Table of Content

18 March 2007, Volume 18 Issue 03

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Articles

Dynamics of forest community structure and complexity in the process of secondary succession in bedrock area of West Shanxi Province

DONG Lin-shui¹; ZHANG Xu-dong¹; ZHOU Jin-xing¹; SONG Ai-yun²

2007, 18(03):  471-475 . 

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In this paper, four plots representing the typical secondary succession stages of forest community were selected at the shady slope of bedrock area in Zhongyang County of West Shanxi, aimed to study the variation patterns of the structure and complexity of forest community in the process of secondary succession. The results showed that in the succession process of the community, there was an evident regularity in the variation of height and diameter class structure. The proportion of high and big individuals in the community increased gradually, while that of low and small ones increased first but decreased then. From the viewpoint of height class structure, the compositional complexity of tree species H(X), structural complexity of tree species H(Y|X), and complexity of whole community H(X,Y) all increased first, but decreased then with the succession. At the early, middle and arbor stages of succession, the H(X)value was 2.96, 3.85 and 3.75,while H(Y|X) value was 1.27, 1.66 and 1.37, respectively.

Age estimation and age structure of Cycas fairylakea population in Shenzhen City

WANG Dian-pei¹; JI Shu-yi²; CHEN Fei-peng²; PENG Shao-lin³

2007, 18(03):  476-480 . 

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Based on the structural characteristics of Cycas trunk, including vegetative leaf base scars, sporophyll concave rings, and average occurrence probabilities of vegetative leaf and sporophyll, a method for the age estimation of Cycas fairylakea population was developed, and the age of each individual was calculated. Three approaches, i.e., age structure diagram, age distribution curve and curve estimation were used to study the age structure of C. fairylakea population at genet and clone population levels. The age structure diagram showed that the clone population of C. fairylakea was stable, but the genet population was in declining. However, both of the clone and genet populations were in declining when using the other two approaches. It was considered that the C. fairylakea population was in declining, and needed an urgent protection.

Effects of tree species fine root decomposition on soil active organic carbon

LIU Yan^1,2; WANG Si-long¹; WANG Xiao-wei^1,2; YU Xiao-jun¹; YANG Yue-jun³

2007, 18(03):  481-486 . 

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With incubation test, this paper studied the effects of fine root decomposition of Alnus cremastogyne, Cunninghamia lanceolata and Michelia macclurei on the content of soil active organic carbon at 9 ℃, 14 ℃, 24 ℃ and 28 ℃. The results showed that the decomposition rate of fine root differed significantly with test tree species, which was decreased in the order of M. macclurei> A. cremastogyne > C. lanceolata. The decomposition rate was increased with increasing temperature, but declined with prolonged incubation time. Fine root source, incubation temperature, and incubation time all affected the contents of soil microbial biomass carbon and water-soluble organic carbon. The decomposition of fine root increased soil microbial biomass carbon and water-soluble organic carbon significantly, and the effect decreased in the order of M. macclurei> A. cremastogyne > C. lanceolata. Higher contents of soil microbial biomass carbon and water-soluble organic carbon were observed at medium temperature and middle incubation stage. Fine root decomposition had less effect on the content of soil readily oxidized organic carbon.

Physico-chemical characteristics of ambient particles settling upon leaf surface of six conifers in Beijing

WANG Lei¹; HASI Eerdun²; LIU Lian-you², GAO Shang-yu²

2007, 18(03):  487-492 . 

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The study on the density of ambient particles settling upon the leaf surface of six conifers in Beijing, the micro-configurations of the leaf surface, and the mineral and element compositions of the particles showed that at the same sites and for the same tree species, the density of the particles settling upon leaf surface increased with increasing ambient pollution, but for various tree species, it differed significantly, with the sequence of Sabina chinensis and Platycladus orientalis>Cedrus deodara and Pinus bungeana>P. tabulaeformis and Picea koraiensis. Due to the effects of road dust, low height leaf had a larger density of particles. The density of the particles was smaller in summer than in winter because of the rainfall and new leaf growth. The larger the roughness of leaf surface, the larger density of the particles was. In the particles, the overall content of SiO₂, CaCO₃, CaMg(CO₃)₂, NaCl, 2CaSO₄·H₂O, CaSO₄·2H₂O and Fe₂O₃ was about 10%—30%,and the main minerals were montmorillonite, illite, kaolinite and feldspar. The total content of 21 test elements in the particles reached 16%—37%, among which, Ca, Al, Fe, Mg, K, Na and S occupied 97% or more, while the others were very few and less affected by sampling sites and tree species.

Soil infiltration characteristics under main vegetation types in Anji County of Zhejiang Province

LIU Dao-ping¹; CHEN San-xiong²; ZHANG Jin-chi¹; XIE Li³; JIANG Jiang¹

2007, 18(03):  493-498 . 

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The study on the soil infiltration under different main vegetation types in Anji County of Zhejiang Province showed that the characteristics of soil infiltration differed significantly with land use type, and the test eight vegetation types could be classified into four groups, based on soil infiltration capability. The first group, deciduous broadleaved forest, had the strongest soil infiltration capability, and the second group with a stronger soil infiltration capability was composed of grass, pine forest, shrub community and tea bush. Bamboo and evergreen broadleaved forest were classified into the third group with a relatively strong soil infiltration capability, while bare land belonged to the fourth group because of the bad soil structure and poorest soil infiltration capability. The com-prehensive parameters of soil infiltration (α) and root (β) were obtained by principal component analysis, and the regression model of α and β could be described as α=0.1708e^β-0.3122. Soil infiltration capability was greatly affected by soil physical and chemical characteristics and root system. Fine roots (≤1 mm in diameter) played effective roles on the improvement of soil physical and chemical properties, and the increase of soil infiltration capability was closely related to the amount of the fine roots.

Simulation of crown leaf area index of Korean pine and broadleaved mixed forest in Changbai Mountains

GUAN De-xin;WU Jia-bing;WANG An-zhi;JIN Chang-jie;SHI Ting-ting;HAN Shi-jie

2007, 18(03):  499-530 . 

