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    21 March 2008, Volume 19 Issue 03
    Articles
    Biomass of Quercus fabri population under different ecological restoration regimes in subtropical China.
    XU Wen-jia1,3; LIU Qi-jing1,2; MA Ze-qing1; LIU Ying-chun1,3
    2008, 19(03):  459-466 . 
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    In this paper, the tissue-specific biomass and above-ground biomass of Quercus fabriunder different ecological restoration regimes in subtropical China were analyzed by establishing allometric models with different parameters. The best-fitted equations were adopted for estimating the biomass and its annual growth, and the below-ground biomass and its increment were estimated on the basis of its linear relationship with aboveground biomass. The results showed that the biomass of the branches and of the total above-ground tissues was best described by power-function models, and the best fitted independent variables were d2l and D2H, respectively. The tissue-specific biomass and total biomass of Q. fabri population were all greater in secondary forest than in Pinus elliottiiplantation. The above-ground biomass and below-ground biomass of Q. fabri population in secondary forest were 3.592 and 1.723 t·hm-2, respectively, in which, different tissue components were ranked in the order of stem>branch>leaf; while those in P. elliottii plantation were 0.666 and 0.462 t·hm-2, respectively, in which, different tissue components were ranked in the order of stem>leaf>branch. From 2004 to 2006, the annual increments of above-ground, below-ground, and total biomass increased with time, and the increment of above-ground biomass had an ascent tendency, which was from 54.35% to 62.20% in P. elliottii plantation and from 67.27% to 68.94% in secondary forest. In comparing with that in secondary forest, the biomass increment of Q. fabri population in P. elliottii plantation was small, despite its relatively high growth rate.
    Seasonal dynamics and spatial distribution patterns of herbs diversity in broadleaved Korean pine (Pinus koraiensis) mixed forest in Changbai Mountains.
    LI Bu-hang1,2; ZHANG Jian1,2;YAO Xiao-lin1,2; YE Ji1,2;
    2008, 19(03):  467-473 . 
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    In this paper, the species composition, seasonal dynamics, and spatial distribution patterns of herbs were examined in a 25 hm2 broadleaved Korean pine (Pinus koraiensis) mixed forest plot in Changbai Mountains. The results showed that the plot had a relatively high herbaceous richness, with 102 species belonging to 40 families and 84 genera, and the Shannon index, Simpson index, and Pielou index was 3.52, 0.96 and 0.75, respectively. The three indices varied dramatically with growth season, whereas the species abundance decreased linearly from early spring to autumn. The species richness and abundance showed irregular distribution, indicating that herbaceous species were microenvironment-dependent. Slope aspect had significant effects on herbaceous species richness and abundance. Northern and eastern slopes had higher species richness and abundance in early spring than southern and western slopes, whereas it was in adverse in late summer and autumn.
    Population structure of endangered Monimopetalum chinense and its relationships with environmental factors.
    ZHANG Xiao-ping1; HAO Chao-yun1,2; FAN Rui1,2; LI Wen-liang1,2; ZHANG Yu1,2; CHEN Xiao-bao3
    2008, 19(03):  474-480 . 
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    Based on the field investigation data obtained from the typical plots of four community types, i.e., secondary shrub, Phyllostachys edulis forest, Cunninghamia lanceolata forest, and Pinus massoniana forest, in the Zongli Village of Qimen County in Anhui Province, this paper studied the mean basal diameter and structure of Monimopetalum chinense population, and the effects of environmental factors on the population characteristics. The results showed that the mean basal diameter of M. chinense in the communities was in the rder of P. edulis forest >P. massoniana forest>C. lanceolata forest>secondary shrub, and significantly larger in the two former forests than in the others (P<0.05). The population structure of M. chinense also differed with habits. In secondary shrub and P. massoniana forest, the structure was a aptypical pyramid-like form, suggesting that the population was stable; in P. edulis forest, it was a spindle type, indicating that the population was at the early stage of declining; whereas in C. lanceolata forest, it was a typical pyramid-like form, with most young individuals in the population. The survival curve of the whole population belonged to Deevey II, suggesting that the population was in developing tendency with no declination. M. chinense preferred the sites with low altitude, high soil moisture and organic matter contents, gentle slope, and high coverage of tree layer; while frequent human disturbance decreased its natural regeneration and stability. Based on the results obtained, some preliminary protection suggestions were proposed.
    Aerodynamic parameters and their affecting factors over Panjin reed wetland.
    HE Qi-jin1,2; ZHOU Guang-sheng2,3; ZHOU Li3; WANG Yun-long3
    2008, 19(03):  481-486 . 
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    Based on the observation data from eddy covariance tower and meteorological gradient tower in Panjin reed wetland observation plot, and by the method combined eddy covariance with microclimate gradient observation, two fundamental aerodynamic parameters, i.e., zero-plane displacement (d) and roughness length (z0 ), were evaluated, with their affecting factors analyzed. The results showed that the method adopted was suitable for estimating the aerodynamic parameters. There existed obvious seasonal variations in d and z0, with the maximum (1.85 and 0.24 m) in September and the minimum (0.02 and 0.03 m) in December, respectively. The seasonal variations were closely related to vegetation characteristics, plant height (h) and leaf area index (LAI). There was a close linear relationship between d and h, and a conic relationship between z0 and h. Both d/h and d/z0 had power relationships with LAI, and the R2 values were 0.99 and 0.78, respectively.
    Spatial pattern of land surface dead combustible fuel load in Huzhong forest area in Great Xing’an Mountains.
    LIU Zhi-hua1,2; CHANG Yu1; CHEN Hong-wei1,2; ZHOU Rui1,2; JING Guo-zhi3; ZHANG Hong-xin3; ZHANG Chang-meng3
    2008, 19(03):  487-493 . 
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    By using geostatistics and based on timelag classification standard, a comparative study was made on the land surface dead combustible fuels in Huzhong forest area in Great Xing’an Mountains. The results indicated that the first level land surface dead combustible fuel, i.e., 1 h timelag dead fuel, presented stronger spatial auto-correlation, with an average of 762.35 g·m-2 and contributing to 55.54% of the total load. Its determining factors were species composition and stand age. The second and third levels land surface dead combustible fuel, i.e., 10 h and 100 h time-lag dead fuels, had a sum of 610.26 g·m-2, and presented weaker spatial auto-correlation than 1 h timelag dead fuel. Their determining factor was the disturbance history of forest stand. The complexity and heterogeneity of the factors determining the quality and quantity of forest land surface dead combustible fuels were the main reasons for the relatively inaccurate interpolation. However, the utilization of field survey data coupled with geo-statistics could easily and accurately interpolate the spatial pattern of forest land surface dead combustible fuel loads, and indirectly provide a practical basis for forest management.
