Table of Content

08 July 2010, Volume 29 Issue 07

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Articles

Phyllostachys pubescens sap flow and its relationships with environmental factors.

2010, 29(07):  1263-1269. 

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A Dynamax sap flow measuring system was applied to monitor the diurnal variation of sap flow velocity of Phyllostachys pubescens stands in Miaoshanwu Nature Reserve in Zhejiang. In the meantime, Equitensiometer (EQ-15) was applied to measure the soil water potential at 0-100 cm, and an automatic weather station was utilized to record the total solar radiation, air temperature, air relative humidity, and wind speed. The diurnal variation of the sap flow velocity exhibited mono-peak curve, with a distinct diurnal course on clear days, and a multi-peak pattern on cloudy or rainy days. The average daily sap flow rate and the diurnal sap flux were lower on cloudy or rainy days than on sunny days. The magnitude of the sap flow changed considerably between sunny and rainy days. The daily sap flux of P. pubescens with different stem diameter followed similar pattern, but the stands with bigger stem diameter had the faster sap flow velocity and the higher daily sap flux. When the soil water potential in 0-100 cm layer was between -13 to -10 kPa, no obvious correlation was found between the sap flow velocity and the soil water potential. However, when the soil water potential was less than -200 kPa, the sap flow velocity was positively correlated with the soil water potential, and soil moisture content became one of the main limiting factors. The sap flow velocity had significant positive correlations with solar radiation, air temperature, vapor pressure deficit, and wind speed, but negative correlation with air relative humidity. Taking the solar radiation, air temperature, vapor pressure deficit, air relative humidity, and wind speed as independent variables and the sap flow velocity as dependent variable, the multiple linear equations of the sap flow velocity and environmental factors were established by stepwise regressing.

Seasonal variation and resorption characteristics of leaf N, P, and K in two aged Xanthoceras sorbifolia  plantations.

2010, 29(07):  1270-1276. 

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Taking the 8-and 50-year-old Xanthoceras sorbifolia plantations in Wudan area of southwestern Horqin Sandy Lands as test objects, this paper studied the seasonal variation and nutrient resorption efficiency of their leaf N, P, and K. Throughout the growth season, the leaf N, P, and K concentrations in the two plantations had a decreasing trend, with the decrement being larger from May to June and from August to October, but less from June to August. The nutrient concentrations in living and fallen leaves, except the N concentration in fallen leaves, were significantly (P<0.01) higher in 8-year-old plantation than in 50-year-old plantation. The leaf nutrient resorption efficiency in 8-year-old plantation was in the order of N (50%) > P (32%) > K (30%), while that in 50-year-old plantation was in the order of K (63%) > P (62%) > N (48%). No significant difference (P>0.05) was observed in the leaf N resorption efficiency between 8-year-old and 50-year-old plantations. However, the leaf P and K resorption efficiency in 50-year-old plantation was significantly higher than that in 8-year-old plantation (P<0.01). On the whole, the leaf nutrientresorption efficiency in 50-year-old plantation was higher than that in 8-year-old plantation, reflecting the higher leaf nutrient conservation capability and use efficiency in 50-year-old X. sorbifolia plantation, and the better adaptation capability of this plantation to nutrient-poor habitat.

Distribution characteristics and seasonal dynamics of wetland plant N, P, and K in lower shoal of Jiuduansha at Yangtze River estuary.

2010, 29(07):  1277-1288. 

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From April to December 2005, an investigation was made on three main types of wetland plant community composed of Scirpus mariqueter, Spartina alterniflora, and Phragmites australis, respectively in the lower shoal of Jiuduansha at Yangtze River estuary, with their plants sampled monthly, and the N, P, and K contents and biomass determined. The three species had different characteristics in their N, P, and K contents, distribution, storage, and dynamics, and the nutrient contents in different species and in different organs of same species differed with plant growth. The order of N, P, and K contents was obviously different in different species and in different organs of same species. The storages of N, P, and K were mainly affected by plant species, their organs, and biomass, among which, biomass was the main limiting factor. The nutrient contents and storages of the three species and their organs were generally lower in lower shoal wetlands than in upper shoal wetlands. The nutrient contents of the plant species showed obvious seasonal dynamics, i.e., higher at the initial stage of plant growth and lower at the withered stage. The dynamic characteristics of N, P, and K contents differed with plant species, but had an overall tendency of decreasing with plant growth and in the order of K>N>P. Under the effects of local environmental factors, there existed differences in the characteristics and patterns of  N, P, and K contents, distribution,storage, and dynamics in the wetland plants between lower and upper shoals of Jiuduansha.

Eco-physiological responses of Sonnerratia apetala seedlings to different levels of shading.

2010, 29(07):  1289-1294. 

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An in situ measurement of light intensity was conducted in the Sonnerratia apetala plantations under different environmental conditions, and the eco-physiological responses of the S. apetala seedlings to different light intensities were studied. The seed germination rate and the seedling’s eco-physiological parameters of S. apetala all decreased with the increasing level of shading. At 80% and 40% of full light, the stem height, basal diameter, node number, and lamina number of seedlings decreased to some extent; while at 20% of full light, the seedling’s growth was seriously restricted. At weak light intensity, the germination rate was very low, and the eco-physiological parameters such as chlorophyll content, net photosynthetic rate, soluble sugar contents, and nitrate reductase activity decreased, with significant differences to those at strong light intensity. Therefore, low light intensity could be the main reason for the low level eco-physiological parameters and high death rate of S. apetala seedlings. The natural regeneration and dispersal of S. apetala and the techniques for S. apetala forestation were also discussed.