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Based on the 3-year successive automatic measurement of photosynthetic active radiation above and under the crown of Korean pine and broadleaved mixed forest in Changbai Mountains, as well as the seasonal observation on leaf area index, a semi-empirical model was established to esti-mate the crown leaf area index of the forest. The results showed that this model could well reflect the seasonal variation of crown leaf area. From the comparison of 3-year leaf area index series, it was found that the date when the leaf area index began to rise was postponed if the date when its air temperature stably surpassed 0 ℃ came late. The dynamics of the leaf area index in whole growth season could be divided into three stages, i . e . , rising, relatively stable, and dropping, and at each stage, there was a greater correlation between the leaf area index and the accumulated temperature above 0 ℃, which could be expressed by Logistic curve and linear equation. The problems existing in the observation and estimation of forest crown leaf area index were discussed.

Effects of moss crust on soil seed bank at southeast edge of Tengger Desert

SU Yan-gui^1,2; LI Xin-rong¹; JIA Rong-liang¹;PAN Yan-xia¹

2007, 18(03):  504-508 . 

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An investigation was made on the soil seed bank at southeast edge of Tengger Desert with moss crust under natural and artificial vegetations. The results showed that the density of soil seed bank increased with the development of moss crust, which was 3.4 times higher under natural vege-tation than under 24 years old artificial vegetation. In the seed bank, a total of 12 species belonging to 6 families were identified, among which, annuals occupied more than 70%. No perennial seeds were found under artificial vegetation, but under natural vegetation, 20% of the seeds were of pe-rennials. As for semi-shrub seeds, they occupied 20% and 10% under artificial and natural vegeta-tion, respectively. Under artificial vegetation, the species richness index of soil seed bank was rela-tively lower, being about a half of that under natural vegetation. The species diversity index of the seed bank had a slight decrease with the development of moss crust under artificial vegetation, but increased to the maximum (0.693) under natural vegetation. The species similarity index was 1 among the seed banks under artificial vegetations, and 0.4 between those under artificial and natu-ral vegetation. The development of moss crust increased the roughness of surface soil and improved soil environment significantly, which could have positive effects on seed entrapment and plant establishment.

Isolation and identification of an antioxidant from Monochoria vaginalis

ZHOU Yong-jun¹; XU Xiao-hua²; QIAO Feng-yun¹; ZHANG Jian-ping¹; YU Liu-qing¹

2007, 18(03):  509-513 . 

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With solvent extraction, a total of four fractions were separated from 75% alcohol extract of Monochoria vaginalis, and their antioxidative activities were measured by iodine method. The re-sults showed that among the fractions , n-butanol fraction exhibited the highest antioxidative activity, which was not only significantly higher than CK (water), but also equivalent to the natural antioxidant tea polyphenols and synthetic antioxidant butylated hydroxyl toluene(BHT). A compound was isolated from the n-butanol fraction by using column chromatography, and identified as stigmasterol 3-O-β-D-glucopyranoside. Its antioxidative activity estimated by the determination of the percentage of scavenged free radicals indicated that this compound exhibited a higher activity than BHT in scavenging free radicals.

Coupling effect of two drought-resistant agents on photosynthetic characteristics of Euonymus japonicus

WANG Yong^1,2; YANG Pei-ling¹; REN Shu-mei¹

2007, 18(03):  514-518 . 

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A field study on the coupling effect of new drought-resistant agents FA Handilong(FA HDL) and Beijing Green Angel (BGA) on the photosynthetic characteristics of Euonymus japonicus showed that these two agents could all decrease the stomatal conductance (g_s) and transpiration rate (T_r), and increase the net photosynthesis rate (P_n) and P_n/T_r of E. japonicus leaves. The inhibitory effect of FA HDL on g_s and T_r was more significant when BGA was not applied. FA HDL inhibited the P_n and P_n/T_r when applied with BGA, but stimulated them when BGA was not applied. Applying BGA could obviously shorten the action period of FA HDL on E. japonicus. The fact that BGA could influence the effect of FA HDL was attributed to the properties of BGA and the photosynthetic characteristics of E. japonicus. The appropriate concentration of FA HDL to the E. japonicus without BGA application was 2 g·L^-1, and FA HDL was not appropriate to the E. japonicus applied with BGA.

Effects of free-air CO₂ enrichment on nitrogen uptake and utilization of wheat

YANG Lian-xin¹; HUANG Jian-ye¹; LI Shi-feng¹;YANG Hong-jian¹;ZHU Jian-guo²; DONG Gui-chun¹; LIU Hong-jiang¹; WANG Yu-long¹

2007, 18(03):  519-525 . 

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In this paper, the effects of free-air CO₂ enrichment (FACE) and its interaction with nitrogen supply on the nitrogen content, uptake, allocation,and use efficiency of winter wheat variety Ningmai 9 at its different growth stages were studied in 2001—2003. The results showed that under FACE treatment, the nitrogen content in wheat plant sampled at different growth stages all de-creased significantly, with an average decrement of 4.4% to 13.4% compared with the control. The nitrogen accumulation under FACE increased significantly (9.2%—32.3%), and the increas-ing rate was larger at middle growth stage than at early and late growth stages. Nitrogen fraction was higher in stem, but lower in leaf. As for spike, the accumulation of nitrogen depended on the growth stage. FACE resulted in a significant increase (5.5%—10.3%) of nitrogen use efficiency for biomass production at all growth stages, of nitrogen harvest index (16.3%) at maturing stage, and of nitrogen use efficiency (9.3%) for grain yield. Nitrogen application increased the nitrogen content of wheat plant and its N uptake at all growth stages, decreased the nitrogen use efficiency, but had less effect on the nitrogen allocation in different organs.

Dynamic simulation on shoot dry matter partitioning and yield formation of rapeseed.

TANG Liang; ZHU Yan; JU Chang-hua; CAO Wei-xing

2007, 18(03):  526-530 . 

