Table of Content

18 July 2006, Volume 17 Issue 07

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Articles

Responses of canopy stomatal conductance of Acacia mangium forest to environmental driving factors

ZHAO Ping; RAO Xingquan; MA Ling; CAI Xi’an; ZENG Xiaoping

2006, 17(07):  1149-1156 . 

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Employing Granier's probes, this paper measured the sap flow of 14 sample trees in an Acacia mangium forest on the Heshan hilly lands of Guangdong Province, and recorded the photosynthetic active radiation (PAR), air relative humidity (RH), and air temperature (T) above the forest canopy. The wholetree transpiration (E), stand transpiration (E_t), and mean canopy stomatal conductance (g_c) were calculated, and the relationships between tree morphological characters and whole-tree water use as well as the responses of g_c to PAR and vapor pressure deficit (D) were analyzed. The results showed that the whole-tree transpiration had logarithmical positive correlations with tree diameter at breast height (DBH) (P＜0.0001), sapwood area (P＜0.0001) and canopy size (P=0.0007), and an exponential positive correlation with tree height (P=0.014). The maximum g_c (g_cmax) changed with PAR hyperbolically (P＜0.0001), and with D logarithmically (P＜0.0001). The sap flow measurement system used in this study was reliable and accurate in estimating the transpiration of whole-tree and stand and the canopy stomatal conductance, being an effective tool in studying the relationships between forest water use and environmental factors.

Effects of different removal disturbance intensity on plant diversity of Bursaphelenchus xylophilus invaded Masson pine community

SHI Juan¹;LUO Youqing¹;SONG Jiying¹;YAN Xiaosu²;JIANG Ping²;WANG Yijiao³

2006, 17(07):  1157-1163 . 

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The study on the plant diversity of Bursaphelenchus xylophilus invaded Masson pine community under effects of different removal disturbance intensity showed that the species diversity indices (richness, ShannonWiener index and evenness) of arbor layer decreased in the sequence of broadleaved stand after the removal of all infected pine trees in the pure pine stand in Fuyang＞ lightly infected Masson pine-Schima superba mixed stand in Fuyang＞ uninfected stand mixture of Masson pine and Castanopsis fargessi as the control＞lightly infected pure Masson pine stand in Fuyang>Quercus variables stand formed after selective removal of infected pine trees from a mixed Masson pine and Q. variables stand in Zhoushan Islands＞ pure young Masson pine stand formed after the removal of all infected pine trees from a pure Masson pine stand> pure Liquidambar formosana stand after the removal of infected pine trees from a pure pine stand in Zhoushan Islands > mixed stand consisted of Pinus thunbergii and the Masson pine in Zhoushan Islands>moderately infected Masson pine stand in Zhoushan Islands. All the three indices of shrub layer did not show any significant differences among different communities, except for the pure pine stand in Zhoushan Island, which were the lowest. The three indices of herb layer were higher in pure young Masson pine, Q. variables stand, and L. formosana stand than in other stands. The Masson pine forest at different geographical situation and with different harm extent had distinct disparity, as well as that in different disturbance degree and restoring manner. The “Index of Disturbing Intensity of Stump and Fallen Woods” or IDISF was created to represent the disturbance degree of tree removal on plant diversity. It was found that for both less and more removal disturbing degree, the relationship between species diversity indices and IDISF followed the “Mid-altitude bulge” theory. Specifically, both excessive and insufficient removal of infected trees would cause the decline of plant species diversity in certain degree. Covariance analysis of IDISF indicated that different IDISF had no significant effects on the species diversity of arbor layer, but had different effects on that of shrub and herb layers, which could be used to assess the changes in species diversity of different Masson pine communities after the invasion of pine wood nematode.

Modules biomass structure and growth pattern of Acanthopanax senticosus population in different habitats

HAN Zhongming^1,2;HAN Mei^1,2;WU Jinsong^1,2; YANG Limin^1,2

2006, 17(07):  1164-1168 . 

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In this paper, a quantitative analysis was conducted on the functional modules’ biomass structure and the relationships between biomass allocation and age of Acanthopanax senticosus population in three different habitats of coniferous and broad-leaved mixed forest, Quercus mongolica forest, and secondary miscellaneous forest. The results showed that the individual growth and modules’ biomass accumulation of A. senticosus population were closely related to habitat conditions. The mean values of all functional modules’ biomass under different ecological environments exhibited the same regularity, i.e., stem modules>rhizome modules >leaf modules, and there were some similarities in the whole population of A. senticosus. The individual and each module’s biomass of the population differed with the canopy density of forests, being larger in Q. mongolica forest with 40% of canopy density than in coniferous and broad-leaved mixed forest and secondary miscellaneous forest. The variations of ramet biomass allocation under different habit conditions indicated the important strategies in growth regulation and biomass allocation, i.e., more biomass was allocated to the leaves preferentially on small ramets, especially in the secondary miscellaneous forest with biggest canopy density, to ensure the full material product. There was the same regulation of heterogeneous speed growth in the relative weight increase of the leaves, stems and ramets of the population under the three habitat conditions.

Ecological characteristics of Artemisia halodendron community and population on Horqin sandy land

YIN Hang¹;PIAO Shunji^1.2;WANG Zhenjie¹;YAN Xiuling¹;ZHANG Bincai¹;ZHAI Jiwu¹;DING Yong¹

2006, 17(07):  1169-1173 . 

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Based on the analysis of species important values and Shannon-Wiener index of Artemisia halodendron community on different type sandy lands in Horqin, A. halodendron community was classified into three types, i.e., A. halodendron-annual herbage, A. halodendron-perennial grass, and A. frigida-A.scoparia+ perennial grass, which distributed on shifting sandy land, semi-fixed sandy land, and fixed sandy land, respectively. With the sand fixed, the community succession was ranked from A. halodendron-annual herbage (pioneer stage, coverage ＜10%, Shannon-Wiener index 0.33) to A.halodendron-perennial grass (coverage 30%～35%, Shannon-Wiener index 0.56), and then to A. frigida-A. scoparia+ perennial grass (steppe community, coverage 40%～45%, Shannon-Wiener index 0.59). The A. halodendron population on shifting sandy land and that planted 5 years ago showed growing age distribution, that planted 18 years ago showed stable age distribution, and that on semi-fixed and fixed sandy lands showed declining age distribution. The results proved that A. halodendron populations had different ecological effects on A. halodendron community.