    Relationships between phosphorus fractions concentrations in Pinus sylvestris var. mongolica needles and soil available phosphorus.
    LIU Xing-yu1,2;ZHAO Qiong1; ZENG De-hui1; LIU Jin-huan1; HU Ya-lin1,2; DENG Dong-zhou1,2; WANG Hong1,2
    2008, 19(03):  494-498 . 
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    To make clear whether Mongolian pine (Pinus sylvestris var.mongolica) plantation is limited by soil phosphorus (P) supply in southeast Horqin sand land and to find out the best leaf indicator of soil P supply, the concentrations of total P, inorganic P and organic P in the needles of different age ofP. sylvestris var. mongolica and the soil available P were analyzed. The results showed that in the study area, soil available P was rather low (0.12-0.63 mg·kg-1), and had significant correlations with the inorganic P (cPi) and total P (cPt) concentrations in the current-year needles of P. sylvestris var. mongolica. The significant correlation between soil available P and needle cPt derived from the significant correlation between cPi and cPt. Compared with cPt, cPi could reflect the level of soil P supply more accurately and directly.
    Effects of shading light quality at seedling stage on the photosynthesis and growth of ginger.
    ZHANG Rui-hua;XU Kun
    2008, 19(03):  499-504 . 
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    With different color plastic films as shading materials, this paper studied the effects of shading light quality at seedling stage on the growth and photosynthesis of ginger. The results showed that shading with green or blue film induced the greatest chlorophyll content in ginger leaves, followed by shading with white film, and red film. In parallel, the photosynthetic rate under green film-shading was the highest, being 14.9 μmol·m-2·s-1 in the 4th leaves, which was 5.7%, 10.4%, and 18.3% higher than that under white, red, and blue film-shading, respectively. After removing the films at vigorous growth stage, the photosynthetic rate became larger, and its change pattern in different shading treatments was similar to that at seedling stage. No significant differences in the chlorophyll content of young leaves were observed among the shading treatments, except the low chlorophyll content under red film-shading. In contrast, the chlorophyll content in low position leaves under blue and red filmshading was lower than that under green and white filmshading. In the whole growth period, the plants under blue film-shading were higher in height and with thinner stem and lesser shoot, compared with those shaded with other color films. The fresh mass of root, stem, leaf, and rhizome decreased in the order of green, white, red, and blue film-shading, and the yields at harvesting stage were 57 000, 53 709, 51 487, and 48 712 kg·hm-2, respectively, illustrating that shading with green film at seedling stage could increase the leaf photosynthesis, plant growth, and yield of ginger.
    Photosynthetic characteristics and dry matter accumulation of hybrid rice varieties under different light conditions.
    TONG Ping1;YANG Shi-min2; MA Jun1; WU He-zhou1; FU Tai-lu1; LI Min1;WANG Ming-tian3
    2008, 19(03):  505-511 . 
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    The study on the photosynthetic characteristics and dry matter accumulation of twelve hybrid rice varieties in the eco-environments with low- and high light intensity showed that the adaptation ability of the varieties to eco-environment was mainly depended on the varieties themselves, and there existed greater differences among them. The differences in net photosynthetic rate (Pn) and chlorophyll content (Chl) were more significant among the varieties than between the eco-environments. The grain yield had significant positive correlations with Pn and total dry matter mass (TDM), the etermination coefficientR2 being 0.584 and 0.590, respectively, but no significant correlations with the export percentage of the matter in stem-sheath (EPMSS) and the transformation percentage of the matter in stem-sheath (TPMSS). In the eco-environment with high light intensity, the leaf thickness and dry matter accumulation increased, while the EPMSS and TPMSS decreased. Under enough sunlight condition, the high proportion of matter in grain yield was mainly come from the photosynthesis at late growth stages; while under insufficient sunlight condition, it was mainly originated from the early growth stages photosynthesis.
    Effects of low temperature and weak light on the functions of photosystem in Prunus armeniaca L. leaves in solar greenhouse.
    SUN Shan1,2;ZHANG Li-tao2; WANG Jia-xi1; WANG Shao-min1; GAO Hua-jun1; GAO Hui-yuan2,3
    2008, 19(03):  512-516 . 
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    In this paper, the net photosynthetic rate (Pn), actual photochemical efficiency of PSⅡ(ΦPSⅡ), photochemical quenching(qP), and maximal photochemical efficiency of PSⅡ in light (Fv/Fm) of apricot (Prunus armeniaca) leaves in solar greenhouse were measured, and the effects of low temperature (7 ℃) and weak light (200 μmol·m-2·s-1 PFD) on the photoinhibition of PSⅠ and PSⅡ were investigated. The results showed that the optimal temperature for the photosynthesis of apricot leaves was around 25 ℃, and the photosynthetic capacity was reduced greatly by the low temperature and weak light, inducing a markedly increased excitation press (1-qP) and in turn, resulting in photoinhibition. The functions of both PSⅠ and PSⅡ were damaged by the low temperature and weak light. Comparing with those only subjected to low temperature, the leaves subjected to both low temperature and weak light had a decreased activity of PSⅠ, with a decrement of 2826% within 2 h, but their maximal photochemical effeciency of PSⅡ (Fv/Fm) had little change in the same period, suggesting that under low temperature and weak light, PSⅠ was more suffered from photoinhibition than PSⅡ.
    Dynamic changes of soil microbial biomass in the restoration process of shrub plantations in loess hilly area.
    XUE Sha1,2; LIU Guo-bin1; DAI Quan-hou1,3; LI Xiao-li1; WU Rui-jun1
    2008, 19(03):  517-523 . 