Growth and reproductive characteristics of Solidago canadensis with different population densities.

2010, 29(07):  1295-1300. 

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As an ornamental plant, Solidago canadensis was first introduced from North America to Shanghai and Nanjing in 1935, which has become one of the important invasive alien plants in China. Its seeds can diffuse by wind, its rhizomes can be cloned, and thus, the reproductive capacity of S. canadensis is very high. In 2006-2008, an investigation was made on the growth and reproductive characteristics of S. canadensis with different population densities (30-50, 60-80, and 90-120 plants per square meter) in Xiasha of Hangzhou, aimed to approach the grow and reproduction patterns of S. canadensis under natural conditions. At  the population density of 90-120 plants per square meter, the average plant height of  S. canadensis was higher than that at other population densities, with the biggest difference of 57.6 cm. At the population density of 60-80 plants per square meter, the stem diameter of S. canadensis was the largest, being averaged 10.3 mm, and 2 mm larger than that at the population density of 30-50 plants per square meter. The leaf number of S. canadensis increased most at population density of 60-80 plants per square meter, with the mean daily increment of 3.4 leaves. At the population density of 90-120 plants per square meter, S.canadensis bloomed earliest, being 8 and 3 days earlier than at the population densities of 60-80 and 30-50 plants per square meter, respectively. The seed dispersal was also the earliest at the population density of 90-120 plants per square meter, being 7 and 2 days earlier than that at the population densities of 60-80 and 30-50 plants per square meter, respectively. At the population density of 60-80 plants per square meter, S. canadensis produced the largest number (77896) of seeds, and the seeds had the highest germination rate. This study could provide scientific basis for preventing and controlling the invasion and dispersal of S. canadensis in China.

Effects of irrigation and nitrogen fertilization on hay yield and water use efficiency of Medicago sativa.

2010, 29(07):  1301-1306. 

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A field experiment was conducted in Hexi oasis of Gansu Province to study the effects of different irrigation amount (conventional irrigation, 330 mm; 20% watersaving irrigation, 264 mm; and 40% water-saving irrigation, 198 mm) and N application rate (0, 40, 80, and 120 kg N·hm^-2) on the plant height, hay yield, and water use efficiency (WUE) of Medicago sativa. Under the experimental condition, both irrigation and N fertilization had no significant effects on the plant height of M. sativa. However, irrigation had significant effects on the hay yield, which was increased with increasing irrigation amount, being 7232, 7603, and 7796 kg·hm^-2 under 40% water-saving irrigation, 20% water-saving irrigation, and conventional irrigation, respectively, and there existed significant differences between the treatments. Irrigation also had significant effects on the WUE of M. sativa, which was decreased with increasing irrigation amount, being 15.56, 13.86, and 12.60 kg·hm^-2·mm^-1under 40% water-saving irrigation, 20% water-saving irrigation, and conventional irrigation, respectively, and the difference between the treatments was significant. When the N application rate was 40 kg N·hm^-2, the total hay yield (8223 kg·hm^-2) and the WUE of M. sativa(15.18 kg·mm^-1·hm^-2) reached the maximum, and the increment of hay yield and WUE was 15% and 14%, 16% and 14%, and 7% and 8% higher than that when the N application rate was 0, 80, and 120 kg N·hm^-2, respectively. From the viewpoints of economic return, ecology, and environment, it was considered that 40% water-saving irrigation combined with 40 kg N·hm^-2 N supply would be the best choice for the first year of M. sativa  planting in Hexi oasis of Gansu Province.

Effects of supplemental irrigation and nitrogen- and phosphorus fertilization on yield formation and soil water- and nitrogen use of winter wheat.

2010, 29(07):  1307-1313. 

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A split plot experiment was conducted to study the effects of supplemental irrigation and nitrogen (N)- and phosphorus (P) fertilization on the soil water utilization, Nuptake, and grain yield of Triticum aestivum on loess tableland.   In the study year, supplemental irrigation and N- and P fertilization increased the grain yield of T. aestivum by 0-24.6% and 134.1%-240.2%, respectively. Nitrogen fertilization was the main factor in improving the grain yield of T. aestivum, while supplemental irrigation and P fertilization had little effects. Supplemental irrigation and N fertilization increased the water consumption by T. aestivum significantly. Supplemental irrigation decreased the consumption of soil water to some extent, whereas N- and P fertilization increased the soil water consumption significantly. Supplemental irrigation decreased the water use efficiency (WUE) by 0.2-2.3 kg·mm^-1·hm^-2, compared with rain-fed treatment, but the difference was not significant. Nitrogen- and P fertilization increased the WUE by 4.0-7.2 kg·mm^-1·hm^-2, being significantly higher than the control (CK). The N uptake by T. aestivum  increased significantly with increasing N application rate, and the increment was 26.9-33.4 kg N·hm^-2and 60.9-66 kg·hm^-2 under low and high N application rates, respectively, compared with CK. Supplemental irrigation promoted the allocation of absorbed N in the aboveground parts of T. aestivum. Supplemental irrigation combined with high fertilization rates of N and P could obtain high yield and higher WUE. In the years with adequate soil moisture for sowing, the key factor affecting the grain yield, WUE, and N absorption of T. aestivum on loess tableland was the N fertilization rate.

