Table of Content

18 October 2006, Volume 17 Issue 10

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Articles

Effects of ramets adjustment on Quercus liaotungensis growth and seed generation

MENG Lingbin^1,2; BAO Weikai¹; PANG Xueyong¹; SUN Fan²

2006, 17(10):  1771-1776 . 

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This paper studied the effects of different ramets adjustment measures on the growth and seed generation of Quercus liaotungensis shrub in the upper reach of Minjiang River. The results showed that artificially adjusting ramets number largely affected the growth of plant height and sexual reproduction of Q. liaotungensis. The adjustment had little effect on the basal diameter of remained ramets, but obviously affected their height if 2 or 3 ramets per shrub were remained. The number, total length, and total biomass of new branches of adjusted shrub had more increase than those of unadjusted one, especially for the shrub of remaining 2 ramets. In adjusted shrub, the number and total biomass of leaves increased obviously, and the leaf area decreased gradually with increasing number of remained ramets. The shrub with three remained ramets generated most seed, while natural shrub had the biggest weight of single seed.

Responses of Shenyang urban tree phenology to climate warming

XU Wenduo; HE Xingyuan; CHEN Wei; HU Jianbo; WEN Hua

2006, 17(10):  1777-1781 . 

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By using statistic and linear regression methods, this paper studied the last 40 years responses of Shenyang urban tree phenology to climate warming. The results showed that there was a significant correlation between the duration of tree dormancy and the mean air temperature in winter. Appropriate cold condition was beneficial to bud break, and a significant negative correlation was observed between the outset of sprouting and the mean air temperature in winter and early spring. Leaf expansion started 15 days after sprouting, which was mainly affected by the mean air temperature in spring but had nocorrelation with the temperature in winter. The air temperature within 20～80 days and especially 20～40 days before flowering had a significant effect on the outset of flowering, i.e., an increasing temperature in spring could advance the outset of flowering. Both sprouting and leaf expansion were negatively correlated with cold index (CI), but no significant correlation was observed between the outset of flowering and CI. An increase of mean annual air temperature by 1 ℃ would advance the outset of sprouting by 9 days, leaf expansion by 10 days, and outset of flowering by 5 days.

Canopy rainfall storage capacity of tropical seasonal rainforest and rubber plantation in Xishuangbanna

WANG Xin^1,2; ZHANG Yiping¹

2006, 17(10):  1782-1788 . 

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Based on the 2003～2004 laboratory and field observation data, and with scaling-up method, this paper studied the canopy rainfall storage capacity of tropical seasonal rainforest and rubber plantation in Xishuangbanna. The results showed that the canopy rainfall storage capacity was 0.45～0.79 mm for tropical seasonal rainforest and 0.48～0.71 mm for rubber plantation, and that of the branch and bark accounted for ＞50 % of the total. For these two forests, the canopy rainfall storage capacity was much higher in foggy season (from November to February) and dry-hot season (from March to April) than in rainy season (from May to October), and the duration needed to reach water saturation was about 5 min for leaf, 2～3 h for bark, and 2.5～4 h for branch. During the processes of wetting and air-drying, leaf was easier while branch and bark were somewhat difficult to hold water and then be air-dried, suggesting that leaf played an important role in intercepting rainfall in short-duration rainfall events, while branch and bark could work much better in doing this in long-duration or high-intensity rainfall events. Compared with rubber plantation, tropical seasonal rainforest had a stronger rainfall-storage capacity due to its multi-layer structure of canopy and excellent water-holding performance.

Respiration rate of broadleaved Korean pine forest ecosystem in Changbai Mountainns

WANG Miao¹;LIU Yaqin²; HAO Zhanqing¹; WANG Yuesi³

2006, 17(10):  1789-1795 . 

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In this paper, the respiration rates of soil, foliage, and stem and branch in the broadleaved Korean pine forest ecosystem of Changbai Mountains were measured by Li-6400 CO₂ analysis system in 2003, with the microclimate factors determined synchronously. The correlation models of ecosystem respiration with environmental factors were established, and the respiration rate of each component of the ecosystem was estimated based on the vegetation characteristics of the broadleaved Korean pine forest. The results showed that the annual total respiration rate of the ecosystem was 1 602.8 g C·m^-2, with a mean of （4.37±2.98） μmol·m^-2·s^-1, and the respiration of soil, foliage, and stem and branch contributed about 63%, 21%, and 16% of the total, respectively. There was a significant correlation between system respiration and daily mean air and soil temperature, and about 87% and 95% of the ecosystem respiration could be explained by the air and soil temperature, respectively.

Genetic diversity of arbuscular mycorrhizal fungi associated with four Alnus species in Changbai Mountains: A nested PCR-RFLP analysis

DONG Tian^1,2; ZHANG Huiwen¹;ZHANG Yue¹; HE Xingyuan¹

2006, 17(10):  1796-1800 . 

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In this paper, the colonization of arbuscular mycorrhizal fungi (AMF) on the root samples of 4 Alnus species in Changbai Mountains was investigated by using nested PCR-RFLP technique, and the PCR results were tested by restriction endonuclease analysis method. The results revealed that the uncultured AMF had a high genetic diversity, and the colonization had a trend from promiscuity to specialization. The AMF from Alnus mandshuica showed the greatest specialization to the host, and Glomus was the dominant colonizer of A. mandshuica. The AMF from A. sibirica var. hirsuta, A. sibirica, and A. tinctoria showed promiscuity, and host had more significant effects on the colonization of AMF than altitude.

Anatomical and water physiological plasticity of Grewia biloba var. parvif lora leaf and secondary xylem

SHI Gangrong¹; CHENG Xuelian¹; LIU Lei¹; MA Chengcang^1,2

2006, 17(10):  1801-1806 . 

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Based on the anatomical observations of leaf and secondary xylem as well as the measurements of leaf water physiological parameters, this paper studied the anatomical and water physiological plasticity of Grewia biloba var. parviflora growing in different succession stage communities. The results showed that G. biloba var. parviflora leaf was characterized by thin bifacial with thin cuticle and few stoma, indicating that it was mesophyte anatomically, while the secondary xylem had typical xeromorphic traits, such as short and thin vessel, high vessel frequency, low percentage single pores, and short fibers and rays. G. biloba var. parviflora had high plasticity in the anatomical structure and water physiological features of leaf and secondary xylem, and the plasticity index was in the order of secondary xylem anatomical structure (0.24) ＞water physiological traits (0.19) ＞ leaf anatomical structure (0.18). Compared with those growing in mixed forest and Platycladus orientalis forest, the individuals of G. biloba var. parviflora in shrub communities had the xeromorphic traits in the aspects of ① their secondary xylem had shorter vessel elements, higher vessel frequency, less single porous percentage, lower rays, higher relative conductivity and lower vulnerability index, and ② their leaf had lower water potential, lower water content and free water content, higher bound water content, high ratio of bound to free water content, and less specific leaf area. The phenotypic plasticity, both anatomical and physiological, made G. biloba var. parviflora tolerate to the drought at earlier succession stages and better adapt to the mesophytic condition at later stages, and consequently, become a widely distributed and dominant species in mixed forests.

