Table of Content

18 December 2011, Volume 22 Issue 12

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Articles

Effects of litter and mineral nitrogen input on soil organic carbon decomposition in subtropical mixed forest in Dinghu Mountain, South China.

2011, 22(12):  3087-3093. 

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In July-December 2010,  a complete factor-controlled experiment was conducted to study the effects of litter and mineral nitrogen addition on soil organic matter decomposition (soil respiration) at the depths of 0-10 cm and 20-30 cm in Dinghu Mountain National Reserve. Coniferous needle litter and broadleaved litter were added, respectively, and 70 g N·m^-2·yr^-1 of NH₄NO₃ was applied to simulate soil nitrogen saturation whereas soil mineral nitrogen was removed by ion-exchange membrane to simulate the decreased nitrogen absorption by root. The addition of both needle litter and broadleaved litter increased the respiration rate of soil-litter system significantly from July to November, but this effect disappeared in December. Both mineral nitrogen application and soil mineral nitrogen removal increased the soil-litter respiration significantly. These results suggest that  litter decomposed completely in a short period therefor had limited effects on soil organic matter decomposition and accumulation, and thus, foliar litters could be not the major source of soil organic matter, whereas soil mineral nitrogen removal could obviously promote the soil organic matter decomposition in the system.

Characteristics of foliar δ¹³C values of common shrub species in various microhabitats with different karst rocky desertification degrees.

2011, 22(12):  3094-3100. 

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By measuring the foliar δ¹³C values of 5 common shrub species (Rhamnus davurica, Pyracantha fortuneana, Rubus biflorus,Zanthoxylum planispinum, and Viburnum utile) growing in various microhabitats in Wangjiazhai catchment, a typical karst desertification area in Guizhou Province, this paper studied the spatial heterogeneity of plant water use at niche scale and the response of the heterogeneity to different karst rocky desertification degrees. The foliar δ¹³C values of the shrub species in the microhabitats followed the order of stony surface > stony gully > stony crevice > soil surface, and those of the majority of the species were more negative in the microhabitat soil surface than in the others. The foliar δ¹³C values decreased in the sequence of V. utile> R. biflorus> Z. planispinum> P. fortuneana> R. davurica, and the mean foliar δ¹³C value of the shrubs and that of typical species in various microhabitats all increased with increasing karst rocky desertification degree, differed significantly among different microhabitats. It was suggested that with the increasing degree of karst rocky desertification, the structure and functions of karst habitats were impaired, microhabitats differentiated gradually, and drought degree increased.

Responses of Pinus sylvestris var. mongolica radial growth to climate warming in Great Xing’an Mountins: A case study in Mangui.

2011, 22(12):  3101-3108. 

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Based on the theory and methodology of dendrochronology, the tree ring width chronology of Pinus sylvestris var. mongolica in Mangui of Great Xing’an Mountains was developed, and the relationships between the standardized tree ring width chronology and local climate factors (temperature and precipitation) as well as the effects of climate factors on the P. sylvestris var. mongolica radial growth were analyzed. In this region, the mean monthly temperature in April-August of current year was the main factor limiting the radial growth, and the increasing mean monthly temperature from April to August had negative effects to the radial growth. The simulation of the variations of the radial growth by the mean monthly temperature change in April-August showed that the radial growth of P. sylvestris var. mongolica would present a declining trend accompanied with the warmer and drier regional climate condition.

Complexity and its integrative effects of the time lags of environment factors affecting Larix gmelinii stem sap flow.

2011, 22(12):  3109-3116. 

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Based on the one-year (2005) observations with a frequency of half hour on the stem sap flow of  Larix gmelinii plantation trees planted in 1969 and the related environmental factors air humidity (RH), air temperature (T_air), photosynthetic components active radiation (PAR), soil temperature (T_soil), and soil moisture (TDR), principal analysis (PCA) and correction analysis were made on the time lag effect of the stem flow in different seasons (26 days of each season) and in a year via dislocation analysis, with the complexity and its integrative effects of the time lags of environment factors affecting the stem sap flow approached. The results showed that in different seasons and for different environmental factors, the time lag effect varied obviously. In general, the time lag of PAR was 0.5-1 hour ahead of sap flow, that of T_air and RH was 0-2 hours ahead of or behind the sap flow, and the time lags of T_soil and TDR were much longer or sometimes undetectable. Because of the complexity of the time lags, no evident improvements were observed in the linear correlations (R², slope, and intercept) when the time lags based on short-term (20 days) data were used to correct the time lags based on whole year data. However, obvious improvements were found in the standardized and non-standardized correlation coefficients in stepwise multiple regressions, i.e., the time lag corrections could improve the effects of RH, but decreased the effects of PAR, T_air, and T_soil. PCA could be used to simplify the complexity. The first and the second principal components could stand for over 75% information of all the environmental factors in different seasons and in whole year. The time lags of both the first and the second principal components were 1-1.5 hours in advance of the sap flow, except in winter (no time lag effect).

Effects of eutrophic nitrogen nutrition on carbon balance capacity of Liquidambar formosana seedlings under low light.

2011, 22(12):  3117-3122. 

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To investigate the effects of atmospheric nitrogen deposition on the seedlings regeneration of Liquidambar formosana, a greenhouse experiment was conducted, in which, the low light- and nitrogen supplies were controlled similar to those in typical L. formosana secondary forests, with the effects of different light- and nitrogen supply on the L. formosana seedlings survival, leaf functional traits, biomass allocation, and gas exchange studied. The whole plant light compensation point (LCP_whole-plant) of the seedlings was estimated with a whole plant carbon balance model, and then compared with the understory photosynthetic active radiance (PAR) of the typical secondary forests. Under 3.0% and 6.0% of full sunlight, eutrophic nitrogen supply led to a decrease of seedlings survival (shade tolerance) and specific leaf area (SLA), but had no obvious effects on the seedlings biomass allocation. At eutrophic nitrogen supply, light intensity had significant effects on the leaf area based maximum assimilation rate, whereas increasing nitrogen supply under low light induced the increase of leaf mass based dark respiration rate. Both light intensity and nitrogen supply had significant effects on the mass based leaf respiration rate, and the interaction of light and nitrogen had significant effects on the mass based stem respiration rate. Increasing nitrogen supply increased the LCP_whole-plant under 3.0%, 6.0%, and 12.0% of full sunlight, but decreased the LCP_whole-plant  under 25.0% of full sunlight. The decrease of the seedlings shade tolerance induced by the increasing  nitrogen supply under low light was correlated with the variations of the seedlings carbon balance capacity. Under the background of elevated atmospheric nitrogen deposition, the maintenance of L. formosana populations in China would more depend on disturbances and gap regeneration, and the population dynamics would be deeply affected.

Regeneration characteristics of woody plant seedlings in typical secondary forests in Qinling Mountains.

2011, 22(12):  3123-3130. 