Plant composition and diversity in uranium tailings reservoir area.

2010, 29(07):  1314-1318. 

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This paper studied the plant composition and diversity in a uranium tailings reservoir area in Central South China, and measured the environmental radiation. A total of 79 plant species were recorded, belonging to 32 families and 67 genera. The importance value of the plants at the habitats with different radiation intensity differed greatly. At the habitats of low or medium radiation intensity, the importance value of the plants was relatively disperse, and the three layers of tree-bush-grass all had many dominant species; while at the habitats with high radiation intensity, a few of dominant species appeared. Based on the plant importance value, community similarity coefficient, and cluster analysis, the plant community in the study area could be divided into four types, i.e., Cinnamomum camphora＋Broussonetia papyrifer—Loropetalum chinense＋Vitex negundo—Macleaya cordata＋Phytolacca acinosa community at the habitats of low radiation intensity, Melia azedarach＋B. papyrifer—V. negundo＋Mallotus apelta—M. cordata＋Miscanthus floxidulus community at the habitats of medium radiation intensity, and Mallotus apelta—Phragm ites australis＋Imperata cylindrica community and Rhus chinensis—Setaria viriisd＋Imperata cylindrica＋Paspalum scrobiculatum community at the habitats of high radiation intensity. Shannon diversity index (H) ranged from 0.463 to 1.734, with the order of low radiation intensity habitat ＞medium radiation intensity habitat ＞high radiation intensity habitat. The Margalef richness index (D_MA) ranged from 33.962 to 9.024, and the Pielou evenness index (Jsw) ranged from 0.463-0.986. The eco-environmental problems of the uranium tailings reservoir area were discussed.

Effects of different land use pattern soils in low latitudinal plateau on tobacco growth and photosynthetic physiology.

2010, 29(07):  1319-1325. 

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Six soils with different land use patterns, i.e., rice field (Eshan, E), corn fields (Beicheng 1, B1; Beicheng 2, B2), mountain slope dry land (Xinping, X), and vegetable fields (Tonghai Sijie, T1; Tonghai Sangyuan, T2), in low latitudinal plateau Yuxi tobacco-growing area were sampled and cultivated with tobacco variety K326 in pots, aimed to study the effects of the soils on the K326 growth and photosynthetic physiology under the same climatic condition and same managements. The tobacco plants grew better on the soils of mountain slope dry land, rice field, and corn fields than on the soils of vegetable fields (except B1). The netphotosynthetic rate (P_n) was higher on the soil of Xinping (X) than on the others; and the stomatal conductance (G_s), intercellular CO₂ concentration (C_i), and transpiration rate (T_r) were higher but the stomatal limitation value (L_s), water use efficiency (WUE), and intrinsic water use efficiency (IWUE) were lower on the soils of Xinping (X) and Eshan (E). The P_n of K326 growing on the soils of corn fields and vegetable fields was mainly affected by stomatal factors, while the P_n of K326 grown on the soil of rice field was mainly affected by nonstomatal factors, such as lower carboxylation capability, photosynthetic pigments, and soluble protein content. The K326 grown on the soils of Eshan and Xinping had poor stomatal regulation capability. The higher soil water content in the soils of Eshan and Xinping caused the increase of G_s and T_r and the decrease of WUE. No significant differences were observed in the leaf fresh weight water content and natural water saturation deficit among the tobacco plants grown on the test soils, but the watercontent of per unit leaf area was significantly lower for the plants grown on the soils of vegetable fields, compared with that on the soil of rice field, which could be related to the specific leaf mass (SLM) to some extent. The results indicated that the effects of different land use pattern soils on tobacco growth and photosynthetic physiology were complicated, which not only related to the soil characteristics, but also related to the plant itself physiological characteristics under different soil conditions.

Spatial heterogeneity of soil moisture in apple orchards with different productivity level.

2010, 29(07):  1326-1332. 

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By means of classical statistics and geo-statistics, a comparative study was made on the spatial distribution and variation patterns of soil moisture in the appleorchards with different productivity level on the Loess Plateau. Vertically, the soil moisture content was increased with the distance from root layer, and horizontally, it was increased with the distance from tree trunk. The soil moisture stability was increased with the distance from ground surface and from tree trunk. Significant differences were observed in the soil moisture content in apple orchards with different productivity level. With the decrease of orchard productivity, the soil moisture consumption by apple trees reduced, soil moisture stability improved, and the soil moisture spatial heterogeneity caused by spatial autocorrelation increased while that caused by random part decreased. Our results suggested that the excess consumption of soil water resource and its impact on environment could be reduced by adjusting the productivity level of apple orchard.

Effects of freezing-thawing cycle on soil respiration under different land-use patterns in Keerqin Sandy Lands.

2010, 29(07):  1333-1339. 

