAN Guo-Liang1
    2007, 18(07):  1546-1553 . 
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    A new estimation model of vegetation net primary production (NPP) based on remote sensing data and climatic data was presented, with which, the NPP of China terrestrial vegetation in 1982-2000 was estimated, and the intra- and inter- annual variation patterns of the NPP and its responses to climate factors were studied. The results showed that there was an obvious seasonal regularity in the intra-annual variation of the NPP. In 1982-2000, all the terrestrial vegetation types presented an increasing annual NPP, with the greatest increment for deciduous needle leaf forests and the smallest one for grasses. Evergreen broadleaf forests had the largest inter-annual variation, while grasses had the smallest one. Comparing with temperature, precipitation played a stronger driving role in the intra-annual variation of the NPP, and the effects of precipitation and temperature were more obvious in North China than in South China. The driving roles of the climate factors varied with season and latitude.
    Multi-scale ecological security evaluation of typical fragile areas in Loess Plateau.
    LIU Shi-liang1;GUO Xu-dong2; LIAN Gang3; WANG Jing2
    2007, 18(07):  1554-1559 . 
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    Regional ecological security has been paid more and more attention, and it’s of special significance to study the ecological security and its driving factors in ecological fragile areas. In this paper, the ecological security and its driving factors in typical fragile regions in Loess Plateau were analyzed at district and county scales. Yulin District and Hengshan County were taken as the cases, and ecological security index system was constructed to assess the security levels of the two regions. By using AHP method, the spatial differentiation of ecological security at different scales was studied, and the results showed that there existed differences among the twelve counties in Yulin District, with the security level being generally higher in southwest and lower in northeast. Similar tendency was observed in Hengshan County, with the security level being lower in north and northeast, and varying among different scales in southwest. Climate and topography were the weak driving forces, while human disturbances had great influence on ecological security.
    Statistic dynamics analysis of fractal hierarchical structure in complex ecosystem.
    WANG Hui; CHAI Li-he
    2007, 18(07):  1560-1567 . 
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    Ecosystem is typically characteristic of heterogeneity, non-linearity, and multi-hierarchy etc. Aimed at the complexity of ecosystem and from the viewpoint of statistical dynamics, this paper approached the dynamic mechanisms of fractal hierarchical structure in complex ecosystem, analyzed the affecting factors of fractal dimension, compared the theoretical analyses with practical examples, and discussed the possible applications in practice.
    Effects of exogenous nitric oxide donor on lipid peroxidation of pear leaves infected by Physalosproa pirico Nose.
    LIU Zhao-long1,2; ZHANG Shao-ling1; SUEN Yi-lin1
    2007, 18(07):  1568-1572 . 
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    This paper studied the effects of 0.3 mmol·L-1 SNP on the antioxidant enzymes and reactive oxygen in pear leaves infected by Physalosproa piricola Nose. The results showed that compared with CK1 (spraying leaves with water and infecting with P. piricola Nose), 0.3 mmol·L-1 SNP could increase the activities of leaf POD, SOD, CAT and PPO and the contents of leaf ASA, GSH and proline by 39.41%, 21.11%, 41.61%, 13.04%, 44.45%, 48.32% and 33.80%, while decrease the contents of leaf MDA and H2O2 and the generating rate of O2- by 20.45%, 6.93% and 6.27%, respectively, indicating that lower concentration SNP could reduce the damage of P. piricola Nose to pear leaves.
    Intraspecific variations of Paecilomyces fumosoroseus in temperature fitness and carbendazim resistance.
    ZHENG Wu; FENG Ming-guang
    2007, 18(07):  1573-1577 . 