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By using sampling plot method, an investigation was conducted on the regeneration characteristics of woody plant seedlings in five kinds of typical secondary forests (Pinus tabulaeformis, Quercus valiena var. acuteserrata, Betula albo-sinensis, Picea asperata, and Pinus armandii) in Qinling Mountains. There was an obvious species differentiation of woody plant seedlings and saplings in the forests. Except for Q. valiena var. acuteserrata and P. armandii forests, the similarity coefficient of the seedlings and saplings species in the forests was lower. The seedlings and saplings quantity, species richness index, Simpson dominance index, and evenness index were higher in P. tabulaeformis and Q. valiena var. acuteserrata forests, the lowest in B. albo-sinensis forest, and basically the same in P. asperata and P. armandii forests. The percentages of the seedlings and saplings in the five forests had significant differences (P＜0.05). Except in B. albo-sinensis forest where the percentage of the saplings was higher, the percentage of the seedlings in the other stands was larger, and in the order of P. asperata forest ＞P. tabulaeformis forest ＞Q. valiena var. acuteserrata forest ＞P. armandii forest,respectively. The sprouting percentage of the seedlings in different forests had significant difference (P＜0.05), and was in the sequence of P. armandii forest＞P. asperata forest ＞B. albo-sinensis forest ＞Q. valiena var. acuteserrata forest ＞P. tabulaeformis forest. In Q. valiena var. acuteserrata and P. tabulaeformis forests, the percentage of tree seedlings was the highest, occupying 68% and 51.4% of the total number of woody seedlings, respectively, and their communities were in the medium succession period,with a stronger persistent regeneration capability; in P. asperata and P.armandii forests,the percentage of tree seedlings was 40% and 15%, respectively, and their communities were in the late succession period, with a rather poor regeneration capability; while in B. albo-sinensis forest, the seedlings were difficult to develop into saplings, and thus, its continuous persistent regeneration capability was lack.

Effects of fertilization on arbuscular mycorrhizal fungi in Elymus nutans roots.

2011, 22(12):  3131-3137. 

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By using traditional staining and DNA cloning and sequencing techniques, this paper studied the effects of fertilization on the arbuscular mycorrhizal (AM) colonization and AM fungal community in Elymus nutans roots across an 8-year nitrogen (N) and phosphorus (P) fertilization gradient. With the increasing level of fertilization, the AM colonization and arbuscular colonization per unit root length reduced from 67.5% to 7.3% and from 5.2% to 0.1%, respectively. A total of 24 AM fungal phylotypes were detected in E. nutans roots, whilst the mean AM fungal richness reduced from 6 to 2.6 across the fertilization gradient. Different fertilization had significant effects on the AM fungal community composition, and there existed significant correlations between the AM fungal community composition and the soil available P and root N contents. The availability of N and P increased gradually across the fertilization gradient, and had significant negative correlations with both AM colonization and AM fungal richness. It was suggested that high level fertilization would reduce the activity of AM symbionts, and result in the large loss of AM fungal biodiversity.

Interspecific allelopathic effect of different organs’ aqueous extracts of Betula platyphylla and Larix olgensis on their seed germination and seedling growth.

2011, 22(12):  3138-3144. 

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In this paper, the Betula platyphylla root-, branch-, and foliage aqueous extracts and Larix olgensis root-, branch-, foliage-, and bark aqueous extracts over a range of concentrations 5.0, 12.5, 25.0, 50.0, and 100.0 mg·mL^-1 were used to study their interspecific allelopathic effect on the seed germination and seedling growth of the two tree species. All the L. olgensis organs’ extracts, except its root extracts at concentration 5.0 mg·mL^-1, had inhibition effect on B. platyphylla seed germination rate, which was 54%, 58%, 59%,and 66% under the effects of L. olgensis foliage-, branch-, bark-, and root extracts, respectively, as compared with the control. With increasing concentration, the inhibition effect of L. olgensis root- and branch extracts increased while that of L. olgensis foliage- and bark extracts decreased. The L. olgensis organs’ extracts, especially the foliage extracts at concentration 100.0 mg·mL^-1, had strong inhibition effect on B. platyphylla seed radicle- and hypocotyl length growth, with a decrement of 38% and 55% (P<0.05), respectively. L. olgensis branch- and foliage extracts promoted, but root- and bark extracts inhibited B. platyphylla seedling growth and biomass production.  B. platyphylla organs’ extracts promoted L. olgensis seed germination, root- and branch extracts promoted hypocotyl length growth, but foliage extracts at 50.0 and 100.0 mg·mL^-1 decreased the hypocotyl length growth by 27% and 28% (P<0.05), respectively. B. platyphylla organs’ extracts mainly promoted L. olgensis seedling growth, with the height- and collar diameter growth and biomass accumulation at B. platyphylla foliage extracts concentration 5.0 mg·mL^-1 increased by 54%, 60%, and 100% (P<0.05), respectively. Our results suggested that there existed obvious allelopathic effect between B. platyphylla and L. olgensis, and thus, mixed planting B. platyphylla and L. olgensis could have promotion effects on the growth of the two tree species.

Changes of plant community biomass and soil nutrients during the vegetation succession on abandoned cultivated land in desert steppe region.

2011, 22(12):  3145-3149. 

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By the method of substituting temporal serial with spatial serial, and taking five abandoned cultivated lands with different ages (1, 4, 9, 12, and 20 years) in desert steppe region as test objects, this paper studied the change characteristics of plant community biomass and soil nutrients during vegetation succession. With the increasing abandoned years, the plant community aboveground biomass on the abandoned lands increased after an initial decrease, whereas the total nitrogen, total phosphorus, organic carbon contents, and carbon density in 0-60 cm soil layer increased first, decreased then, and increased again, with the maximum values of soil total nitrogen and phosphorus contents appeared on the abandoned lands with the ages 4 and 20 years. During vegetation succession, the effects of soil total nitrogen and organic carbon on plant community biomass were greater than those of soil total phosphorus and soil bulk density.

Effects of exogenous abscisic acid (ABA) on the photosynthesis and chlorophyll fluorescence parameters of Tripterygium wilfordii seedlings exposed to low temperature.

2011, 22(12):  3150-3156. 