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Soil freezing-thawing cycle is common in mid-high latitude and high altitude regions, which may affect soil physicochemical and/or biological properties, and further, soil respiration process. To study the variations of soil respiration rate under  freezing-thawing cycle is of significance in accurately estimating global carbon budget. Taking the sandy grassland (SG), Mongolian pine savanna (MPS), and farmland (FD) in Keerqin Sandy Lands as test objects, a laboratory experiment was conducted to study their soil respiration rates under  freezing-thawing. Land use pattern had significant effects on the soil respiration rate. In the control (no freezing-thawing), the respiration rate was higher in SG than in MPS and FD (P<0.05), with the value being 0.339, 0.258, and 0.234 μmol CO₂·m^-2·s¹ , respectively; while under freezingthawing, the soil respiration rate was significantly higher in SG and MPS than that in FD (P<0.05). The mean soil respiration rate in SG, MPS, and FD under one freezing-thawing cycle was 0.276, 0.243, and 0.233 μmol CO₂·m^-2·s^-1, and that under multi freezing-thawing cycles was 0.314, 0.274, and 0.259 μmol CO₂·m^-2·s^-1respectively. The Q₁₀value in SG, MPS, and FD was 116.0, 26.2, and 16.4, respectively, suggesting the strong effects of land use pattern on the temperature dependence of soil respiration at low temperature in winter.

Effects of citric acid and oxalic acid on the growth and physiology of Iris lactea var. chinensis  under Pb stress.

2010, 29(07):  1340-1346. 

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A hydroponic experiment was conducted to study the effects of exogenous citric acid (0.5 and 5 mmol·L^-1) and oxalic acid (0.5 and 5 mmol·L^-1) on the growth and physiology of Iris lactea var. chinensis  under 100 and 500 mg·L^-1 Pb stress. Comparing with Pb stress alone, adding 5 mmol·L^-1of citric acid promoted the shoot growth of I. lactea var. chinensis significantly. The addition of oxalic acid mitigated the impact of 500 mg·L^-1Pb stress on the root growth of I. lactea  var. chinensis. Adding 0.5 mmol·L^-1of oxalic acid alleviated the 500 mg·L^-1Pb stress on the shoot growth, and increased the root dry mass significantly under 100 and 500 mg·L^-1 Pb stress. The SOD activity in I. lactea var. chinensis  leaves under 100 mg·L^-1Pb stress was increased significantly by adding 0.5 mmol·L^-1of citric acid, and the POD activity of  I. lactea var. chinensis under 100 mg·L^-1 Pb stress was increased significantly by adding 0.5 and 5 mmol·L^-1 of citric acid or 0.5 mmol·L^-1of oxalic acid. The impact of 500 mg·L^-1 Pb stress on the photosynthetic pigments of I. lactea var. chinensis was alleviated by the addition of 5mmol·L^-1 of citric acid or 0.5 mmol·L^-1of oxalic acid. Adding 0.5 and 5 mmol·L^-1of citric acid or 0.5 mmol·L^-1 of oxalic acid reduced the membrane damage of I. lactea var. chinensis leaves under 100 and 500 mg·L^-1 Pb stress.

Biodegradation of carbazole and biphenyl by Arthrobacter sp. PJ3.

2010, 29(07):  1347-1352. 

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A strain PJ3 was isolated from soil, and identified as Arthrobacter sp. by 16S rDNA. Homology tree showed that the Arthrobactersp. PJ3 had the highest homology value with carbazole-degrading bacterium IC177, followed by with biphenyl-degrading bacteria K37 and R04. In order to evaluate the degradation capability of Arthrobacter sp. PJ3 to carbazole and biphenyl, the medium pH for Arthrobacter sp. PJ3 growth was optimized, and spectrophotometry was applied to measure the growth rate of the strain on the mineral medium with different concentration carbazole or biphenyl, and the degradation rate of the two aromatic compounds. The growth rate of the strain was the same at medium pH 7, 8, and 9, and higher than that at other medium pH values. At pH 7 and 0。1 mg·ml^-1of carbazole, the growth rate of the strain on CNFMM medium was the highest. After cultured for 15 days, the degradation rate of carbazole was up to 73%. At pH 7 and 0.5 mg·ml^-1 of biphenyl, the growth state of PJ3 on MSB medium was the best. When the PJ3 was cultured on MSB medium with 0.1 and 0.5 mg·ml^-1of biphenyl for 15 days, the degradation rate of biphenyl was 80%-85%. Therefore, 0.1-0.2 mg·ml^-1 of carbazole and 0.1-0.5 mg·ml^-1 of biphenyl could be the optimal concentrations for the degradation of the two aromatic compounds by Arthrobacter sp. PJ3.

Effects of Flaveria bidentis  invasion on soil nutrient contents and enzyme activities.

2010, 29(07):  1353-1358. 

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Aimed to approach the effects of alien plant invasion on soil ecosystem, this paper studied the change patterns of soil nutrient contents and enzyme activities under different levels of Flaveria bidentis invasion. Comparing with non-vegetated and native plant soils, the F. bidentis invaded soil had higher contents of soil organic carbon, total nitrogen, NO₃^--N, and NH⁺₄-N but lower contents of soil total and available phosphorus, and the change trends of these parameters became more obvious with increasing invasion level. Comparing with those in native plant soil, the organic carbon and total nitrogen contents in F. bidentis heavily invaded soil increased by 5.7% and 23.4%, while the total and available phosphorus contents decreased by 85% and 50%, respectively. The urease activity in F. bidentis heavily and lightly invaded soils was 0.04 and 0.03 mg·g^-1·24 h^-1, respectively, being higher than that in non-vegetated and native plant soils, the phosphatase activity changed with same manner, while the polyphenol oxidase activity had less change. It was suggested that F. bidentis invasion induced the changes of soil nutrient contents and enzyme activities, and in return, endowed the superiority of  F. bidentis in its inter-specific competition.

Effects of lead exposure on the activities of alkaline phosphatase, lactate dehydrogenase and creatine kinase in juvenile Acipenser sinensis blood.

