Table of Content

08 November 2011, Volume 30 Issue 11

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Articles

Local formation mechanisms of Hemiptelea davidii forest in Keerqin Sandy Land of North China.

2011, 30(11):  2389-2393. 

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Hemiptelea davidii forest is a peculiar forest type in Keerqin Sandy Land not recorded in references so far. Aimed to understand the biological and ecological mechanisms of the regeneration and expansion of H. davidii,a sampling line transect survey was conducted on the seed dispersal and seedling recruitment of H. davidii in its forest edges and forest understory, and an observation was made on the fruit shape and fruit-shedding characteristics of the plant. A majority of H. davidii seeds were found in the understory and around the edges, and the seed rain density decreased significantly beyond 3 m of the edges. Within the stands with high coverage, the regeneration of H. davidii population was mainly relied on root sucker recruitment. Because the distribution of H. davidii seedlings was not limited by terrain, the spatial expansion of the forest was mainly relied on the seedlings. Based on the observation on the fruit shape and fruit-shedding characteristics, it was considered that the biological features of H. davidii fruits could be the foundations of the local formation of H. davidii in Keerqin Sandy Land, whereas in other geographic distribution regions, H. davidii could only be a companion species.

Spatiotemporal distribution pattern of photosynthetically active radiation in subtropical evergreen broadleaved forest in Ailaoshan Mountains of Southwest China.

2011, 30(11):  2394-2399. 

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Photosynthetically active radiation (PAR) is an important ecological factor affecting the energy transformation and matter production of plant ecosystem. Studies on the spatiotemporal distribution patterns of PAR in a plant ecosystem are helpful to understand the physiological and ecological characteristics and photosynthesis of the ecosystem. In this paper, the temporal and vertical distributions of PAR in a coniferous and subtropical evergreen forest in Ailaoshan Mountains of Southwest China were analyzed. At daily scale, the intensity of PAR during  passing through the forest canopy decreased gradually. At monthly scale, the PAR flux varied in each forest layer, with the maximum and minimum values above the canopy in February and January, respectively. The diurnal change of the PAR above the canopy (PAR₁) presented a single-peak curve, while that of the PAR at the bottom of the canopy (PAR₂) and in the arbor sub-layers (PAR₃ and PAR₄) and shrub layer (PAR₅) presented an irregular single-peak curve. The PAR₁, PAR₂, PAR₃, PAR₄ and PAR₅ fluxes at yearly scale were 8824.98, 682.20, 403.09, 216.62 and 208.52 mol·m^-2, and the ratios of yearly PAR₂, PAR₃, PAR₄ and PAR₅ to PAR₁ were 7.73%, 4.57%, 2.45% and 0.92%, respectively. The average PAR₁, PAR₂, PAR₃, PAR₄ and PAR₅ in rain season were 89.77%, 89.34%, 97.32%%, 116.36% and 115.09% of those in dry season, respectively.

Carbon storage and its allocation in an artificial Tsoongiodendron odorum ecosystem in southern subtropical region of China.

2011, 30(11):  2400-2404. 

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Based on the biomass investigation，  this paper evaluated the carbon storage and its allocation in a 27-year-old Tsoongiodendron odorum plantation ecosystem in southern subtropical region of China. In the ecosystem, the total biomass of vegetation layer was 101.26 t·hm^-2, and the biomass of tree layer occupied 86.90%. The carbon storage in various organs of the trees ranged from 426.5 to 496.9 g·kg^-1, with the order of trunk > branch > dead branch > root tip > coarse root > leaf > middle root > bark > fine root. The total carbon storage of the ecosystem was 180.49 t·hm^-2, and the carbon storage in 0-80 cm soil layer was 2.67 times of that in vegetation layer. The annual net carbon sequestration of the tree layer was 3.07 t·hm^-2·a^-1, mostly in aboveground part.

Tree growth and carbon sequestration in different land-use types in Hangzhou City. 

2011, 30(11):  2405-2412. 

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With the ever more rapid urbanization around the world, cities, as an ecological system greatly dominated by human activities, have had great changes in their land use, and also, in the vegetations carbon sequestration. In this study, Cinnamomum camphora and Platanus aceriforia, the two representative tree species in Hangzhou area, were chosen to determine their carbon storage and carbon sequestration in different types of land use in Hangzhou. The tree DBH (diameter at breast height), height, planting distance, and crown area of 720 individuals were measured, and the mean annual increment of the tree ring area of 230 individuals in recent 10 years was calculated. Then, the carbon storage and carbon sequestration rate of C. camphora and P. aceriforia in different land-use types in Hangzhou City were estimated and compared. It was estimated that the carbon storage of C. camphora and P. aceriforia was 45 kg C·m^-2 and 104 kg C·m^-2, respectively. The carbon sequestration rate of C. camphora was the highest in government agencies sites and the lowest in residential sites, whereas that of P. acerifolia was far greater in residential sites than in commercial and government agencies sites.For C. camphora, crown area was the main factor affecting the carbon sequestration rate; for P. acerifolia, both the crown area and the tree age were important. The carbon sequestration of the trees within Hangzhou was 5-fold or more of the equivalent age trees out of the city.

Responses of morphological structure and competition capability of dominant plant species in subalpine timberline to elevated atmospheric CO₂ concentration and air temperature. 

2011, 30(11):  2413-2420. 