Forest carbon storage and fuel carbon emission in Tanjiang River basin

CHEN Zhiliang^1,2; XIA Nianhe¹; WU Zhifeng²; CHENG Jiong²; LIU Ping²

2006, 17(10):  1807-1810 . 

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The investigation on the forest carbon storage and fuel carbon emission in Tanjiang River basin showed that since 1990, the forests in Tanjiang River basin acted as a carbon sink, and this action was increased with time and with economic development. The net carbon uptake by the forests was 1.0579×10⁷ t in 1990 and 1.28061×10.7 t in 2002, with an annual increment of 1.856×10⁵ t, while the fuel carbon emission was 9.508×10⁵ t in 1990 and 1.8562×10⁶ t in 2002, with an annual increment of 7.0×10⁴ t. In 2003, the fuel carbon emission was up to 2.1968×10⁶ t, 3.406×10⁵ t more than that in 2002. In 2002, the energy consumption per 10⁴ yuan GDP in Tanjiang River basin was 2.21 t standard coal, higher than the average consumption (1.81 t standard coal) in the Pearl River delta. If the fuel consumption decreased to the average level, the carbon emission in Tanjiang River basin would be reduced by 3.360×10⁵ t, which was higher than the annual increment of forest net carbon uptake in the basin. From the viewpoint of net carbon uptake and emission in a basin, more attention should be paid to the relations between forest carbon sink and human activities.

Diurnal dynamics of photosynthetic and transpiration rates of alfalfa under dry farming and their relationships with environmental factors

LIU Yuhua^1，2; SHI Ji’an^1，2; JIA Zhikuan¹; HAN Qingfang¹

2006, 17(10):  1811-1814 . 

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In this paper, the diurnal dynamics of photosynthetic rate (P_n) and transpiration rate (T_r) of four years planted alfalfa under dry farming, as well as those of photosynthetic active radiation (PAR), CO₂ concentration in field (C_a), relative humidity (RH) and air temperature (T_a) were measured , and the relationships between the diurnal dynamics of P_n, T_r and climatic factors were analyzed by correlation coefficient, path coefficient, and decision coefficient analyses. The results showed that T_a had the greatest effect on the diurnal dynamics of P_n, while RH, PAR and C_a affected P_n mainly through their acting on T_a. PAR had the greatest effect on the diurnal changes of T_r, and RH, T_a and C_a affected T_r indirectly by acting on PAR. For the characteristics of photosynthesis and transpiration, PAR was the primary determining factor, and T_a was the main limiting factor.

Nitrogen and phosphorus removal from septage filtrate in a ryegrass hydroponic system

XU Xiaofeng^1,2; YANG Linzhang¹; XU Hai¹; ZHOU Xiaoping¹

2006, 17(10):  1815-1819 . 

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With hydroponic method, this paper studied the ryegrass Lolium multiflorum growth and its N and P removal under the application of septage filtrate. The results showed that a medium application rate of septage filtrate gave the highest yield of L. multiflorum. The N and P removal in the ryegrass hydroponic system was increased with increasing application rate of septage filtrate, but the water quality was declined when super high volume of septage filtrate was added. The N and P uptake by L. multiflorum had no significant difference under medium, high, and super high application rate of septage filtrate, with the maximum uptake of N and P being 13.6g·m^-2 and 3.17 g·m^-2_, respectively. The removed proportion of N and P through ryegrass uptake declined with increasing septage filtrate application rate. Under the same total load, increasing the application frequency of septage filtrate could improve ryegrass yield, water quality, and nutrients removal. To select an appropriate application rate and frequency of septage filtrate was the key in improving the nutrients removal efficiency of ryegrass hydroponic system.

Nutrient leaching and acidification of Southern China coniferous forest red soil under stimulated N deposition

SUN Benhua ^1,2; HU Zhengyi¹; LV Jialong²; ZHOU Lina¹; XU Chengkai¹

2006, 17(10):  1820-1826 . 

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In an eight months interval leaching experiment with soil column (10 cm in diameter and 60 cm in height) at 20 ℃, this paper studied the effects of N deposition on the leaching losses of soil NO₃^-,NH₄⁺, H⁺,Ca²⁺, Mg²⁺, K⁺ and Na⁺, and on soil acidification. Soil columns were taken from the coniferous forest experimental plot at the Red Soil Ecological Experiment Station of Chinese Academy of Sciences in Southern China, and the N deposition loads were 0, 7.8, 26 and 52 mg N·month^-·¹column^-1, respectively. The results indicated that the leaching losses of total exchangeable cations, Ca²⁺, and Mg²⁺ increased with increasing N deposition loads, but K⁺ and Na⁺ were little affected. The proportion of net cations leaching loss (difference of cations in eluate and leachate) to total exchangeable cations was 13.9%, 18.6%, 31.8% and 57.9% under 0, 7.8, 26 and 52 mg N·month^-1·column^-1 N deposition loads, respectively, and that for exchangeable Ca²⁺ and Mg²⁺ was 19.6%, 25.8%, 45.3% and 84.8%, and 4.4%, 6.1%, 10.9% and 17.1%, respectively. The leaching losses of inorganic N, NO₃^- and H⁺ also increased with increasing N deposition loads. Topsoil pH decreased with increasing N deposition loads, being 3.85, 3.84, 3.80 and 3.75 under 0, 7.8, 26 and 52 mg N·month^-1·column^-1 N deposition loads, respectively. N deposition could increase the apparent mineralization rate of soil organic nitrogen, and accelerate the nutrient losses and acidification of coniferous forest red soil.

Effects of land use type on soil organic carbon, total nitrogen, and microbial biomass carbon and nitrogen contents in Karst region of South China

LI Xinai^1,2; XIAO Heai¹; WU Jinshui¹; SU Yirong^1,3; HUANG Daoyou¹; HUANG Min¹; LIU Shoulong¹; PENG Hongcui^1,2

2006, 17(10):  1827-1831 . 