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Taking one year-old Tripterygium wilfordii cutting seedlings as test materials, this paper studied the effects of foliar spraying 0, 5, 10, 15, 20, and 25 mg·L^-1 of abscisic acid (ABA) on the leaf photosynthesis and chlorophyll fluorescence characteristics of the seedlings under low temperature stress. Spraying 20 mg·L^-1of ABA increased the cold- resistance of the seedlings significantly, manifesting in the slowing down of the decrease amplitudes of leaf net photosynthetic rate (P_n), transpiration rate (T_r), stomatal conductance (g_s), and intercellular CO₂ concentration (C_i) and the increase of photosynthetic capacity. After 6 days exposure to low temperature, the initial fluorescence (F_o) decreased with increasing concentration of applied ABA, the maximum fluorescence (F_m) and maximal photochemical yield(F_v/F_m) increased, the actual photochemical efficiency of system Ⅱ (Φ_PSⅡ) and photochemical quenching coefficient (q_P) increased after an initial decrease,and the non-photochemical quenching coefficient (q_N) showed a ‘decreasing-increasing-decreasing’ trend. The P_n, g_s,q_P, F_m,and F_v/F_m reached their peak values at 20 mg·L^-1 of ABA. In all treatments, with the increase of photosynthetically active radiation (PAR), the relative electron transport rate (rETR) increased first and decreased then, reached the peak when the PAR was 395 μmol·m^-2·s^-1, and the peak value of the rETR in treatments 25 and 20 mg·L^-1of ABA was 17.1% and 5.2% higher than that of the control, respectively. The light response curves of the Φ_PSⅡdecreased with increasing PAR, whereas those of q_N performed in adverse.

Effects of foliar spraying methyl jasmonate on  leaf chlorophyll fluorescence characteristics of flue-cured tobacco seedlings under drought and re-watering.

2011, 22(12):  3157-3162. 

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Taking the flue-cured tobacco variety of “Longjiang 911” from Heilongjiang Province of Northeast China as test material, a pot experiment was conducted to study the effects of foliar spraying different concentration methyl jasmonate (MeJA) on the seedlings leaf chlorophyll content and chlorophyll fluorescence characteristics during the transplantation stage under drought and re-watering. Under drought condition, the leaf chlorophyll content, maximum fluorescence (F_m), potential activities of PSII (F_v/F_o), maximum photochemical efficiency (F_v/F_m), actual photochemical efficiency (Ф_PSⅡ), apparent electron transport rate (ETR), and photochemical quenching (q_P) decreased, but the minimal fluorescence (F_o) and non-photochemical quenching (q_N) increased. Foliar spraying 0.2 and 0.5 mmol·L^-1 of MeJA had obvious positive effects in mitigating the decrease of F_v/F_m, F_v/F_o, Ф_PSⅡ, ETR, and q_P and the increase of q_N under drought stress, while spraying 1.0 mmol·L^-1of MeJA had lesser effects. After re-watering, all the leaf chlorophyll fluorescence indices had obvious recovery, and spraying MeJA made the indices more close to the original levels before drought. It was suggested that foliar spraying MeJA could alleviate the degradation of chlorophyll and play definite role in protecting the PSII under drought stress, decrease the damage of drought stress on the seedlings, promote the rapid MeJA recovery of chlorophyll fluorescence parameters after re-watering, and thus, ensure the regrowth of flue-cured tobacco seedlings.

Soil nutrient distribution and its relations with topography in Huangshui River drainage basin. 

2011, 22(12):  3163-3168. 

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By using GIS and geostatistic techniques, this paper studied the spatial distribution patterns of soil nutrients and their relationships with topographic factors in Huangshui River drainage basin, a water source of Danjiangkou Reservoir. In the study area, the soil total nitrogen, total phosphorus, and organic matter varied spatially at medium level, with the variation coefficients being 51%, 66%, and 85%, respectively, whereas the soil available phosphorus displayed a strong spatial variation, with the variation coefficient reached 161%. The soil total nitrogen and organic matter exhibited a spatially positive autocorrelation, while the soil total and available phosphorus presented a spatially weak autocorrelation.Altitude was one of the main topographic factors affecting the spatial distribution patterns of the soil nutrients, having significant effects on the spatial distribution of total nitrogen, total phosphorus, and organic matter. Slope and profile curvature also had significant effects on the spatial distribution of the soil total nitrogen and organic matter. Based on these, the regression prediction models of topographic factors and soil nutrient spatial distribution were established, and the digital mappings of the soil nutrients were made, which provided data support for the precise management of soil resources in the study area.

Evaluation of soil quality under different land use types in Naban River watershed, Yunnan Province of Southwest China.

2011, 22(12):  3169-3176. 

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Eighty-six topsoil (0-20 cm) samples were collected from 8 land use types (natural forest land, maize field, tea garden, paddy field, rubber plantation, flax field, banana plantation, and sugarcane field) in the Naban River Watershed National Nature Reserve and its surrounding areas, and the soil physical and chemical properties were analyzed, aimed to study the effects of land use type on the soil quality by the method of soil quality index (SQI). Comparing with natural forest land, all the cultivated lands had somewhat decreased soil organic matter content and higher soil bulk density, and the soil bulk density was significantly higher in tea garden, paddy field, rubber plantation, and banana plantation. In cultivated lands, fertilization and reclamation made the soil available potassium and phosphorus contents maintained at a higher level, probably due to the input of mineral potassium and phosphorus and the decomposition of soil organic matter. The SQI of the 8 land use types was in the order of flax field (0.595)> natural forest land (0.532)> maize field (0.516) > banana plantation (0.485)> tea garden (0.480)> sugarcane field (0.463)> paddy field (0.416)> rubber plantation (0.362). The soils in higher altitude production demonstration areas (1614±115 m) had significant higher SQI, compared to the soils in lower altitude buffer areas (908±98 m) and junction areas (926±131 m). Among the 8 land use types, the rubber plantation in lower altitude areas had the lowest SQI, due to the lower soil organic matter and available potassium and phosphorus contents and the highest soil bulk density. Application of organic manure or intercropping with leguminous plants could be an available practice to improve the soil quality of the rubber plantation.

Changes of China agricultural climate resources under the background of climate change: Ⅸ. Spatiotemporal change characteristics of China agricultural climate resources.

2011, 22(12):  3177-3188. 

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Based on the 1961-2007 ground surface meteorological data from 558 meteorological stations in China, this paper analyzed the differences of agricultural climate resources in China different regions, and compared the change characteristics of the agricultural climate resources in 1961-1980 (periodⅠ) and 1981-2007 (period Ⅱ), taking the year 1981 as the time node. As compared with period Ⅰ, the mean annual temperature in China in period Ⅱ increased by 0.6 ℃, and the ≥ 0 ℃ active accumulated temperature in the growth periods of chimonophilous crops and the ≥ 10 ℃ active accumulated temperature in the growth periods of thermophilic crops increased averagely by 123.3 ℃·d and 125.9 ℃·d, respectively. In 1961-2007, the mean annual temperature increased most in Northeast China, and the ≥ 10 ℃ active accumulated temperature in the growth periods of thermophilic crops increased most in South China. The whole year sunshine hours and the sunshine hours in the growth periods of chimonophilous crops and of thermophilic crops in period Ⅱ decreased by 125.7 h, 32.2 h, and 53.6 h, respectively, compared with those in periodⅠ.In 1961-2007, the annual sunshine hours decreased most in the middle and lower reaches of Yangtze River,while the sunshine hours in the growth periods of chimonophilous crops and of thermophilic crops decreased most in North China and South China, respectively.In the whole year and in the growth periods of chimonophilous and thermophilic crops, both the precipitation and the reference crop evapotranspiration in this country all showed a decreasing trend, with the largest decrement in the precipitation in the whole year and in the growth periods of chimonophilous and thermophilic crops in North China, the largest decrement in the reference crop evapotranspiration in the whole year and in the growth periods of thermophilic crops in the middle and lower reaches of Yangtze River, and the largest decrement in the reference crop evapotranspiration in the growth periods of chimonophilous crops in Northwest China. In 1961-2007, the climate in China in the whole year and in the growth periods of thermophilic crops showed an overall tendency of warm and dry, and the climate in the growth periods of thermophilic crops became warm and dry in Southwest China, North China, and Northeast China, but warm and wet in the middle and lower reaches of Yangtze River, Northwest China, and South China, whereas the climate in the growth periods of chimonophilous crops became warm and dry in North China, but became warm and wet in Northwest China.