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    By the method of spatiotemporal substitution and taking a slope farmland and a natural Platycladus orientailis L. forest as the controls, this paper studied the dynamic changes of soil microbial biomass, microbial respiration, metabolic quotient (qCO2) and physicochemical properties under the Caragana korshinkii and Hippophae rhamnoides plantations with different restoration age in loess hilly area. The results showed that with the increasing restoration age of the shrubs, soil physicochemical properties improved obviously, and soil microbial biomass had a significant increase. After 7 years restoration of C. korshinkii plantation, soil microbial biomass C increased apparently, compared with that in farmland, and the increments after each 5-7 years were all significant. Microbial biomass N and P had no significant increase in the first 13 years but kept relatively stable in the 20-30 years restoration of C. korshinkii plantation, and were significantly higher than those in farmland but lower than those under P. orientailis plantation after 30 years restoration of C. korshinkii plantation. Soil microbial respiration was enhanced with the increasing restoration age of the shrubs,with the peak in the 20-25 years restoration. After then,it decreased rapidly,and bottomed out in the 30 years restoration.qCO2 was significantly higher underP. orientailis plantation than in farmland in the early periods of shrubs restoration, and then decreased rapidly. After 30 years restoration of C. korshinkiiplantation, qCO2 was lower than that in farmland but still much higher than that under P. orientailis plantation. Different shrub plantations had different effects on soil properties. H. rhamnoides with the same restoration age of C. korshinkii contributed more to the increase of soil microbial biomass and respiration. There were significant correlations between the restoration age of test shrub plantations and the microbial biomass, qCO2, and hysicochemical properties of soil. It was considered that vegetation restoration could be a feasible way in improving the eco-environment and soil quality in loess hilly area, but a longer period should be required to reach to the climax before vegetation destruction. It is necessary to strengthen and improve forest management to interfere and accelerate plant succession for a sustainable and healthy ecosystem.
    Variations of Picea crassifolia tree-ring cell structure and their implications to past climate in eastern margin of Qaidam Basin, Northwest China.
    LI Yan1,3; LIANG Er-yuan2; SHAO Xue-mei1,2
    2008, 19(03):  524-532 . 
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    Treering samples of Picea crassifolia were collected from the upper treeline in the eastern mountainous area of Qaidam Basin in Qinghai Province. The tree-ring width and the cell number and size of the tree-ring were measured, and the standard chronologies for the early-wood cell number, late-wood cell number, total cell number of tree-rings, maximum cell size, and minimum cell size were constructed. By using correlation analysis and the response functions between cell characteristic indices and 1970-2000 climate factors at Chaka meteorological station which was close to the sampling site, the relationships between P. crassifolia growth at cell scale and climate factors were discussed. The results showed that the earlywood cell number was positively correlated to the wintertime temperature from previous October to current March, while the late-wood cell number was positively correlated to the minimum temperature in previous November and December and to the mean temperature in current July and August. Both the early-wood and the latewood cell numbers were negatively correlated to the precipitation in July, and the early-wood cell number was positively correlated to the precipitation in May. The chronology of maximum cell size of earlywood was positively related to the precipitation in February, while that of minimum cell size of late-wood was positivelyrelated to the precipitation in August. It was concluded that the cell number and cell size could not only reveal the information of temperature change, which was recorded by tree ring width as well, but also provide additional information of precipitation. Since different types of tree-ring indices contained different climate information, multiple aspects of climate change information could be extracted from different treering indices of the same species at the same site, and the cell level tree ring characteristics had great potential to supply the information regarding past climate.
    Characteristics of net ecosystem flux exchanges over Stipa kryloviisteppe in Inner Mongolia.
    YANG Juan1,3;ZHOU Guang-sheng1,2; WANG Yun-long2; WANG Yu-hui2
    2008, 19(03):  533-538 . 
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    Based on an entire year continuous measurement of surface fluxes by eddy covariance (EC) tower and microclimate gradient observation system, the diurnal and seasonal dynamics of net ecosystem fluxes including carbon, water, and heat fluxes over Stipa krylovii steppe in Inner Mongolia were investigated. The results indicated that the diurnal pattern of carbon fluxes during growing season could be expressed as U curve. S. krylovii steppe ecosystem emitted CO2 before the sunrise and absorbed CO2 after the sunrise, with the maximum CO2 uptake around noon. The ecosystem had weaker CO2 uptake after the noon, and turned to emit CO2 after sunset. The CO2 uptake by S. krylovii steppe ecosystem reached the maximum in September, followed in August, and got the minimum in October. The diurnal dynamic patterns of sensible heat flux (Hs) and latent heat flux (LE) could be expressed as inverse U curves. The Hs and LE over S. krylovii steppe ecosystem were positive during the daytime, while Hs was negative and LE was close to zero during the nighttime. The ecosystem had the highest Hs and LE in May and September, respectively. In winter, the steppe acted as a weak carbon source, with the CO2 flux being small; while in summer, it became an obvious carbon sink.
    Variations of soil labile organic carbon along an altitude gradient in Wuyi Mountain.
    XU Xia1; CHEN Yue-qin1; WANG Jia-she2; FANG Yan-hong2; QUAN Wei1; RUAN Hong-hua1; XU Zi-kun2
    2008, 19(03):  539-544 . 
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    By using sequential fumigationincubation method, this paper determined the soil labile organic carbon (LOC) content under evergreen broadleaf forest, coniferous forest, sub-alpine dwarf forest, and alpine meadow along an altitude gradient in Wuyi Mountain National Nature Reserve in Fujian Province of China, with its relations to soil microbial biomass carbon (MBC), total organic carbon (TOC), total nitrogen (TN), and fine root biomass (FRB) analyzed. The results showed that soil LOC occupied 3.40%-7.46% of soil TOC, and soil MBC occupied 26.87%-80.38% of the LOC. The LOC under different forest stands increased significantly with altitude, and decreased with soil depth. Soil LOC had very significant correlations with soil MBC, TOC, TN and FRB, and its content was obviously higher at higher altitudes than at lower altitudes.
    Effects of long-term fertilization on water-stable aggregates in calcic kastanozem of Loess Plateau.
    HUO Lin1,2;WU Tian-yun2; LIN Hai-ming1; CAO Shi-yu2; TANG Wen-xue2
    2008, 19(03):  545-550 . 