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By using enclosed-top chambers to simulate the future climate change, this paper studied the responses of the morphological structure and competition capability of subalpine dominant plant species (Abies faxoniana, Deyeuxia scabrescen, Carex kansuensis, Fragaria orientali, and Cardamine tangutorum) to elevated atmospheric CO₂ concentration and air temperature. After two years exposure, the crown volume, specific crown volume, specific leaf area, and specific root length of A. faxoniana under elevated atmospheric CO₂ concentration increased by 42%, 65%, 17%, and 19%, respectively. Under elevated air temperature, A. faxoniana grew faster lengthways, its crown volume increased by 22%, and its root/shoot ratio and specific root length increased by 17%. The interaction of elevated atmospheric CO₂ concentration and air temperature increased the crown volume, specific crown volume, specific leaf area, and specific root length of A. faxoniana by 79%, 197%, 17%, and 18%, respectively. Under elevated atmospheric CO₂concentration, the D. scabrescen had an increase of plant height, basal diameter, and leaf number per plant but a decrease of specific leaf area, whereas the C. kansuensis, F. orientali, and C. tangutorum were in adverse. Under elevated air temperature, the root/shoot ratio of D. scabrescen,C. kansuensis, F. orientali, and C. tangutorum decreased, and the plant height and basal diameter of the herbs except C. tangutorum also decreased. The interaction of elevated atmospheric CO₂ concentration and air temperature increased the basal diameter and leaf number per plant of the four herbs, but decreased their specific leaf area and root/shoot ratio. In sum, both elevated atmospheric CO₂ concentration and elevated air temperature promoted the formation of A. faxoniana crown, which was beneficial to the capture of resources and the enhancement of the competition ability per unit mass, but had definite negative effects on the morphological structure and competition ability of the four herbaceous species.

Genetic diversity of natural Pinus tabulaeformis populations at different altitudes and in four communities types in Dawopu of Chengde, Hebei Province of North China.

2011, 30(11):  2421-2426. 

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To clarify the relationships between natural Pinus tabulaeformis population’s genetic diversity and main ecological factors, this paper analyzed the genetic diversity of different natural P. tabulaeformis populations at three altitudes and in four community types in Dawopu of Chengde, Hebei Province by using ISSR DNA technique. High genetic diversity was observed in these populations. A total of 180 loci were detected with 13 randomly selected primers, and the total percentages of polymorphic loci at altitude and community scales reached 73.33% and 91.11%, respectively. The genetic diversity of the P. tabulaeformis populations was affected by altitude. At medium altitude (1070-1130 m), the genetic diversity was higher than that at high altitude (1230-1350 m) and low altitude (910-970 m), with the percentages of polymorphic loci being 63.33%, 51.67%, and 59.4%, respectively. There existed definite inherent associations between community type and genomic variation. The genetic variation mainly occurred within the populations (90.45% at altitude scale and 75.22% at community scale). As compared with altitude, community type had stronger effects on the genetic variation and gene flow among the P. tabulaeformis populations, with G_st=0.248 and N_m=1.517 under effects of altitude, and G_st=0.095 and N_m=4.738 under effects of community type. It could be concluded that the genetic differentiation of natural P. tabulaeformis populations in Dawopu was more affected by community type.

Differential absorption of nitrogen and magnesium by Conyza japonica plants under different illumination levels.

2011, 30(11):  2427-2431. 

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Nitrogen and magnesium are two essential elements for plant photosynthesis. In this paper, annual Conyza japonica plants were hydroponically cultured in three climate chambers to study the nitrogen and magnesium absorption by the plants under three illumination levels (high, (168 ± 3) μmol·m^-2·s^-1; medium, (66 ± 1) μmol·m^-2·s^-1; and low, (23 ± 2) μmol·m^-2·s^-1), aimed to explore the nitrogen and magnesium absorption strategies of the plants under different illumination conditions. Illumination level had significant effects on the nitrogen and magnesium absorption by the plants. With the increasing level of illumination, the mass-based nitrogen absorption increased significantly, while the mass-based magnesium absorption was in adverse (P<0.05). The leaf area-based chlorophyll content increased with the decrease of illumination level,but the leaf mass-based chlorophyll content was the highest under medium illumination level and the lowest under low illumination level (P<0.05). These results suggested that under high illumination level, the plants increased their nitrogen absorption to synthesize more photosynthetic enzymes to improve electron transfer and carboxylation efficiency, whereas under low illumination level, they increased their magnesium absorption to synthesize more chlorophyll to capture more light energy. The differential absorption of nitrogen and magnesium by the C. japonica plants under different illumination levels could be explained by  their different requirements of nitrogen and magnesium for the photosynthesis under different illumination conditions.

Effects of Reaumuria soongorica on its underlying soil properties and herb plant characteristics.

2011, 30(11):  2432-2436. 

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This paper studied the differences of soil moisture and nutrients under shrub canopy and in open space as well as the effects of Reaumuria soongorica during its germination on the herb growth and vegetation composition in desert grassland of western Loess Plateau. Under shrub canopy, the soil water regime, especially in 30-110 cm layer, was better, and the soil silt and clay contents, especially in 0-10 cm layer, were much higher while the soil sand content was lower, as compared with those in open space. The soil organic matter, total N, P, and K, and available N, P, and K were more enriched under shrub canopy, with the enrichment rate being 1.40, 1.25, 1.04, 1.05, 1.37, 1.77, and 1.49, respectively. From shrub canopy to open space, the herb plant coverage and height decreased, while the species richness increased. The relative interactive intensity of R. soongorica to herb plants density, coverage, and height were positive, whereas to herb plants species richness was negative. These results suggested that shrub R. soongorica had obvious “fertile island” effect, and had promotion effect on the growth of underlying herb plants.

Interspecific competition between Avena sativa and Vicia vilosa in mixed sowing grassland in alpine mountainous region.

2011, 30(11):  2437-2441. 

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Plants can adapt to interspecific competition by adjusting their growth behaviors and morphological characteristics at their different growth stages. In this study, a grassland with mixed sowing Avena sativa and Vicia vilosa was established in Qilian mountainous region, aimed to understand the interspecific competitive relationships of the two annual species at their different phonological phases. To evaluate the competitive relationships, the relative yield (RY), relative density (RD), and relative yield total (RYT) of the two species were measured. It was observed that the interspecfic relationships of the two species changed with phenological phase. At seeding stage, there was a strong competition between the two species, manifesting in the mutual limitation of relative number and the slow increase of plant height and leaf number; at tillering stage, the interspecfic competition transformed into interspecfic collaboration, manifesting in the rapid increase of tiller number and leaf number and the increasing RYT; at jointing stage, V. vilosa started to increase its relative number, which limited the development of A. sativa and caused strong intraspecfic competition; at grain-filling stage, the intraspecfic competition transformed into interspecific competition again. Through the adjustment of morphological plasticity at different phonological phases, the two species better responded the transformation of their interspecfic relationship.

Soil carbon mineralization potential under different configuration of vegetation.