2010, 29(07):  1359-1364. 

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By using static replacement method, this paper studied the effects of different Pb concentrations (0, 0.2, 0.8, and 1.6 mg·L^-1) in water on the activities of alkaline phosphatase (ALP), lactate dehydrogenase (LDH) and creatine kinase (CK) in the blood of juvenile Chinese sturgeon (Acipenser sinensis). To start with the zygote having developed for 96 hours, the juveniles were exposed to Pb for 16 weeks, and then transferred to Pb-free water for 6 weeks. After Pb exposure, the ALP activity in the blood presented a downward trend with increasing Pb concentration, and the decrease was significant when the Pb concentration was 1.6 mg·L^-1 (P<0.01). The activities of LDH and CK in the blood increased with increasing Pb concentration, and only LDH activity had a significant increase when the Pb concentration was 1.6 mg·L^-1 (P<0.05). The CK activity in the blood was more sensitive to Pb, which was 7 times higher when the Pb concentration was 0.8 mg·L^-1, and 19 times higher when the Pb concentration was 1.6 mg·L^-1, compared with the control (P<0.01). After 6-week recovery in Pb-free water, the ALP activity in the blood still presented a downward trend with increasing Pb concentration, but no significant differences were observed among all treatments (P＞0.05). The LDH activity in the blood also had no significant differences among the treatments (P>0.05). After transferring to Pb-free water, the ALP activity in the blood had somewhat recovery, whereas the LDH activity recovered significantly. It was considered that after exposure to 1.6 mg·L^-1 of Pb, the juvenile A. sinensis could have metabolic abnormality and tissue (liver or muscle) injury. The CK activity in the blood was more sensitive than the ALP and LDH activities, and thus, could be used as a useful index of Pb pollution for fish.

Control of Dianshan Lake eutrophication based on the primary productivity of silver carp and bighead carp.

2010, 29(07):  1365-1370. 

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By using dark and light bottle dissolved oxygen method, the fishery primary productivity in the south part and the experimental enclosure of Dianshan Lake was measured monthly from October 2008 to September 2009. Based on the measurement in the south part, the potential productivity and reasonable stocking amount of silver carp and bighead carp in the experimental enclosure were estimated, and the correlations of the primary productivity with the water temperature,transparency, nutrients, and chlorophyll-a were discussed. The nutrient removal effect of stocking silver carp and bighead carp was also discussed. In the south part of the Lake, the daily gross primary productivity (P_G) was 4.02 g O₂·m^-2 on average, with the maximum in August and the minimum in January, the net primary productivity (P_N) was 1.99 g O₂·m^-2, and the yearly P_N/P_G ratio was averaged 52%. The 0-0.5 m water layer contributed most to the primary productivity, with its contribution occupied 32.3% and 32.2% of the total in the south part and the experimental enclosure, respectively. The primary productivity was positively correlated with water temperature and transparency, but not significantly correlated with other physical and chemical factors. The yearly production of phytoplankton in the Lake was 28.18×10.4 t. If the stocking ratio of silver carp  to bighead carp was 3∶1, the potential productivity of silver carp and bighead carp would be 1621.58 t and 1216.18 t, and their reasonable stocking amount was 16.94 t·km^-2 and 6.35 t·km^-2, respectively. Based on these estimations, the total nitrogen and total phosphorus absorbed by the 2837.76 t fish would be 85.50 t and 7.63 t, and the nitrogen and phosphorus concentrations in the water body of Dianshan Lake would be decreased by 0.67 mg·L^-1 and 0.06 mg·L^-1, respectively.

Effects of breeding density on the growth and tissues biochemical indices of juvenile silver pomfret (Pampus argenteus).

2010, 29(07):  1371-1376. 

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Breeding density is one of the most important variables in aquaculture, because it directly affects the survival, growth, behavior, health, feeding, and productivity of aquatics and the water quality. Breeding at high density can cause the deterioration of water quality, overcrowding of aquatics, and adverse colony effect. Silver pomfret (Pampus argenteus) is a new candidate species for aquaculture. Until now, few studies have been conducted on the breeding biology of P. argenteus. The aim of this study was to evaluate the effects of breeding density on the growth of juvenile P. argenteus (5.33±0.07 g), and the glycogen and lactate contents as well as the superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-PX) activities in the liver and muscle of the juveniles. The juveniles were kept at the breeding densities of 5, 10, 15, and 25 individuals·m^-3(named D₁, D₂, D₃ and D₄, respectively) for 60 days. At the density up to D₃, the growth rate of the juveniles increased; whereas at D₄, the growth rate decreased. No significant difference was found in the hepatopancreas index and survival rate among the treatments. The glycogen content in the liver and muscle of the juveniles was negatively correlated with breeding density, being the lowest at D₄, while the lactate content in the muscle had no significant correlation with the breeding density. At the densities from D₁ to D₃, the activities of SOD and CAT in the liver and muscle had less change; but at D₄, the SOD activity in the liver and muscle was significantly lower than that at D₂ and D₃, and the CAT activity in the liver was significantly lower than that at D₃. No significant differences in the activities of muscle CAT and liver-and muscle GSH-PX were observed among all treatments. In general, the test breeding densities were not very stressful to the juvenile P. argenteus during the whole experimental period.

Population characteristics and species conservation of Rhinogobio ventralis in upper reaches of Yangtze River.

2010, 29(07):  1377-1381. 