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    The study on the size distribution of water-stable aggregates (WSAs) in calcic kastanozem of Loess Plateau after 27 years fertilization showed that compared with those of natural soil, the contents of >0.25 mm WSAs in 0-10 cm and 10-20 cm layers of cultivated soil decreased by 21.35% and 38.82%, respectively, and those of ≥0.5 mm WSAs also had a decreasing trend, with the greatest decrement of >5 mm and 5-2 mm WSAs. On the contrary, the contents of 0.5-0.25 mm WSAs in the two soil layers increased by 104.75% and 23.13%, respectively. All sizes WSAs had higher contents in 0-10 cm than in 10-20 cm soil layer. Fertilization had remarkable effects on the formation of WSAs. Under the applications of organic manure and its combination with chemical fertilizers, the content of 5-2 mm WSAs increased most, followed by that of >5 mm WSAs. After applying organic manure, organic manure plus chemical fertilizers, and straws, the contents of larger sizes WSAs increased significantly, being beneficial to the improvement of soil structure. In all fertilization treatments, the mean mass diameter (MMD) of WSAs was larger in 0-10 cm than in 10-20 cm soil layer. Compared with non-fertilization, long-term fertilization increased the MMD of WSAs, and organic manure was superior to chemical fertilizers. The MMD of WSAs was positively correlated with the amount of >0.25 mm WSAs.
    Effects of long-term fertilization on enzyme activities in black soil of Northeast China.
    WANG Shu-qi; HAN Xiao-zeng; QIAO Yun-fa; WANG Shou-yu
    2008, 19(03):  551-556 . 
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    In this paper, black soil samples at the depths of 0-20 cm and 20-40 cm were collected from the Hailun Agricultural Ecology Station of Chinese Academy of Sciences to study the effects of long-term fertilization on their urease, invertase, phosphatase and catalase activities and total C and N contents. The results showed that long-term application of chemical fertilizers and organic manure increased the activities of urease, invertase and phosphatase in 0-20 cm and 20-40 cm soil layers in different degree, and the combined application of them increased the activities of the three enzymes significantly, with an increment of 43.6%-113.2%, 25.9%-79.5% and 14.7%-134.4% in 0-20 cm soil layer and 56.1%-127.2%, 14.5%-113.8% and 16.2%-207.2% in 20-40 cm soil layer, respectively. However, long-term application of chemical fertilizers without organic manure had little effects on catalase activity. The activities of urease, invertase and phosphatase decreased with increasing soil depth. Long-term application of N fertilizer increased urease activity, and P fertilization had obvious positive effect on phosphatase activity. Long-term fertilization also had obvious effects on the soil total C and N contents and C/N ratio.
    Seasonal variation of light fraction organic matter in degraded red soil after vegetation restoration.
    XIE Jin-sheng1; YANG Yu-sheng1; YANG Zhi-jie1; HUANG Shi-de2; CHEN Guang-shui1
    2008, 19(03):  557-563 . 
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    This paper studied the seasonal variation of light fraction organic matter (LFOM) in the red soils of severely eroded bare land, and of the bare lands restored to Pinus massoniana forest land,Castanea mollissima plantation, and Paspalum notatum grassland in the Hetian Town of Changting County, Fujian Province, with secondary forest soil as the control. The results showed that in the surface soil of the bare land, LFOM content was between 0.05-0.14 g·kg-1 and with no significant seasonal variation, while in that of P. massoniana forest land, C. mollissima plantation and P. notatum grassland, LFOM content had a distinct seasonal variation, and was 58%-122% higher in spring, autumn, and winter than in summer. The C content and C/N ratio of the LFOM in the three restored lands were lower in summer than in other seasons, while the nitrogen content of the LFOM was in adverse, indicating that the high temperature and humidity in summer induced a rapid decomposition of soil LFOM. The LFOM in secondary forest soil had the similar variation trend to that in the three restored lands, but the variation range was significantly narrower. The seasonal dynamics of surface soil LFOM was affected not only by micro-climate but also by vegetation types, and the variation range was greater in P. notatum grassland than in forest lands. It was suggested that to enhance the observation precision of soil LFOM, repeated sampling or integrating the factors such as climate, vegetation type, and management measures should be taken to determine the appropriate sampling time.
    Regulation effect of soil P availability on mycorrhizal infection in relation to root architecture and P efficiency of Glycine max.
    LIU Ling1,2; LIAO Hong1; WANG Xiu-rong1; YAN Xiao-long1
    2008, 19(03):  564-568 . 
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    A pot experiment with thirty soybean (Glycine max) genotypes differing in root architecture was conducted to investigate the effects of soil phosphorus (P) availability on the colonization of arbuscular mycorrhizae (AM) fungus (Glomus mosseae) as well as the relationships of the colonization with the root architecture and P efficiency of soybean. The results indicated that soil P availabilityhad significant effects on the colonization of G. mosseae. Under low P condition, the AM had a higher infection rate and contributed more to the P uptake by soybean; while under high P condition, it was in adverse. There was a significant interaction between soybean genotypes and soil P availability on the colonization of G. mosseae. Under low P condition, the soybean genotypes with intermediate and deep root architectures had the highest infection rate of AM, but on the contrary, no significant correlation was observed between root architecture and AM colonization under highP condition. In general, Pefficient soybean genotypes had better root architecture or higher AM colonization, indicating that a complementary relationship between root architecture and AM colonization was existed on their contribution to soybean P efficiency.
    Effects of NaCl stress on cation contents in different pumpkin cultivars’seedlings.
    LI Wei-xin1,2;CHEN Gui-lin1; REN Liang-yu1;WANG Peng2
    2008, 19(03):  569-574 . 
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    With the seedlings of 19 pumpkin cultivars as test materials, this paper studied the variations of Na+, K+, Ca2+, Na+/K+, Na+/Ca2+, SNa+,K+ and SNa+,Ca2+ in their shoots and roots under the stress of 300 mmol NaCl·L-1. The results showed that after an 8-day exposure to 300 mmol NaCl·L-1, the Na+ content in the seedlings increased significantly while the K+ content decreased, resulting in the brokenness of ion balance. The root Na+ content, shoot Na+/K+ and Na+/Ca2+ ratios, and SNa+,K+ and SNa+,Ca2+ of Cucurbita moschata (Q1) were significantly higher than those of C. maxima (H2) and C. ficifolia (H3). The variation tendency of these parameters of different pumpkin cultivars’ seedlings were nearly consistent with the salt injury index of the seedlings under NaCl stress, which further proved that the strong salttolerance of Q1 was related to the lower values of shoot Na+/K+, Na+/Ca2+, SNa+,K+ and SNa+,Ca2+, and the high contents of K+ and Ca2+, while the saltsensitivity of H2 and H3 was related to the higher values of shoot Na+/K+, Na+/Ca2+, SNa+,K+ and SNa+,Ca2+, and low contents of K+ and Ca2+ under NaCl stress.