2011, 30(11):  2442-2448. 

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Soil samples were collected from the plots of different vegetation configuration (Caragana korshinskii, Artemisia ordosica, and C. korshinskii-A. ordosica) in Shapotou region of Ningxia Province, Northwest China, and an incubation was conducted to study the mineralization potential of soil carbon and the litter decomposition in soil. During 103 days incubation, no significant differences were observed in the soil carbon mineralization under the same vegetation configuration and with or without litter addition, but the mineralization rate of soil carbon was higher under the vegetation configuration with high density C. korshinskii.There was a significant difference (P=0.047) in the soil CO₂-C release from the single row of A.ordosica and from the double rows of C.korshinskii under C. korshinskii-A. ordosica and without litter addition, but no significant difference under the other vegetation configurations and with or without litter addition.Overall, the soil carbon mineralization potential under C. korshinskii was higher than that under Artemisia ordosica and C. korshinskii-A. ordosica. At early phase, the decomposition rate of the litters in soil was in the order of C. korshinskii-A. ordosica > A. ordosica > C. korshinskii. After 40 days incubation, the decomposition rate of the litters tended to be the same. The higher decomposition rate of annual plant litter could be attributed to its high C and N contents and its high C/N ratio. The soil amended with A. ordosica litter under C. korshinskii had a higher potential of carbon mineralization than the soil amended with C. korshinskii litter under A. ordosica, because of the differences in the litter chemical composition and the soil nutrient availability. However, a turning point appeared during incubation, due to the higher C and N contents and the higher C/N ratio of C. korshinskii litter. Under different vegetation configuration, the soil carbon mineralization potential was higher under the canopy than outside the canopy. The existence of shrub created a ‘fertile island’ with higher organic matter and nutrient contents and higher microbial activity under canopy, and contributed more to C sequestration.

Distribution patterns of soil organic carbon and total nitrogen in Zoige peat land with different ground water table.

2011, 30(11):  2449-2455. 

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Taking the typical peat land in Zoige National Nature Reserve at the eastern edge of Qinghai-Tibet Plateau as test object, four sites with different ground water tables were selected in summer 2009 to study the distribution patterns of organic carbon and total nitrogen in soil profile (0-50 cm), aimed to understand the effects of underground water table fluctuation on peat land soil carbon and nitrogen. In the soil profiles, both the organic carbon and the total nitrogen decreased exponentially with decreasing ground water table, and the coefficient of variation presented an increasing trend, implying that the decrease of ground water table was the main cause of the losses of soil carbon and nitrogen. There was a significant positive correlation between soil organic carbon and soil total nitrogen, and the two of them were significantly negatively correlated with soil pH and soil bulk density. The soil C/N ratio at the four sites had a small variation (from 15.76 to 18.16), implying low decomposition rate of soil organic carbon under the plateau climate and little effects of ground water table and soil pH on the soil C/N ratio.

Methane emission from riparian constructed wetland in Ohio, USA.

2011, 30(11):  2456-2464. 

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In November 2008-October 2009, a field research by the method of static chamber-gas chromatography was conducted on the spatiotemporal pattern of methane (CH₄) emission from two riparian wetlands (constructed and natural) in the Wilma H. Schiermeier Olentangy River Wetland Research Park in Columbus, Ohio, USA, with the effects of soil temperature, carbon content, hydrological condition, and vegetation on the CH₄ emission approached. Both of the wetlands had an obvious seasonal variation of CH₄ flux, and the CH₄ emission from natural wetland was significantly higher than that from constructed wetland (P<0.05), being 114 and 68 g CH₄-C·m^-2·a^-1, respectively, possibly due to the higher cumulative productivity in natural wetland. For the two wetlands, the CH₄ emission was higher in deep water zone than in transition zone, and the median value (average) was 4.7 (59.9 mg·m^-2·h^-1) and 0.09 (1.17 mg·m^-2·h^-1), respectively (P<0.01). Intermittent flooded area produced lesser methane than permanently inundated area, and soil temperature and organic carbon content had definite effects on the CH₄emission. It was suggested that to configure proper vegetation and proper hydrological conditions in riparian wetland and to implement proper management could effectively reduce the CH₄ emission from the wetland.

Decomposition characteristics of horse dung in Inner Mongolia typical steppe.

2011, 30(11):  2465-2471. 

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From June 2008 to September 2009, a field experiment was conducted to study the decomposition characteristics of horse dung in Inner Mongolia typical steppe. The dung pats were deposited on the ground surface and buried into soil at a depth of 10 cm. In a paddock with an area of about 47 hm² and 100 pursang horses free-grazing, the inputs of horse dung were 48.8 kg·hm^-2 per month and 277.1 kg·hm^-2 per year. The horse dung decomposition mainly occurred in the initial period of the experiment (0-60 days), with a mass loss rate of 45.0%. After  this period, there was a slight variation of the mass loss. The total organic matter content in fresh horse dung was 77.0%, and decreased to 48.7% and 28.3% at the 60th and 330th days of the experiment, respectively. The nitrogen in fresh horse dung was mainly in organic form, and its mineralization rate and release rate were lower. In contract, the phosphorus in fresh horse dung was mainly in inorganic form, and its release rate was higher. Burying horse dung pats into soil eliminated the fragmentation of the pats by wind erosion and livestock’s trampling and mitigated the impact of water erosion on the nutrient concentrations in the pads, but had little effects on their organic matter decomposition rate.

Characteristics of soil organic pollution in Shenyang suburbs of Liaoning Province, Northeast China.

2011, 30(11):  2472-2477. 

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Based on the survey of 35 organic pollutants in the soils of Shenyang suburbs, this paper studied the detection characteristics of the pollutants and their spatial distribution characteristics. Fifteen of the 35 organic pollutants were detected, among which, benzopyrene, hexachlorobenzene, DDT, and BHC had the coefficients of variation >1, and their local enrichment degree was high, with greater fluctuation in concentration. The soil organic pollution in the suburbs presented a pattern of “one more and three less”, i.e., more sampling points with detected organic pollutants, less kinds of detected organic pollutants, less concentration of the organic pollutants, and no sampling points exceeded the standards. Due to the effects of the lithology of soil vadose zone, the suburb soils showed an obvious vertical stratification pattern of organic pollution. It was considered that the regional distribution of suburb soil organic pollution had higher consistency with land use function, and thus, to analyze the main factors affecting the concentrations and distribution characteristics of organic pollutants in suburb soils would be of significance in preventing and controlling the organic pollution of the soils to ensure food security and water safety.