Quantitative classification and ordination of subalpine meadow in Wolong Nature Reserve

SONG Aiyun¹; LIU Shirong¹; SHI Zuomin¹; DONG Linshui²

2006, 17(07):  1174-1178 . 

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Based on the field investigation of 114 sampling plots at Balong Mountain in Wolong Nature Reserve, this paper studied the plant species composition and community structure of subalpine meadow communities. Two-way indicator species analysis and detrended correspondence analysis were employed to classify and ordinate the subalpine meadow communities in these sampling plots, aimed to understand the key factors determining the structure and distribution pattern of subalpine meadow communities. Through TWINSPAN analysis, the subalpine meadow was classified into 12 types. DCA ordination gave the ecological significance of ordination axes. Axis 1 indicated the altitude the meadow distributed, while axis 2 indicated the soil humidity of the distribution site. The ordination of dominant species was similar to the classification of community types, reflecting the change trend of community type and species distribution with changing environmental factors.

Effects of climate change on winter wheat growth and yield in North China

ZHANG Jianping¹; ZHAO Yanxia²; WANG Chunyi²; HE Yong³

2006, 17(07):  1179-1184 . 

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With the combination of crop model and climate mode, this paper simulated and predicted the effects of climate change on the winter wheat production of North China in future 100 years. The results showed that from 2000 to 2004, the variation trend of simulated winter wheat production in North China was accordant with the measured one, and the difference of winter wheat’s lifecycle and yield was not obvious. In the future 100 years, the lifecycle of winter wheat would be shortened by 8.4 days, and its yield would be decreased to different extent, with 10.1% as the average. If proper measures such as adjusting crop parameters and management measures were adopted, the decline of winter wheat yield could be mitigated effectively.

Biological fertility and its dynamics of degraded soil in Tibet Plateau

QIAN Cheng; PENG Yuelin; JIA Junyan; WEI Na

2006, 17(07):  1185-1190 . 

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In a three-year field trial, this paper studied the dynamics of biological fertility of degraded cultivated mountain shrubby steppe soil in the lower reaches of Lisa River as affected by fertilization. The results showed that under nonfertilized condition, the organic matter (OM) content in soil surface layer declined slightly, but after fertilization, the OM in this layer accumulated with a relatively high rate, humus structure improved obviously, soil bacteria had a significant multiplication, while soil microbial community was still in unharmonious state. With the increasing application rate of organic manure or chemical fertilizers, the OM content in 0～30 cm and 30～60 cm soil layers showed a significant increasing trend, with an annual increment being 1.35 and 0.67 g·kg^-1, respectively, and the ratio of humus carbon (C) to organic C and of humic acid C to humus C was also increased. Fertilization had a significant promotion effect on the multiplication and activity of soil bacteria. There was a significant positive correlation between the numbers of bacteria and OM content in 2～30 cm (r=0.7194**) and 30～60 (r=0.6042*) cm soil layers, while soil fungi and actinomycetes were not affected by fertilization. The numbers of azotobacter and cellulosedecomposing bacteria in different soil layers were lower in most fertilization treatments than in the control, and azotobacter in soil surface layer had a negative correlation with cellulosedecomposing bacteria (r = - 0.4799).

Allelopathic potentials of different wheat varieties in Northeast China against ryegrass

ZHANG Xiaoke^{1, 2}; LIANG Wenju¹; JIANG Yong¹

2006, 17(07):  1191-1195 . 

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By using equal compartment agar method (ECAM), and through measuring the root length, shoot height, and rootand shoot dry weights of test ryegrass, this paper evaluated the allelopathic potentials of thirty-three wheat varieties with different origins in Northeast China against ryegrass. The results showed that different wheat varieties had significantly different allelopathic effects on ryegrass growth. With RI value as allelopathic index and through cluster analysis, these varieties could be divided into three groups, among which, four varieties (Longfu 9, Longfu 13, Jin 2003, and Xiaobing 33) were demonstrated to be obviously allelopathic, and inhibited the ryegrass growth strongly.

Effects of nitrogen, phosphorus and potassium fertilization on sucrose accumulation in flag leaf and starch accumulation in kernel of weak gluten whea

LI Youjun^1,2; XIONG Ying^1,3; CHEN Mingcan¹; LUO Bingshan²

2006, 17(07):  1196-1200 . 

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With weak gluten wheat Yumai 50 as test material, this paper studied the sucrose accumulation in flag leaf and starch accumulation in kernel under effects of nitrogen, phosphorus and potassium fertilization. The results showed that nitrogen and potassium fertilization increased the sugar content in flag leaf at early and late filling stage, respectively, while phosphorous fertilization had little effect. Nitrogen, phosphorous, and potassium fertilization increased the sucrosesynthase activity in flag leaf, but the effect differed with time, i.e., at mid filling stage for nitrogen fertilization, early filling stage for phosphorous fertilization, and early and mid stage for potassium fertilization. As for the sucrose phosphate-synthase activity in flag leaf, it was increased by nitrogen fertilization in 24 days after anthesis, by potassium fertilization at early and mid filling stage, and by phosphorus fertilization at late filling stage. Nitrogen, phosphorus and potassium fertilization increased the sugar and starch contents in kernel, and the effect of potassium fertilization was most significant. Phosphorus fertilization increased the accumulation of amylose, while potassium fertilization improved that of amylopectin in kernel.

Effects of water stress during grainfilling period on rice grain yield and its quality under different nitrogen levels

CAI Yixia^1,2; WANG Wei²; ZHU Zhiwei³; ZHANG Zujian¹; LANG Youzhong¹; ZHU Qingsen¹

2006, 17(07):  1201-1206 . 