    Effects of stem numbers per ground area on the quality of standard cut Chrysanthemum morifolium in greenhouse: Simulation model.
    YANG Zai-qiang1,2; DAI Jian-feng1; LUO Wei-hong1; CHEN Fa-di3; GU Jun-jie4; DING Qi-feng1; MO Dan3; JIANG Bei-bei3
    2008, 19(03):  575-582 . 
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    In order to understand the effects of stem numbers per ground area on the quality of standard cut Chrysanthemum morifolium, an experiment with different cultivars, different stem numbers per plant, different planting densities, and different planting dates was conducted in a greenhouse in Shanghai in 2005 and 2006. The effects of stem numbers per ground area on the canopy leaf area index and external quality of standard cut C. morifolium were quantified using the experimental data. Based on the physiological product of thermal effectiveness and PAR (PETP) the canopy- absorbed, a model for predicting the effects of stem numbers per ground area on the quality of standard cut C. morifolium was developed, and validated with independent experimental data. The results showed that with the increase of stem numbers per ground area, the leaf area index increased, whereas plant height, stem diameter, leaf number, and flower diameter decreased. The model gave satisfactory predictions of the quality of standard cut C. morifolium cultivated with different stem numbers and planting density. The coefficient of determination (R2) and relative prediction error (RSE) based on the 1∶1 line for fresh mass per stem, plant height, stem diameter, leaf number, flower diameter, and the number of qualified stem harvested per ground area were 0.95, 0.96, 0.94, 0.91, 0.81 and 0.97, and 16.1%, 10.1%, 12.8%, 13.4%, 15.9%, 16.1%, respectively. The model developed in this study could be used for the optimization of light and temperature management for standard cut C. morifolium cultivated with different stem numbers and planting densities in greenhouse.
    Effects of root zone hypoxia on respiratory metabolism of cucumber seedlings roots.
    KANG Yun-yan; GUO Shi-rong; DUAN Jiu-ju
    2008, 19(03):  583-587 . 
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    With the seedlings of Lübachun No.4, a hypoxia-resistant cultivar, and Zhongnong No.8, a hypoxia-sensitive cultivar, as test materials, and by the method of solution culture, this paper studied the effects of root zone hypoxia on their roots’ respiratory metabolism. The results showed that root zone hypoxia inhibited the tricarboxylic acid (TCA) cycle significantly, but accelerated the anaerobic respiration of cucumber roots. Under root zone hypoxia stress, the decrement of succinic dehydrogenase (SDH) and isocitric dehydrogenase (IDH) activities and the increment of lactate dehydrogenase (LDH) activity and lactate and pyruvate contents were lesser in Lübachun No.4 than in Zhongnong No.8 seedlings roots, but conversely, the increment of pyruvate decarboxylase (PDC) and alcohol dehydrogenase (ADH) activities and alcohol and alanine contents in Lübachun No.4 seedlings roots were higher than those in Zhongnong No.8 seedlings roots. On the 8th day of hypoxia stress, the ADH activity and alcohol and alanine contents increased by 409.30%, 112.13% and 30.64% in Lübachun No.4 roots and by 110.42%, 31.84% and 4.78% in Zhongnong No.8 roots, respectively, compared with the control. No significant differences in the alanine aminotransferase (AlaAT) activity and acetaldehyde content were observed between the two cultivars. It was concluded that the acceleration of alcohol fermentation and the accumulation of alanine were in favor of the enhancement of root zone hypoxia tolerance of cucumber roots.
    Sex ratio adjustment of a non-pollinating fig wasp species on Ficus semicordata in Xishuangbanna.
    SONG Bo1,2; PENG Yan-qiong1; GUAN Jun-ming1,2; YANG Pei1,2; YANG Darong1
    2008, 19(03):  588-592 . 
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    Through controlling the number of ovipositing foundresses inside a fig, and combining with the observation of ovipositing behavior and mating behavior, this paper studied the sex ratio of Apocryptophagussp., a species of nonpollinating fig wasps hosted on Ficus semicordata in Xishuangbanna. The results showed that female Apocryptophagussp. started to visit the fig on the 3rd day after pollinator Ceratosolen gravelyi oviposited. Apocryptaphagus sp. oviposited on the outside of the fig, and the ovipositing lasted for 2 days. Male Apocryptophagus sp. emerged at the same time with pollinators. The males opened a small hole on the wall of gall where the females developed, and mated with the females. Mated females emerged from their development fig, and left for a new receptive fig. The sex ratio of Apocryptaphagus sp. was in agreement with local mate competition theory, i.e., it was female-biased. Meanwhile, the total number of offspring increased with increasing foundress number. In contrast, the average number of offspring per foundress decreased. At individual level, when a female laid eggs inside a fig, the sex ratio of offspring correlated negatively with the number of offspring.
    Community structure of collembolan in degraded red soil under different restoration vegetation types.
    DING Cheng-cheng;DAI Zheng-kai; LI Hui-xin; CHEN Xiao-yun; CHENG Yan-hong; ZHOU Jing; ZHANG Bin; HU Feng
    2008, 19(03):  593-598 . 
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    With the degraded red soils of eroded bare land (Ⅰ), xeric mesophilous herbosa (Ⅱ), sparse coniferous woodland (Ⅲ), coniferous woodland (Ⅳ), coniferous-broadleaf mixed woodland (Ⅴ), and evergreen broadleaf forest (CK) as test objects, this paper studied the effects of vegetation restoration on the collembolan communities in degraded red soil. A total of 23 genera belonging to seven families and two suborders were observed, including dominant taxa such asFolsomia, Folsomina, and Sminthurinus. The characteristics of soil collembolan community were analyzed by using the indices such as individual density, taxa number, diversity, abundance, and evenness. The test indices were the lowest in Ⅰ, and the highest in CK. The soil collembolan communities in Ⅱ, Ⅲ, Ⅳ and Ⅴ were restored to some extent, but the restoration was still at early stage, with less difference observed. Bray-Curtis index had the largest difference (0.99) between eroded bare land and CK, larger differences between the four restored plantations and CK, and less difference between four restored plantations.