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A total of 721 surface (0～20 cm) soil samples were collected from the paddy field, upland, and woodland in the Karst region of Dacai, Huanjiang County, Guangxi Province, and the contents of their organic carbon (O_C), total nitrogen (TN), microbial biomass carbon (B_C), and microbial biomass nitrogen (B_N) were determined. The results showed that the O_C and B_N contents and soil pH value showed the trend of paddy field=woodland＞upland, while TN and B_C contents had the trend of woodland＞paddy field＞upland. There was a significant positive correlation between B_C and O_C, and between B_N and TN. Soil microbial biomass C and N had rapid responses to the changes of land use type, which could be used as the sensitive biological indicators in evaluating soil quality and fertility in Karst region.

A comparison of water balance in small basins with different landscape pattern in the upper reaches of Minjiang River

XU Shenlai^1,2; LI Xiuzhen¹; HE Xingyuan¹

2006, 17(10):  1832-1838 . 

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This paper studied the effects of landscape pattern (land cover types, altitude, slope, aspect, patch density and maximum patch index) on the elements of water balance (precipitation, evapotranspiration, and runoff) in two small basins (Zhenjiangguan River and Heishui River) in the upper reaches of Minjiang River during 1988～2002. Based on the spatial distribution of mean annual precipitation and evapotranspiration as well as the mean annual runoff on different land cover (woodland, grassland and cropland) during 1988～2002, the relationships of landscape pattern with water balance was approached, and the results showed that in these two basins, the precipitation, evapotranspiration / precipitation ratio, and runoff / precipitation ratio had a greater difference with the altitude, slope, and aspect of woodland, and grassland had a similar hydrological effect as woodland. On the farmland of Heishui River basin, which was distributed in dry valley, evapotranspiration was much higher than precipitation. This abnormal water balance was caused by the arid valley climate in the upper reaches of Minjiang River but not the landscape pattern of farmland, being totally different with that in Zhenjiangguan River basin.

Use efficiency and fate of fertilizer N in tomato field of Nanjing suburb

CAO Bing^1,2; HE Fayun¹; XU Qiuming²; CAI Guixin¹

2006, 17(10):  1839-1844 . 

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Field plot and micro-plot experiments were conducted to investigate the use efficiency (UE), fate, and loss of chemical fertilizer N in tomato field of Nanjing suburb. The results showed that the application of chemical fertilizer N did not show any benefit to the tomato yield, due to the adequate N supply from native soil and organic manure amendment. The UE of fertilizer N calculated by difference method ranged from 14.5% to 22.5%. In micro-plot experiment, 16.6%～28.8% of applied urea ¹⁵N was recovered by the plant, and 34.2%～46.0% of it was lost. Applying fertilizer N increased the nitrate content in 0～100 cm soil layer, and 10%～10.2% of urea ¹⁵N was leached to the depth below 40 cm at harvest time. N application increased the denitrification loss and N₂O emission significantly, which occupied 5.50%～6.01% and 2.62%～4.92% of the applied N, respectively. No ammonia volatilization was detected during the whole growth season. Reducing N application rate or applying coated urea could decrease the environmental risks of N application in vegetable fields, especially the risks from nitrate leaching and nitrification-denitrification loss.

Effects of P application on P concentrations in paddy soil and its surface water: A simulation test

ZHOU Quanlai^1,2; ZHAO Muqiu^1,2; LU Caiyan^1,2; SHI Yi¹; CHEN Xin¹

2006, 17(10):  1845-1848 . 

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An anaerobic incubation test was conducted to study the effects of different P application rate on the P concentrations in paddy soil and its surface water. The results showed that soil available P (Olsen-P) decreased rapidly at the beginning, but approached to stable after 60 days of P application. Both Olsen-P and residual P increased with increasing P application rate, and Olsen-P had a positive correlation with P application rate, suggesting that the test soil had a strong P adsorption capacity. After P application, the total P (TP) in soil surface water increased rapidly, and then decreased slowly, showing that there was a P exchange between soil and its surface water. After 120 days of P application, there was an exponential relationship between soil surface water TP and P application. The TP in soil surface water increased rapidly when the P application rate was 400～800 kg·hm^-2, and easy to be lost when the P application rate was higher than 800 kg·hm^-2. The simulation with split line model on the relationship between soil Olsen-P and soil surface water TP showed that the change point of soil OlsenP, which induced a sharp increase of soil surface water TP concentration, was 82.7 mg·kg^-1, corresponding to a P application rate being about 712 kg·hm^-2. Soil Olsen-P could be a good indicator in forecasting the P loss from soil surface water.

Effects of soil moisture on the compensation effect of winter wheat with its partial roots cut off at returning green stage

MA Shouchen^1,4; XU Bingcheng^1,2; LI Fengmin^1,2; HUANG Zhanbin³; LIU lin^1,4; ZHANG Xiaohong^1,4; YANG Shenjiao^1,4

2006, 17(10):  1849-1853 . 

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The study with pot experiment showed that after cutting partial roots at returning green stage, the growth of winter wheat was restrained at early growth stage, and the leaf area was decreased significantly from returning green to jointing stage but restored to the level of the control at flowering stage. Under high soil moisture condition, root cutting increased the values of chlorophyll fluorescence parameters ETR, Φ_{PS Ⅱ}, q_P and q_N at jointing stage significantly. The accumulated dry matter weight per stem after anthesis was significantly higher in root-cut wheat (0.81 g) than in the control (0.56 g), with the accumulation coefficient (AC) of root-cut wheat increased by 38.79%, but no significant difference was observed in root weight. Under low soil moisture condition, there were no significant differences in the values of chlorophyll fluorescence parameters and accumulated dry matter weight per stem after anthesis between root-cut wheat and the control, but the root weight of root-cut wheat decreased significantly. Soil moisture didn’t enhance the compensation effect of the aboveground biomass and grain yield of root-rut wheat. Root cutting reduced the water consumption of winter wheat significantly. Under high soil moisture condition, root-cut wheat saved 2 000 ml of water, and its water use efficiency (WUE) (1.97 g·kg^-1) was significantly higher than that of the control (1.70 g·kg^-1). Under low soil moisture condition, root-cut wheat saved 1 500 ml of water, but there was no significant difference in the WUE between root-cut wheat and the control.

Effects of short-term high temperature stress on flag leaf photosystem Ⅱ functions of high-yielding wheat at late grain-filling stage

CHEN Feng¹; TIAN Jichun²; MENG Qingwei^1,3; ZHAO Shijie^1,3

2006, 17(10):  1854-1858 . 