Climatic potential productivity of winter wheat and summer maize in Huanghuaihai Plain in 2011-2050.

2011, 22(12):  3189-3195. 

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Based on the daily data under B2 climate scenario (2011-2050) and baseline climate condition (1961-1990) extracted from the regional climate model PRECIS, and by using the Agro-Ecological Zone (AEZ) model, a prediction was conducted on the possible spatiotemporal changes of the climatic potential productivity of the two crops in the Huanghuaihai Plain in 2011-2050. Under baseline climate condition, the climatic potential productivities of winter wheat and summer maize presented a regional differentiation, i.e., higher in southeast and lower in northwest regions, and higher along coast and lower in inland at the same latitudes, and fluctuated within the ranges of 3893-11000 kg·hm^-2 and 5908-12000 kg·hm^-2,respectively. Under B2 climate scenario, the climatic potential productivity of winter wheat and summer maize would have a greater inter-annual change, due to the different matching degrees of light, temperature and water during the growth periods of the crops. The climatic potential productivity of winter wheat in 2011-2030 and  summer maize in 2021-2040 would have an obvious increase, with great potential for development. Under the conditions of maintaining the present production, the climatic potential productivity of winter wheat in 2011-2050 would present an overall regional differentiation of reverse change in southeast and northwest regions and the same change in coastal and inland areas, whereas the climatic potential productivity of summer maize in 2011-2050 would have little regional differentiation.

Carbon sequestration effects of rice straw return in double season paddy field in Southern China.

2011, 22(12):  3196-3202. 

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In a long term site-specific experiment with rice straw return (RSR) and in a short term experiment with different RSR modes, this paper studied the effects of RSR on the soil organic carbon (SOC) sequestration, methane emission, and net carbon sink in a double season paddy field. RSR increased the SOC content, and the annual increasing rate of soil carbon sink in plow layer (0-15 cm) under long term RSR was 0.07 t C·hm^-2·a^-1. With the increasing amount of RSR, the apparent SOC transformation rate decreased. RSR promoted the methane emission from the paddy field significantly, and the methane emission flux in treatment RSR plus NPK during early- and late rice growth seasons increased by 75.0%  and 251.5% (P<0.01), respectively, compared with that in treatment NPK. The methane emission increased with the increasing amount of RSR. Under the similar tillage mode and rice yield, the rice straw returned had the similar apparent methane transformation rate. Considering the soil carbon sequestration and the net carbon sink after methane emission in the paddy field comprehensively, treatment RSR plus NPK had significant negative effect on the carbon sink which was basically approached to the bio-fixation of carbon by rice and increased by 158.3%, as compared with treatment NPK. Among different RSR modes, rice straw mulching plus no tillage decreased soil methane emission significantly, with the net carbon sink decreased by 50.9% as compared with the treatment high stubble plus tillage, and benefited the high and stable yielding of rice.

Effects of irrigation amount and frequency on soil water distribution and water use efficiency in a cotton field under mulched drip irrigation.

2011, 22(12):  3203-3210. 

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A 2-year (2009 and 2010) field experiment was carried out to investigate the effects of irrigation amount (300, 375, and 450 mm) and irrigation frequency (once every 3-, 7-, and 10 days) on the soil water distribution and cotton water use efficiency (WUE) under mulched drip irrigation in North Xinjiang. When the irrigation amount was 375 mm, irrigation once every 3 days induced a higher water content in surface soil (0-20 cm) in the whole growth season of cotton but made the deeper (below 40 cm) soil not moistened enough. Irrigation once every 10 days benefited the irrigation water penetrated downward or sideways and made the deeper soil have a higher water content; however, this drip irrigation did not replenish water in time, and made the surface soil water content lower. Overall, drip irrigation once every 7 days benefited the uniform distribution of irrigation water in soil profile. Under the same irrigation frequencies, the larger the irrigation amount, the higher the soil water content. The cotton water consumption in all treatments had the similar pattern, i.e., lower at seedling stage (averagely <1.7 mm·d^-1), increased gradually since squaring stage and reached the maximum at full bloom stage (about 8.7 mm·d^-1), and decreased at open-boll stage (about 1.0 mm·d^-1). Under the natural condition, the total cotton water consumption had close correlation with irrigation amount but poor correlation with irrigation frequency, and the cotton WUE decreased significantly with increasing irrigation amount. When the irrigation amount was 300 mm, the WUE was higher but the yield production decreased markedly,whereas excessive irrigation(450 mm)had no significant yield-increasing effect but wasted water. It was suggested that irrigation with an amount of 375 mm and a frequency of once every 7- or 10 days could be an appropriate drip irrigation mode for the local cotton field under natural condition.

Characteristics of nitrogen and phosphorus runoff losses from croplands with different planting patterns  in a riverine plain area of Zhejiang Province, East China.

2011, 22(12):  3211-3220. 

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By the method of site-specific observation, and selecting 27 field plots with 7 planting patterns in Shaoxing county of Zhejiang Province as test objects, this paper studied the characteristics of nitrogen (N) and phosphorous (P) runoff losses, loads, and their affecting factors in the croplands with different planting patterns in riverine plain area of the Province under natural rainfall. The mean annual runoff loads of total P, dissolved P, and particulate P from the field plots were 4.75, 0.74 and 4.01 kg·hm^-2, respectively, and the load of particulate P was much higher than that of dissolved P. The mean annual runoff loads of total N,dissolved total N, dissolved organic N,NH₄⁺-N, and NO₃^--N were 21.87, 17.19, 0.61, 3.63 and 12.95 kg·hm^-2, respectively, and the load of different fractions of dissolved total N was in the sequence of NO₃^--N > NH₄⁺-N > dissolved organic N. As for the field plots with different planting patterns, the runoff loads of total N, dissolved total N, dissolved organic N, and NO₃^--N were in the sequence of fallow land < nursery land < single late rice field < double rice field < rape (or wheat)-single late rice field < wheat-early rice-late rice field < vegetable field, while those of total P and particulate P were in the sequence of fallow land < nursery land < single late rice field and double rice field < wheat-early rice-late rice field < rape (wheat)-single late rice field < vegetable field. No significant difference was observed in the load of water-dissolved P among the test plots with different planting patterns. The runoff losses of N and P mainly occurred in crop growth period, and the proportions of N and P losses in the growth period increased with increasing multiple crop index. The runoff losses of total N, dissolved N, and NO₃^--N were mainly related to the application rate of N fertilizer, and soil NO₃^--N content also had obvious effects on the runoff losses of total N and dissolved N. The runoff loss of dissolved organic N was related not only to N application rate, but also to soil total N and organic carbon. The runoff loss of NH₄⁺-N was mainly related to soil available NH₄⁺-N, but not related to N application rate. The runoff losses of total P and particulate P were related to both P application rate and soil available P, while the runoff loss of water dissolved P was less related to P application rate but had relations to soil total P and available P.