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Based on the 2005-2007 investigation data of fishery resources in Panzhihua, Yibin, Hejiang, Mudong, and Wanzhou of the upper reaches of Yangtze River, and by using length-frequency method (FiSAT Ⅱ package), this paper estimated the growth and mortality of Rhinogobio ventralis. The regression equation of the body weight and body length of R. ventralis could be expressed as W=8×10^-6L^3.1577, and the parameters in von Bertalanffy formula estimated by Shepherd’s method were L_∞＝530.5 mm, K＝0.21 a^-1, and t₀＝-0.5 a. The natural mortality coefficient calculated with Pauly’s empirical equation was M=0.24, the total mortality coefficient estimated by the length-converted catch curve was Z＝2.67, and the fishing mortality coefficient was F=2.43. Recruitment pattern analysis indicated that R. ventralis had a recruitment period from May to September, its exploitation rate in recent years was 91.2%, and its resource was at the state of overexploitation.

Aphid-resistance of chrysanthemum cultivars.

2010, 29(07):  1382-1386. 

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In order to discover aphid-resistant germplasm, 32 cut chrysanthemum (Chrysanthemum grandiflorum) cultivars were artificially inoculated with aphids, and the aphid number and its ratio on the cultivars were investigated. Different chrysanthemum cultivars had different levels of aphid-resistance. After 21 days inoculation, the aphid number varied with cultivars, ranging from 0 to 267. The aphid-resistance of chrysanthemum could be divided into five grades in terms of aphid number ratio, i.e., high resistance (aphid number ratio 0-0.25), moderate resistance (0.26-0.50), resistance (0.51-0.75), low resistance (0.76-1.25), and non-resistance (>1,25). Among 32 test cultivars, 14 cultivars were of non-resistance, 4 cultivars were of low resistance, 3 cultivars were of resistance, 1 cultivar was of moderate resistance, and 10 cultivars were of high resistance.

Effects of temperature on the growth and development of Lasioderma serricorne (Coleoptera: Anobiidae) experimental population on Codonopsis pilosula. 

2010, 29(07):  1387-1392. 

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Taking the Chinese medicinal herb Codonopsis pilosula as host feed, an incubation test was conducted to study the effects of temperature on the growth and development of Lasioderma serricorne (Coleoptera: Anobiidae). The development threshold and effective accumulated temperature for the growth and development of L. serricorne were calculated, and the mathematical equations expressing the relationships between L. serricorne development and temperature were tested with Logistic model and “Wang-Lan-Ting” model. The development threshold temperature of L. serricorne at its egg, larva, pupae, and egg-pupae stages was 16.51, 11.07, 11.78, and 12.20℃, and the effective accumulated temperature was 89.59, 669.53, 137.12, and 912.72 day degree, respectively. Higher temperature was beneficial to the growth and development of L. serricorne. Comparing with Logistic model, the “Wang-Lan-Ting” model could better fit the relationships between L. serricorne development and temperature. This study supplied technical support to the pest control in the storage of C. pilosula.

Nest site selection of blue-eared pheasant (Crossoptilon auritum) in south Gansu, China.

2010, 29(07):  1393-1397. 

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Blue-eared pheasant (Crossoptilon auritum) is endemic to China, and only distributed in east and northeast Qinghai, northwest and south Gansu, northwest Sichuan, and west Ningxia. In 2007 and 2008, an investigation was made on the nest site selection of C. auritum in a forest area in south Gansu, China. Of the 12 nests found, four (33.3%) were under conifer trees, four (33.3%) on rock and in cavity, two (16.7%) under fallen trees, and two (16.7%) in thick shrub. The U and T tests showed that there were significant differences in the slope position, slope gradient, shrub height, shrub number, shrub cover, vegetation cover at 0.5 m, 1.0 m and 2.0 m height, and disturbance level between nest sites (n=12) and control sites (n=24). A stepwise discriminate analysis on the 13 variables that potentially affected the nest site selection of C. auritum indicated that the high position of slope, great cover of understory vegetation, and farther distance from human settlements had the priority for the nest site selection of C. auritum.

Calculation of instream ecological water requirement of Taizi River based on the allocation of ecological water right.

2010, 29(07):  1398-1402. 

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Ecological water right is an important component of initial water rights, while ecological water requirement (EWR) is the manifestation of ecological water right. To calculate the instream EWR can provide basis for the allocation of water right and the protection of ecological environment. Based on the investigation of Taizi River, and by the monthly-guaranteed-frequency method and fish habitat method, this paper calculated the instream EWR of Taizi River, and the calculated results were verified with Tennant method. It was shown that the calculated results by the monthly-guaranteed-frequency method and fish habitat method were reasonable. According to the tradeoff between water resources and actual water use status, the minimum, medium, and ideal grades of annual EWR in different reaches were determined. Comparisons between the calculated results of different grade EWR and the measured streamflow in different reaches indicated that the measured streamflow at different hydrological stations basically satisfied the minimum grade of EWR. As for the medium and ideal grade EWR, various measures should be taken to reserve the water in the instream for the guarantee of ecological water right.

Nitrogen pollution of surface water in Tianjin based on nitrogen isotope approach.

2010, 29(07):  1403-1408. 