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To examine the effects of nitrogen (N) supply and water stress on rice grain yield and its quality, a pot experiment was conducted at Yangzhou University. Three rice cultivars were grown under two N levels (high N and normal N) from initial heading, and two water conditions (well watering and water stress) were installed for each of the two N levels from flowering to maturity. The results showed that when the plants of test cultivars were grown under normal N level, water stress markedly reduced the grain-filling percentage and grain weight, resulting in a significant decrease of grain yield by 11.6%～14.7%. Though the head-milled rice had a slight increase, the percentage of chalkiness was significantly increased by 18.7%～33.1%, which resulted in an inferior performance in grain-apparent quality. In contrast, when the plants were grown under high N level, water stress increased the grain yield by 18.8%～22.2% because of the increase of grain-filling percentage and grain weight. As compared with well watering, water stress decreased the percentages of chalky grain and chalkiness by 15.3%～37.2% and 13.7%～29.9%, respectively, which improved the performance of grain-apparent quality. The pronounced effects of N application and water treatment were observed on the RVA profile and cooked quality. Under both two N levels, water stress decreased the peak viscosity and breakdown (except for Yangdao 6) while increased the setback. According to the performance in the indices of cooked quality, the palatability became poor when subjected to water stress under normal N level, as the result of the increase of hardness and cohesiveness. In contrast, under high N level, water stress availed the ascending of viscosity at the early stage when rice flours were pasting, peak viscosity and breakdown were increased, and setback was decreased, suggesting that the palpability got well. It was concluded that mild water stress during grain-filling period was benefit for the development of high quality grain when rice plants were grown under high N level.

Distribution characters and affecting factors of Al_i/(Ca+Mg) molar ratio in acid forest soils

GUO Jingheng¹; ZHANG Xiaoshan¹; JIANG Chunlai¹; ZHAO Dawei²; TU Zhijiang³; XIANG Renjun⁴; LUO Jiahai⁵

2006, 17(07):  1207-1212 . 

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By using principle component analysis (PCA) and partial least square (PLS) regression, this paper studied the distribution characters and their affecting factors of Al_i/(Ca+Mg) molar ratio in acid forest soils in southern and southwestern China. The monitoring data from 2000 to 2002 showed that in most cases, the Al_i/(Ca+Mg) molar ratio in soil moisture was lower than assumed critical value 1.0, indicating that significant aluminum toxicity to vegetation was not occurred in the study regions. PLS regression suggested that soil aluminum saturation (AlS) was the dominant factor affecting the Al_i/(Ca+Mg) molar ratio in soil A horizon. Higher AlS led to a higher Al_i/(Ca+Mg) molar ratio in soil moisture. Despite of its lower acid deposition, Liuxihe basin had a higher Al_i/(Ca+Mg) molar ratio in soil A horizon than other catchments, mainly due to its higher AIS. In deeper soil horizons (B₁, B₂ and BC), the inorganic aluminum (Al_i) in soil moisture was the main factor affecting Al_i/(Ca+Mg) molar ratio. Higher inorganic aluminum concentration resulted in higher Al_i/(Ca+Mg) molar ratio. In each of study catchments, the vertical distribution of Al_i/(Ca+Mg) molar ratio was basically identical with the distribution of inorganic aluminum (Al_i) through soil profile. It was concluded that soil aluminum saturation was the main factor controlling the regional variation of Al_i/(Ca+Mg) molar ratio in soil moisture, and the vertical distribution of soil Al_i/(Ca+Mg) molar ratio in each site was mainly due to the vertical change of inorganic aluminum in soil moisture.

Effects of cadmium on mitochondrion structure and energy metabolism of Pelteobagrus fulvidraco gill

BAI Shijun, XU Zirong

2006, 17(07):  1213-1217 . 

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To explore the effects and possible mechanisms of environmental cadmium (Cd) on the mitochondrion structure and cellular energy metabolism of Pelteobagrus fulvidraco gill, specimens of P. fulvidraco were exposed to different Cd concentrations (0, 50, 500 μg·L^-1 freshwater) for 7 days. The results showed that when exposed to 50 μg Cd·L^-1, the mitochondrion structure of P. fulvidraco was intact, and no significant differences were observed in all test biochemical indicators, compared with the control (P＞0.05). But, when exposed to 500 μg Cd ·L^-1, mitochondria were damaged severely, and except that the LD, MDA, ADP and AMP contents in mitochondria as well as the K⁺ concentration in plasma were significantly higher than the control, all other test biochemical indicators were decreased significantly (P＜0.05). It was suggested that short-term exposure to higher concentrations of Cd would lead to the obstruction of energy supply and utilization due to the inhibition of PFK and ATPase activity and the oxidative damage of mitochondria resulted from the decrease of SOD activity, and decrease the ability of gills in regulating plasma ion composition and osmolality, which could be one of the possible mechanisms for Cd toxicity.

Changes of algal communities in water body with different proportions of nitrogen and phosphorus

SUN Ling¹; JIN Xiangcan²; ZHONG Yuan¹; ZHANG Dongmei¹; ZHU Lin¹; DAI Shugui¹; ZHUANG Yuanyi¹

2006, 17(07):  1218-1223 . 

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A simulation test was conducted in aquaria to study the responses of algal communities to different N/P ratios in urban water body. The water sample was taken from a small artificial lake in Tianjin, and its initial N/P ratio was adjusted to 0.5∶1,7.2∶1, 25∶1 and 50∶1, respectively. The results showed that in high N/P ratio groups, the numbers of Chlorophyta species decreased, while those of Cyanophyta species didn’t change very much. The numbers of these two species were both decreased in low N/P ratio group. Algal biomass, cell density and chlorophyll a content in medium and high N groups were higher than those in control and high P groups. The mean value of chlorophyll a reached the highest (69.7 μg·L^-1) in high N group, and was 54.3, 30.3 and 29.7 μg·L^-1 in medium N, control, and high P groups, respectively. At the midlate stages of culture, green algae Dictyosphaerium pulchellum was dominant in high P group, while blue algae Phormidium tenue, P. corium, Lyngbya limnetica and Microcystis aeruginosa were dominated in high N/P ratio groups. Control group had the highest species richness, while medium and high N groups had the highest and lowest ecological species dominance, respectively.

Storage and diurnal change of organic carbon pools in rotifer-culturing pond ecosystem

LI Xiaodong^1,2; ZHAO Wen¹; ZHAO Zhenxing¹; DONG Shuanglin²

2006, 17(07):  1224-1228 . 