Effects of returning maize straw into field on the Zn forms and their availability in a calcareous soil.

2011, 22(12):  3221-3226. 

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Maize straws were put into nylon mash bags and buried in a calcareous soil to study the effects of returning maize straw into field on the calcareous soil Zn forms and their availability. Compared with Zn fertilization, returning maize straw into field had little contribution to the soil total Zn content. Both Zn fertilization and straw returning increased the soil DTPA-Zn content significantly, and the increment was larger under Zn fertilization. As compared to that in low Zn concentration straw, the Zn released from high Zn concentration straw after returned into soil was more easily transformed into soil DTPA-Zn, with the transformation rate reached 49.0%. The transformation rate of soil DTPA-Zn had a trend of decreasing first and increasing then after straw returned into soil, but had little change under Zn fertilization. The soil exchangeable Zn (Ex-Zn), carbonate bound Zn (Carb-Zn), manganese oxide bound Zn (OxMn-Zn), tightly organic bound Zn (Sbo-Zn), and mineral Zn (Min-Zn) contents had no significant differences among the treatments, but the soil weakly organic bound Zn (Wbo-Zn) content was significantly higher under Zn fertilization, compared with the treatments control and straw addition alone. It was considered that the Zn in maize straw could be easily transformed into soil DTPA-Zn, though the Zn concentration in straw was rather low. Therefore, Zn fertilization combined with returning maize straw into filed could be an effective way to improve the Zn supply capacity of calcareous soil.

Effects of different planting modes on soil nitrogen transformation and related enzyme activities.

2011, 22(12):  3227-3235. 

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A 2-year field experiment was conducted to study the dynamics of soil nitrogen content and urease, proteinase, and nitrate reductase activities in a wheat/maize/soybean relay strip intercropping system under effects of five planting modes, i.e., wheat-soybean (A₁), wheat-sweet potato (A₂), maize (A₃), wheat/maize/soybean (A₄), and wheat/maize/sweet potato (A₅). Among the five planting modes, A₄ increased the soil total nitrogen content and urease and protease activities at flowering (or spinning) and maturing stages, and the total nitrogen content and urease and protease activities were relay strip intercropping > single cropping, soybean > sweet potato, and fringe row > central row. A₄ decreased the NO₃^--N and NH₄⁺-Ncontents of wheat and maize soil, and the nitrate reductase activity of wheat soil. The nitrate reductase activity of maize soil was higher in single cropping than in relay strip intercropping at jointing stage but was in adverse at maize spinning and maturiting stages, and the nitrate reductase activity of soybean soil was higher than that of sweet potato soil. At the branching stage of soybean, the soil NO₃^--N and NH₄⁺-N contents and nitrate reductase activity were higher in single cropping than in relay strip intercropping; whereas at flowering and maturing stages, the soil NO₃^--N and NH₄⁺-Ncontents and nitrate reductase activity were in the sequences of strip intercropping > single cropping, soybean > sweet potato, and center row > fringe row.

Translocation and transformation characteristics of fertilizer nitrogen in paddy soil: A study with simulated soil column.

2011, 22(12):  3236-3242. 

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Aimed to understand the translocation and transformation characteristics of applied fertilizer nitrogen in paddy soil, a simulated soil column experiment was conducted in laboratory to study the variations of soil mineral nitrogen along the profile under the application of 360 mg·kg^-1 (3 folds of conventional application rate) of urea- and ammonium sulfate nitrogen. In the experimental period, the soil NH₄⁺-N and NO₃^--N contents in the control (no fertilization) had less change, and no significant differences among different soil layers. Applying urea- and ammonium sulfate nitrogen resulted in a significant increase of soil NH₄⁺-N and NO₃^--N in 0-50 mm layer, being 186.0-2882.1 mg·kg^-1 and 268.7-351.5 mg·kg^-1, and 4.8-242 times and 5.7-316 times of those in CK, respectively. However, the NH₄⁺-N and NO₃^--N contents below 50 mm soil depth were similar to those in CK, indicating that the translocation and transformation of applied fertilizer nitrogen mainly occurred in 0-50 mm soil layer. The translocation of fertilizer nitrogen mostly occurred in the first 14 days after fertilization. In the whole experimental period, the NH₄⁺-N and NO₃^--N contents in each soil layer under the application of ammonium sulfate were 0.7-2.0 times of those under the application of urea, and the nitrification rate was 0.9-1.4 times of that, suggesting the higher transformation rate of applied ammonium sulfate in paddy soil, as compared with applied urea.

Effects of nitrogen fertilization rate and planting density on cotton biomass and nitrogen accumulation in extremely early mature cotton region of Northeast China.

2011, 22(12):  3243-3251. 

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Taking two cotton cultivars Liaomian 19 and NuCOTN 33B with different growth periods as test materials, a field experiment was conducted to study the effects of different nitrogen fertilization rates (0, 240 and 480 kg N·hm^-2) and different planting densities (75000, 97500 and 120000 plants·hm^-2) on the cotton biomass, nitrogen accumulation, and accumulative nitrogen utilization in the planting region of extremely early mature cotton in Northeast China. The dynamics of cotton biomass and nitrogen accumulation of the two cultivars with their growth process followed Logistic model. Both nitrogen fertilization rate and planting density had significant effects on the cotton nitrogen accumulation dynamics and the cotton yield and quality. In all treatments, the beginning time of rapid accumulation of nitrogen was about 13 d earlier than that of biomass. In treatment plant density 97500 plants·hm^-2 and nitrogen fertilization rate 240 kg·hm^-2, the eigenvalues of the dynamic accumulation models of nitrogen and biomass for the two cultivars were most harmonious, lint yield was the highest, fiber quality was the best, and accumulative nitrogen utilization efficiency was the highest. In the study region, the earlier beginning time of rapid accumulation of nitrogen and biomass and their higher accumulation rates were benefit to the formation of higher cotton yield.

Effects of exogenous spermidine on lipid peroxidation and membrane proton pump activity of cucumber seedling leaves under high temperature stress.

2011, 22(12):  3252-3258. 