Effects of cadmium stress on the physiological and biochemical indices of Sorghum plants.

2011, 30(11):  2478-2482. 

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Taking the annual Sorghum plants (Sorghum bicolor (L.) Moench. cv. Hunnigreen, Sorghum bicolor × S. sudanense cv. Everlush, and Sorghum sudanense (Piper) Stapf cv. Xinjiang) as test materials, a pot experiment was conducted to study their root vitality, leaf proline content, and leaf- and root cell membrane permeability under the stress of different concentration soil cadmium (Cd). When the soil Cd concentration was higher than 25 mg·kg^-1, the root vitality of the Sorghum plants decreased significantly (P<0.05), and in all treatments with Cd, the leaf proline content had a significant increase (P<0.05), and the leaf- and root cell membrane permeability increased to some extent.

Effects of biochar on soil nitrogen leaching: A laboratory simulation test with yellow soil column.

2011, 30(11):  2483-2488. 

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Soil nitrogen leaching not only causes soil nitrogen loss, but also has great contribution to the water body eutrophication. By the method of laboratory simulation test, this paper studied the effects of applying biochar on the leachate volume, pH, electrical conductivity (EC), and ammonium nitrogen (NH₄⁺-N) and nitrate nitrogen (NO₃^--N) concentrations in a batch of yellow soil columns under simulated raining condition. The biochar was made from eucalyptus chips, and its application rates were 1%, 2%, 4%, and 10% of soil mass. Comparing with the control, applying 10%, 4%, 2%, and 1% biochar decreased the leachate volume by 14%, 0.03%, 0.02%, and 0.01%, respectively. With the increasing amount of applied biochar, the leachate pH and EC increased. Under the application of 10%, 4%, and 2% biochar, the leachate NH₄⁺-N and NO₃^--N concentrations increased by 235%, 28.1% and 31.6%, and 4.2%, 14.5% and 25.6%, respectively,while under the application of 1% biochar, the leachate NH₄⁺-N and NO₃^--N concentrations decreased by 15.8% and 19.2%, respectively. This study showed that the effects of applying eucalyptus chips on the nitrogen leaching of yellow soil depended on the applied amount of the biochar. The addition of 1% biochar reduced the nitrogen leaching, while excessive biochar increased the nitrogen leaching. Whether the species of biochar materials may affect soil nitrogen leaching would be an issue to be investigated in the future.

Phytoplankton community structure and water quality of Daliaohe river system in summer. 

2011, 30(11):  2489-2496. 

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As a basic work for establishing China water environment ecological criteria, an investigation was conducted on the phytoplankton community structure and water quality in Daliaohe river system in July 2010, based on relevant guidelines. A total of 124 phytoplankton species were recorded, most of which belonged to Chlorophyta and Bacillariophyta, occupying 43.55% and 31.45% of the total, respectively. The total cell density at different sampling sites varied from 2.05×10⁵ to 1.46×10⁷ ind·L^-1, with an average of 6.35×10⁶ ind·L^-1 and dominated by Chlorophyta and Bacillariophyta. At all sites,Melosira granulata var. angustissim of Bacillariophyta was the dominant species. Forty-four indicator species of water pollution were detected, and most of them were of β-mesosaprobic, with 36 species and occupying 81.81% of the total. The Shannon index of the phytoplankton community was 1.43-2.68, Margalef index was 1.00-1.78, and the Pielou index was 0.52-0.83. Based on this investigation, it was considered that the Daliaohe river system was in eutrophic state and at moderate pollution level.

Effects of 24-epibrassinolide on root growth and anaerobic respiration isozyme expression of cucumber seedlings under hypoxia stress.

2011, 30(11):  2497-2502. 

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A hydroponic experiment was conducted to investigate the effects of exogenous 24-epibrassinolide (EBR) on the root growth and anaerobic respiration isozyme expression of cucumber seedlings under hypoxia stress. Hypoxia stress induced the isozyme expression of root pyruvate decarboxylase (PDC), alcohol dehydrogenase (ADH), and lactate dehydrogenase (LDH), while the application of EBR increased the expression of PDC and ADH isozymes by 18.8% and 28.8% on the 3rd day and decreased the expression of PDC, ADH,and LDH isozymes by 19.5%, 25.6% and 53.4%, and 26.4%, 26.0% and 28.4% on the 6th and 9th day, respectively. On the 9th day of hypoxia stress, the root growth was inhibited significantly (P<0.05), while the application of EBR alleviated the growth inhibition, as indicated by the significant increase of root length, dry weight, and root tips (P<0.05). These results indicated that hypoxia stress inhibited the root growth of cucumber seedlings, whereas EBR could alleviate the inhibitory effect of hypoxia stress via regulating the isozyme expression of anaerobic respiration enzymes in seedling roots.

Identification and degradation characteristics of a bacteria strain degrading high concentration of polycyclic aromatic hydrocarbons.

2011, 30(11):  2503-2508. 

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By the method of selective enrichment culture, a high efficient polycyclic aromatic hydrocarbons (PAHs)-degrading bacterial strain N12 was isolated from a soil collected from Shenfu Irrigation Area, Liaoning Province, and was immobilized as a microbial agent to remedy the high concentration PAHs-polluted soil in a coking plant. Based on the physiological and biochemical analysis and 16S rRNA sequencing, the N12 was identified as Mycobacterium sp., with the isogenous dioxygenase genes nidA and pdoA2 of other Mycobacterium species. After 30 d degradation test, the removal rates of the individuals of PAHs were all >68%, and the total removal rate of PAHs was 80%, suggesting that the N12 could be used for the remediation of high concentration PAHs-polluted soil.

A kit for rapid detection of bacterial physiological characters.

2011, 30(11):  2509-2515. 