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Based on the quantitative relationships between rapeseed growth and environmental fac-tors, a simulation model was developed to estimate the shoot dry matter partitioning and yield forma-tion of rapeseed. The dry matter partitioning indices of green leaf, stem and pod varied with the physiological development, and were influenced by the genotype, sowing date, nitrogen level and water status. Green leaf dry matter was regulated by nitrogen nutrition index (NNI). The higher the NNI, the higher the partitioning index of green leaf was. The factor of sowing date was introduced to regulate the partitioning index of pod. A delayed sowing date often induced an increased partitioning index of pod. The validation with different data sets involving variety, sowing date, and nitrogen application rate showed that this model had a good predictability and practicability.

Effects of silicon on photosynthesis and antioxidative enzymes of maize under drought stress

LI Qing-fang¹; MA Cheng-cang^1，2; SHANG Qi-liang¹

2007, 18(03):  531-536 . 

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With pot experiment, this paper studied the effects of silicon supply on drought-resistance capability of maize plant. The results showed that under mild and severe drought stress, supplying silicon could increase the plant biomass by 31.1%—33.3% and 23.7%—40.5%, respectively, compared with the control. Silicon enhanced the net photosynthetic rate by 10.9%—28.8%, increased the chlorophyll content and POD, SOD and CAT activities by 4.0%—11.9%, 6.4%—26.4%, 17.8%—26.8% and 3.2%—33.5%, respectively, and restrained the increase of leaf plasma membrane permeability and MDA content. Correlation analysis indicated that there was a significant correlation between plant dry matter accumulation and diurnal photosynthetic cumulates (r=0.9357, P<0.05), demonstrating that the enhancement of photosynthesis under effect of silicon supply was the main factor inducing the increase of dry matter accumulation under drought stress. The higher antioxidative enzyme activities with silicon supply lightened the injury effect of free radicals, being another important factor inducing the increase of plant drought-resistance capability.

Effects of NaCl stress on the growth, antioxidant enzyme activities and reactive oxygen metabolism of grafted eggplant

LIU Zheng-lu; ZHU Yue-lin; HU Chun-mei; WEI Guo-ping; YANG Li-fei; ZHANG Gu-wen

2007, 18(03):  537-541 . 

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By the method of hydroponics and with the salt-tolerant eggplant cultivar ‘Torvum Vigor’(Solanum torvum) from Japan as rootstock and the cultivar ‘Suqiqie’ (Solanum melongena L.) as scion, this paper studied the differences between grafted and own-root seedlings in their photosynthetic characteristics, antioxidant enzyme activities, and reactive oxygen metabolism under 80 mmol·L^-1 NaCl stress. The results showed that under NaCl stress, the dry mass, chlorophyll content and photosynthetic rate of grafted seedlings were 67.8%, 8.8% and 31.1% higher than those of own-root seedlings, respectively, and the antioxidant enzyme activities were significantly higher while the O₂^-_· producing rate and the hydrogen peroxide (H₂O₂) and malondiadehyde (MDA) contents were significantly lower in grafted seedlings leaves than in own-root seedlings. For both grafted and own-root seedlings, NaCl stress reduced the chlorophyll content and photosynthetic rate, but increased the O₂^-_· producing rate and the H₂O₂ and MDA contents significantly. However, the growth of grafted seedlings was less affected by NaCl stress. The stronger salt tolerance of grafted eggplant seedlings was related to their higher antioxidant enzyme activities and less oxidative damage.

Effects of exogenous betaine on physiological responses of peach tree under water stress

WANG Yi-ming^1,4; WANG You-nian^1，2; SHI Guang-lu^2，3; DU Dong⁵; LIU Rui-dong⁶; YANG Ai-zhen³; GE Shui-lian¹; MENG Hai-ling¹

2007, 18(03):  542-548 . 

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With four-year-old potted Prunus persica L. cv. Qingfeng as test material, this paper studied the change pattern of its leaf betaine content under water stress, and its physiological responses under effects of foliage-spraying exogenous betaine. The results showed that under normal water supply, the betaine content in Qingfeng’s leaf was 75.9—80.5 μg·g^-1 FM, which was increased with increasing water stress, and up to 278.9 μg·g^-1 FM on the 16th day after cutting off the water supply. The leaf plasma membrane permeability was 8.06%—8.61% under normal water supply, but increased to 28.62% under water stress. When 100 and 500 mg·L^-1 of betaine were applied exogenously, the plasma membrane permeability was 26.25% and 21.79% after 16 days, respectively. The hydrogen peroxide (H₂O₂) content increased from 27.2—32.5 μmol·g^-1 FM to 76.4 μmol·g^-1 FM in the course of water stress, and decreased to 73.2 and 68.5 μmol·g^-1 FM after spraying 100 and 500 mg betaine·L^-1, respectively. During the period of intensified water stress, the peak value of ascorbate peroxidase (AsA-POD) activity was 0.435 mg·g^-1 FM, and up to 0.490 mg·g^-1 FM when treated with exogenous betaine. When the peach tree was subjected to water stress, the contents of free proline and soluble sugar accumulated dramatically, but produced on approximately decrease in 500 mg·L^-1 endogenous betaine application on the 16th day which was slightly less than that of control and 100 mg·L^-1 betaine application. There was a gradual decline in the content of soluble protein under water stress, and an increment of 20.3% was observed when betaine was applied exogenously. These results strongly suggested that foliage-spraying exogenous betaine could increase the drought resistance of peach tree through decreasing its leaf plasma membrane permeability and H₂O₂, free proline and soluble sugar contents and increasing its leaf AsA-POD activity and soluble protein content.

Changes in diversity of culturable microorganisms on leaf surface of transgenic Bt cotton

WANG Yuan-ge¹; TAN Mao-yu²; LI Jin-e¹; XIE Qing-en¹; FAN Zuo-xiao¹; SHEN Fa-fu¹

2007, 18(03):  549-553 . 