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Taking a relatively heat-resistant cucumber (Cucumis sativus) cultivar ‘Jinchun No. 4’ as test material, a sand culture experiment was conducted in growth chamber to investigate the effects of foliar spraying spermidine (Spd) on the lipid peroxidation, membrane proton pump activity, and corresponding gene expression of cucumber seedling leaves under high temperature stress. Compared with the control, foliar spraying Spd increased the plant height, stem diameter, dry and fresh mass, and leaf area significantly, and inhibited the increase of leaf relative conductivity, malondialdehyde (MDA) content, and lipoxygenase (LOX) activity effectively. Foliar spraying Spd also helped to the increase of leaf plasma membrane- and tonoplast H⁺-ATPase activity, but no significant difference was observed in the gene expression levels. These results suggested that exogenous Spd could significantly decrease the leaf lipid peroxidation and increase the proton pump activity, and thus, stabilize the leaf membrane structure and function, alleviate the damage induced by high temperature stress, and enhance the heat tolerance of cucumber seedlings.

Carbon source utilization characteristics of microbial communities in a petroleum-contaminated soil in Daqing Oil Field, Northeast China.

2011, 22(12):  3259-3264. 

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By using Biolog technique, this paper studied the carbon source utilization characteristics of microbial communities in different layers (0-10 cm, 10-20 cm, and 20-30 cm) of a petroleum-contaminated soil near an oil well having exploited for 36 years in Daqing Oil Field. Petroleum contamination enhanced the metabolic activity of the soil microbial communities obviously. In the three layers of the petroleum-contaminated soil, the metabolic activity of the microbes was higher than that of the control, and there existed significant differences between different layers of the petroleum-contaminated soil. The carbon source metabolic capacity of the microbes in different layers of the petroleum-contaminated soil was in the order of 20-30 cm ＞10-20 cm ＞ 0-10 cm. Petroleum contamination made the kinds of soil carbon source and the metabolic diversity of soil microbes increased, being more obvious in 10-20 cm and 20-30 cm soil layers but less change in 0-10 cm soil layer. In the contaminated soil, the majority of the carbon sources utilized by the microbes in 10-20 cm soil layer were carbohydrates instead of the carboxylic acids in non-contaminated soil, whereas the majority of the carbon substrates utilized in 20-30 cm soil layer were carboxylic acids. All the results suggested that petroleum-contaminated soil had its unique microbial community structure and peculiar microbial carbon source utilization characteristics.

Effects of plant hedgerow on population dynamics of wheat aphid and its natural enemies.

2011, 22(12):  3265-3271. 

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This paper studied the effects of planting different kinds of plant hedgerow (Amorpha fruticosa, Vetiveria zizanioides, Eulaliopsis binata, and Medicago sativa) on the population dynamics of wheat aphid and its natural enemies in the hillside wheat fields in Ziyang City of Sichuan Province, Southwest China. On the 20° hillside, A. fruticosa hedgerow inhibited the occurrence of wheat aphid in the wheat field significantly, and the parasitoid densities were equal to or significantly lower than those in the wheat field with V. zizanioides hedgerow. On the 12° hillside, M. sativa and E. binata hedgerows delayed the peak time of wheat aphid occurrence, and E. binata hedgerow suppressed the wheat aphid population density significantly. In the wheat field with M. sativa hedgerow, the parasitoid densities were significantly higher than those with no hedgerow. An equal or significantly higher ladybird density was observed in the field with M. sativa hedgerow. The olfactory responses showed that E. binata volatiles had repellent effect on both Sitobion avenae and Rhopalosiphum padi, but attracted a spider species of oxyopidae. M. sativa volatiles attracted S. avenae, whereas neither M. sativa nor E. binata volatiles caused obvious behavior response of ladybird adults. Therefore, planting A. fruticosa and E. binata as the hedgerows in hillside wheat fields could not only prevent the soil erosion from seasonal rainfall, but also benefit the control of pest insects.

Ecosystem health assessment of economic zone on the west side of Taiwan Strait, China.

2011, 22(12):  3272-3278. 

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Based on the standards of regional ecosystem health, including vigor, organizational structure, resilience, ecological function, and public health, and in considering of anthropogenic pressure and response countermeasures, an index system for the ecosystem health assessment of the economic zone on the west side of the Taiwan Strait (Haixi Zone) was built, and, aiming at the characteristics of nature and humanity of regional ecosystem health, the weights of the indices were given by analytic hierarchy process and mean square difference method. Fuzzy comprehensive assessment was utilized to establish the ecosystem health assessment model of Haixi Zone. The assessment showed that in 2008, the ecosystem health state of Haixi Zone was superior, and the anthropogenic pressure was relatively gentle. Overall, the regional ecosystem health status was good, but had spatial difference. Owing to the restriction of response countermeasures such as fixed assets investment and education expenditure. The regional ecosystem health status of Longyan, Quanzhou, Wenzhou, Chaozhou and Jieyang was worse than the health state of these cities in 2008. The overall ecosystem health status of the Zone in 2000 and 2008 was better than that in 1992, and the main driving factors were mainly economic vigor, organizational structure, human health, population pressure, and investment. However, the overall ecosystem health status of Haixi Zone in 2008 was worse than that in 2000, due to the expansion of built-up land, the decrease in natural landscape, and the enhancement of human disturbances.

Spatial patterns of eco-environmental vulnerability in Daqing City.

2011, 22(12):  3279-3284. 

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This paper established an index system for the assessment of eco-environmental vulnerability in Daqing City, from the aspects of sensitivity and response capability, and aiming at the major disturbances from crude oil exploitation and production activities. The improved entropy method was adopted to evaluate the weights of the indices, and the spatial patterns of eco-environment vulnerability in the City were analyzed, according to the model functions. In 2009, the more sensitive areas of the eco-environment in the City were mainly concentrated in the intensive regions of crude oil exploitation, processing, and petrochemical industry, and the ecological problems such as land salinization were the secondary causes for this higher sensitivity. The overall response capability of the eco-environment to unfavorable disturbances was relatively high, which reduced the eco-environment vulnerability to some extent. There was a great spatial difference in the eco-environment vulnerability in the City. The vulnerability was comparatively higher in the districts of Honggang, Sartu and Longfeng, with the degree being 0.80, 0.71 and 0.68, but lower in Ranghulu and Datong, with the degree of 0.20 and 0.04, respectively.

Distribution and composition of organochlorine pesticides in farmland top soils of Anhui Province.

2011, 22(12):  3285-3292. 