    Dynamic changes of cold-resistant substances of overwintering Chilo suppressalis (Walker) larvae.
    QIANG Cheng-kui1; DU Yu-zhou1; YU Ling-ya1; CUI Ya-dong1,2; LU Ming-xing1; ZHENG Fu-shan1,3
    2008, 19(03):  599-605 . 
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    Aimed to understand the mechanisms of coldresistance of overwintering Chilo suppressalis (Walker) larvae at physiological and biochemical levels, the supercooling point (SCP) and the contents of water, ash, elements, fat, fatty acid, glycrol, total sugar, and protein in the larvae samples collected at different time were determined. The results showed that the SCP and the contents of free water, dissociated fat, total sugar, and protein in the overwintering larvae decreased first and increased then, whereas the contents of bound water, ash, combined fat, K, Na, Mg, Fe, Ni and Cr, and glycerol decreased after an initial increase. The components of fatty acids in overwintering larvae had some changes, but the main components were still 9-hexadecenoic acid, 9-exadecanoicacid, and 9-octadecenoic acid. The contents of 9hexadecenoic acid and 9-hexadecanoic acid decreased first and increased then, while that of 9-octadecenoic acid was in adverse. The dynamic changes of the contents of test substances could reflect the coldresistance of overwinteringC. suppressalis larvae.
    Changes of characteristic scale of Nanjing urban landscape.
    HUANG Gui-fang;LIU Mao-song;XU Chi;YU Wen;CHEN Hong
    2008, 19(03):  606-612 . 
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    Based on 3 scenes of Landsat TM image taken in 1988, 1998 and 2006, the changes of the structural characteristics of Nanjing central urban area were studied with one-dimensional wavelet analysis. The results showed that it was necessary to select an optimal sampling width when using wavelet analysis to detect the characteristic scales of landscape transects. Too narrow transects could cause lack of stabilization, while too wide ones could cause loss of some minor characteristic scales. From the TM images (30 m resolution) of Nanjing urban area, the optimal sampling width was identified as four pixels. The results from onedimensional wavelet transform indicated that the landscape of Nanjing central urban area had four relatively stable characteristic scale domains in 1988, 1998 and 2006, corresponding to functional clumps, small blocks, middle-sized blocks, and large blocks, respectively. From 1988 to 2006, the scales of large blocks were nearly unchanged, while the other three domains all changed significantly with a similar trend. Moreover, the variations among the characteristic scales within each scale domain declined from 1988 to 2006, indicating that the landscape structure of Nanjing central urban area tended to be more stable and accordant. The scale domains showed synchronous changes as well.
    Regional difference of land use/cover change in farming-pasturing zone of Naiman Banner in Inner Mongolia.
    ZHANG Ji-ping; CHANG Xue-li; LI Jian-ying; CAI Ming-yu
    2008, 19(03):  613-620 . 
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    Based on the four TM images of Naiman Banner in Inner Mongolia in 1975, 1985, 1995 and 2005, the extent and relative rate of land use change were used as the indices to analyze the regional difference of land use/cover change in the farmingpasturing zone of Naiman Banner, and the indices abundance and importance value were adopted to analyze the spatial distribution features of land use/cover change in the study area. The results showed that from 1975 to 2005, the types of land use/cover became diversified. The annual change rate was high, and the regional difference was significant. In the northern alluvial plain sub-area, woodland area increased rapidly and largely, while sandy land area decreased obviously. The changing speed of the areas of meadow and sandy land was the fastest, while that of residential area was the slowest. The main forms of land conversion were the conversion from sandy land to cropland and woodland. In the middle sandy land subarea, sandy land had a wide distribution. The changes of other land use types were comparatively small, and the main form of land conversion was the interconversion between cropland and sandy land. In southern loess sub-area, cropland was the dominant land use type and had the smallest change, meadow and sandy land changed most quickly, and the conversion from meadow to cropland and woodland was the most important land conversion form. Natural factors determined the principal characteristics of land use structure in each sub-area of the study area, and artificial factors determined the changing trends of each land use type in each sub-area.
    Effects of Emergent Water Project on vegetation coverage in the lower reaches of Tarim River.
    YAN Zheng-long1,2; HUANG Qiang1; NIU Bao-ru2; MA Kai1
    2008, 19(03):  621-626 . 
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    Based on the TM in 1999, ETM in 2000, ASTER in 2004, and the background data of the lower reaches of Tarim River, the dynamic changes of vegetation coverage and land desertification before and after the implementation of Emergent Water Project were studied. The results showed that with the implementation of the Project, the areas with medium and higher vegetation coverage increased from 7 447.16 hm2 and 17 146.80 hm2 in 1999 to 9 129.16 hm2 and 26 236.61 hm2 in 2004, and those with lower and poor vegetation coverage decreased by 9 989.10 hm2 and 782.71 hm2, respectively. In 1990-2004, the total area of desertification decreased from 506 258.06 hm2 to 498 043.93 hm2, and the ecological environment in parts of the esertification area tended to be improved, indicating that the Emergent Water Project played an important role in improving the ecological environment in the lower reaches of Tarim River.
    Emergy analysis of ecological-economic system in Liaoning Province.
    LIU Hao1;WANG Qing1;LI Xiu-juan2;SONG Yang1;LI Guang-jun1
    2008, 19(03):  627-633 . 
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    By the methods of emergy analysis, this paper studied the emergy flow in the ecological-economic system in Liaoning Province in 1990-2005, and the relationships between the environmental stress caused by resources’ input, output and consumption and the sustainable development of the Province. The results showed that in Liaoning Province, the nonrenewable resources occupied over 74% of the total consumed emergy, and the realistic population in 2005 was 3.26 times higher than the supportable population. In 1990-2005, the emergy yield ratio decreased from 65.40 to 10.13, emergy loading ratio increased from 2.72 to 7.18, and emergy sustainable index decreased from 24.03 to 1.41. The rapid economic growth in Liaoning Province was chiefly supported by the consumption of vast non-renewable resources, which caused the pressure of economic development on ecosystem getting more and more intense, the economic development increasingly depending on exogenous resources, and the sustainable development of Liaoning ecological-economic system having a continuing decrease. To realize the sustainable development in Liaoning Province, the principles of reduction, reutilization and recycling should be taken as the guidelines for promoting the reuse of wastes and the closed fine circulation of resources to minimize the discharge of wastes.