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This paper studied the storage and diurnal change of various organic carbon pools in two rotifer (Brachinus plicatilis) culturing ponds with different models in Panjin Photosynthesis Fisheries Limited Company, Dawa County, Liaoning Province from May to June 2001. The results indicated that the mean storage of particulate organic carbon (POC) and dissolved organic carbon (DOC) in static water pond was 5.69±2.90 mg·L^-1 and 24.56 ± 2.12 mg·L^-1, and that in current water pond was 9.61±3.17 mg·L^-1 and 24.13 ± 2.91 mg·L^-1, respectively. The ratio of total organic carbon (TOC), DOC and POC in current and static water ponds was 1∶0.75∶0.25 and 1∶0.82∶0.18, respectively. The pond with a high POC concentration was also with a high DOC content. The diurnal change of POC and DOC in current water pond was bigger than that in static water pond, i.e., the POC concentration in current water pond increased in daytime (from 5:00 to 17:00), while that in static water pond was more stable. The POC concentration in the two ponds was decreased from 15:00 to 23:00 but increased from 23:00 to next 5:00, and its peak time was 17:00 for current water pond and 5:00 for static water pond. The DOC/POC ratio in current water pond was increased gradually in daytime (from 5:00 to 17:00), while that in static water pond was decreased. The DOC/POC ratio in the two ponds was increased at night, and tended to dicline from 23:00 to next 5:00.

Effects of interspecies difference of arbuscular mycorrhizal fungi on Citrus grandis cv

TONG Ruijian¹; YANG Xiaohong^1,2; LI Dongyan¹

2006, 17(07):  1229-1233 . 

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In a pot experiment, axenic pomelo (Citrus grandis cv. Changshou Shatian You) seedlings were inoculated with arbuscular mycorrhizal (AM) fungi Gigaspora margarita, Glomus mosseae and Glomus versiforme, respectively, and their vegetative growth and mineral contents were studied. The results showed that the seedlings inoculated with test AM fungi could be infected effectively, and their shoot and root growth, especially fibrous root growth, was significantly improved, compared with the control. After inoculated with G. mosseae, the root length, lateral root number, and fibrous root number and length of the seedlings were increased by 22.7%, 35.7%, 160.8% and 1032%, respectively. The inoculation of these three AM fungi could significantly elevate the N, P, K, Ca, Mg, Zn, Cu and Mn contents in seedlings leaves. For example, the P content was increased by 46.8%, 88.7% and 32.3%, respectively, compared with the control. Among the three treatments, the seedlings inoculated with G. mosseae had the best vegetative growth, and the highest mycorrhizal dependence and N, P, K, Ca, Zn and Cu contents. The relative occurrence of AM fungal species decreased in the order of G. mosseae>G. margarita >G. versiforme, indicating that G. mosseae was most suitable for C. grandis seedlings inoculation.

Population structure and niche of main scale insects in jujube orchards intercropped with wheat

SHI Guanglu^1,2; WANG Younian¹; LIU Suqi¹; MIAO Zhenwang³; CAO Hui²; LI Dengke⁴; ZHANG Teiqiang¹; YU Tongquan¹

2006, 17(07):  1234-1238 . 

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To effectively control the scale insects in jujube orchards, a field study was made on the population structure and niche of Pseudococcus comstock Kuwane, Ceroplastes japonicus Green and Quadraspidiotus perniciosus Comstock in the jujube orchards intercropped with wheat in Taigu area of Shanxi Province. The results showed that at the early development stage of jujube trees, these three kinds of scale insects mainly distributed on the southeast direction of the lower and central parts of the tree crown, and P. comstock was the dominant species, with a wider breadth of two-dimensional temporal-spatial niche than the other two scale insects. At the mid-stage of jujube trees development, these scale insects mainly distributed on the northwest direction of the upper part of the tree crown, C. japonicus had a wider breadth of two-dimensional temporal-spatial niche than the other two scale insects, and the niche proportional similarity and interspecific competition of the three kinds of scale insects were not obvious. At the later stage of jujube trees development, there was no significant difference (P＞0.05) in the population structure of the three kinds of scale insects on the different parts and directions of tree crown, but the density of Q. perniciosus was bigger, and C. japonicus had a wider breadth of two-dimensional temporalspatial niche. The average values of niche proportional similarity and interspecific competition of the three kinds of scale insects were smaller (P＜0.05) at the later development stage of jujube trees. Therefore, P.comstock should be controlled at the early development stage of jujube trees, all the three kinds of scale insects should be controlled selectively at the mid-stage of jujube trees development, and their overwinterings should be decreased by all means at the later development stage of jujube trees.

Spatial patterns of Bemisia tabaci (Gennadius) population in cotton fields

ZHOU Fucai1,2, REN Shunxiang²; DU Yuzhou¹; QIN Jieyang¹; ZHOU Guisheng¹; LIU Zongquan³

2006, 17(07):  1239-1244 . 

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Field investigations on the vertical and horizontal distribution patterns of Bemisia tabaci (Gennadius) population on Bt cotton Guokang No. 22 and non-Bt cotton Simian No. 3 showed that in July, no obvious difference was found in the vertical distribution of B. tabaci population on cotton plant, but in August, the population density was significantly higher on the upper part of cotton plant than on its middle and lower parts. The horizontal distribution patterns of B. tabaci adult and nymph were similar. B. tabaci distributed evenly on cotton leaves when its population density was low, but aggregated when its population density was high. The greater the population density, the higher the aggregation rate was observed. Throughout the incidence stage, B. tabaci adult and nymph aggregated and diffused alternatively. No significant difference was observed in the spatial distribution pattern of B. tabaci on Bt and non-Bt cotton plants.

UV-induced DNA mutation of peach aphid

DU Erxia; GUO Jianwen; ZHAO Huiyan

2006, 17(07):  1245-1249 . 

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By using PCR technique and microsatellite marks, this paper studied the DNA polymorphism of peach aphid (Myzus persicae) under UV-radiation. The fragments of three primers were amplified, and the gene diversity and the rate of loci polymorphisms of their genomic DNA, which could reflect the damage degree of DNA after UV-radiation, were measured. The results revealed that after treated with different radiation intensity (15, 30, 45 W) and duration (2, 4, 6 h), the UV-induced DNA mutations were genetic and could be delivered to F₂ generation. The mutations depended on the interaction of radiation intensity and duration. Variance analysis on the gene diversity and the rate of loci polymorphisms showed that there existed a significant difference between UV-treated and control groups, except the rate of loci polymorphisms under 2 h radiation. The average value of the control was higher than that of 2 h radiation treatment. According to the cluster analysis of the genetic distance, the aphids were divided into three groups,板i.e., control group, 2 h (15, 30 W) treatment group, and the other, which was consistent with the result of variance analysis.

Effects of high temperature on laboratory Trichogramma ostriniae population

CHEN Kewei; ZHOU Jing; GONG Jing; HE Yurong; HUANG Shoushan

2006, 17(07):  1250-1253 . 