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By using fast OJIP chlorophyll a (Chl a) fluorescence transients, this paper studied the effects of short-term high temperature stress on the flag leaf photosystem Ⅱ (PSⅡ) functions of high-yielding winter wheat cultivar 01-35 at its late grain filling stage. The results showed that with the temperature raised from 37 ℃ to 43 ℃, the extent and velocity of Q_A reduction enhanced gradually, being 23.89% and 24.09% higher at 43 ℃ than at room temperature, respectively, which suggested that the electron transport from Q_A to Q_B was inhibited. The electron acceptor pool of PSⅡ including Q_A, Q_B and PQ at 43 ℃ decreased to 47.4% of that at room temperature, indicating its being damaged. The electron donor side of PSⅡ was not damaged from 37 ℃ to 43 ℃. When temperature raised to 46 ℃, the extent and velocity of Q_A reduction were 13.95% and 20.48% higher than those at room temperature, respectively, but decreased obviously, compared with those at 43 ℃. In contrast, the electron acceptor pool of PSⅡ at 46 ℃ had no obvious change, compared with that at 43 ℃, indicating that the electron donor side of PSⅡat 46 ℃ was damaged. Comparing with cultivar Lumai 14, the light harvesting complex (LHCⅡ) of high-yielding wheat cultivar 01-35 could harvest more sun energy, and distributed more absorbed energy into electron transport, suggesting that the LHCⅡ of cultivar 01-35 could endure a certain higher temperature, and maintain higher electron transport capacity.

Effects of different irrigation modes on biological characteristics and water use efficiency of paddy rice

CHENG Jianping¹; CAO Cougui¹; CAI Mingli¹; WANG Jinping¹; YUAN Baozhong¹; WANG Jianzhang²; ZHENG Chuanju²

2006, 17(10):  1859-1865 . 

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With hybrid rice cultivar Liangyou Peijiu as test material, this paper studied its biological characteristics and water use efficiency under effects of four irrigation modes. Compared with continuous flooding irrigation, intermittent irrigation increased the leaf area index, photosynthetic rate and water use efficiency, and decreased the leaf transpiration rate. Semi-dry cultivation increased the leaf water use efficiency, while dry cultivation decreased the leaf area index, photosynthetic rate, and water use efficiency, and induced the leaf senescence in later growth period. Under intermittent irrigation, semi-dry cultivation and dry cultivation, the water consumption of paddy rice was 8.75%, 17.96% and 29.69% lower, and its grain yield was 24.02% higher but 5.07% and 38.93% lower than that under continuous flooding irrigation, respectively. The water use efficiency was the highest under intermittent irrigation, relatively high under semi-dry cultivation, but relatively low under continuous flooding irrigation and dry cultivation. Compared with other irrigation modes, intermittent irrigation increased the milled rice rate, head rice rate and grain length, while decreased the chalky rice and chalkiness. With the reduction of water consumption, the amylose content of rice grain decreased, but the gel consistency and protein content increased. Intermittent irrigation could be a favorable irrigation mode for the paddy rice planting in Southern China.

Enzyme activities in nitrogen metabolism of winter wheat and its grain quality under different environmental conditions

ZHAO Chun¹; JIAO Nianyuan²;NING Tangyuan³; WANG Hao⁴; LOU Jinhua¹; HOU Xiangshan¹; LI Zengjia³

2006, 17(10):  1866-1870 . 

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The study with three wheat cultivars grown in two places of Shandong Province showed that the nitrate reductase (NR) and glutamine synthetase (GS) activities in flag leaf and the GS activity in grain were in the sequence of Jimai 20＞Youmai 3＞PH971942, and higher in Longkou than in Taian. The strong gluten wheat cultivars in Longkou had better grain qualities than those in Taian. There were significant correlations between the environmental factors at grain-filling stage and the grain qualities and enzyme activities of wheat. Higher temperature, moderate drought and less sunshine at grain filling stage were benefit to the grain qualities. The protein content of grain was positively correlated with the NR and GS activities in flag leaf for the medium and strong gluten wheat cultivars in Longkou and for the medium gluten wheat cultivars in Taian. Wheat cultivars for different use needed different environmental conditions, while suitable environmental conditions could promote the enzyme activities in nitrogen metabolism of wheat, and thus, improve the qualities of wheat grain.

Salt resistance and its mechanism of cucumber under effects of exogenous chemical activators

SONG Shiqing^1,2,3; LIU Wei¹; GUO Shirong²; SHANG Qingmao³; ZHANG Zhigang³

2006, 17(10):  1871-1876 . 

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With root injection and foliar spray, this paper studied the effects of different concentrations salicylic acid, brassinolide, chitosan and spermidine on the growth, morphogenesis, and physiological and biochemical characters of cucumber (Cucumis sativus L.) seedlings under 200 mmol·L^- NaCl stress. The results showed that at proper concentrations, these four exogenous chemical activators could markedly decrease the salt stress index and mortality of cucumber seedings, and the decrement induced by 0.01 mg·L^-1 brassinolide was the largest, being 63.0% and 75.0%, respectively. The activities of superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) increased significantly, resulting in a marked decrease of malondialdehyde (MDA) content and electrolyte leakage.The dry weight water content and morphogenesis of cucumber seedlings improved, and the stem diameter, leaf number, and healthy index increased significantly. All of these suggested that exogenous chemical activators at proper concentrations could induce the salt resistance of cucumber, and mitigate the damage degree of salt stress. The salt resistance effect of test exogenous chemical activators decreased in the sequence of 0.005～0.05 mg·L^-1 brassinolide, 150～250 mg·L^-1 spermidine, 100～200 mg·L^-1 chitosan, and 50～150 mg·L^-1 salicylic acid.

Photosynthetic and growth characteristics of different ecotype capsicum under weak light

SUI Xiaolei¹;ZHANG Zhenxian¹; ZHANG Baoxi²; MAO Shengli²; WANG Lihao²; LI Wei¹

2006, 17(10):  1877-1882 . 

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This paper studied the effects of weak light on the photosynthetic characteristics, assimilates allocation, yield formation, and seedling growth of different ecotype capsicum (hot pepper and sweet pepper). The results showed that under weak light, the net photosynthetic rate (P_n), dark respiration rate (R_d) , night respiration rate (R_n), transpiration rate (T_r), water use efficiency (WUE), light compensation point (LCP), CO₂ compensation point (CCP) and carboxylation efficiency (CE) of test capsicums decreased, while their apparent quantum yield (AQY) increased. The decrease of P_n was considered as a result of non-stomata restriction. Weak light increased plant height/stem diameter ratio and specific leaf area, but decreased root/shoot ratio, total dry mass, and seedling’s healthy index. Under the effect of weak light, the formation of biological and economic yields was inhibited significantly, and the allocation of assimilates to stem and leaf was increased while that to fruit decreased. Hot pepper under weak light had lower light compensation point, higher relative healthy index, higher relative yield per plant, and higher relative setting rate, showing a stronger capability of weak light tolerance than sweet pepper.