    Effects of gravel mulch technology on soil erosion resistance and plant growth of river flinty slope.
    ZHU Wei1,2;XIE San-tao2,3; RUAN Ai-dong1; BIAN Xun-wen2
    2008, 19(03):  634-640 . 
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    Aiming at the technical difficulties such as the stability and water balance in the ecological rehabilitation of river flinty slope, a gravel mulch technology was proposed, with the effects of different gravel mulch treatments on the soil anti-erosion capacity, soil water retention property, and plant growth investigated by anti-erosion and pot experiments. The results showed that mulching with the gravels 1.5-2 cm in size could obviously enhance the soil anti-erosion capacity, soil water retention property and plant biomass, but no obvious differences were observed between the mulch thickness of 5 cm and 8 cm. It was indicated that mulching with the gravels 1.5-2 cm in size and 5 cm in thickness was an effective and economical technology for the ecological rehabilitation of river flinty slope.
    Removal effects of citric acid, oxalic acid and acetic acid on Cd, Pb, Cu and Zn in sewage sludge.
    HUANG Liang1,3,4;ZHOU Qi-xing1,2;ZHANG Qian-ru1,4
    2008, 19(03):  641-646 . 
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    This paper studied the effects of applying citric acid, oxalic acid and acetic acid on the removal of heavy metals Cd, Pb, Cu and Zn from sewage sludge, and the form transformation and bioavailability of these heavy metals before and after the application of tested organic acids. The results showed that the removal rates of tested heavy metals except Cu increased with increasing acid concentration and action time. Among the tested organic acids, citric acid was more effective in removing heavy metals from sewage sludge, with the removal rate of 52.0% for Pb and 74.2% for Zn after a 7-hour action, and 76.0% for Pb and 92.5% for Zn after 24-hour action. The removal rates of the heavy metals by oxalic acid and acetic acid were relatively low. The Pb and Zn removed by citric acid were mainly in stable form, resulting in a relative increase of their unstable and exchangeable forms in the sludge. Though the removal rate of Cu and Cd was lower, their exchangeable forms still had somewhat increase after the action of tested organic acids.
    Enhanced fixation of phenanthrene in soils amended with exotic organic materials.
    REN Li-li;LING Wan-ting; GAO Yan-zheng
    2008, 19(03):  647-652 . 
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    This paper studied the enhanced fixation of phenanthrene in clay loam soil, sandy silt soil, and silt loam soil under effects of exotic organic materials (EOMs) commercial organic fertilizer and peat. The results showed that after the addition of EOMs, the adsorption isotherms of phenanthrene in test soils were still linear, and distribution was the predominant mechanism for phenanthrene adsorption by soil. The adsorption of phenanthrene was significantly enhanced by the addition of EOMs, and the enhancement of distribution constant (Kd) was positively correlated with the content of soil organic carbon (foc), indicating that the higher the soil foc, the more significant the promotion effect of EOMs addition on phenanthrene adsorption. On the contrary, the desorption of phenanthrene was obviously inhibited by the addition of EOMs. After 64 days of EOMs addition, the extractable amount of phenanthrene was decreased significantly, compared with the control. Since the organic matter content of peat was higher than that of commercial organic fertilizer, the decrease of extractable phenanthrene in soils added with peat was more significant. In addition, the higher the soil foc, the stronger inhibition effect of EOMs on extractability of phenanthrene. On the whole, exotic EOMs could promote the adsorption, while inhibit the desorption and reduce the extractability of phenanthrene in soils.
    Adsorption behavior of copper ion and methylene blue on citric acid-esterified wheat straw.
    SUN Jin;ZHONG Ke-ing;FENG Min;LIU Xing-an;GONG Ren-min
    2008, 19(03):  653-657 . 
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    A cationic adsorbent with carboxyl groups derived from citric acid- esterified wheat straw (EWS) was prepared by the method of solid phase preparation, and a batch experiment was conducted to study the adsorption behaviors of Cu (II) and methylene blue (MB) in aqueous solution on the EWS under conditions of different initial pH, adsorbent dosage, adsorbate concentration, and contact time. The results showed that the maximum adsorption of Cu (II) and MB was obtained when the initial solution pH was ≥ 4.0. 96% of Cu (II) in 100 mg·L-1 Cu solution and 99% of MB in 250 mg·L-1 dye solution could be removed by ≥2.0 g·L-1 of EWS. The adsorption of Cu (II) and MB fitted the Langmuir sorption isothermal model. The maximum removal capacity (Qm) of EWS was 79.37 mg·g-1 for Cu (II) and 312.50 mg·g-1 for MB, and the adsorption equilibrium of Cu (II) and MB was reached within 75 min and 5 h, respectively. The adsorption processes of Cu (II) and MB could be described by pseudo-first order and pseudosecond order kinetic functions, respectively.
    Size-fractionated biomass of phytoplankton in the Yangtze River estuary and its adjacent waters in winter and spring.
    SONG Shu-qun;SUN Jun;SHEN Zhi-liang;WANG Dan;LUAN Qing-shan
    2008, 19(03):  658-666 . 
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    Based on the multi-discipline investigation in 28th February-10th March and 30th May-4th June, 2005, this paper studied the distribution of sizefractionated phytoplankton in the Yangtze River estuary and its adjacent waters, and the environmental factors that affected this distribution. The results showed that in winter, the average chlorophyll a concentration was 1.28 mg·m-3, and the region with high concentration chlorophyll a was located near the river mouth. Small-sized phytoplankton (SSP, <20 μm) contributed 66.7% to the total phytoplankton biomass, but big-sized phytoplankton (BSP, >20 μm) was dominant in the plume system. In spring, the average chlorophyll a concentration in inner river and outer estuary was 0.67 and 6.03 mg·m-3, respectively, and the maximum of chlorophyll a concentration appeared in the waters between 122.5° E and 123.0° E. The SSP dominated in the plume system, especially in the algal bloom frequently occurring area which located at south of survey area, contributed 83.5% to the total phytoplankton biomass. The vertical profile of size-fractionated chlorophyll a showed that with the increase of water depth, the SSP and BSP became equal in the offshores. Among the environmental factors in the Yangtze River estuary and its adjacent waters, salinity and nutrients were the main factors affecting the distribution and composition of size-fractioned phytoplankton biomass in winter and spring.