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To quickly detect bacterial physiological characters, the authors developed a kit to test the utilization of various carbon sources by bacteria and their responses to medium pH and antibiotics. In the kit, 95 kinds of carbon sources were utilized for target bacteria, and the indicator MTT was used to test the utilization of specific carbon sources by the target bacteria. The growth of target bacteria at a series of medium initial pH and NaCl concentration and the sensitivities of the bacteria to various kinds and different concentrations of antibiotics were also tested. For result observation, an optimization was made on the MTT concentration, medium solidification, bacterial inoculation amount, and observation duration. Accordingly, a kit with BiobiqA (C-source utilizing spectra) and BiobiqB (antimicrobial sensitivity pattern) was developed. The test and validation with model bacteria (Enterobacter cloacae ATCC13047^T and Rhizobium NZP2213^T) showed that our newly developed kit had the advantages of broad spectrum, easy operation, high accuracy, cost-saving, and time-saving, being able to rapidly detect the physiological characters of bacteria

Effects of dissolved copper in water body on serum biochemical indices of juvenile Chinese sturgeon (Acipenser sinensis).

2011, 30(11):  2516-2522. 

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Detections were made on the serum biochemical indices and ion concentrations of juvenile Chinese sturgeon (Acipenser sinensis) after exposed to the water body added with different concentration Cu²⁺ for 30 and 60 days, aimed to understand the toxic effect of Cu²⁺ on the juveniles. With the increasing concentration of Cu²⁺in water body, the concentrations of glucose (Glu), alkaline phosphatase (ALP), urea, total cholesterol (TC), and creatinine (CREA) in the serum increased, while that of triglycerides (TG) decreased.The Cu²⁺ had little effects on the concentrations of total protein (TP), aspartate aminotransferase (AST),alanine aminotransferase (ALT), and lactate dehydrogenase (LDH), and there were no significant differences in the test biochemical indices except ALP between the treatment low concentration Cu²⁺ and the control. At medium (0.89 μg·L^-1) and high (2.00 μg·L^-1) concentrations of Cu²⁺, the concentrations of GLU, ALP, urea, TC, CREA, and TG were significantly higher than those of the control (P<0.05). The  pH and Na⁺, Cl^-, and P concentrations decreased significantly with increasing concentration of Cu²⁺ while the Ca²⁺ and Mg²⁺ concentrations were in adverse, and the  K⁺ concentration was less affected. The minimum observable and the maximum unobservable effect concentrations of Cu²⁺  were 0.89 and 0.40 μg·L^-1, respectively. Among the test indices, ALP was most affected by Cu²⁺, and increased significantly with increasing time of Cu²⁺ exposure, being able to be the sensitive index of juvenile Chinese sturgeon under water body Cu²⁺ pollution.

Fast-start swimming performances of juvenile Cyprinus carpio and the effects of electrical stimulation parameters.

2011, 30(11):  2523-2527. 

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An ethological experiment was conducted to study the fast-start swimming performances of juvenile Cyprinus carpio and to explore how the electrical stimulation parameters affect these performances. Four stimulation field strengths (0.25, 0.40, 0.55, and 0.70 v·cm^-1) and five stimulation durations (10, 50, 90, 130, and 170 ms) were installed to measure the fast-start swimming performances of ninety experimental fish with a body length of 6.47 cm ± 0.09 cm and a body weight of 6.36 g ± 0.03 g at water temperature 25.0 ℃±0.5 ℃. When the stimulation field strength raised from 0.25 v·cm^-1 to 0.44 and 0.55 v·cm^-1, the fish’s somersault angle at stage 1 (θ_s1) and the maximum linear acceleration (α_max) and maximum velocity (V_max) at stage 2 all increased significantly (P < 0.05), while a further raise of the field strength had no significant effects on the three parameters (P>0.05). Both the α_max and the V_max increased significantly (P<0.05) with the increase of stimulation duration from 10 to 50 ms, but had less change (P>0.05) with the further increase of the stimulion duration. When the stimulation field strength was 0.55 v·cm^-1 and the stimulation duration was 50 ms, the θ_s1, α_max,and V_max were (56.51 ± 4.11) deg, （31.60 ± 3.62） m·s^-2, and （1.34 ± 0.07） m·s^-1, respectively. This study suggested that the juvenile C. carpio exhibited a ‘fast and straight line’ escape maneuver and had stronger fast-start swimming performances, and there existed threshold values in response to the electrical stimulation parameters.

Differences of female and male Pomacea canaliculata in foraging and heterosexual choice.

2011, 30(11):  2528-2533. 

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Pomacea canaliculata is an invasive alien species very harmful to the rice production in South China. In this paper, an indoor incubation test was conducted to study the differences in the foraging rate and hepatic glycogen content of female and male P. canaliculata, and the self-designed T-maze and three-room connected device were adopted to observe the food selection and heterosexual choice of the females and males. At both hungry and full states, the females had a significantly higher foraging rate than the males. At hungry state, the females spent a shorter time for food selection but the selection frequency was not significantly different from that of the males, and also, the females spent a shorter time and had a higher frequency for food selection than at full state whereas the males didn’t show any difference. In reproductive season (August), the females stored more hepatic glycogen in their body, but did not in non-reproductive season (November). The males more chose the rooms with females whereas the females had less choice for males, indicating that the females were attracted by the males, while the latter had less attraction to the females.

Population resource and habitat selection in summer of black knobby newt (Tylototriton asperrimus) in surrounding areas of Houhe National Nature Reserve, Hubei Province, China.

2011, 30(11):  2534-2539. 

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By using sampling plot method, an investigation was conducted on the population resource and habitat selection in summer of black knobby newt (Tylototriton asperrimus) in the Houhe National Nature Reserve and its surroundings areas in July-August 2010, and the Favorite index P and principal component analysis were used to study the micro-habitat selection in summer of  T. asperrimus.  T. asperrimus was mainly distributed in the Changleping Town and its nearby areas adjacent to the Reserve, 450-1400 m in altitude and about 550 km² in size. A total of 68 T. asperrimus individuals were collected in 18 of 103 investigated plots, suggesting that there existed a few T. asperrimus populations. Favorite index P analysis indicated that the favorite micro-habitats of T. asperrimus were the grasslands with litters, which were 51-100 m away from the stagnant pounds with a size of ≤20 m², 61%-80% coverage, 21-40 cm vegetation height, 61%-80% surface humidity, 24 ℃-27 ℃ surface temperature, ≤50 m away from farmlands, ≤100 m away from roads, and 101-500 m away from settlements. Principal component analysis indicated that surface temperature, vegetation, water body type, human disturbance, and food were the key factors contributing to the micro-habitat selection in summer by T. asperrimus.