Effects of salt stress on the root growth and leaf water use efficiency of cucumber seedlings

WANG Suping;GUO Shirong; LI Jing; HU Xiaohui; JIAO Yansheng

2006, 17(10):  1883-1888 . 

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By the method of water culture, and with the seedlings of two cucumber cultivars having different tolerance to salt stress as test materials, this paper studied their root growth, vitality, and membrane permeability, as well as their leaf growth, transpiration rate (T_r), relative water content (RWC), and water use efficiency (WUE) under effects of different NaCl levels. The results showed that under salt stress, the absorption surface area of root was declined, whereas its membrane permeability was increased significantly. The leaf number per cucumber seedling was decreased, compared with that of the control. Both T_r and RWC were markedly decreased after 2 days exposure to salt stress. During the period of salt treatment, root vitality and leaf WUE were increased initially, but decreased then. For the salt-susceptible cultivar Jinchun No. 2, the decrement of its root vitality was 18.01%, 12.17% and 10.95 % higher than that of the salt toleran cultivar Changchun Mici on the 9th day exposure to 50, 75 and 100 mmol·L^-1 NaCl, and the decrement of its leaf WUE was 2.74%, 5.27% and 0.23 % higher than that of Changchun Mici on the 8th day exposure to 50, 75 and 100 mmol·L^-1NaCl, respectively. Under short-term salt stress, the absorption capacity of root was raised to compensate its reduced absorption surface area, while the decrease of T_r and the increase of WUE could reduce the leaf water loss, which alleviated the imbalance between water demand and need and improved the salt-tolerance of cucumber seedlings. After 5 days exposure to salt stress, both root vitality and leaf WUE decreased, which showed more severe water imbalance. It could be concluded that the decrease of root absorption capacity was one of the main reasons of water imbalance, and the decrease of leaf WUE was one of the responses to water imbalance. Both the absorption capacity of root and the WUE of leaf were closely related to the salt-tolerance of cucumber cultivar.

Cold tolerance and wintering cultivation effect of different Welsh onion varieties

SU Hua¹; XU Kun¹; LIU Wei^1,2; XU Ligong¹

2006, 17(10):  1889-1893 . 

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With Welsh onion Zhangqiu as the contrast, this paper measured the physiological indices including electrolyte leakage, malondialdehyde content, protective enzyme activity, chlorophyll content, photosynthetic rate and root vitality of two introduced Welsh onion varieties Chunwei and Changbao, and identified their cold tolerance and wintering cultivation effect. The results showed that during wintering cultivation, all test Welsh onion varieties suffered low temperature stress, which led the electrolyte leakage and malondialdehyde content arrived at the maximum, while the chlorophyll content and photosynthetic rate dropped to the bottom at 15 January. At this time, the function data of physiological indices were 0.452, 0.364, and 0.226 for Chunwei, Changbao and Zhangqiu, respectively, suggesting that Chunwei had stronger cold tolerance, followed by Changbao, and Zhangqiu. The bolting rate of Chunwei, Changbao and Zhangqiu when harvested was 0, 35.2% and 81.0%, respectively. Although the biological yield of Changbao was 25.67% and 52.94% higher than that of Chunwei and Zhangqiu, respectively, the economic yield of Chunwei was the highest (5.49 kg·m^-2), with an increment of 18.57% than Changbao, and that of Zhangqiu was only 0.86 kg·m^-2. It could be concluded that Chunwei was fit to cultivate in low tunnel in winter,while Zhangqiu was weaker in cold tolerance and not fit to wintering cultivation.

Dry matter accumulation and allocation models of rice in FACE

SUN Chengming¹; ZHUANG Hengyang¹;YANG Lianxin¹; YANG Hongjian¹; HUANG Jianye¹; DONG Guichun¹; ZHU Jianguo²; WANG Yulong¹

2006, 17(10):  1894-1898 . 

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A fertilization experiment with 150 kg N·hm^-2, 250 kg N·hm^-2 and 350 kg N·hm^-2 was conducted on the free-air CO₂ enrichment (FACE) platform at Wuxi of Jiangsu Province in 2001～2003, aimed to build a simulation model of dry matter accumulation and allocation of rice in FACE. Physiological development time and CO₂ concentration were selected as the driving factor and the main affecting factor, respectively, and nitrogen application rate was introduced as the factor adjusting the dry matter accumulation and allocation in green leaf, stem and panicle. The results showed that with the increase of atmospheric CO₂ concentration, the drymatter accumulation in above-ground part of rice increased remarkably, but the allocation index dropped in green leaf, changed little in panicle, while increased in stem at early stage and equaled to the CK at last. The model was tested with different experimental data, and the results indicated that the model had high fitting degree and preferable applicability and predictability.

Energy accumulation and caloric value in yieldforming process of different rice cultivars

LIN Ruiyu^1,2; LIANG Yiyuan¹; CAI Biqiong¹;CHEN Weining¹; HE Haibin¹; LIN Wenxiong^1,2

2006, 17(10):  1899-1904 . 

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Based on the determination of dry matter and caloric value, this paper studied the characteristics of energy accumulation and the dynamics of caloric value in the yield-forming process of rice cultivars Shanyou 63 (three-line hybrid rice), Liangyou 2186 (two-line hybrid rice), and IR64 (conventional rice). The results showed that at fully grain-maturing stage, the amount of dry matter in Shanyou 63, Liangyou 2186 and IR64 was 1926.38 g·m^-2, 1933.80 g·m^-2 and 1842.30 g·m^-2, and that of accumulated energy was 31137.05 kJ·m^-2, 31060.63 kJ·m^-2 and 30454.89 kJ·m^-2, respectively, showing no significant difference among the cultivars. In the process of grain filling, the apparent transformation ratio of energy in Shanyou 63, Liangyou 2186 and IR64 was about 38.95%, 28.38% and 32.66%, respectively, implying that the energy flow in Shanyou 63 and IR 64 was smoother than that in Liangyou 2186, and the output of energy from stem to the sink of grain was blocked in Liangyou 2186. The ratio of energy partitioning to the sink of grain was 53.03%, 46.43% and 50.11% for Shanyou 63, Liangyou 2186 and IR64, respectively, showing the energy partitioning heterosis in three-line hybrid rice Shanyou 63. As for the caloric value, it had no significant difference among the three cultivars, but decreased in the order of leaf＞grain＞sheath＞stem＞root, ranging from 16.81～17.25 kJ·g^-1, 15.89～16.54 kJ·g^-1, 14.33～15.49 kJ·g^-1, 14.23～15.15 kJ·g^-1, and 11.51～13.25 kJ·g^-1, respectively. It was also shown that there was a significant positive correlation of caloric value with carbon content, chlorophyll a content, and nitrogen content in rice plant, with the determination coefficient R² being 0.609, 0.471 and 0.485, respectively.