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In a field study, the quantitative changes of bacterial, actinomycetic and fungal populations on the leaf surface of transgenic Bt cotton (GK-12) and non-transgenic Bt cotton (Simian No.3) were monitored at seedling, squaring, flowering and boll-opening stages, respectively, and the diversity of bacterial physiological groups was analyzed at flowering and boll-opening stages. The results showed that there was a positive correlation between the quantity of culturable microorganisms and the development of cotton. The total number of bacteria, fungi and actinomyces began to rise at seedling stage, reached its peak at flowering stage, and decreased markedly at boll-opening stage. The Simpson index, Shannon-Wiener index, and evenness index of bacterial physiological groups were higher at flowering stage, but lower at boll-opening stage on GK-12 than on Simian No.3.

Isolation, identification and field control efficacy of an endophytic strain against tobacco bacterial wilt (Ralstonia solanacarum)

YI You-jin¹; LIU Ru-shi²; YIN Hua-qun³; LUO Kuan¹; LIU Er-ming¹; LIU Xue-duan³

2007, 18(03):  554-558 . 

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In this paper, an endophytic strain B-001 against tobacco bacterial wilt (Ralstonia solanacarum) was isolated from the stem of healthy tobacco in R. solanacarum-infected fields, which had a stronger inhibitory effect on some kinds of gram-positive bacteria, gram-negative bacteria, and pathogenic fungi. This strain belonged to Bacillus, and its 16S rDNA after PCR and sequencing had an accession of GenBank being DQ444283. The 16S rDNA phylogenetic tree was constructed with MEGA3, and compared with the published 16S rDNA sequences of relative bacteria species. B-001 had a 99.2% sequence similarity with Bacillus subtilis (DQ415893). According to the mor-phological, physiological and biochemical characteristics, and based on phylogenetic analysis, B-001 was identified as a strain of B. subtilis. Field experiments in Guiyang and Ningxiang counties of Hunan Province showed that in 2005 and 2006, the control efficacy of B-001 on R. solanacarum ranged from 40.03% to 78.14%, better than that of Streptomycini.

Effects of root exudates from cucumber and squash on Fusarium wilt occurrence

HUANG Ben-li; XU Yun-dong; WU Ye; ZHANG Shun-qi; CHEN Xue-hao

2007, 18(03):  559-563 . 

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With the root exudates of two cucumber varieties Jinyan 4 (susceptible variety) and Jin-chun 4 (resistant variety) and of black seed squash variety as test materials, this paper studied their effects and action mechanisms on the occurrence of Fusarium wilt on Jinyan 4. The results showed that the occurrence of Fusarium wilt was earlier when treated with the root exudates of Jinyan 4, and the infection rate was significantly higher at 15 days after inoculation, but nearly the same as the control at 20 days after inoculation. On the contrary, the infection rate was significantly lower than the control when treated with the root exudates of Jinchun 4. The plant height and fresh mass of Jinyan 4 treated with its own root exudates were lower than those of the control, and the root vigor decreased but conductance increased. No significant effect was observed in the plant height and fresh mass of Jinyan 4 treated with the root exudates of Jinchun 4 and black seed squash. It could be concluded that the root exudates of susceptible cucumber variety stimulated the growth of Fusarium oxysporum pathogen, while those of resistance cucumber variety and black seed squash were in adverse.

Molecular evaluation on the efficacy of sustainable control of Monochamus alternatus by non-woven fabric fungal bands impregnated with Beauveria bassiana

DING De-gui^1,2; FAN Mei-zhen¹; MENG Yan-qiong¹; LI Zeng-zhi¹; XIA Cheng-run¹

2007, 18(03):  564-568 . 

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By using molecular marker of group Ⅰ intron, a field evaluation was made on the efficacy of sustainable control of Monochamus alternatus by non-woven fabric bands impregnated with Beauveria bassiana. The results showed that the control efficacy in two treated plots was 19.5% and 10.8%, and 14.2% and 11% when evaluated with conventional and molecular evaluation methods, respectively, suggesting that the conventional method which evaluated the control efficacy in terms of microbes mortality or infection rate couldn’t distinguish the efficacies caused by released biocontrol agents and indigenous pathogens, while molecular method could avoid the interference of indigenous pathogens and give an objective and reasonable evaluation on the efficacy of microbial control.

Landscape change and its spatial driving force of farmlands in Wenchuan County of Minjiang River upper reach

LIU Miao^1,2; HU Yuan-man¹; CHANG Yu¹; BU Ren-cang^1,2; ZHANG Wei^1,2

2007, 18(03):  569-574 . 

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Based on remote sensing images and geographic information system, and by using land-scape metrics and Kappa coefficient, this paper studied the farmland landscape change in Wen-chuan County of Minjiang River upper reach. A logistic regression model was used to analyze the driving forces of this change, with elevation, gradient, aspect, and the distances to road, river and settlement as the affecting factors. The results showed that from 1974 to 2000, the farmland area in Wenchuan County kept increasing, with the greatest increment in 1974—1986.In 1986—2000, farmland area had no evident increase, but converted with other landscape types frequently and had an evident spatial position change, especially in the period from 1994 to 2000. Such a farmland change was mainly driven by policy, and the spatial driving forces differed in different periods.

Remote sensing estimation of vegetation coverage in Guangzhou based on the correction of atmospheric radiation

GONG Jian-zhou;XIA Bei-cheng

2007, 18(03):  575-580 . 

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Vegetation coverage is a basic parameter in describing landscape ecosystem, and an im-portant index in assessing ecosystem health and security. Based on the four TM images in 1990, 1995, 2000 and 2005, and by using the correction model to deduct atmospheric radiation effect and the spatial operating model for TM image under unsupervised classification, the relationship model between vegetation coverage and normalized vegetation index was established, and the vegetation coverage in different phases in Guangzhou was calculated. The results showed that the vegetation coverage in Guangzhou decreased continuously from 1990 to 2000 but began to increase thereafter, which accorded with the economic development and environmental construction of the city. The model established in this paper could simulate well the dynamics of regional vegetation cover, and have the advantage in describing the dynamics of vegetation coverage more accurately, being availa-ble to the assessment of urban eco-environmental quality and its dynamic characters.