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By using ultrasonic method and GC/ECD, this paper analyzed the distribution and composition of 8 kinds of organochlorine pesticides (α-HCH, β-HCH, γ-HCH, δ-HCH, op′-DDE, pp′-DDD, α-endosulfan, and chlorothalonil) in farmland top soils (0-20 cm) in 19 districts of Anhui Province, East China. The total concentration of the pesticides in the top soils ranged from 0 to 23.75 μg·kg^-1, among which, pp′-DDD and γ-HCH were the major pollutants, with the mean concentration being 13.83 and 13.49 μg·kg^-1, respectively. As compared with the analyses in 1990, the present mean concentration of HCH had an obvious decreasing trend, but was still higher than that in the top soils in other regions of China and in other countries. The mean concentrations of OCPs, HCHs and pp′-DDD in the test top soils were 48.58, 28.64 and 13.83 μg·kg^-1, respectively, not surpassed the first grade level (<50 μg·kg^-1) of the China National Soil Environmental Quality Standards (GB 15618-1995), suggesting that the farmland top soils in these districts of Anhui Province were less polluted.

Biosorption of crystal violet and malachite green by Rhodotorula graminis Y-5.

2011, 22(12):  3293-3299. 

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With a shaker, this paper studied the characteristics of the biosorption of crystal violet and malachite green by Rhodotorula graminis Y-5 under different adsorption time, initial pH, and temperature, as well as the desorption and recycling use of the dyes. The biosorption of crystal violet and malachite green by R. graminis Y-5 had the peaks (93.8% and 87.7%, respectively) at pH 7.0,dye concentration 50 mg·L^-1,150 r·min^-1, 30 ℃, and lasting 10 hours. After desorption, the biosorption rate of crystal violet and malachite green by R. graminis was 85.5% and 78.5%, respectively, indicating that the biosorption of crystal violet and malachite green was reversible, and the recycling use of the dyes by R. graminis was quite good, i.e., the dyes were renewable and could be recycled. Biosorption could be the mechanism of the decolorization of the dyes. The dyes were mostly adsorbed on the R. graminis surface -OH. The adsorption process was fast, efficient, and reversible, suggesting that R. graminis had a high potential for waste water treatment.

Induce of laccase from Trametes gallica and its degradation on neutral dyes and organophosphorus pesticides.

2011, 22(12):  3300-3306. 

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The characteristics of the induction of laccase in Trametes gallica under different initial cultural pH, incubation time by different inducers were discussed, as well as the effects of temperature, pH and time on laccase degradation of six dyes and four organophosphors. The results showed that RB-bright blue, ABTS and o-toluidine affected the production of laccase at different levels, and ABTS was the best inductive agent in our test conditions, whose optimal initial pH and incubation time were 4.0 and 13 days, respectively. The appropriate reaction temperature of the laccase produced was 38 ℃, and it got a good stability, for it could retain 78.6% of the enzyme activity after 20 min holding at 40 ℃. Mediated by ABTS, the optimal temperature for laccase to degrade the six types of neutral dyes could be divided into two cases, that was 30 ℃ (neutral black, neutral bordeaux, neutral pink, methyl orange) and 60 ℃ (neutral dark yellow, cresol red), the optimal pH were 6.0 (neutral black), 2.0 (neutral bordeaux, neutral pink) and 4.0 (methyl orange, neutral dark yellow, cresol red), respectively, while the optimal times separately were 6 h (methyl orange, neutral dark yellow, cresol red), 12 h (neutral pink) and 24 h (neutral bordeaux). And using the same inductive agent, the best temperature for laccase to degrade dimethoate, chlorpyrifos, trichlorfon and parathion-pyridazine was 25 ℃, the suitable time was 9 h, and the optimal pH was 10.0 for dimethoate, chlorpyrifos and parathion-pyridazine, and 8.0 for trichlorfon.

Location selection for Shenyang urban parks based on GIS and multi-objective location  allocation model.

2011, 22(12):  3307-3314. 

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Based on geographic information system(GIS)technology and multi-objective location-allocation (LA) model, and in considering of four relatively independent objective factors (population density level, air pollution level, urban heat island effect level, and urban land use pattern), an optimized location selection for the urban parks within the Third Ring of Shenyang was conducted, and the selection results were compared with the spatial distribution of existing parks, aimed to evaluate the rationality of the spatial distribution of urban green spaces. In the location selection of urban green spaces in the study area, the factor air pollution was most important, and, compared with single objective factor, the weighted analysis results of multi-objective factors could  provide optimized spatial location selection of new urban green spaces. The combination of GIS technology with LA model would be a new approach for the spatial optimizing of urban green spaces.

Drought-resistance evaluation of marigold cultivars based on multiple statistics analysis.

2011, 22(12):  3315-3320. 

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By the methods of principal component analysis, subordinate function, and cluster analysis, a comprehensive evaluation was conducted on the drought-resistance of 16 physiological indices of nine marigold cultivars. Under drought stress, the 16 physiological indices had different responses, among which, free proline (Pro), H₂O₂, and ascorbate peroxidase (APX) showed the greatest sensitivity. There existed significant correlations in the drought-resistance coefficients of parts of the physiological indices. Four principal factors presented 88.6% of the information of the 16 indices, and the cultivars ‘Janie’ and ‘Gate gold’, ‘Bonanzn’, ‘Janie’, and ‘Chokdee’ had the strongest drought-resistance for the 4 principal factors, respectively. The comprehensive evaluation value of the drought-resistance of the 9 cultivars was in the order of ‘Janie’ > ‘Gate gold’ > ‘Bonanza’ > ‘Chokdee’ > ‘Giant’ > ‘Great hero’ > ‘Little hero’ > ‘Durango’ > ‘Discovery’. The 9 cultivars could be clustered into 3 groups, and ‘Gate gold’, ‘Janie’, ‘Bonanza’ and ‘Chokdee’ belonged to the drought-resistance group.

Effects of macro-jellyfish abundance dynamics on fishery resource structure in the Yangtze River estuary and its adjacent waters.

2011, 22(12):  3321-3328. 

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Based on the bottom trawl survey data in May 2007 and May and June 2008, this paper analyzed the effects of the abundance dynamics of macro-jellyfish on the species composition, distribution, and abundance of fishery resource in the Yangtze River estuary and its adjacent waters. From May 2007 to June 2008, the average catch per haul and the top catch per haul of macro-jellyfish increased, up to 222.2 kg·h^-1 and 1800 kg·h^-1 in June 2008, respectively. The macro-jellyfish were mainly distributed in the areas around 50 m isobath, and not beyond 100 m isobath where was the joint front of the coastal waters of East China Sea, Yangtze River runoff, and Taiwan Warm Current. The main distribution area of macro-jellyfish in June migrated northward, as compared with that in May, and the highest catches of macro-jellyfish in May 2007 and May 2008 were found in the same sampling station (122.5° E， 28.5° N). In the sampling stations with higher abundance of macro-jellyfish, the fishery abundance was low, and the fishery species also changed greatly, mainly composed by small-sized species (Trachurus japonicus, Harpadon nehereus,and Acropoma japonicum) and pelagic species (Psenopsis anomala,Octopus variabilis） and Trichiurus japonicus, and P. anomala accounted for 23.7% of the total catch in June 2008. Larimichthys polyactis also occupied higher proportion of the total catch in sampling stations with higher macro-jellyfish abundance, but the demersal species Lophius litulon was not found, and a few crustaceans were collected. This study showed that macro-jellyfish had definite negative effects on the fishery community structure and abundance in the Yangtze River estuary fishery ecosystem, and further, changed the energy flow patterns of the ecosystem through cascading trophic interactions. Therefore, macro-jellyfish was strongly suggested to be an independent ecological group when the corresponding fishery management measures were considered.