Dynamic prediction and evaluation method of maize chilling damage

MA Shuqing¹; LIU Yuying¹; WANG Qi²

2006, 17(10):  1905-1910 . 

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In order to prevent and alleviate the chilling damage of maize, a dynamic prediction and evaluation method on its emergence and loss was developed by using an improved dynamic model of maize growth and dry matter accumulation, and new parameters and damage indices. The method followed the thermal constant theory and the principles of maize biology and ecology, utilized relative accumulated temperature as the leading factor of maize development stage prediction and damage discretion, and took dry matter shortage rate as the loss rate of the damage. The results of test and tryout showed that the method was objective and applicable, and suited for various places of Northeastern China through areal adjustment of parameters and indices.

Estimation of N loss loading by runoff from paddy field during submersed period in Hangjiahu area

TIAN Ping; CHEN Yingxu; TIAN Guangming;LIANG Xinqiang; ZHANG Qiuling; YU Qiaogang;LI Hua

2006, 17(10):  1911-1917 . 

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As the largest bread basket in Zhejiang Province, Hangjiahu area is facing more and more serious water pollution, while the N loss loading by runoff from the paddy field during its submersed period is the main cause of the pollution. Through field experiment and fixed spot observation, the model of precipitation-runoff in Yangtze delta was testified, and the results showed that the precipitation-runoff model from HE Baogen was basically accorded with the fact after considering the impact of field overflow mouth, and the error was between -19.9% and + 18.0%. The model of N concentration with precipitation-runoff in paddy field during submersed period was brought forward, with the R value being 0.948. These two models consisted of the model of N loss loading by runoff from paddy field during submersed period. Based on this model as well as the past 30 years data of fertilization and precipitation, 1∶250 000 topography map, land use map, and water system map, the N loss loading and its distribution were estimated by using GIS method, and the results showed that the N loss loading was different from place to place, with an average of 35.26 kg N·hm^-2, and accounting for 12.69% of the applied N. The N loss loading in Anji and Yuhang with obviously more precipitation was higher than that in other places, while Haining also had a serious N loss problem because of the huge amount of applied N.

Urban greenbelt eco-service value of Hangzhou City under effects of land use change: An evaluation with CITYgreen model

ZHANG Kan;ZHANG Jianying;CHEN Yingxu;ZHU Yinmei

2006, 17(10):  1918-1922 . 

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Based on the Landset TM information of land use/cover change and greenbelt distribution in Hangzhou city in 1994 and 2004, and by using CITYgreen model, this paper estimated the eco-service value of urban greenbelt in the city under the effects of land use change and economic development. The results showed that in the 10 years from 1994 to 2004, the greenbelt area in the city decreased by 20.4%, while its eco-service value increased by 168 million yuan. The annual increment of greenbelt eco-service value and GDP was 111.92% and 5.32%, respectively . Suitable adjustment of land use pattern in the city harmonized the relationships between urban economic development and urban eco-function, and achieved higher eco-service efficiency of land utilization.

Application of entropy weight and fuzzy synthetic evaluation in urban ecological security assessment

GAO Changbo^1,2; CHEN Xingeng²; WEI Chaohai³; PENG Xiaochun 4

2006, 17(10):  1923-1927 . 

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Ecological security is one of the foundations of regional security, and the basis of sustainable development. Urban ecological security refers to the ecological support and main ecological issues of a city, which do not threaten its survival and development. To develop the research method on the ecological security of urban social-economic-natural complex ecosystem, an assessment indicator system of urban ecological security was set up based on Pressure-State-Response Model, which included 3 key factors and 33 concrete items. The five most developed cities of China were taken as the cases to assess their ecological security situation by using entropy weight and fuzzy synthetic evaluation method. The results showed that the urban ecological security of Suzhou and Beijing was at relatively safe level, while that of Shenzhen, Shanghai and Guangzhou was critical safe in the year of 2003. The urban ecosystem of Shenzhen was under heavy press, while that of Suzhou behaved best both in system status and system response. Comparing with other assessment methods, this evaluation method was easier and more reasonable. The results were basically consistent to the fact of these cities, suggesting that the urban ecological security indicator system and the entropy weight and fuzzy synthetic evaluation approach were feasible to some extent.

Predation of Axinoscymnus cardilobus to Bemisia tabaci

HUANG Zhen¹; REN Shunxiang¹; YAO Songlin^1,2

2006, 17(10):  1928-1932 . 

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The laboratory study on the predation of Axinoscymnus cardilobus to Bemisia tabaci showed that the functional response of A. cardilobus to B. tabaci was of Holling's type II. With the increasing age of B. tabaci, the searching rate of A. cardilobus adult decreased, and its handling time became longer. The searching rate of A. cardilobus larva was increased with its age, and the handling time became shorter. The mutual interference in individual predator could be described by Hassell and Varley equation, and the relationship between predation ratio (E) and natural enemies density (P) was E=0.5205P^-0.6631. The predation efficiency (E) of predator varied with environmental temperature, and the effects of the temperature on search rate (a) and handling time (T_h) could be described by a=-0.0002T³+0.0166T²-0.3492T+3.2329 and T_h=4×10^-7T³-3×10^-5T²+0.0006T-0.0009, respectively.

Control effect of natural enemies on Plutella xylostella under ecological restoration condition

CHEN Kewei; HUANG Shoushan; HE Yurong

2006, 17(10):  1933-1936 . 

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A field study on the life table of diamondback moth (DBM) Plutella xylostella showed that the population increase index of DBM in chemical control plot was 52.52, while that of four continuous generations of DBM in ecological restoration plot was 16.9, 7.16, 3.71 and 4.02, respectively, indicating that the control effect of natural enemies on target pest was greatly improved. The main factor affecting the first and forth generations of DBM was the parasitism of Cotesia plutella, while those affecting the second and third generations of DBM were the predator of the 4^th instar larva and the parasitism of Trichogramma, with the corresponding exclusive index of population control (EIPC) being 1.39, 1.54, 1.56 and 1.74, respectively. There was an obvious time lag effect of natural enemies on their target pest, and thus, to protect and multiply the population of natural enemies in the field should be the key point of fully exerting the potential of natural enemies in their pest control.

Effects of cropping system and cultivation pattern on bacterial populations and anti-fusarium wilt bacteria in melon soils

LI Bin^1,2; XIE Guanlin¹; CHEN Ruoxia²; HUANGFU Weiguo²;LIU Bo³

2006, 17(10):  1937-1940 . 