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In order to understand the situation of surface water nitrogen pollution in Tianjin, this paper analyzed the nitrogen (nitrate, ammonium, and nitrite) concentrations in the river, reservoir, salt water, and sewage, and the isotopic composition of nitrate and ammonium nitrogen in most water samples. The NO^-₃-N concentration in the waters ranged from 0.01 mg·L^-1 to 16.51 mg·L^-1, with a mean value of 2.25 mg·L^-1. Some waters had the NO^-₃ concentration >50 mg·L^-1 (11.29 mg·L^-1 of NO^-₃-N), showing their high nitrate pollution. The NH⁺₄-N concentration in the waters was from 0 to 10.60 mg·L^-1, with a mean value of 1.15 mg·L^-1. One fourth of the waters had the NH⁺₄-N concentration >1.5 mg·L^-1. About 1/12 of the waters had higher NO^-₂-N. In most water samples, nitrate was the dominant species of inorganic nitrogen. Ammonium was the main nitrogen species in some waters, especially in sewage. The δ¹⁵NO^-₃-N value ranged from -5.5‰ to +28.6‰ (n=49, mean +9.0‰, median +8.5‰), and the δ¹⁵NH⁺₄-N value ranged from -8.8‰ to +34.3‰ (n=11, mean +11.6‰, median +13.6‰). All the results suggested that domestic sewage was the main source of surface water nitrogen pollution in Tianjin, and the nitrogen isotopic composition was obviously affected by nitrification, ammonia volatilization, and denitrification.

Variability and human impacts of urban wetland water quality in urban multifunctional landscape areas.

2010, 29(07):  1409-1413. 

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Based on the division of landscape functional areas in the Xianlin University Town in Nanjing City, a one-year monitoring of wetland water quality in each landscape functional area of the town was made to reveal the seasonal patterns of the water quality, and fuzzy comprehensive evaluation method was used to evaluate the wetland water quality of the landscape functional areas. The relationships between wetland water quality and human impact degree in each landscape functional area were also analyzed. The wetland water quality in the town had an obvious seasonal fluctuation, being below Ⅲ degree in spring and summer and above Ⅲ degree in autumn and winter. Among the pollution factors, total phosphorus had the highest load, with an average concentration of 0.11 mg·L^-1. The wetland water quality had obvious spatial variability, with the best in College Landscape Area, followed by in Agricultural Landscape Area, Leisure Landscape Area, and Commercial Landscape Area, and was significantly negatively correlated with human impact degree (R²=0.938).

Landscape pattern change of tourism-type islands in Fujian Province: Taking Meizhou Island, the Mazu holy land, as an example.

2010, 29(07):  1414-1419. 

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With the support of RS and GIS, and based on the remote sensing images in 1993 and 2005, this paper analyzed the landscape pattern change of Meizhou Island, a typical representative of tourism-type islands in Fujian Province. In 1993-2005, the total number of landscape patches on the Island increased obviously, the landscape diversity index had a slight decrease but was overall high, and the landscape fragmentation index showed an obvious increasing trend. Among the landscape types, three of them closely related with tourism, i.e., construction land, woodland, and beach and bare rock increased in their size and fragmentation degree, suggesting that the intensity of human intervention increased. At the same time, the size and fragmentation degree of cropland, grassland, pond water, and beach decreased, suggesting the decreasing intensity of human intervention on these landscape types.

Landscape pattern change in mountainous areas along an altitude gradient in the upper reaches of Shule River.

2010, 29(07):  1420-1426. 

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Based on the Landsat TM images in July 1986, Landsat ETM images in July 2001, and 1∶50000 DEM data, the landscape pattern change in the mountainous areas along an altitude gradient in the upper reaches of Shule River from 1986 to 2001 was studied by using software ArcView GIS 3.3 and Fragstats 3.3. In the study areas, grassland was the matrix, while shrubs and other landscape types were the mosaic patches. The landscape had simple structure, single composition, regular shape, centralized patch distribution, and a few dispersed residential points. Among the landscape types, sparse grassland had the largest area, followed by naked gravel land. The vegetation coverage was about 52%, and dense grassland only accounted for 5%. In the 15 years, the areas of shrubs, dense grassland, sparse grassland, and swamp meadow decreased due to degradation, while those of mid-density grassland, barren land, bottom land, and cropland increased. The grassland at the altitude 3800-4000 m, the lower limit of permafrost distribution, was undergone most serious degradation. The thickening of active permafrost layer and the decrease of soil moisture content due to climate warming could be the main reasons of grassland degradation.

Estimation of resources consumption by farming |in Shenyang region based on ecological footprint method.

2010, 29(07):  1427-1431. 

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By the method of ecological footprint (EF), an EF model of farming industry was established to calculate the EF of farming industry in Shenyang region in 2001-2006, and to analyze the change patterns and causes of the EF per unit weight agricultural product (EFunit). In 2001-2006, the EF of farming industry in Shenyang region increased after an initial decrease, while the EF unit had a decreasing trend. Cropland EF was the main component of the EF, followed by water EF, and energy EF. The cropland EF decreased from 56.8% in 2001 to 54.4% in 2006, water EF fluctuated between 27.6% and 32.1%, and energy EF increased from 14.0% to 16.2%. The growth of per unit agricultural product was accompanied with the increase of the inputs of potash fertilizer, compound fertilizer, pesticides, and agriculture-used film, steel, and diesel. All the results indicated that in recent years, the dependence of farming industry in Shenyang region to fossil energy was increasing.

Effects of freezing-thawing cycle on greenhouse gases production and emission from soil: A review.

2010, 29(07):  1432-1439. 