Production dynamics and mass flux of dominant chironomid species in Hujiaxi stream of Qingjiang River.

2011, 30(11):  2540-2546. 

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A one-year investigation from April 2006 to March 2007 was conducted on the production dynamics, trophic basis, and yearly ingestion currency of dominant chironomid species in a second order tributary (Hujiaxi stream) of Qingjiang River, a tributary of Yangtze River. Six types of habitat from the upper to the lower reaches of Hujiaxi stream were selected for sample collection, with the life cycles of the two dominant chironomid species Conchapelopia sp. and Eukiefferiella potthasti analyzed based on monthly instar-frequency distribution, the cohort and annual production estimated by size frequency method, and the production dynamics, trophic basis, and yearly ingestion currency examined by  the methods of Benke and Wallace (1997) and Benke (1980). Conchapelopia sp. had two generations a year, while E.potthasti had one generation a year. The mean annual density and mean annual biomass of Conchapelopia sp. were 105 ind·m^-2 and 0.1 g·m^-2, and those of E.potthasti were 280 ind·m^-2 and 0.3 g·m^-2, respectively. The annual production (wet weight) and the annual production/biomass ratio of Conchapelopia sp. were 1.2 g·m^-2 and 2.3, and those of E.potthasti were 1.4 g·m^-2 and 2.5, respectively. The temporal overlap of the production of the two species measured with proportional similarity index was 0.7, and the overlap mainly occurred in winter and spring. Amorphous detritus was the main food of Conchapelopia sp. and E. potthasti, occupying more than 84% of their diets and contributing 80.1% and 68.6% to their production, respectively. The yearly ingestion currency of Conchapelopia sp. and E. potthasti was 7.2 and 7.1 g·m^-2, respectively.

Effects of litter and soil cover on Quercus liaotungensis seed predation and removal by animals.

2011, 30(11):  2547-2556. 

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In this study, Quercus liaotungensis seeds were released on the ground of a Larix principis-rupprechtii plantation in Liupan Mountains, and an investigation was conducted on the seed predation and removal by animals in the treatments litter elimination, litter cover, and soil cover, taking no litter elimination and releasing seeds directly to the ground as the control. After 3 days of release, the retention rate of Q. liaotungensis seeds in treatments litter cover and soil cover was 10.7% and 7.0%, respectively. After 14 days of release, the retention rate of the seeds (0.7%) was highest in treatment of soil cover, but null in treatment litter cover. In treatments litter cover and soil cover, the in situ eaten rates of the seeds was quite high (45.9% and 41.5%, respectively), but in treatment litter elimination, the in situ eaten rates of the seeds was the lowest (27.0%) whereas the eaten rate after removal was the highest (49.8%). The burial rate of the seeds in treatments litter elimination, litter cover, and soil cover after removal by animals was significantly higher than that of the control (P<0.01). The seeds after the removal were mainly distributed in the areas with a distance of 5 m, especially <1 m and 1-2 m, from the original places. The mean distance of the seeds eaten after the removal was longer than that of the seeds buried after removal, with the maximum being 2.38 m ± 0.55 m and 1.44 m ± 0.26 m, respectively.

Insect community composition, structure, and diversity in Tetraena mongolica stands.

2011, 30(11):  2554-2561. 

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Endangered plant Tetraena mongolica is a deciduous dwarf shrub endemic to China, belonging to a monotypic genus of Zygophyllaceae. In this paper, an investigation was conducted on the insect community in T. mongolica stands. A total of 11363 insect specimens were collected, belonging to 263 species, 11 orders, and 67 families or super-families, among which, Homoptera had the highest abundance and dominance, Hymenoptera had the greatest species richness and diversity, whereas Diptera had the highest evenness index. The most abundant groups (>10%) were Psyllidae and Cicadellidae, and the common groups (1%-10%) were Curculionoidea, Chalcidoidea, Meenoplidae, Tenebrionidae, Formicidae, Pentatomidae, Piesmidae, Miridae, and Catantopidae. As for the trophic structure, herbivorous insects had the greatest species richness and abundance, among which, sucking groups were most abundant. Most of the insect natural enemies were of parasitic, and their diversity index was the highest. Both the species richness and the abundance of predacious and neutral insects were relatively smaller, but predators had the highest evenness index. Compared  with the herbaceous layer in the stand, shrub layer was higher in insect species richness and abundance, with a higher dominance of dominant species, but lower in diversity and evenness index. The two layers had a low similarity in insect community structure, but both of them had numerous species in Hymenoptera.

Factors affecting the foraging of Rhinopithecus roxellana in Shennongjia Nature Reserve in winter and spring. 

2011, 30(11):  2562-2569. 

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Through quadrat investigation and feces micro-histological analysis, this paper studied the food composition of Rhinopithecus roxellana in Qianjiaping of Shennongjia Nature Reserve in winter and spring,and analyzed the nutritional components of main food plants, aimed to approach the main factors affecting the foraging of R. roxellana in the two seasons. In winter, the food composition of R. roxellana had positive correlation with the crude ash content of food plants (r=0.709, P=0.015), but no correlations with the relative abundance (r=0.543,P=0.084), crude protein content (r=0.036, P=0.916), crude fiber content (r=0.458, P=0.156), ether extract content (r=0.445, P=0.170), water content (r=-0.099, P=0.771), and nitrogen-free extract content (r=-0.522, P=0.100) of the plants. In spring, the food composition had positive correlation with food plants relative abundance (r=0.721, P=0.000), but no correlation with their water content (r=0.114, P=0.507), ether extract content (r=0.151, P=0.380), nitrogen-free extract content (r=0.084, P=0.625), crude protein content (r=-0.275, P=0.105), crude fiber content (r=-0.010, P=0.956), and crude ash content (r=-0.178, P=0.299). Principal component analysis indicated that the main factors affecting R. roxellana foraging in winter were crude fiber (0.992), ether extract (0.944), crude protein (0.905), and food abundance (0.885), whereas those in spring were crude protein (0.946), nitrogen-free extract (0.939), water content (0.920), and food abundance (0.898).