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A total of 132 soil samples were collected from Xinjiang, Fujian and Zhejiang provinces to study the effects of different cropping system and cultivation pattern on the amount of bacterial populations and the distribution of anti-fusarium wilt bacteria in melon soils. The results of plate counting showed that the amount of culturable bacteria was 15.2 times higher in melon soils than in uncultivated soil, 1.0 times higher in rhizosphere than in non-rhizosphere, 2.5 times higher in the soil with rotation than in that with monoculture, and 0.5 times higher in the soil with non-graft than in that with graft. The Biolog determination of anti-fusarium wilt bacteria in melon soils showed that the soil with water-drought rotation or graft had more antagonistic bacteria, and more than 80% of them were classified as fluorescent Pseudomonas spp.

Sustainable rice pest management and its economic benefits

LIU Guangjie¹; Kazushige SOGAWA²; CHEN Shigao³; PU Zhengguo³; SHEN Junhui¹;SHI Dungui³; QIAO Qingchun³; LIU Xianggui⁴

2006, 17(10):  1941-1947 . 

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With rice varieties Jiahua 1 (resistant to the white backed plant hopper Sogatella furcifera) and Shanyou 63 (susceptible) as test materials, this paper studied the effects of different insecticide treatments on the pest population and quality and yield of rice grain, and evaluated their actual economic benefits (AEB). The results indicated that in the control plot, the peak density of S. furcifera on Jiahua 1 was only 1/10 of that on Shanyou 63. Throughout the whole rice growth period, the S. furcifera population on Jiahua 1 kept below economic injury level, while Shanyou 63 suffered heavy infestation by S. furcifera. The spider density in the control plot was 3～7 times higher than that in the plots treated with insecticide following farmers’ practice. No application of insecticide decreased the grain yield of Jiahua 1 and Shanyou 63 by 11.8% and 43.4%, respectively. Compared with the control, spraying with insecticide one time decreased the AEB of Jiahua 1 and Shanyou 63 by 0.9%～2.6% and 2.6%～4.7%, respectively. Without insecticide application, the AEB of Shanyou 63 decreased by 32.9%～36.1%, while that of Jiahua 1 increased by 2.2%～4.8%. The income of planting Jiahua 1 without insecticide application was 9403 yuan·hm^-2, which was remarkably higher than that (8632 yuan·hm^-2) of Shanyou 63 protected by spraying insecticide 3 times. It was worthwhile to point out that insecticide treatment did not affect the processing of rice grain and its commercial and edible quality, but decreased its protein content of Jiahua 1 and Shanyou 63.

Enrichment and toxicity effect of heavy metals in soil ecosystem

WANG Zhenzhong¹; ZHANG Youmei¹; DENG Jifu²; LI Zhongwu³

2006, 17(10):  1948-1952 . 

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The study on the heavy metals-polluted soil of Qingshuitang District, Zhuzhou City showed that the main enriched heavy metals in the soil were Cd, Hg, As, Zn,Pb and Cu, among which, the former three had strong biotoxicity while the others had definite toxicity, with the average integrative pollution index being 6.40. The heavy metals enrichment in soil animals increased with increasing pollution degree. Especially for some species of Megascoiecidae, they had a high enrichment of Cd, with the enrichment index being 11.96. The species and quantity of soil animals decreased with increasing Cd concentration. Cd had an obvious biotoxic effect on Megsacoiecidae’s isozyme activity. The heavy metals enrichment in vegetables also increased with increasing pollution degree, but there existed obvious interspecies difference in Cd enrichment.

Effects of chlorine ion and EDTA on cadmium availability to plants

WANG Fang;ZHENG Ruilun; HE Ren; LI Huafen

2006, 17(10):  1953-1957 . 

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In a water culture experiment with rice and rape, different concentrations of chloride or EDTA were added to study the effects of chlorine ion and EDTA complexation on the uptake of cadmium by the plants. The results showed that the cadmium concentration in the shoots and roots of test plants decreased with increasing concentration of chloride or EDTA. With the increase of Cl^-concentration, the cadmium content in rice shoot and root decreased from 212.2 mg·kg^-1 and 345.1 mg·kg^-1 to 34.1 mg·kg^-1 and 209.1 mg·kg^-1, respectively. EDTA addition decreased the cadmium content in rice shoot and root from 212.l2 mg·kg^-1 and 345.2 mg·kg^-1 to 50.0 mg·kg^-1 and 4.2mg·kg^-1, and that in rape shoot and root from 86.7 mg·kg^-1 and 149.2 mg·kg^-1 to 22.2 mg·kg^-1 and 12.3 mg·kg^-1, respectively. EDTA also affected the cadmium translocation from root to shoot. The complexation of Cl^- or EDTA with cadmium reduced the uptake of Cd by plants, and the effect of EDTA was more obvious than that of Cl^-.

Effects of methamidophos and copper on ecological detoxification of acetochlor by earthworm in phaeozem

LIANG Jidong^1,2; ZHOU Qixing^1,3

2006, 17(10):  1958-1962 . 

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By using microcosm culture method, this paper studied the dynamic changes of acetochlor degradation by earthworm in phaeozem with methamidophos or copper addition, aimed to approach the feasibility of using earthworm to intensify the detoxification of acetochlor. The results showed that the dynamics of acetochlor degradation accorded with the first-order reaction kinetics, whether earthworm existed or not. The activities of earthworm accelerated the detoxification of acetochlor, and the coexistence of methamidophos or copper with acetochlor evidently inhibited the degradation of acetochlor. The coexistence of methamidophos and acetochlor or of copper and higher concentration acetochlor altered the dynamics of acetochlor degradation, while the coexistence of copper and lower concentration acetochlor didn’t have any obvious effect on the detoxification of acetochlor.

Rhizodeposition and its role in carbon cycling in plant-soil system

WANG Zhenyu^1,2; LV Jinyin¹; LI Fengmin^1,2; XU Bingcheng^1,2

2006, 17(10):  1963-1968 . 

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Rhizodeposition is an important interface process of the exchange between plant and soil, and plays an important role in soil carbon turnover. The rhizodeposition of carbon is also the bridge linking plant, soil, and microorganisms. This paper reviewed the researches on the rhizodeposition in carbon balance and carbon cycling, expounded the mechanisms of carbon rhizodeposition, and discussed the problems in related experiments, the differences of rhizodeposition with plant species, cultivars and growth stages, the relationships between rhizodeposition and soil respiration, and the significance of rhizodeposition in the carbon cycling in plant-soil system. Some related research tasks in the future were also proposed.

Contribution of seed size and its fate to vegetation renewal: A review

WU Gaolin¹; DU Guozhen^1,2; SHANG Zhanhuan²

2006, 17(10):  1969-1972 . 