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Soil freezing-thawing cycle is very common in the regions at mid-high latitude and high altitude. During this cycle, soil physical properties, chemical composition, and microbial activities could be affected. Many researches indicated that the soils in the above-mentioned regions were the important source of greenhouse gases, and the accumulative emission of soil greenhouse gases during freezing-thawing cycle could contribute greatly to their total annual fluxes budget, especially of N₂O. Under global warming, the extension and frequency of soil freezing-thawing cycle could be increased in some regions, and the soil greenhouse gases emission in these regions would be enhanced, which in turn would promote global climate change. This paper summarized the research progress in the effects of freezing-thawing cycle on the greenhouse gases production and emission from soil, and the major related mechanisms. Some deficiencies in the study of soil freezing-thawing were pointed out, and the main issues in the future study were suggested.

Evolvement of soil properties during reversal of desertification: Research progress.

2010, 29(07):  1440-1450. 

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Land desertification is becoming more and more serious, while its reversal is of ecological, economic, and social significances. In some revegetated regions, mobile sand dunes have been successfully transformed into stable and productive ecosystems, and the structure and function of the revegetated ecosystems have changed considerably. Based on the related researches, this paper summarized the changes of soil physical properties (water-holding capacity, mechanical composition, and structure, etc.), chemical properties (carbon, nitrogen, and phosphorus, etc.), and biological properties (microbial biomass, respiration, and enzyme activities, etc.) during the reversal of desertification, aimed to elucid
ate the responses of soil properties to desertification reversal. Some suggestions for further researches in this field, e.g., the studies on soil quality change by microorganism community, and the roles of functional microorganisms in soil evolvement, were put forward, aimed to promote the research on the biological properties of desertified soil during the process of reversal.

Inter-regional biological invasion in China: Present status and countermeasures
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2010, 29(07):  1451-1457. 

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Inter-regional biological invasion is a new concept, which is defined as the invasion of alien species from one region to another region within a country. Because of the intensive personnel- and goods flow and its difficulty to control, the inter-regional biological invasion is now very serious in China. Based on the cases of the inter-regional biological invasion at home and abroad, this paper analyzed the main pathways of the invasion and its dangers, and put forward some countermeasures. Alien species introduction, transportation, and anthropogenic disturbances are the main pathways of the inter-regional biological invasion, which can cause the native species extinction, genetic contamination, and biodiversity decrease,etc. Some future research directions on the inter-regional biological invasion in China, including climate change, South-to-North Water Diversion Project, and Cross-Straits exchanges, were proposed.

Comparisons of agroecology textbooks from China and the United States.

2010, 29(07):  1458-1462. 

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In order to understand the development trend of agroecology teaching, the related textbooks written by the authors from China and the United States in recent 30 years were compared and analyzed. The common features of the textbooks are: (1) proposing new directions for agricultural development to overcome the unsustainable problems facing by industrialized agriculture, (2) setting theoretic framework of agroecology on agroecosystem level, and (3) introducing alternatives of industrial methods, which can coordinate the social, ecological, and economic effects of agriculture. The differences of the textbooks from China and the US are: (1) the examples cited in the US textbooks are not only from the country, but also from abroad, many of which are from the US authors themselves, and the ways of the arrangement and expression in the US textbooks are quite personal, while the examples cited in the China’s textbooks are mainly from China, and from the second hand research reports, (2) the theoretical framework and the arrangement logic are more stable and rigid in China’s textbooks but more flexible in the US textbooks. The development trends of the textbooks from the two countries are: (1) paying more attention to balance the contents of basic ecology and agricultural practice, (2) introducing more practical methods and new research results, (3) emphasizing more on the organizational aspects of the society for agricultural sustainable development; (4) strengthening the practical skills of students through laboratory experiments and field activities, and (5) utilizing more visual and internet resources. The reasons for these phenomena were discussed.

Hotel ecological footprint model: Its construction and application.

2010, 29(07):  1463-1468. 

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A hotel ecological footprint model was constructed, which could calculate the total and average ecological footprint of hotel’s built-up area, energy, water, food, fabrics, paper products, and wastes, and a hotel eco-efficiency model was also constructed based on ecological footprint assessment. The two models were applied to calculate the ecological footprint and eco-efficiency of five mid/high grade hotels in Qingdao. For each of the hotels, the sum of the ecological footprints of food and energy occupied >94% of the total. The higher the hotel’s grade, the larger the total and average ecological footprint and eco-efficiency were. However, there were significant differences in the ecological footprint and the eco-efficiency among the same grade hotels, suggesting that it still had large space to reduce the ecological footprint and to improve the eco-efficiency through a series of green management measures.

Simulation of climate change impacts on grassland productivity in Northern Tibet.
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2010, 29(07):  1469-1476. 

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Based on the Intergovernmental Panel on Climate Change (IPCC) Special Report on Emission Scenarios (SRES) A2 and B2, and by using the Regional Climate Model (PRECIS) and grassland SPUR model, the changes of grassland productivity in Northern Tibet in 2071-2100 were simulated. It was predicted that under  scenarios A2 and B2, the aboveground biomass of all kind grasslands in the regions, where temperature raised, total solar radiation decreased, and precipitation increased, would be increased, while that of Kobrezsia pygmaea grassland in the regions, where precipitation decreased, would be decreased. Our results suggested that the grassland productivity in Northern Tibet might not benefit from CO₂ fertilization.