Temporal and spatial variation of MODIS vegetation indices in Hunan Province

LIN Hui; XIONG Yu-jiu; WAN Ling-feng; MO Deng-kui; SUN Hua 

2007, 18(03):  581-585 . 

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Based on MODIS images and by using the algorithm of maximum value composite (MVC), the monthly vegetation indices (VIs) in 2005 in Hunan Province were obtained. Through the analysis of the MODIS VIs, Hunan Province was divided into six districts to describe the spatial distribution of the VIs, and by using the monthly mean temperature and rainfall data collected from 5 climatic monitoring stations in this province, the temporal variation of the VIs was analyzed. The results showed that the spatial distribution of MODIS VIs was positively correlated with vegetation cover, and appeared regional characteristics. The MODIS VIs varied with season, and the curves of their monthly mean values were downwards opening quadratic parabolas, with the maximum ap-peared in July. The value of MODIS EVI was smaller than that of MODIS NDVI. MODIS VI was mainly affected by monthly mean temperature, but this effect was decreased with decreasing latitude. The variation pattern of MODIS EVI was more apparent than that of MODIS NDVI, i . e . , the quadratic parabola of MODIS EVI was smoother, going gradually from minimum to maximum and then going down, while that of MODIS NDVI had tiny fluctuations on both sides of the maximum point.

Measurement and dynamic analysis of ecological capital of terrestrial ecosystem in China

ZHU Wen-quan; ZHANG Jin-shui; PAN Yao-zhong; YANG Xiao-qiong; JIA Bin

2007, 18(03):  586-594 . 

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Based on remote sensing and ecological principles, an estimation model of ecological capital was established in this paper. The estimation showed that the ecological capital of terrestrial ecosystem in China was 8.148, 10.86 and 12.44 trillion yuan (RMB) in 1992, 1995 and 2000, respectively. Forest had the highest value (24 673 yuan·hm^-2), and followed by wetland (21 353 yuan·hm^-2), both of which gave the most contribution to the ecological capital. According to its spatial distribution, the ecological capital of terrestrial ecosystem in China descended from east to west, and ascended from middle to northeast and south of this country, which was accordant with the vegetation distribution. Owing to the climate change and human activity, the ecological capital of Chinese terrestrial ecosystem ascended from 1992 to 2000, and the spatial distribution of its largest value moved obviously from north to south, with a total change rate of about 20%. How-ever, the ratio between ecological capital and GDP descended significantly in the 1990s.

Theoretical model for rocky desertification control in Karst area

LIANG Liang; LIU Zhi-xiao; ZHANG Dai-gui; DENG Kai-dong; ZHANG You-xiang

2007, 18(03):  595-600 . 

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Based on the basic principles of restoration ecology, the trigger-action model for rocky desertification control was proposed, i.e., the ability that an ecosystem enables itself to develop was called dominant force, and the interfering factor resulting in the deviation of the climax of eco-logical succession from its preconcerted status was called trigger factor. The ultimate status of eco-logical succession was determined by the interaction of dominant force and trigger factor. Rocky de-sertification was the result of serious malignant triggers,and its control was the process of bening triggers in using the ecological restoration method of artificial designs to activate the natural desig-ning ability of an ecosystem. The ecosystem of Karst rocky desertification in Fenghuang County with restoration measures was taken as a case to test the model, and the results showed that the rest-oration measures based on trigger-action model markedly improved the physical and chemical prop-erties of soil and increased the diversity of plant. There was a benign trigger between the restoration measures and the Karst area. The rationality of the trigger-action model was primarily tested by the results in practice.

Heavy metals removal and its kinetics in contaminated soil under effects of EDTA washing

KE Xin^1,2; LI Pei-jun¹; ZHANG yun³; SUN Tie-heng¹

2007, 18(03):  601-606 . 

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In this paper, batch experiments were made to examine the effects of different EDTA concentrations, pH, and washing duration of EDTA on the removal of heavy metals from contamina-ted soil. An empirical model was employed to describe the kinetics of heavy metals dissolution and desorption, and the form changes of test heavy metals were determined before and after EDTA wash-ing. The results showed that EDTA was effective to the removal of heavy metals from contaminated soil. At 0.1 mol·L^-1 and pH 7 of EDTA and within 24 h, the removal rate of test heavy metals was the maximum, being 89.14% for Cd, 34.78% for Pb, 14.96% for Cu, and 45.14% for Zn. The mass transfer coefficient was in the order of Cd>Zn>Pb>Cu. Sequential fractionations of treated and untreated soil samples showed that EDTA was effective in removing the exchangeable, carbonate and oxide forms of Cd, Pb, Zn and Cu, but ineffective for the organic and residual forms of test heavy metals.

Microbiological characteristics of phytoremediation plant root-soil interface for petroleum contaminated soil

LIN Xin¹; LI Pei-jun^1,2; SUN Tie-heng^1,2; LI Xiao-jun²; SUN Li-na¹

2007, 18(03):  607-612 . 

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With the petroleum-contaminated soil under Ricinus communis L. phytoremediation in Shenfu irrigation area of Shenyang as test material, this paper studied the quantitative variations of bacteria and fungi, physiological and biochemical characteristics of dominant microbial species, and nutritional types of bacteria in root zone, rhizosphere, root plane and root inside. The results showed that the quantity of bacteria decreased in the order of rhizosphere>root plane>root inside, while that of fungi was in the sequence of root inside >root plane> rhizosphere. The dominant spe-cies of bacteria and fungi were most abundant in root plane and root inside, respectively, and the dominant bacterial species in root plane and root inside had a stronger capability in degrading macro-molecular substances. The nutritional demand of bacteria in root plane was of amino acid type.