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In this paper, the life tables of laboratory Trichogramma ostriniae population reared on Corcyra cephalonica eggs at 26 ℃, 29 ℃, 32 ℃ and 35 ℃ were constructed, and the effects of high temperature on the development and reproduction of this population were analyzed. The results showed that high temperature (32 ℃～35 ℃) greatly affected the development of T. ostriniae. The egg-larva survival rate was 94.2% at 26 ℃ and 88.6% at 29 ℃, and decreased to 80.1% at 32 ℃ and 53.2% at 35 ℃. The pupa survival rate also descended with the raise of temperature. The egg load and the body-and egg sizes of newly emerged female wasps were negatively responded to temperature. 12 h-old adult female had an egg load of 37.9, which was decreased with the raise of temperature, and about 29.6, 21.6 and 13.7 mature eggs were found at 29 ℃, 32 ℃ and 35 ℃, respectively. All females could complete their normal copulation and oviposition at 26 ℃ and 29 ℃, but about 6.7% and 60% females could not reproduce at 32 ℃ and 35 ℃, respectively.

Egg cluster pattern of two coexisting melitaeine butterfly species and oviposition site selection of their adult females

LIU Wenhua^1,2; WANG Yifei^1,3; XU Rumei¹

2006, 17(07):  1254-1258 . 

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In this study, the oviposition sites of Euphydryas aurinia and Meiltaea phoebe adult females in the same habitat network were investigated, aimed to identify the factors affecting the patch quality. The results showed that the egglaying females of both melitaeine butterfly species preferred to oviposit in the open areas with large-sized host plants and surrounded by short vegetations, especially on warm and sunny slopes. For E. aurinia, most of its egg clusters were concentrated within the area less than 3 m to the edge of cropland, and the average distance from each egg cluster to the edge of nearest cropland was 3.55 ± 0.33 m (n=246); but for M. phoebe, a few of its egg clusters distributed in the area less than 3 m to the edge, and the average distance was 7.43 ± 1.53 m (n=25). It was suggested that the criteria to evaluate the patch quality and the conservation strategies for the two butterfly species should be different, due to their special habitat requirements of ovipositing females.

Predation of Orius minutus on Odontothrips loti

ZHANG Shize; WU Lin; XU Xiangli; HUA Baozhen

2006, 17(07):  1259-1263 . 

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In this paper, a laboratory study was made on the predation of Orius minutus on the 3rd~4th instar nymphs of Odontothrips loti, and the intraspecific interference within O. minutus. The results showed that the functional responses of adult O. minutus to O. loti nymphs fitted Holling II type equation, i.e., N_a＝1.0113N／(1＋0.04149N) in test tubes, N_a＝0.6777 N／(1＋0.03395N) in Petri dishes, and N_a＝0.6417 N／(1＋0.03934 N) in enveloped pots. The predation of O. minutus had strong intraspecific interference, and the relationship between predation efficiency and individual interference fitted Hassell model. Under the same spatial conditions, the predation rate of O. minutus was positively related, while its searching efficiency was negatively associated with the prey density. With the increase of the space, the attack rate (a′) and maximum predation (N_a) of O. minutus decreased, its handling time (T_h) increased, while the type of its functional responses to the densities of 3 rd~4 th instar O. loti, still fitted Holling II model.

Compatibility of two fungal biocontrol agents conidia with commercial chemical acaricides

JIANG Yu; FENG Mingguang

2006, 17(07):  1264-1268 . 

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In this paper, the biological compatibility of fungal biocontrol agents Beauveria bassiana and Paecilomyces fumosoroseus conidia with 10 commercial chemical acaricides were assayed, based on the conidial germination rates in nutritional liquid and on SDAY plate. The results showed that nutritional liquid was more available than SDAY plate in the assay. So far as the 24 h conidial viability concerned, there were significant differences among the test acaricides with the concentrations of recommended for field spray and 5 and 10 fold dilutions, as well as between the two fungal agents. Since acaricides azocyclotin, liuyangmycin, dicofol and avermectin had strong inhibitory effects on the 24 h germination rate of both fungal agents conidia, their combined application with fungal agents was unsuitable for mite control. However, the combined application of pyridaben, propargite, chlorpyrifos, hexythiazox or amitraz with either B. bassiana or P. fumosoroseus was practical, because of their shortterm compatibility. When the mixtures of oil-based B. bassiana formulation with the three concentrations of pyridaben, propargite and chlorpyrifos were stored at 4 ℃ or at ambient temperature for 12 months, none of the three chemicals was considered to be good enough for a combined formulation due to the great variability in long-term compatibility. Nevertheless, chlorpyrifos exhibited an encouraging long-term compatibility with B. bassiana, because its low concentration in the fungal formulation did not affect the conidial viability during a 6.5-month period of storage at ambient temperature. When stored at 4 ℃ in dark, the B. bassiana formulation containing low or medium concentration of chlorpyrifos retained the conidial viability of ＞90% for up to 12 months.

Ecological functional regionalization of Changsha City based on RS and GIS

CAO Xiaojuan; ZENG Guangming; ZHANG Shuofu; ZHOU Jianfei; ZHU Hua; SHI Lin

2006, 17(07):  1269-1273 . 

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A delineation method based on the idea of regarding urban-suburbansupporting area as a system was presented in this paper, with an ecological-social-economic database created. A total of five ecological suitability regions, four ecological sensitivity regions, four ecological service regions, and five economic development regions were plotted out, and the Changsha City ecosystem was divided into five ecological functional regions, according to the heterogeneity among ecological functional units and the similarity of interior units. The areas of the five functional regions accounted for 29.47%, 32.5%, 25.95%, 9.63% and 2.45% of the total area, respectively. This research method had some advantages over traditional methods. It was flexible and efficient, because it could accept any combination of parameters organized on a polygonal base map. The variables could be added, deleted, or updated to produce new thematic map products in a short period of time. Mapping procedures were quantitative and automated. With the incorporation of remote sensing data and global position system rapid positioning, the ecological and environmental changes could be detected by monitoring the changes of regional boundary patterns. Therefore, the ecological functional regionalization of Changsha City provided a fine way of integrating remote sensing data, global position system, and geographic information system.

Recent 40 years inter-decadal fluctuation of dry and wet climate boundary and its cause in Liaoning Province

SUN Fenghua¹; YUAN Jian²

2006, 17(07):  1274-1279 . 