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Seed is the reproductive body of spermatophytes, and its resource devotion has a direct effect on the offspring fitness and the renewal of vegetation community.Generally, larger size seed has the superiorities of higher germination rate and seedling’s establishment, while smaller size seed has the advantages in escaping the predation of animals and birds, forming soil seed bank, and exhibiting larger potentiality of vegetation renewal. Under various kinds of stress, different size seed has different fate in its life history, and has different contribution in vegetation renewal. This paper reviewed the research findings on the contribution of seed size and its fate to vegetation renewal, and presented some suggestions regarding the domestic research in the future.

Application of chlorophyll fluorescence analysis in forest tree cultivation

WEN Guosheng¹; TIAN Haitao¹; ZHANG Mingru²; JIANG Wenwei³

2006, 17(10):  1973-1977 . 

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In recent years, chlorophyll fluorescence analysis has been developed into a kind of new, fast, simple, and accurate technique in photosynthesis research, and widely applied in agriculture and horticulture but few in forest tree cultivation. This paper introduced the relevant parameters of chlorophyll fluorescence analysis and their biological meanings, and summarized its application in forest tree cultivation and in the research of forest tree stress physiology. Some perspectives and suggestions were put forward.

Degradation of main ecosystems in South China Sea and corresponding conservation countermeasures

LAN Zhuhong;CHEN Guizhu

2006, 17(10):  1978-1982 . 

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South China Sea is a significant area of global biological diversity. Due to the long-term unreasonable exploitation and utilization, the habitat there degenerates obviously, and the biodiversity loses seriously. The estimated annual loss of mangrove area ranges from 0.5% to 3.5%, and that of seaweed area is from 20%to 50%. A total of 82% of coral reefs in the Sea display evident degradation. In this paper, a trans-boundary diagnostic analysis of ecosystem degradation in South China Sea was conducted, with the focus on mangrove, seaweed and coral reef. Based on the analysis of the destruction state of the existing ecosystems as well as the main causes of habitat degradation and its trans-boundary impacts, some countermeasures on habitat conservation and management were put forward, aimed to promote the cooperation both at national and at regional levels to implement appropriate approach to reverse the ecosystem degradation trend in South China Sea.

Research progress on ecological footprint analysis

CHEN Dongdong;GAO Wangsheng;CHEN Yuanquan

2006, 17(10):  1983-1988 . 

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Ecological footprint (EF) model, as an indicator of sustainability, has received broad attention and wide use. With the development and refinement of the research work on EF theory and methodology, it appeared various methods which can be applied at different scales. Ecological footprint analysis has been combined with material flow analysis, life cycle assessment or input-output analysis, and especially, the newest progress in EF methods called allocating EF to final consumption categories with input-output analysis helps to develop a “standardized” EF. In this paper, the underlying causes of these methods were interpreted theoretically, and the research methods were classified into progress analysis and input-output analysis (IOA). In addition, the compound and component-based methods as well as IOA were introduced, with their respective features, application, and development progress discussed. A prospect on the development of EF in term of the tendency and application of EF methods in China and abroad was given,i.e., the common framework should be built at the national and regional scales by using compound analysis, IOA and component-based analysis are expected to develop their application in China, and time series research and multi-scenarios analysis of EF forecast ability must be strengthened.

Major chemical components of poultry and livestock manures under intensive breeding

YAO Lixian^1,2; LI Guoliang¹;DANG Zhi²

2006, 17(10):  1989-1992 . 

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Owing to the wide use of feed additives in modern intensive poultry and livestock production, the major components and their concentrations of domestic animal manures may be greatly changed, as compared with those in traditional breeding. An investigation on the 61 samples of chicken, pig and pigeon manures from the intensive poultry and livestock farms of Guangdong Province showed that the concentrations of total N, P and K in chicken and pig manures were obviously higher than those of traditional breeding, and the P/N ratio of three test manures was greater than that of common crops. The concentrations of total soluble salts (TSS) of test manures averaged 49.0, 20.6 and 60.3 g·kg^-1, respectively, which were mainly composed of the sulfate and chloride of potassium and sodium. The mean concentrations of Cu, Zn and As reached 107.5, 366.6 and 21.6 mg·kg^-1 in chicken manure, 765.1, 1128.0 and 89.3 mg·kg^-1 in pig manure, and 56.1, 210.9 and 2.9 mg·kg^-1 in pigeon manure, respectively. These manures were low in Pb, Cd and Cr contents, from non-detectable to 12.0 mg·kg^-1. According to the limiting criteria of heavy metals in fertilizers, the Cu, Zn and As in the three manures were the major elements exceeding the limits, especially for Zn.

Separation of protein and isoflavone in soybean whey by ultrafiltration

JING Legang^1,2; ZHANG Yongzhong¹

2006, 17(10):  1993-1995 . 

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The study on the technical conditions of separating protein and isoflavone in soybean whey by ultrafiltration showed that before ultrafiltration, soybean whey should be pretreated to reduce membrane contamination. The orthogonal experiment of 2 factors and 3 levels indicated that the optimum pretreatment conditions were 5% of CaCl₂ addition based on the solid substance content in soybean whey, and heating up at 85 ℃ for 15 minutes. Under these conditions, the precipitation rate of whey protein was 49.8%, while the reservation rate of isoflavone was 90.4%. Single factor experiment showed that the optimum ultrafiltration conditions were poly (ether sulfone) membrane of 10 kDa molecular weight cut-off (MWCO), 51～68 kPa, and 30 ℃～40 ℃. Under these conditions, the retention rate of whey protein and isoflavone was 83.9% and 7.6%, respectively.

Halophilous microbial groups in saline lake of Qinghai and the growth characteristics and anti-microbial and anti-tumor activities of F16.

YE Yangfang; YAN Xiaojun;HUANG Xiaochun; CHEN Ye;CHEN Haimin; ZHU Shihua

2006, 17(10):  1996-1998 . 

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A total of forty-five halophilous microorganisms were isolated from the sediment of saline lake in Qinghai Province, among which, filamentous fungus F16 showed the highest activity of anti-microorganism and anti-tumor. The ethyl acetate extract of F16 culture filtrate showed a strong cytotoxicity, and could inhibit the growth of four kinds of bacteria, especially Escherichia coli. When the concentration of the crude extract was 50 μg·ml^-1, the inhibition rate to liver cancer cell BEL7402 reached 76.91%. The optimal temperature for F16 growth was 15 ℃,and the increase of salt concentration in media would inhibit its growth. When the concentration of salt surpassed 15%, F16 could not survive. F16 grew well when the pH value ranged from 5 to 9.