    Quantification of fish starvation treatments and randomization test for the contribution rates of treatment factors by BP network.
    ZHU Yi-feng;CHEN Zhi-dan;GUAN Wen-jing;WU Zhong-ning;XUE Liang-yi
    2008, 19(03):  667-673 . 
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    In this paper, four feeding treatments including continuous feeding (SR00), recycling of 2 days starvation and 2 days refeeding (SR22), recycling of 7 days starvation and 2 days refeeding (SR72), and recycling of 7 days starvation and 7 days refeeding (SR77) were designed, and the feeding treatments were quantified as two treatment factors, i.e., starvation stress (SS) and starvation frequency (CF). Combining these two factors with the factors dry matter feed intake (FI), body weight (BW), water temperature (TE), water salinity (SA), water pH (PH) and growth time (GT), three BP artificial neural networks were constructed to predict the weight gain (WG), specific growth rate (SGR), and feed conversion ratio (FCR) of Lateolabrax japonicus, respectively. The results showed that the WG, SGR and FCR of L. japonicus were significantly affected by different feeding treatments. Throughout a 8-week trial, the WG and SGR of starved fish couldn’t catch up to those of control fish. Except for SR72 group whose FCR was markedly higher than that of control group, no differences in FCR were observed between control group and experimental groups SR22 and SR77. The study also indicated that artificial neural network could well predict WG and SGR, but was unavailable forFCR. Among the eight factors, FI, SS, CF and GT had significant contributions to both WG and SGR. Furthermore, WG and SGR were predominantly dependent on FI and SS, respectively. Based on 4999 randomizations, the contribution rate of the treatment factors (including related FI) to WG and SGR was 64.9% and 79.7%, respectively.
    Application of stable carbon isotope technique in the research of carbon cycling in soil-plant system.
    LIU Wei;Lü Hao-hao;CHEN Ying-xu; WU Wei-xiang
    2008, 19(03):  674-680 . 
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    As a main life element, carbon plays important role in the matter cycling in soilplant system. Stable carbon isotope 13C has been widely used in the study of carbon cycling in soil-plant system, due to its safe, no pollution, and easy to be handled. Through the analysis of both natural and labeled 13C organic matter in soil-plant system, a better understanding of the mechanisms of photosynthesis, the distribution of photosynthates in plant-soil system, the fate of plant litter, and the source of new carbon in soil could be achieved. In this paper, the applications of stable carbon isotope technique in the researches of photosynthesis, reconstruction of paleoclimate, turnover of soil organic matter, and interactions between plants and rhizosphere microorganisms were briefly summarized, and the perspectives of the application of stable carbon isotope technique were also discussed, based on the issues existed in current researches.
    Research progress in molecular ecology of Puccinia striiformis f. sp. tritici.
    ZHENG Wen-ming1; KANG Zhen-sheng2;JIANG Shi-jun3;CHEN Chang-qing2
    2008, 19(03):  681-685 . 
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    Stripe rust caused by Puccinia striiformis f. sp. tritici Westend is one of the most important epidemic diseases of wheat in the world. To understand the population evolution of this rust fungus will facilitate the control of this disease and the breeding of rust-resistant wheat. In the past decades, DNA molecular markers have been applied to investigate the population genetics of wheat stripe rust fungus, and rapid progress has brought out in the research of P. striiformis molecular ecology. In this paper, the main research progress in the molecular ecology of stripe rust was reviewed, and the limitations and trends of related research in China were discussed.
    Characteristics of urea 15N absorption, allocation, and utilization by sweet-cherry (Prunus avium L.).
    ZHAO Feng-xia1,2;JIANG Yuan-mao1,2;PENG Fu-tian1,2; GAO Xiang-bin1,2;LIU Bing-hua1,2;WANG Hai-yun1,2;ZHAO Lin1,2
    2008, 19(03):  686-690 . 
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    With five-year old ‘Zaodaguo’ sweetcherry (Prunus avium L.) as test material, this paper studied the characteristics of its urea 15N absorption, allocation, and utilization when applied before bud-break. The results showed that the Ndff of different organs increased gradually with time, and was higher in fine roots and storage organs at full-blooming stage. At fruit core-hardening stage, the Ndff of long shoots and leaves increased quickly, reaching to 0.72% and 0.59%, respectively. From fruit core-hardening to harvesting stage, the Ndff of fruit had a rapid increase, with the peak (1.78%) at harvesting stage. After harvest, the Ndff of neonatal organs increased slowly while that of storage organs increased quickly. At full-blooming stage, the absorbed 15N in roots was firstly allocated to storage organs, with the highest allocation rate (54.91%) in large roots. At fruit core-hardening stage, the allocation rate in fine roots and storage organs decreased from 85.43% to 55.11%, while that in neonatal branches and leaves increased to 44.89%. At harvesting stage, the allocation rate in different organs had no significant change, but after harvest, the absorbed 15N had a rapid translocation to storage organs, and the allocation rate in fine roots and storage organs reached the highest (72.26%) at flower bud differentiation stage. The 15N allocation rate in neonatal branches and leaves at flower bud differentiation stage was decreased by 19.31%, compared with that at harvesting stage. From full-blooming to flower bud differentiation stage, the utilization rate of urea 15N was increasing, and reached the peak (16.86%) at flower bud differentiation stage.
    Effects of cutting on the population dynamics of main insect pests on alfalfa.
    LIU Chang-zhong1; YAN Lin2;WEI Lie-xin1;ZHANG Fang3; QIAN Xiu-juan1
    2008, 19(03):  691-694 . 
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    A systematic investigation was made on the effects of cutting on the population dynamics of main insect pests on alfalfa in Dingxi of Gansu Province. The results showed that the effects of cutting varied significantly with the kinds of insect pests. The seasonal average population densities of Therioaphis trifolii, Acyrthosiphon pisum and thrips decreased significantly and maintained at a low level under the first cutting in early June, but less variation was observed under the second cutting in mid-July. Plant bug presented somewhat different picture. In the early period of first cutting, its seasonal average population density decreased significantly but increased then, and was significantly higher in early August, compared with that in uncut field. Opposite with T. trifolii, A. pisum and thrips, the seasonal average population density of plant bug was more affected by second cutting.