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Based on the 1961~2004 observation data of temperature, precipitation, humidity, wind, and solar radiation from 52 weather stations, and by using revised Penman formula, this paper calculated the potential evapotranspiration in Liaoning Province during the past 40 years, with its temporal and spatial distribution and representativeness discussed and the aridity index and water budget in surface soil computed. According to the aridity index, Liaoning Province was compartmentalized into three climatic regions, i.e., semi-arid region, semi-humid region, and humid region. The analysis of the inter-decadal fluctuation of dry and wet climate boundary in Liaoning Province showed that during the past 40 years, the dry and wet climate boundary fluctuated markedly and differentiated greatly, but the semi-humid and humid and the semi-arid and semi-humid climate boundaries did not move forward east and back west synchronously on the interdecade scale. In 1990’s, the dry and wet climate had an abrupt change. The semi-humid and humid climate boundary moved toward east, and the semiarid and semi-humid climate boundary moved toward west. The semi-arid and humid areas were reduced, while the semi-humid area was enlarged markedly. The main factors affecting the fluctuations of dry and wet climate boundary and the variations of dry and wet climate in Liaoning Province should be the Southeast Monsoon, Southwest Monsoon, and West Pacific Subtropical High. In western Liaoning, West Pacific Subtropical High and Southeast Monsoon mainly controlled the dry and wet climate status; while in eastern Liaoning, the factor topography precipitation should also be considered.

Comprehensive assessment of urban ecosystem health

SANG Yanhong¹; CHEN Xingeng¹; WU Renhai¹; PENG Xiaochun²

2006, 17(07):  1280-1285 . 

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Ecosystem health is one of the research hotspots in ecology. This paper discussed the concept of urban ecosystem health, and from the viewpoint of complex ecosystem, presented a new method and a calculation model for the comprehensive assessment of urban ecosystem health to overcome the current researches shortcomings. The application of the method and model in Foshan City of Guangdong Province showed that the assessment results could reflect not only the overall health status of the city, but also the relative health level of the city’s sub-systems

Toxic effects of monosodium glutamate wastewater on crop seed germination and root elongation

LIU Rui^1,2,3; ZHOU Qixing²; ZHANG Lanying¹; GUO Hao³

2006, 17(07):  1286-1290 . 

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To make a comprehensive assessment on monosodium glutamate wastewater pollution, a pollution exposure experiment was carried out on the seed germination and root elongation of wheat, Chinese cabbage and tomato by using the wastewater discharged from different processing phases of monosodium glutamate production. The results showed that there were significantly positive linear relationships between the inhibition rates of wheat seed germination and root elongation and the COD_Cr of mother liquor scraps. The toxicity of monosodium glutamate wastewater to the test crops was in the order of tomato ＞ Chinese cabbage ＞ wheat, indicating that tomato was most sensitive to the wastewater, and could be considered as an ideal toxic bioindicator. The half-effect concentration (IC₅₀) based on the seed germination and root elongation of test crops exposed to the wastewater discharged from various processing phases of monosodium glutamate production was 22.0～32432 mg·L^-1 and 17.3～3320 mg·L^-1, respectively.

Spatial variability of temperature in semi-aerobic landfilling structure

LI Fan^1,2; HUANG Qifei¹; ZHANG Zengqiang²; WANG Qi¹

2006, 17(07):  1291-1294 . 

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The study indicated that the semivariogram function of temperature in semi-aerobic landfilling structure could be well modeled by the linear with sill model. The correlation range of the profile was 3.5 m, and the sill value was 83.6. The unmeasured temperature values were interpolated with Kriging method, and the temperature isoline showed that high temperature region located at 3~5.5 m in the vertical direction of the middle part, while low temperature area laid in 0~1 m on the two sides of the landfill structure and substrate. The weighted average temperature of the profile was 59.80 ℃, which could be regarded as the indicator of landfilling structure’s formation.

Effects of dissolved organic matter in landfill leachate on soil Cd-and Pb bioavailability

FU Meiyun^1,2; ZHOU Lixiang¹

2006, 17(07):  1295-1300 . 

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A pot experiment was conducted to study the effects of dissolved organic matter (DOM) in landfill leachate on ryegrass growth and its uptake of soil Cd and Pb. Fresh sample and Shuige leachate were collected from the municipal waste landfills established 0 and 12 years, respectively. The results showed that after the landfill leachate added, the average concentration of DOM remained in soil was 1.39 (fresh sample) and 1.47 (Shuige) times higher than the control (CK). The bioavailability of Cd and Pb in the soils treated with the two leachates was fluctuated in early period, and then raised. Compared with CK, the bioavailability of soil Cd was increased by 4.81% (fresh sample) and 48.97% (Shuige), and that of soil Pb was enhanced by 7.22% (fresh sample) and 1899% (Shuige). The total concentrations of plant Cd and Pb in the treatments of fresh sample and Shuige were 19.59% and 104.4%, and 36.03% and 44.66% higher than CK, respectively, while the total biomass of ryegrass was decreased by 14.03%～52.24%, in compared with CK. It could be inferred that the dissolved organic matter (DOM) in landfill leachate, especially in that from the landfills established for a longer time, could enhance the bioavailability of soil heavy metals and their accumulation in plant, and thus, suppress the growth of plants.

Photochemical degradation of chlorpyrifos in water

WU Xiangwei¹; HUA Rimao¹; TANG Feng¹; LI Xuede¹; CAO Haiqun¹; YUE Yongde²

2006, 17(07):  1301-1304 . 

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In this paper, the effects of different light sources, temperature, pH, and water quality on the photochemical degradation of chlorpyrifos in water were examined under natural and simulated solar irradiation. The results showed that the photochemical degradation of chlorpyrifos in water followed the first order reaction, and its half-life was 0.62, 6.92, 19.74 and 22.50 h under high pressure mercury lamp (HPML), xenon lamp (XL), ultraviolet lamp (UV), and sunlight (SL) irradiation, respectively. Temperature had a significant effect on the degradation rate of chlorpyrifos, which was increased with increasing temperature and reached the maximum at 35 ℃. The degradation rate of chlorpyrifos was stable both in acid and in neutral buffer solution, but enhanced in alkaline buffer solution. Water quality also had a significant effect, with a decreasing degradation rate of chlorpyrifos in the sequence of distilled water＞tap water＞river water＞lake wate＞paddy water.