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    A total of six wild strains of fungal biocontrol agent Paecilomyces fumosoroseus were grown at 15 ℃-35 ℃ to reveal their variations in colony growth, conidiation, and conidial viability. The results showed that the test three indices were the best at 25 ℃, but differed significantly at different temperatures for a given strain or at a given temperature among test strains. The strains Pfr116 and Pfr6206 behaved better or more stably than other strains at 15 ℃-35 ℃. The sensitivities of the fungal strains to gradient concentrations of fungicide carbendazim were assayed at the optimal temperature, based on their colony growth diameters and the counts of colony forming units (CFU). The inhibitory effect of carbendazim concentration on CFU counts fitted well to a Logistic model, with high coefficients of determination being achieved for all the strains (r2≥0.90). The fitted minimal inhibitory concentration (MIC) values showed a low carbendazim resistance of strains Pfr4205 and Pfr116 (MIC≤20.0 μg·ml-1), whereas the other four strains fell within medium resistance to the fungicide (20≤MIC≤100). The MIC of strain Pfr6206 (93.5 μg·ml-1) was very close to the high resistance level of MIC>100 μg·ml-1. Therefore, strain Pfr6206 was satisfactory with both the temperature fitness and the carbendazim resistance, and could be considered as a candidate strain for a fungal formulation adapting to more variable crop systems against insect pests.
    Insecticide resistance of Bemisia tabaci field populations.
    HE Yu-xian1; WENG Qi-yong1; HUANG Jian2; LIANG Zhi-sheng2; LIN Gui-jun2; WU Dong-dong2
    2007, 18(07):  1578-1582 . 
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    Resistance to 13 insecticides in field populations of Bemisia tabaci from six regions (Fuzhou, Zhangzhou, Longyan, Sanming, Nanping, Ningde) of Fujian Province, China was monitored by adult leaf-dipping bioassay. Compared with the susceptible SUD-S strain, all the six field populations exhibited high levels of resistance to lambda-cyhalothrin (838.38-2460.52 fold), fenpropathrin (244.64-834.29 fold), cypermethrin (116.02-266.35 fold), deltamethrin (81.75-124.18 fold), acephate (425.18-875.56 fold) and chlorpyrifos (54.53-78.43 fold), moderate levels of resistance to dimethoate (14.16-17.66 fold), low to moderate levels of resistance to dichlorvos (6.23-11.25 fold) and low levels of resistance to methomyl (4.07-5.66 fold), respectively. Among these six field-collected populations, only Zhangzhou population had moderate resistance to imidacloprid, acetamiprid and thiamethoxam (23.08 fold, 10.32 fold and 24.60 fold, respectively). All field strains tested displayed no resistance to abamectin.
    Effects of different elicitors on olfactory response and oviposition selection of Dendrolimus superans (Butler).
    YAN Shan-chun1; XU Wei1,2; YUAN Hong-e1; WANG Qi1; LU Dan2
    2007, 18(07):  1583-1588 . 
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    This paper studied the behavioral responses of Dendrolimus superans larvae and adults to Z-jasmone, methyl jasmonate (MeJA) and methyl salicylate (MeSA), and to Larix gmelinii seedlings treated with different elicitors including mechanic wounding, insect feeding, jasmonic acid (JA), salicylic acid (SA), Z-jasmone, MeJA, MeSA, and JA+SA. The results showed that D. superans larvae were repelled by MeJA and MeSA at the concentrations of 0.1%-10% V/V. L. gmelinii seedlings were induced resistance by wounding, JA, MeJA, Z-jasmone and MeSA, which decreased the feeding selection of D. superans larvae. D. superans adults exploited evident electroantennogram (EAG) responses to Z-jasmone and MeSA, and the sensitivity of the females was enhanced with the increasing concentration of Z-jasmone and MeSA. Significantly low amount of eggs was observed on the L. gmelinii seedlings treated with test elicitors.
    Species composition, diversity and density of small fishes in two different habitats in Niushan Lake.
    YE Shao-wen1,2; LI Zhong-jie1; CAO Wen-xuan1
    2007, 18(07):  1589-1595 . 