Macrobenthos community structure and its relations with environmental factors in Taihu River basin.

2011, 22(12):  3329-3336. 

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An investigation was conducted on the macrobenthos at 37 sampling sites in the Taihu River basin in August 2009 and May 2010.A total of 69 macrobenthos species were collected, of which, 15 species (21.7% of the total) were oligochaetas, 16 species (23.2%) were mollusks, 5 species (7.2%) were crustaceans, 27 species (39.1%) were aquatic insects, and 6 species (8.7%) were polychaetes. Based on the species composition and relative abundance, and by using two-way indicators species analysis (TWINSPAN) and detrended correspondence analysis (DCA), the 37 sampling sites were divided into four groups. In the first group, polychaetes and mollusks such as Nephthys sp. and Corbicula fluminea were the indicator species; in the second group, polychaetes and mollusks such as Grandidierella aihuensis and Semisulcospira libertina were the indicator species; in the third and fourth groups, the indicator species were the annelids such as Limnodrilus hoffmeisteri and the Tubifex tubifex and chironomidae larvae, respectively. The canonical correspondence analysis (CCA) indicated that water conductivity and total nitrogen were the main environmental factors affecting the distribution of macrobenthos, and the factors water depth, diaphaneity, COD_Cr, ammonium nitrogen, nitrate nitrogen, and chlorophyll a also had definite effects.

Effects of water temperature and edible algal density on the population dynamics and sexual reproduction of Moina irrasa.

2011, 22(12):  3337-3342. 

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This paper studied the population dynamics and sexual reproduction of Moina irrasa at different water temperature and edible algal density. The population density of M. irrasa was obviously higher at high than at medium and low densities of edible algae, with the maximum at high edible algal density and 20 ℃. At the same temperatures, the average number of the offsprings first produced by per female M. irrasa declined with decreasing edible algal density, and the maximum value appeared at 25 ℃ and at high edible algal density. The male offsprings produced were obviously higher at high than at medium and low edible algal densities. There was a significant correlation between the male density and the population density of M. irrasa. The number of ephippia produced by M. irrasa declined with decreasing edible algal density, and was higher at 25 ℃ than at other temperatures. Edible algal density had larger effects on the population dynamics and sexual reproduction of M. irrasa, as compared with temperature.

Potential errors in measuring tree transpiration based on thermal dissipation method.

2011, 22(12):  3343-3350. 

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Transpiration is a major component of vegetation evapotranspiration, and a core in the study of plant water physiological ecology. Its measurement methods attracted extensive attention, among which, thermal dissipation is considered as an optimal method for measuring tree transpiration. Numerous studies showed that thermal dissipation method was relatively accurate in measuring individual tree transpiration and stand-scale water consumption.However, there exist potential errors between the true value and the measurements during measurement process. In this paper, the potential errors of thermal dissipation method in measuring sap flux density and of the temperature difference determination from single tree to stand-scale were reviewed, and the research prospects on the potential errors of thermal dissipation method in China were discussed. The corresponding solutions were also proposed.

Sexual difference of insect phototactic behavior and related affecting factors.

2011, 22(12):  3351-3357. 

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Flight-to-light is one of the major behaviors of nocturnal insects. Previous studies have demonstrated that many nocturnal insect species have noticeable sexual difference in the behavior of flight-to-light, and many factors may contribute to this kind of difference. This paper reviewed the sexual difference of insect phototactic behavior in terms of the difference in flying distance and height between female and male adults due to their different flying capability, the distinct difference in the response to light resource due to the different structure of compound eyes between female and male adults, and the difference in the sensitivity to the light source and other environmental factors between female and male adults. The applied aspects and future research directions of the sexual difference of nocturnal insect phototactic behavior were also discussed.

Ecosystem services evaluation based on geographic information system and remote sensing technology: A review.

2011, 22(12):  3358-3364. 

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Ecosystem services evaluation is a hot topic in current ecosystem management, and has a close link with human beings welfare. This paper summarized the research progress on the evaluation of ecosystem services based on geographic information system (GIS) and remote sensing (RS) technology, which could be reduced to the following three characters,i.e.,  ecological economics theory is widely applied as a key method in quantifying ecosystem services, GIS and RS technology play a key role in multi-source data acquisition, spatiotemporal analysis, and integrated platform, and ecosystem mechanism model becomes a powerful tool for understanding the relationships between natural phenomena and human activities. Aiming at the present research status and its inadequacies, this paper put forward an “Assembly Line” framework, which was a distributed one with scalable characteristics, and discussed the future development trend of the integration research on ecosystem services evaluation based on GIS and RS technologies.

Effects of drought stress on the biomass distribution and photosynthetic characteristics of cluster mulberry.

2011, 22(12):  3365-3370. 

Asbtract ( 1978 )   PDF (619KB) ( 630 )  

One-year-old Morus alba seedlings were cultivated in pots containing soil with different water contents to study the biomass, chlorophyll fluorescence parameters, net photosynthesis rate, stomatal conductance, transpiration rate and water use efficiency of the seedlings in response to diverse water stress. The results showed that the  aboveground biomass  and total biomass decreased with increasing water stress. However, more photosynthetic products were transferred to the roots in relation to the aboveground parts to make the root-shoot ratio increase. The fluorescence parameters, such as F_o, F_v and F_v/F_m, and stomatal conductance, transpiration rate and water use efficiency decreased with increasing water stress.

Effects of wheat planted adjacent to rape on the major pests and their natural enemies in wheat field.

2011, 22(12):  3371-3376. 

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Based on the dynamic analysis of insect community structure characteristics, an investigation was conducted on the composition, abundance, and stability of wheat aphids and their major natural enemies in the wheat field adjacent to rape field in Handan City, Hebei Province in 2008-2009. The wheat and rape fields had the similar composition of insect communities. The main pests were aphids, their predatory natural enemies included ladybirds, green lacewings, spiders, and hover flies, and their parasitic natural enemies were wasps. In 2008-2009, the composition of insect communities in the wheat and rape fields had definite changes, but the common features were the lowest abundance of aphids and the highest abundance of predatory and parasitic natural enemies in wheat field adjacent to rape field. The insect community, aphid sub-community, and predatory natural enemy’s sub-community had a high stability in the wheat field adjacent to rape field and a low stability far from the rape field, suggesting that planting wheat adjacent to rape could effectively protect and make use of the natural enemies and promote their control ability on wheat aphids in wheat field.