Effects of pesticides metolachlor and S-metolachlor on soil microorganisms in aquisols Ⅱ. Soil respiration

ZHOU Ying^1.2; LIU Weiping^1,3; YE Huina²

2006, 17(07):  1305-1309 . 

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An incubation test on the soil microbial respiration as affected by 0, 5, 20, and 100 mg·kg^-1 of metolachlor and S-metolachlor (Dual Gold) showed that at the early period of incubation, 5 mg·kg^-1 of metolachlor had a stronger stimulation effect on the respiration than 5 mg·kg^-1 of Dual Gold, but after then, metolachlor presented an inhibition effect while Dual Gold had the effects of stimulation or recovery. 20 mg·kg^-1 of Dual Gold had little effect on the respiration, while metolachlor with the same concentration stimulated it. 100 mg·kg^-1 of metolachlor had a stronger stimulation effect on the respiration than 100 mg·kg^-1 of Dual Gold, but both of them had the same inhibition effect during the later period. The higher the concentration of metolachlor or Dual Gold, the greater the stimulation effect was. There was a significant difference in soil microbial respiration between treated and blank soil at the beginning of incubation, while no significant difference was observed during the later period. With the same concentration of 20 or 100 mg·kg^-1, metolachlor had more harm than Dual Gold. It was suggested that metolachlor and Dual Gold belonged to lower poisonous pesticides, and had less harm on soil microbes.

Effects of cadmium stress on xanthine oxidase and antioxidant enzyme activities in Boleophthalmus pectinirostris liver

LIU Weicheng¹; LI Mingyun¹; HUANG Fuyong^1,2; ZHU Junquan¹; DONG Wu³; YANG Jingfeng³

2006, 17(07):  1310-1314 . 

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This paper approached the feasibility of using the xanthine oxidase (XOD), superoxide dismutase (SOD) and catalase (CAT) activities and malonyldialdehyde (MDA) content in Boleophthalmus pectinirostris liver as the indicators of Cd²⁺ toxic effects on this marine fish. Three concentrations of cadmium chloride (0.05, 0.5 and 5 mg Cd²⁺·L^-1) were enacted. The results showed that in treatment 0.05 mg Cd²⁺·L^-1, the XOD and SOD activities in B. pectinirostris liver increased with time and reached the maximum on the 10th day, while in treatments 0.5 and 5 mg Cd²⁺·L^-1, they increased significantly or extremely significantly, compared with the control. The CAT activity in treatments 0.05 and 5 mg Cd²⁺·L^-1 decreased significantly within 12 hours, but recovered then in treatment 005 mg Cd²⁺·L^-1. After moved into clean seawater for 5 days, the CAT activity increased extremely significantly in treatments 0.5 and 5 mg Cd²⁺·L^-1, but reversed in treatment 0.05 mg Cd²⁺·L^-1. As a product of antioxidation and oxidation, the content of MDA in treatments 0.5 and 5 mg Cd²⁺·L^-1 decreased extremely significantly after recovered for 5 days. It was suggested that the XOD and SOD activities in B. pectinirostris liver could be used as a biomarker of Cd²⁺ pollution, while the CAT activity and MDA content in this marine fish liver were not sensitive to Cd²⁺ stress.

Enzyme activities in Paeonia ostii rhizosphere and non-rhizosphere soil of Tongling copper mining

LIU Dengyi¹; SHEN Zhangjun²; YAN Mi¹; WANG Youbao¹; LI Jing¹

2006, 17(07):  1315-1320 . 

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The study on the calatase, polyphenol-oxidase, invertase, urease and phosphatase activities in Paeonia ostii rhizosphere and nonrhizosphere soil of Tongling copper mining showed that all test enzyme activities were higher in rhizosphere than in non-rhizosphere soil. Soil calatase, urease and phosphatase were sensitive to heavy metals pollution, and their activities could be used as the indicators of heavy metals’ joint pollution. The effects of rhizosphere environment on the soil enzyme activities were in the sequence of phosphatase＞urease＞calatase＞invertase＞polyphenoloxidase, and the affecting rate was 131.562%, 92.492%, 87.557%, 59.673% and 34.076%, respectively. The test enzyme activities were negatively correlated with soil heavy metals pollution, and the correlation coefficients were all higher than -0.898, suggesting the inhibitory effects of heavy metals’ joint pollution on soil enzyme activities. P. ostii could effectively improve soil environment, and thus, enhance the activities of soil enzymes.

Effects of environmental pollutants on arbuscular mycorrhiza formation and function

WANG Shuguang¹; FENG Zhaozhong²; WANG Xiaoke²

2006, 17(07):  1321-1325 . 

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Arbuscular mycorrhiza (AM) possesses the characteristics of both microbe and plant. Considerable attention has been focused on the use of AM in the remediation of polluted soil, but AM could be poisoned by pollutants when exposed to polluted soil, and thus, the significance of its application might be reduced. Therefore, how to reduce the negative effects of pollutants on AM is an issue to be considered in remedying polluted soil by AM. This paper briefly reviewed the effects of different organic and inorganic pollutants on AM structure, formation and function, and discussed the possible mechanisms. Both organic and inorganic pollutants could have detrimental effects on AM structure, formation and function, such as low spore germination, colonization rate, and hyphal growth. Organic pollutants indirectly affect the activity of AM fungi through affecting the carbohydrates allocation from plant to the fungi, while heavy metals directly inhibited the activity of AM fungi.

Research advances in ecotoxicology and risk assessment of chemical mixtures at low doses

LI Xinxin^1,2; SONG Yufang^1,4; ZHANG Wei^1,2; YANG Daoli³; ZHOU Qixing^1,4; SUN Tieheng^1,4

2006, 17(07):  1326-1330 . 

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Chemicals in the environment often exist as mixtures and at low doses, whose ecotoxicological diagnosis and risk assessment are hard to be done with the help of the research results on the ecotoxicity of high-level exposure of single chemicals. This paper reviewed the research advances in ecotoxicology and risk assessment of low-dose chemical mixture contamination, with the focus on the molecular toxicological methods and the risk assessment approaches and schemes of simple and complex mixtures. Comments were given on the development directions of low-dose chemical mixture research, including the necessity of searching for sensitive endpoints, involving the approaches of other disciplines, increasing data accumulation, and setting up a comprehensive and identical risk assessment system.