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    This paper studied the spatial distribution of small fishes in a shallow macrophytic lake, Niushan Lake in spring 2003, and its relations with habitat heterogeneity. Based on the macrophyte cover condition, distance from lake shore and water depth, two representative habitat types in the lake were selected. Habitat A was near the shore with dense submersed macrophyte, while habitat B was far from the shore with sparse submersed macrophyte. Small fishes were sampled quantitatively by block net (180 m2), and their densities within the net area were estimated by multiple mark-recapture or Zippin’s removal method. The results showed that there were some differences in species composition, biodiversity measurement, and estimated density of small fishes between the two habitats: 1) the catches in habitat A consisted of 14 small fish species from 5 families, among which, benthopelagic species Rhodeus ocellatus, Paracheilognathus imberbis and Pseudorasbora parva were considered as dominant species, while those in habitat B consisted of 9 small fish species from 3 families, among which, bottom species Rhinogobius giurinus and Micropercops swinhonis were dominant; 2) the Bray-Curtis index between the two small fish communities was 0.222, reflecting their low structure similarity, and no significant difference was observed between their rank/abundance distributions, both of which belonged to log series distribution; 3) the total density of 9major species in habitat A was 8.71 ind·m-2, while that of 5 major species in habitat B was only 3.54 ind·m-2. The fact that the spatial distribution of the small fishes differed with habitats might be related to their habitat needs for escaping predators, feeding, and breeding, and thus, aquatic macrophyte habitat should be of significance in the rational exploitation of small fish resources as well as the conservation of fish resource diversity.
    Effects of abrupt salinity stress on osmoregulation of juvenile Rachycentron canadum.
    XU Li-wen; LIU Guang-feng; WANG Rui-xuan; SU You-lu; GUO Zhi-xun;FENG Juan
    2007, 18(07):  1596-1600 . 
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    Rachycentron canadum is a thriving mariculture species for offshore cage in southern Mainland and Taiwan of China, due to its rapid growth rate and high quality flesh. In this paper, the gill Na+-K+ATPase (NKA) activity and iono- and osmoregulation of juvenile R. canadum were investigated in a 12 h stress of ambient salinities (0-45), and the results showed that after an abrupt transfer to the salinities of 0, 5, 15, 25, 37 (control) and 45, the death of juvenile R.canadum only occurred in salinity 0, with a mortality of 100% by the end of the experiment. In all treatments, the gill NKA activity and serum osmolality fluctuated in first 3 h, and then changed smoothly. The NKA activity varied with salinity grade in U shape, being significantly (P<0.05)higher in salinity 5 and the lowest in salinity 15 in 12 h, while the serum osmolality (ranged 293-399 mOsmol·kg-1) presented a positive correlation with salinity. Serum [Na+] and [Cl-] concentration slightly increased with salinity within the period of 3-12 h, while serum [K+] displayed a reverse pattern. The isosmotic point was estimated as 328.2 mOsm·kg-1 and corresponded to salinity 11.48. The isoionic points for serum [Na+], [K+] and [Cl-] were estimated as 155.2, 6.16, and 137.1 mmol·L-1, which corresponded to the salinities of 10.68, 20.44 and 8.41, respectively. It was concluded that R. canadum could be chharacterized physiologically as a “higher-NKA-in-hyposmotic media” marine euryhaline teleost with the capability of rapid and effective hyper/hypo iono- and osmoregulation.
    Forest degradation/decline: Research and practice.
    ZHU Jiao-jun; LI Feng-qin
    2007, 18(07):  1601-1609 . 