Effects of solution pH and simulated acid rain on the behavior of two sulfonylurea herbicides in soil

ZHANG Wei;WANG Jin-jun

2007, 18(03):  613-619 . 

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By the methods of batch equilibration and leaching, this paper studied the effects of solution pH and simulated acid rain on the behavior of bensulfur on-methyl and metsulfuron-methyl in soil. The results showed that the adsorption isotherms of these two herbicides fitted Freundlich equation well, and their adsorbed amounts reduced obviously with the increasing pH of water-soil system, which in turn promoted the translocation of the herbicides in soil. The adsorption coefficient (K_f) was positively correlated with soil organic matter and clay contents, while negatively correlated with soil pH. The higher pH of simulated acid rain had a greater contribution on the leaching of the two sulfonylurea herbicides, and their leached amount was increased with increasing acid rain. There was a close relationship between the leaching of the herbicides and the properties of soil. The soils with higher contents of organic matter and clay had a greater retention capability to the herbicides.

Effects of Hg on soil enzyme activity

YANG Chun-lu^1,2,3; SUN Tie-heng^1,2; HE Wen-xiang¹; CHEN Su^2,3

2007, 18(03):  620-624 . 

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With simulation test, this paper studied the effects of Hg on the activities of urease, in-vertase and neutral phosphotase in four soils. The results showed that Hg inhibited soil urease and invertase activities markedly, but its inhibitory effect differed with test soils. There was a significant logarithmic correlation between the concentration of HgCl₂ and the activities of these two enzymes (P<0.05). In test soils, the ED₅₀ of urease activity was 87.99, 5.47, 24.05 and 19.88 mg·kg^-1, and that of invertase activity was 76.68, 727.49, 236.52 and 316.59 mg·kg^-1, respectively. Urease was more sensitive than invertase to Hg contamination, while organic matter had a protective effect on soil enzymes. Soil neutral phosphatase was not sensitive to Hg contamination, except that it was significantly activated by Hg in the meadow brown soil applied with plenty of organic fertilizer.

Cu and Pb absorption and tolerance of Agrostis stolonifera and Festuca arundinacea

WANG Yan¹; XIN Shi-gang¹; MA Lian-ju¹; DAI Bao-qing²; YU Long¹; WANG Lan-lan¹

2007, 18(03):  625-630 . 

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This paper studied the seed germination rate, chlorophyll content, net photosynthetic rate, SOD activity, and Cu and Pb absorption of Agrostis stolonifera and Festuca arundinacea under Cu and Pb pollution. The results showed that Cu and Pb pollution had a significant effect on the seed germination rate of F. arundinacea. The chlorophyll content of F. arundinacea decreased dra-matically under Pb and Cu-Pb pollution, while decreased slightly under Cu pollution. No significant effect of Cu and Pb was observed on the chlorophyll content of A. stolonifera. The SOD activity of A. stolonifera increased under 350 mg Cu·kg^-1 and all test concentrations of Pb, while that of F. arundinacea only increased under 700 mg Pb·kg^-1 and 350 mg Cu·kg^-1+1 100 mg Pb·kg^-1. The net photosynthetic rate of F. arundinacea decreased more under Pb pollution than under Cu pollution, but that of A. stolonifera all decreased under Cu or Pb pollution. It was suggested that A. stolonifera was more tolerant in physiological characteristics to Cu and Pb pollution than F. arundinacea, while F. arundinacea was more tolerant to Cu than to Pb. The Cu absorption amount of F. arundinacea was relatively large, but did not increase with increasing Cu pollution. A. stolonifera had a high absorption ability of Pb, and the absorbed Pb amount was increased with increasing Pb pollution. A. stolonifera and F. arundinace could be the potential phytoremediation plants for Pb and Cu-polluted soil, respectively.

Limiting factors of waste land revegetation in indigenous zinc smelting areas of western Guizhou

LIN Wen-jie^1,2; XIAO Tang-fu³; AO Zi-qiang²; XING Jun²; MA Huan-cheng¹; HU Ting-xing¹

2007, 18(03):  631-635 . 

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With indigenous zinc smelting waste residue, contaminated soil and background soil as test substrates, a pot experiment was conducted to study the growth characteristics of Lolium perenne and Trifolium pretense on these substrates. The results showed that the major limiting factors of waste land revegetation in indigenous zinc smelting areas of western Guizhou were the salt-alkali stress and the lower contents of organic matter, total N, available N and total K. The heavy metals in waste residue had a high concentration, but their available forms only occupied a small proportion, with low toxicity to plant but having potential harmful risk. Contaminated soil had lower concentrations of heavy metals than waste residue, but its contained heavy metals were more in available form. The constraints of revegetation on contaminated soil were the toxicity of heavy metals and the low contents of available P and K. Mixing contaminated soil with zinc smelting waste residue could be one of the effective approaches for the substrate amendment in indigenous zinc smelting areas.

Effects of co-substrates on biodegradation of pyrene by ten bacterial strains

SU Dan^1,2; LI Pei-jun¹; WANG Xin³

2007, 18(03):  636-640 . 

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A total of 10 bacterial strains represented as from SB01 to SB10 were isolated from a petrolium-contaminated sludge, and their potential of degrading pyrene (PYR) was investigated on the substrates pyrene (MS₁), pyrene plus glucose (MS₂), and pyrene plus phenanthrene (MS₃). The results showed that on MS₁, the degradation rate of PYR by SB01 was the highest, with 30.4% of PYR degraded after 5 days. On MS₂, the degradation rate of PYR by SB09 was the highest, being 37.7% after 5 days, while on MS₃, 50.2% of PYR was removed by SB01. The degradation of PYR by SB01 and SB03 was inhibited by glucose, which was more obvious for SB01, but no significant difference was observed among SB02, SB07, SB08 and SB10. The biodegradation rate of PYR by all the ten bacterial strains was enhanced on MS₃, and that by SB10 was increased by 29.8%. For SB04 and SB09, the biodegradation rate of PYR had no significant difference between MS₁ and MS₂, but for other strains, the stimulation effect of phenanthrene on PYR degradation was higher than that of glucose.