Responses of rice growth and development to free-air CO₂ enrichment (FACE): A research review

YANG Lianxin^{1, 2}; WANG Yulong¹; HUANG Jianye¹; YANG Hongjian¹; LIU Hongjiang¹

2006, 17(07):  1331-1337 . 

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The ongoing increasing of atmospheric CO₂ has become a hot topic in the last two decades due to its profound impact on crop growth and development. Oryza sativa L. (rice) is one of the most important crops in the world and the first food in China. This paper reviewed the results based on chamberbased experiments, mainly focused on the effects of free-air carbon dioxide enrichment (FACE) on the photosynthesis, water relationship, growth stage, leaf and root growth, dry matter production and distribution, chemical composition, and grain yield and quality of rice crop. The further research directions in this field were discussed.

Research advances in the relationships between biodiversity and invasiveness within plant communities

ZHENG Jingming^1,2; MA Keping¹

2006, 17(07):  1338-1343 . 

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This paper reviewed the theoretical, observational, and experimental studies on the relationships between biodiversity and invasiveness within plant communities. The contradictory conclusions made from these studies were summarized and analyzed, and suggestions were put forward to improve future researches. In theoretical studies, models were highly simplified and depended on unrealistic assumptions, e.g., single mechanism of biodiversity formation, balance between communities status, and similar characters of alien and native species, which limited the credibility of research conclusions. Most of the observational studies were not directly exploring the relationships between biodiversity and invasiveness, but inferring from invasion patterns occurred in nature. Different research scales always resulted in contradictory conclusions. In small-scale research where some biotic factors dominated species interaction, the relationships between biodiversity and invasiveness might be negative, while in larger-scale research, other co-varying extrinsic factors might override those biotic factors in small-scale research, and the relationships between biodiversity and invasiveness might be positive. Although most experimental studies were conducted in small scale and extrinsic influences were ruled out, some mistakes might still happen when constructing biodiversity gradients in the experimental communities. Among these mistakes, sampling effect was the most common one, and the others included building communities with same species abundance but varying richness and density. Some suggestions were put forward on improving the study of the relationships between biodiversity and invasiveness in plant communities. In future researches, we should integrate observational study with experimental study, pay more attention to research scale, avoid sampling effect, and couple model with experimental design.

Morphological characteristics of resting eggs produced by different Brachionus calyciflorus strains

LIU Guiyun; XI Yilong

2006, 17(07):  1344-1347 . 

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In this paper, the Qingdao and Wuhu strains of Brachionus calyciflorus were cultured at 20 ℃, 25 ℃ and 30 ℃, and fed with 1.0×10⁶ and 5.0×10⁶ cells·ml^-1 of Scenedesmus obliquus. The morphological study of their produced resting eggs showed that at the two food concentrations, the resting eggs produced at 20 ℃ were the largest in length, width and volume, while those produced at 25 ℃ and 30 ℃ were the smallest. The effects of strain on the morphological characteristics of resting eggs also depended on food concentration. When the food concentration was 1.0×10⁶ cells·ml^-1, the length, width and volume of the resting eggs produced by Wuhu strain and Qingdao strain were 156.00 μm, 99.95 μm and 12 269.11 μm3, and 145.13 μm, 91.97 μm and 10 498.19 μm³, respectively, while when the food concentration was 5.0×10⁶ cells·ml^-1, the corresponding values were 155.68 μm, 100.85 μm and 12 348.59 μm³, and 156.63 μm, 98.04 μm and 12 05420 μm³, respectively. For test strains, only Wuhu strain showed a marked curvilinear correlation in the length, width and volume of its resting eggs with temperature. At the same temperature, the volumes of the resting eggs produced by both Qingdao and Wuhu strains were increased with increasing food concentration, with the exception that the resting eggs produced by Wuhu strain at 30 ℃ decreased with increasing food concentration.

Effects of illumination and cold storage on development and reproduction of Carposina niponensis

ZHANG Yueliang; MU Wei; ZHAO De; WEI Guang; PANG Jinju

2006, 17(07):  1348-1350 . 

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The study showed that with the prolongation of illumination, the development duration of Carposina niponensis was shortened. Illumination had most obvious influence on the larval diapause rate, which was the minimum under 15 h of illumination and increased when illumination was prolonged and shortened. Other important parameters such as fecundity, larval weight, hatching rate, leaving rate and emergence rate reached their peak when the illumination duration was 13～17 h. Therefore, the optimal illumination duration for the development and reproduction of C. niponensis was about 15 h. The duration of cold storage had no significant influence on the duration of pupa, longevity of adult, and duration of egg. But, the emergence rate, fecundity, and hatching rate were reduced when the cold storage duration exceeded 7 days. Therefore, pupae and eggs should not be stored at low temperature for a long period.

Sublethal effect of chlorpyrifos on the dynamics of experimental Tetranychus cinnabarinus population

TAO Shiqiang¹; WU Fuan²

2006, 17(07):  1351-1353 . 

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By using Jackknife technique and Wilcoxon (Gehan) statistic method, the LC₃₅ sublethal effect of chlorpyrifos on the population dynamics of Tetranychus cinnabarinus was studied in laboratory. The results showed that under the conditions of 30 ℃±1 ℃, （70±15）% RH and a photoperiod of 16L∶8D, there were no significant differences in the longevity of female adult, F1 hatchability, and sex ratio of T. cinnabarinus between chlorpyrifos treatment and the control, but the total oviposition (42.37±2.270) and the intrinsic rate of increase (0.3279±0.0033) in chlorpyrifos treatment were significantly lower than those (52.50±2.433 and 0.3717 ±0.0043, respectively) in the control.

Effects of pesticides on soil urease activity

YANG Chunlu^1,2; SUN Tieheng^1,2; HE Wenxiang¹; CHEN Su^1,2

2006, 17(07):  1354-1356 . 

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With simulation test, this paper studied the effects of chlorimuron-ethyl and furadan on the urease activity of six meadow brown soil and black soil samples. The results showed that within the range of test concentrations, these two pesticides could activate the urease activity of test soils, with the largest increment in meadow brown soil and black soil being 46.95% and 39.36% by chlorimuron-ethyl, and 21.08% and 12.70% by furadan, respectively. Quadratic polynomial equation could better describe the relationships between the concentrations of chlorimuron-ethyl and furadan and the activity of soil urease (P＜0.05). Judging from the equations for test pesticides, chlorimuronethyl had more significant effect than furadan.