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    As one of the most critical environmental problems in the 21st century, forest degradation has been facing worldwide. There are many definitions about forest degradation, but its common features are the permanent loss of forests, stand structure destructed, forest quality decreased, and forest functions lowered. Forest decline or tree decline in fact is one of the causes of forest degradation, which includes the general reduction of trees in vigor, low level growth of trees in productivity, death of trees, and even, decline of soil fertility. Many researches indicated that deforestation is the permanent loss of forests in area, which is shifted to other land uses. Deforestation is the product of the interactions between environmental, social, economic, cultural, and political forces at work in any given country/region, and thus, more and more attention is focused on the negative socioeconomic and environmental effects after forest degradation, especially on the reduction of forest area induced by deforestation. The effects of any decisions or policies in national and international levels on forest degradation induced by deforestation have been paid attention as well. How to make efforts and strengthen the worldwide cooperation to combat the forest degradation induced by deforestation must be challenged to find appropriate solutions. There are many researches on forest decline, because of its complexity and uncertainties. The major causes of forest decline include: 1) pollution from both industry and agriculture, 2) stress factors, e. g. , desiccation, 3) changes in stand dynamics, 4) decline disease of forest or diseases of complex etiology, 5) degradation of productivity and/or soil fertility in pure plantation forests. Forest degradation in China is similar to that all over the world, but with the characteristics in forest components, i .e. , 1) secondary forests are the major forest resources, 2) China has the most plantation forests in the world, some of which have low qualities or functions. Based on the above reviews and perceptions on forest degradation and related practices, the main causes of contemporary forest degradation were summarized, and the general countermeasures for combating forest degradation/decline were given.
    Research advances in mathematical model of coniferous trees cold hardiness.
    ZHANG Gang;WANG Ai-fang
    2007, 18(07):  1610-1616 . 
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    Plant cold hardiness has complicated attributes. This paper introduced the research advances in establishing the dynamic models of coniferous trees cold hardiness, with the advantages and disadvantages of the models presented and the further studies suggested. In the models established initially,temperature was concerned as the only environmental factor affecting the cold hardiness, and the concept of stationary level of cold hardiness was introduced. Due to the obvious prediction errors of these models, the stationary level of cold hardiness was modeled later by assuming the existence of an additive effect of temperature and photoperiod on the increase of cold hardiness. Furthermore, the responses of the annual development phases for cold hardiness to environment were considered. The model researchers have paid more attention to the additive effect models, and run some experiments to test the additivity principle. However, the research results on Scots pine (Pinus sylvestris) indicated that its organs did not support the presumption of an additive response of cold hardiness by temperature and photoperiod, and the interaction between environmental factors should be taken into account. The mathematical models of cold hardiness need to be developed and improved.
    Feasibility of applying ornamental plants in contaminated soil remediation.
    LIU Jia-nü1,2; ZHOU Qi-xing2,3; SUN Ting1; WANG Xiao-fei4
    2007, 18(07):  1617-1623 . 
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    Phytoremediation is one of the effective ways in resolving problems of contaminated soils, but limited hyperaccumulation plant species were reported and documented. This shortage could be offset if remediation plants can be screened out from various ornamental plants. In addition, such doing can beautify the environment while bring some economic effects. Starting from the importance of phytoremediation, this paper generalized the characters and standards of remediation plants. Through describing the resources of ornamental plants and their functions on environmental protection, particularizing their superiorities to other plants, and analyzing their endurance, accumulation traits and remediation types, the feasibility of applying ornamental plants in the practices of contaminated soil remediation was discussed. To screening out hyperaccumulators from ornamental plants would be an entirely new research area in the remediation of contaminated soils.
    Research advances in sequestration mechanisms of hardly biodegradable organic contaminants in soil.
    LI Xiao-jun1; LI Pei-jun1,2; LIN Xin2
    2007, 18(07):  1624-1630 . 
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    After entering into soil, organic contaminants often become increasingly less available to a variety of organisms and to non-vigorous extraction by organic solvents. This time-dependent reduction in availability results from the molecules sequestration by soil. Because of the sequestration, the exposure risk of hard biodegradable organic contaminants in soil may be overestimated, and the available remediation technologies are assessed incorrectly. The inherent mechanisms of the sequestration are the irreversible adsorption by clay minerals, organic matters and nonaqueous-phase liquids and the entrapment by micropores, while the key factors affecting the sequestration are the physicochemical characteristics of soil, properties of hardly biodegradable organic contaminants, and environmental conditions,e. g. , moisture, temperature, pH and so on. Some critical problems in sequestration mechanisms study were pointed out, and the developing trend in this research field was prospected.
    Research advances in drought resistance and heavy metals tolerance of transgenic plant.