Photosynthetic responses of wheat and pea seedlings to enhanced UV-C radiation and their resistances

LI Xue-mei^1,2; ZHANG Li-hong³; HE Xing-yuan²; HAO Lin¹

2007, 18(03):  641-645 . 

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With wheat and pea seedlings as test materials, this paper studied the effects of UV-C radiation on their leaf photosynthetic characteristics and antioxidant enzyme activities. The results showed that enhanced UV-C radiation could markedly decrease the photosynthetic rate (P_n), stom-atal conductance (G_s), intercellular CO₂ concentration (C_i), transpiration rate (T_r) and carboxylation efficiency (C_E) of pea leaves, but for wheat leaves, these parameters were increased first and decreased then. Under UV-C condition, the CO₂ compensation point of leaf was increased for pea, but decreased first and increased then for wheat. With the increasing duration of UV-C radiation, the antioxidant enzyme activities of both test plants increased first and decreased then, except that the POD activity of pea and SOD activity of wheat decreased gradually. All of these suggested that wheat had a stronger resistance to short-time UV-C radiation than pea, but, with the prolonged duration of UV-C radiation, the photosynthesis and antioxidant enzyme activities of wheat and pea were all decreased.

Decay of genetically engineered microorganisms (GEMs) in activated sludge and its related affecting factors

LIU Chun; HUANG Xia; WANG Hui

2007, 18(03):  646-652 . 

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With batch experiment and continuous-running bioreactor, this paper studied the decay of the population size of genetically engineered microorganisms (GEMs) in activated sludge. The decay models and their parameters were obtained, and several affecting factors were analyzed. The results showed that both in batch experiment and in continuous-running bioreactor, the population size of the GEMs decreased rapidly initially, and then tended to keep constant. The dynamics of decay could be fitted well by Logistic model and Gompertz model, and no difference was observed between the fit goodness of the models. Under different conditions, the value ranges of the parameters in batch experiment were decay coefficient r′=0.5—0.6 h^-1 and stable population size K′=10⁴—10⁵ cfu·ml^-1 for Logistic model, and initial decay coefficient b=0.6—1.2 h^-1 and specific decay coefficient a=0.02—0.09 h^-1 for Gompertz model. The initial population size had a little effect on the decay, but affected stable population size remarkably. Mixed liquor suspended solid (MLSS) and temperature both affected remarkably, i.e., the decay became faster but got larger when MLSS was smaller, whereas the decay became faster and got smaller when temperature was lower. Nutrient conditions and predation by protozoa and metozoa were also the important affecting factors of decay. In continuous-running membrane bioreactor and conventional activated sludge reactor, Logistic model could also fit the dynamics of decay well, and the values of parameters were in the ranges obtained from batch experiment.

Soil moisture and interspecific relationships between grass and legume on mixed grassland: a research review

WANG Ping¹; WANG Tian-hui¹; ZHOU Wen²; ZHOU Dao-wei^1,3

2007, 18(03):  653-658 . 

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From the viewpoints of plant morphology and physiology, this paper discussed the survival strategy of grass and legume on mixed grassland under water stress, their competition for water and the hydraulic facilitation effects of legumes on water resource utilization, and the impact of drought on biological nitrogen fixation and nitrogen transfer of legume. It was indicated that to promote the productivity of grassland in arid area, the mechanisms of competition and coexistence between grass and legume should be further studied, and one of the main aspects should be the effects of water stress on their aboveground and belowground competitions and their feedback on the competitions.

Effects of CO₂ enrichment on grain quality of rice and wheat: a research review

XIE Li-yong^1,2,3; LIN Er-da^1,2

2007, 18(03):  659-664 . 

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Crop grain quality is mainly depended on variety’s genetic characteristics and environ-mental conditions, while elevated CO₂ concentration in atmosphere, one of the main factors resul-ting in global climate change, would have a significant effect on crop grain quality. In this paper, the research progress on the effects of CO₂ enrichment on rice and wheat grain quality was summ-arized from the aspects of protein and nitrogen contents, trace elements, and other characters, emphasized the necessity and urgency of the study in this field, and pointed out the key directions and contents of further study, i . e . , (a)direct effects of CO₂ enrichment on rice and wheat grain quality and their differences for different varieties, (b) integrated effects of CO₂ enrichment and other climate factors on rice and wheat grain quality and their quantitative indices, (c) action mechanisms of CO₂ enrichment and other climate factors on rice and wheat grain quality forma-tion, (d) long-term directions and strategies of rice and wheat breeding in quality improvement to adapt climate change, (e) integrated planting technology systems in quality improvement for adapting climate change, and (f) application of molecule-marker and gene-transfer in rice and wheat breeding for quality improvement.

Research advances in water-fertilizer effect on dry land farmland

MA Qiang^1，2; YU Wan-tai¹; SHEN Shan-min¹; ZHANG Lu¹

2007, 18(03):  665-673 . 

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Water and fertilizer are the keys in improving dry land productivity,and the main factors limiting the agricultural development in dry land regions.For our food security and agricultural sus-tainable development, it’s of significance to bring the effect of water and fertilizer on increasing yield into full play. This paper introduced the design principles of several commonly used methods in researching the effect of water and fertilizer, e . g . , irrigation experiment, rainproof-shed exp-eriment and long-term experiment, compared their advantages and disadvantages, and discussed the mechanisms and models of water-fertilizer interaction on dry land farmland, based on the sum-up of the achievements of related qualitative and quantitative researches. It was indicated that under appropriate conditions, there was a positive interaction between water and fertilizer on grain yield, but the effect differed with research method and natural condition. The development trend of the researches on the water-fertilizer effect on dry land farmland in light of the characteristics of agro-ecosystem was also prospected.

Principles and methodology for ecological rehabilitation and security pattern design in key project construction

CHEN Li-ding¹; LU Yi-he¹; TIAN Hui-ying^1,2; SHI Qian¹

2007, 18(03):  674-680 . 