Extraction of single cropping rice area in Northeast China based on multi-temporal MODIS data.

2011, 30(11):  2570-2576. 

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By using the 2007-2008 MODIS/Terra dataset of normalized difference vegetation index (NDVI), enhanced vegetation index (EVI),and land surface water index (LSWI), this paper analyzed the dynamic variations of five underlying surfaces (rice field, upland field, forestland, wetland, and water body) in Northeast China during growth season.In combination with the observed data during rice growth perod, a model for the extraction of rice planting area in the region was established, and the distribution of the rice planting area was given. The model was validated with the ALOS data of Panjin City, Liaoning Province, and the precision reached to 89.5%, suggesting that the model could be used for the extraction of rice planting area in large scale.

Dynamics of shrubs normalized difference vegetation index and its correlations with climatic factors in Southwest China.

2011, 30(11):  2577-2583. 

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Based on the 1982-2006 normalized difference vegetation index (NDVI) and meteorological dataset of Southwest China, and by using ANUSPLIN, ArcGIS, and SPSS software, this paper analyzed the seasonal and annual variations of six shrubs’ NDVI and their correlations with climatic factors in the area. In the past 25 years, the annual average NDVI of three subalpine shrubs at high altitude (subalpine needle-leaf evergreen shrubs, subalpine broadleaf deciduous shrubs, and subalpine sclerophylla broadleaf evergreen shrubs) increased significantly, whereas that of the other three shrubs at mid and low altitudes (deciduous shrubs in temperate zone, evergreen xeromorphic succulent thorny shrubs in subtropical and tropical zones, and broadleaf evergreen and deciduous shrubs in subtropical and tropical zones) had less increase.The mean annual air temperature in the six shrubs except the evergreen xeromorphic succulent thorny shrubs in subtropical and tropical zones had a significant increase, and the mean annual precipitation presented an increasing trend in subalpine needle-leaf evergreen shrubs but a decreasing trend in the other five shrubs, reached a significant level in the deciduous shrubs in temperate zone. In the three subalpine shrubs at high altitude, the monthly NDVI was significantly positively correlated with mean monthly air temperature and monthly precipitation, and the correlations with the previous month’s mean air temperature and precipitation were the highest, showing a remarkable lag effect. For the other three shrubs at mid and low altitudes, the correlations of NDVI with air temperature and precipitation decreased obviously. At the high altitude, climate warming caused an increase of mean annual NDVI, suggesting that air temperature was the driving factor of the annual NDVI variation of the three subalpine shrubs. At the mid and low altitudes, the significant increase of air temperature didn’t cause a significant increase of NDVI.

Responses of ecological services value to land use change in middle reach of Shulehe River.

2011, 30(11):  2584-2589. 

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This paper studied characteristics of land use change and ecosystem services value in the middle reach of Shulehe River in 1990-2010, based on ecological economics theory and by using ArcGIS 9.2 and ERDAS 9.1 software and the calculation formula of Costanza et al., in combination with the China terrestrial ecosystems services value per unit area. In 1990-2010, the dominant land use types in the study area were unused land, grassland, and cultivated land, occupying 98.2% of the total, and the overall land use characteristics had no significant change. The land use change mainly occurred in cultivated land,built-up land, and grassland, and the dynamic degree was 13.6%, 8.0%, and 7.7%, respectively. The ecosystem services value presented an increasing trend, from 344.85 billion Yuan increased to 485.11 billion Yuan. Grassland and water area contributed most to the total ecological services value. The ecological and economic development in the study area was at the margin of low level coordination, and thus, protection efforts on the ecological environment should be further enhanced.

Effects of park size and plant community structure on urban park air temperature.

2011, 30(11):  2590-2596. 

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The mitigation effect of urban park on urban ‘heat island’ is well known, but how the park size and plant community structure affects urban park air temperature is rather unknown. Selecting 15 urban parks in Shanghai as test objects, this paper analyzed the effects of their size and plant community structure on their air temperature in autumn. It was observed that the air temperature in the parks was lower than that in surrounding residential and commercial areas, indicating that the parks had obvious cool island effect. Park location affected the cool island effect, and there existed significant quantitative relationships among the ‘cool island’ intensity, air temperature in autumn, and park size. The ‘cool island’ intensity was decreased with increasing park size, while the air temperature was increased with increasing park size. Among the plant community structures in the parks investigated, tree-shrub-grass had the best effects on the decrease of the air temperature in autumn in the parks.

Urban expansion and its heat island response in Lanzhou City based on remote sensing analysis.

2011, 30(11):  2597-2603. 

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This paper quantitatively analyzed the effects of urban expansion on city thermal environment, taking the urban area of Lanzhou City as a case, and based on the 1978, 1993, 2001 and 2010 Landsat/TM and ETM⁺ images. The information of urban construction land was extracted by using NDBI-NDVI index, and the land surface temperature was retrieved via mono-window algorithm, with the urban heat-island ratio index and the land surface temperature grade maps built. In 1978-2010, the construction land in the central area of Lanzhou City increased from 87.47 km² to 172.61 km², and the urban expansion had a spatial consistency with the urban heat island expansion. At the same time of urban expansion, the urban surface temperature increased gradually, and the heat island area had an increasing expansion.

Contributions of ruminants and their excreta to N₂O and CH₄ emissions. 

2011, 30(11):  2604-2612. 