    ZHANG Yu-xiu1; XU Jin2; WANG Xiao1; CHAI Tuan-yao2
    2007, 18(07):  1631-1639 . 
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    Drought and heavy metals contamination greatly affect plant growth, while the cloning and function analysis of stress-inducible genes provide an effective approach to improve the stress tolerance and yield of crops by genetic engineering. The expression of LEA (late embryogenesis abundant protein) gene could be induced by various stresses such as drought, high salinity, cold, and heavy metals. The study on transgenic plants showed that LEA could increase plant tolerance to water stress, had ion-binding activity, and acted as an antioxidant under abiotic stresses. Aquaporins largely presented in plasma membrane and vacuolar membrane, and played a key role in root water uptake and transportation both at cellular and at whole plant level. The expression of aquaporins was up-regulated in response to drought and salinity, and conferred the water stress tolerance in plant. Cation-efflux transport proteins were involved in the absorption, transportation, and accumulation of heavy metals in plants. All of the proteins mentioned above could have potential applied profits on improving the biological water-saving, drought resistance, and heavy metals tolerance of lawny grass.
    Research progress on urban green space.
    CHANG Qing1,2; LI Shuang-cheng1;LI Hong-yuan3;PENG Jian1,2;WANG Yang-lin1,2
    2007, 18(07):  1640-1646 . 
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    Nature, diversity, and openness are what we demand from urban green space in the 21st century. Based on the summary of urban green space connotation, types and significance, this paper reviewed the research hotspots of urban green space, i .e. , conservation and planning of urban-rural fringe, restoration and preservation of natural areas and indigenous vegetation, ecological restoration and planning of green way, biodiversity conservation, ecosystem structure and services, and management policy. The difference between foreign and domestic urban green space researches and practices were summarized, and some preferential urban green space research aspects in the future were proposed. It was suggested that in China, urban green space strategy should be integrated into urban planning and land use planning.
    Research progress on seaweed bed ecosystem and its engineering.
    ZHANG Shou-yu; SUN Hong-chao
    2007, 18(07):  1647-1653 . 
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    Seaweed bed ecosystem is one of the typical nearshore ecosystems. Because of its unique structure and function, the ecology and engineering of this ecosystem have received much attention around the world in recent years. In this paper, the concept, structure, and function of seaweed bed ecosystem, as well as the definition and implementing steps of seaweed bed ecosystem engineering were introduced, and the most recent development in the research of seaweed bed ecosystem in developed countries was reviewed, with the research projects in the United States and Japan as examples. More basic research in seaweed bed ecosystems in China was urgent to be conducted to promote the marine economy and the development of relevant sciences and technologies.
    Research advances in microbial degradation of nitrobenzene and its substituted compounds.
    SHENG Lin-xi1;LI Ming-tang1,2;XU Jing-bo1
    2007, 18(07):  1654-1660 . 
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    Nitrobenzene and its substituted compounds are a group of priority pollutants characterized by chemical stability, high toxicity, and biological accumulation. To treat the waste water and gas containing nitrobenzene and its substituted compounds and to remedy the environment polluted by these compounds, microbial degradation had advantages over other methods. This paper summarized the research advances in the microbial degradation of nitrobenzene and its substituted compounds by terms of the acclimation and screening of degradation strains, degradation pathways and mechanisms, co-metabolism, chemotaxis, and molecular genetics. Further studies should be made on the construction and application of engineering bacteria. In the microbial remediation of environment polluted by nitrobenzene and its substituted compounds, co-metabolism and synergetic degradation of co-strains would play an important role.
    Migration and removal of organic matters in reclaimed wastewater during groundwater recharge.
    ZHAO Qing-liang;WANG Li-na;XUE Shuang;LIU Zhi-gang;YOU Shi-jie ;WANG Shao-hua
    2007, 18(07):  1661-1664 . 