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Global ecological security becomes increasingly important with the intensive human activities. The function of ecological security is influenced by human activities, and in return, the efficiency of human activities will also be affected by the patterns of regional ecological security. Since the 1990s, China has initiated the construction of key projects “Yangtze Three Gorges Dam”, “Qinghai-Tibet Railway”, “West-to-East Gas Pipeline”, “West-to-East Electricity Transmission”and “South-to-North Water Transfer”, etc. The interaction between these projects and regional ecological security has particularly attracted the attention of Chinese government. It is not only important for the regional environmental protection, but also of significance for the smoothly implementation of various projects aimed to develop an ecological rehabilitation system and to design a regional ecological security pattern. This paper made a systematic analysis on the types and characteristics of key project construction and their effects on the environment, and on the basis of this, brought forward the basic principles and methodology for ecological rehabilitation and security pattern design in this construction. It was considered that the following issues should be addressed in the implementation of a key project: 1) analysis and evaluation of current regional ecological environment, 2) evaluation of anthropogenic disturbances and their ecological risk, 3) regional ecological rehabilitation and security pattern design, 4) scenario analysis of environmental benefits of regional ecological security pattern, 5) re-optimization of regional ecological system framework, and 6)establishment of regional ecosystem management plan.

Research progress on wetland ecosystem service and its valuation

FU Jiao-yan;DING Zhen-hua

2007, 18(03):  681-686 . 

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With the recognition on the significance of wetland, wetland ecosystem service was come under more and more attention, and its valuation could give the policymakers a scientific support in punishing wetland destroyers and compensating its losers. This paper introduced the definitions of wetland ecosystem service, its function and value, summarized their valuation approaches, including market value approach, production function method, opportunity cost approach, shadow project approach, productivity variety approach, human capital approach, travel cost approach, hedonic value approach, contingent value approach and ecological value approach, and discussed the factors affecting the valuation results of these approaches as well as the existing problems in related researches. The further research directions in these fields were also prospected.

Process, mechanism, and research method of fish invasion

PAN Yong^1,2,3; CAO Wen-xuan¹; XU Li-pu²; YIN Shou-ren²;BAI Lu⁴

2007, 18(03):  687-692 . 

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Fish invasion has become a serious environmental and economic damage, and obtained a priority concern by the conservation ichthyologists and land managers. A better understanding of the invasive mechanisms is of significance in developing ecological theories and in controlling exotic pests. In this paper, the progress in studying the mechanisms of fish invasion was reviewed, involving the biological characteristics of exotic fish, their adaptive evolution, interactions among exotic and indigenous fish, and relationships between species diversity and community resistance to invasion, etc. The study of invasive process and the progress of research methods were discussed.

Effects of intercropping peanut with medicinal plants on soil microbial community

XIE Hui¹; WANG Xing-xiang²; DAI Chuan-chao¹; CHEN Jia-xin¹; ZHANG Tao-lin²

2007, 18(03):  693-696 . 

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With pot experiment, this paper studied the quantitative variations of bacteria, actinomyces, mould and yeast in soils of peanut intercropped with medicinal plants, aimed to test if such an intercropping pattern could remove the obstacles of peanut’s continuous cropping. The results showed that Atractylodes lancea and Euphorbia pekinensis had the strongest inhibitory effect on mould. Compared with CK (mono-cropping peanut), the CFU of mould in the treatments inter-cropped with A. lancea and E. pekinensis was decreased by 53.87% and 29.59%, respectively during flowering-pegging stage of peanut, but increased after harvesting, which was in favor of substance circulation and nutrient returning. The CFU of bacteria in treatments intercropped with A. lancea, E. pekinensis and Pinellia ternate was all increased, and that of yeast in all five intercr-opping treatments was increased during the flowering-pegging stage of peanut. No familiar pathogens were found in the treatments intercropped with A. lancea, E. pekinensis and Diosoren zingiberebsis. Peanut intercropped with medicinal plants could regulate soil microbial community effectively.

Effects of starvation and re-feeding on carbohydrate metabolism of Marsupenaeus japonicus

LIU Lu; WU Li-xin; ZHANG Wei-guang; WU Yin; LIU Yu; DENG Hong-xiang

2007, 18(03):  697-700 . 

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This paper studied the variations of glucose concentration in haemolymph and glycogen concentration in hepatopancreas and muscle of Marsupenaeus japonicus under starvation and re-feed-ing. Groups C, S₁, S₂ and S₃ were deprived of food for 0, 10, 15 and 25 days, respectively, and then re-fed for 10days. Under starvation, the glucose concentration in haemolymph and glycogen concentration in hepatopancreas decreased rapidly at the beginning, and the glycogen concentration in muscle was the lowest after 10-day fasting. In the following 5 days, the glucose concentration in haemolymph and glycogen concentration in hepatopancreas and muscle recovered to their initial levels due to gluconeogenesis, but the glycogen concentration kept declining with fasting. After re-feeding, the glycogen concentration in hepatopancreas and muscle recovered well, and the glucose concentration in haemolymph had a sharper increase in groups S₁ and S₂ than in group C, but was markedly less in group S₃ than in group C. These results indicated that long-term starvation had a greater effect on the glucose concentration in haemolymph.

Relationships between host preference of Liriomyza huidobrensis (Blanchard) and nutrient and chlorophyll contents in host foliage

GAO Jun-ping; PANG Bao-ping; MENG Rui-xia; WANG Juan

2007, 18(03):  701-704 . 

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The laboratory study with no free choice means showed that the host preference of Liriomyza huidobrensis (Blanchard) adult differed significantly with test plants. Phaseolus vulgaris, Chrysanthemum coronarium and Cucurbita pepo were the most preferred, while Lycopersicum esculentum and Brassica oleracea were the least. Correlative analysis indicated that the host preference of L. huidobrensis adult had a significant positive correlation with the content of soluble sugar, but less correlation with soluble protein and chlorophyll contents in host foliage.