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    Artificial groundwater recharge is one of the efficient approaches in mitigating water shortage in China. With laboratory scale soil column system, this paper examined the migration and removal of organic matters in reclaimed wastewater during groundwater recharge. The results showed that after the secondary effluent pretreated by activated carbon was percolated through soil column system, the TOC, UV-254 and BOD5 in the effluent were removed by 44%, 34.36% and 95%,respectively, and the majority of the organic matters was removed in the first 0-0.5 m of soil column. When the TOC concentration of influent was 9-11 mg·L-1, the variation of TOC concentration with soil depth during recharge followed exponential equation C=10e-0.6934h (R2=0.8697).This equation could be used to well predict the TOC concentration of the effluent from soil column system.
    Effects of cadmium on rice seed germination.
    ZENG Xiang1;ZHANG Yu-zhu1;WANG Kai-rong3;LI Xiao-xiang1;DUAN Yong-hong1;XIE Jian-hong1;ZHANG Yue-ping1,2;TU Nai-mei2
    2007, 18(07):  1665-1668 . 
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    With 319 rice varieties as test objects, this paper studied the effects of cadmium on their seed germination. The results showed that after treated with 10 mg·L-1 of Cd2+, seed germination rate was less affected, but root growth was restrained evidently. Cadmium had more serious impact on root than on sprout. Different rice varieties had different germination responses to Cd2+, with the sequence of conventional rice (Japonica rice) > hybrid rice (Indianica rice) > conventional rice (Indianica rice). The root length and number of two-line sterilities were restrained more strongly than those of three-line sterilities. Based on their responses to Cd2+, the test 319 varieties were clustered into 3 types, i. e. , endurant type, medium type, and sensitive type.
    Toxicity evaluation of purified terephthalic acid wastewater by using model Caenorhabditis elegans.
    WANG Xiao-yi1; WANG Da-yong2;YU Hong-xia1;WANG Xiao-rong1;ZHANG Xu-xiang1;CHENG Shu-pei1
    2007, 18(07):  1669-1672 . 
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    By using model Caenorhabditis elegans, the toxicity of purified terephthalic acid (PTA) wastewater was evaluated through a battery of biotest, including life span, days of 50% lethal, generation time, brood size, head thrashes, and body bends. The results revealed that compared with control, the life span and generation time of C. elegans exposed to 660 mg PTA·L-1 were delayed to some degree, and its head thrashes and body bends were inhibited. The procreation function of C. elegans exposed to PTA wastewater was greatly ffected, with the brood size being as low as 25% of the normal one. The most sensitive indicator, brood size of C. elegans, might be a potential indicator in evaluating PTA wastewater toxicity.
    Effects of cadmium stress on photosynthetic functions of strawberry.
    ZHANG Jin-biao1; HUANG Wei-nan2
    2007, 18(07):  1673-1676 . 
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    With pot experiment, this paper studied the effects of cadmium stress on the leaf chlorophyll content, photosynthetic rate, stomatal conductance, transpirationrate, and intercellular CO2 concentration of strawberry. The results showed that cadmium reduced the chlorophyll content, and changed the chlorophyll a/b ratio. Cadmium reduced the photosynthetic rate and stomatal conductance, though they were increased by low concentration cadmium at the initial stage of cadmium stress. Cadmium also reduced the transpiration rate and intercellular CO2 concentration, but the decrement of intercellular CO2 concentration was relatively less.
    Methods and practices of urban planning in Chengnan New District of Jintan City, from ecological perspective.
    HUO Li;BAO Cun-kuan;SHU Ting-fei
    2007, 18(07):  1677-1680 . 
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    Rapid urbanization stimulates the consumption of resources and the damages on ambient environment. The consideration of environmental protection and resource conservation must be involved in urban planning procedures. Actually more and more planners have realized this problem and started to apply ecological theories and methods in urban planning. The practice of urban planning combining with ecology was demonstrated, using Chengnan New District of Jintan City as the case study. In this case study, environmental impact assessment of the plan was simultaneously carried out so that the remarks of environmental impact assessment could be fed back to the planning procedure. Ecological principles and standards were set up as the ecological deadline of the city development.