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To clarify the contributions of ruminants and their excreta to greenhouse gases emission and the main affecting factors is of social, economic,and ecological significances for understanding the global climate change and searching for related mitigation options. Based on the related researches, it was considered that to improve the dietary quality and nutritional balance of ruminants (e.g., to add additives medium-chain fatty acid and others into diets and to increase the proportions of leguminous grasses in grassland) could be the effective measures in enhancing ruminant productivity while decreasing CH₄ emission. The contributions of ammonia, nitrite, and nitrate produced by the ruminants and their excreta should be also paid attention to. As the decrease of a kind of greenhouse gas emission could result in the increase of another kind of greenhouse gas emission during the storage and utilization of ruminants’ excreta, the total emission of the greenhouse gases should be regulated by integrative measures, according to the warming potential of the gases calculated as CO₂-C. Therefore, how to improve the feeding and nutrition of ruminants through adjusting grazing management regime and plant community structure in grassland would be the scientific issue to be solved in the future to realize the balance between the ecological conservation of grassland and the reduction of greenhouse gase emissions per unit ruminant production.

Influence of habitat fragmentation on frugivores and their seed dispersal.

2011, 30(11):  2613-2620. 

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Frugivores and the plants depending on frugivore to disperse their seeds form a mutualism in the process of evolution, but habitat fragmentation can disturb the process and break the mutualism. Habitat fragmentation often reduces the diversity of frugivores, but this situation does not happen in all ecosystems. Frugivores have different adaptability to the habitat fragmentation, being stronger for the forest generalists and food generalists. Habitat fragmentation has negative effects on most of the plants depending on frugivore to disperse their seeds, but some plants are not, and even, benefited. The seed dispersal effectiveness of the frugviores in fragmental habitat is the combined effect of seed dispersal amount, dispersal distance, seed germination, and establishment of seedling population. The changes in the foraging behavior and food choice of frugivores affect the seed dispersal amount, whereas the heterogeneity of habitat patch and the changes in food resource availability determine the seed dispersal distance. The successful establishment of seedling population depends on effective disperser. Three issues to be further studied were proposed: (1) how habitat fragmentation affects the seed dispersal and the relationship between animals and plants, especially how the spatial distribution of heterogeneous landscapes affects the seed dispersal effectiveness of frugivores, (2) how to create a new mutualism between plants and frugivores in habitat fragmentation, and (3) how the plant invasion induced by habitat fragmentation affects the seed dispersal of native plants.

Microbial degradation mechanisms of soil high molecular weight PAHs and affecting factors: A review.

2011, 30(11):  2621-2627. 

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High molecular weight polycyclic aromatic hydrocarbons (HMW PAHs) are a group of widespread and persistent organic pollutants with complex chemical structure and high hydrophobicity, whereas microorganisms play a key role in the biodegradation of HMW PAHs. This paper summarized the bacterial strains that can degrade HMW PAHs, related degradation mechanisms, and the environmental factors (soil nutrient contents, soil pH, soil structure and aeration, and combined pollution) affecting the biodegradation of HMW PAHs, and discussed the further research directions and focuses on the HMW PAHs-contaminated soil, aimed to provide references on the researches of bioremediation of HMW PAHs-contaminated environments and molecular mechanisms involved in the microbial degradation of HMW PAHs.

Microstructure and microbial ecology of biofilm in the bioreactor for nitrogen removing from wastewater: A review. 

2011, 30(11):  2628-2636. 

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Biofilm-based wastewater nitrogen removal reactor is a system mainly making use the metabolic activities of functional microbes in the biofilm to remove wastewater nitrogen to achieve water purification. To understand the microstructure and microbial ecology of the biofilm is of significance to reveal the nitrogen removal mechanisms of the reactor and to promote  nitrogen removal efficiency. This paper introduced the types of biofilm-based wastewater nitrogen removal reactor and the characteristics of biofilm microstructure and related affecting factors, and summarized the research advances on the nitrogen transfer processes and nitrogen removal mechanisms in reactor, the distribution characteristics of functional microbes in  film, the effects of different biofilm-based wastewater nitrogen removal reactors, the running condition,  running time, and substrates on the populations of the functional microbes, as well as the newly-found microbes for wastewater nitrogen removal. The review could provide references for the further study on the biofilm-based nitrogen removal technology.

Significance and methodology of rodent’s food habit research: A review.

2011, 30(11):  2637-2645. 

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Rodent’s food habit is an important component in the study of population ecology, and also, a reference index commonly used in constituting rat pest control strategies. Many convenient and practical methods are adopted to study the rodent’s food habit, and significant achie-vements are gained. This paper introduced the related research methods, summarized the related research results in recent 40 years, and analyzed the prospects of this research area, aimed to provide some useful ideas for the future study.

Assessment and forecast of ecological vulnerability: A review.

2011, 30(11):  2646-2652. 

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How to define, observe, assess, and forecast ecological vulnerability is of significance for maintaining ecosystem stability and realizing regional sustainable development. Based on the analysis of the related researches, this paper discussed the direction, scale, and methodology of ecological vulnerability research, and summarized the researches on the assessment and forecast of ecological vulnerability. It was considered that in the present ecological vulnerability researches, there existed some disadvantages, e.g., imperfect research framework, inconsistent research methods, and uncoordinated relationship between research scale and research precision, and more attention would be paid to the four aspects in the future research: (1) the width and depth of the research, (2) the interdisciplinary collaboration and integration of the research, (3) the establishment of integrative research system containing dynamic monitoring,comprehensive assessment, and trend forecast by using “3S” technology, and (4) the research of related policies and countermeasures in response to ecological vulnerability.

Ecological model for predicting the protein and oil contents in cottonseed. 

2011, 30(11):  2653-2658. 

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Taking different cotton cultivars with different maturity stage as test materials, a field experiment of two sowing dates and three N application rates was conducted in the lower reaches of Yangtze River basin (Nanjing and Huai’an) and Yellow River basin (Xuzhou and Anyang), with the effects of cultivar, main meteorological conditions, and N application rate on the cottonseed protein and oil contents analyzed, aimed to understand the quantitative relations of cottonseed protein and oil contents with environmental factors. Besides cotton cultivar, the major factors affecting the cottonseed protein and oil contents were in the sequence of the mean air temperature at bolling stage, solar radiation, and N application rate. The optimum mean air temperature for the production of cottonseed protein and oil at bolling stage was 26.1 ℃ and 25.7 ℃, respectively. Sufficient illumination did not favor the enhancement of cottonseed protein and oil contents. Increasing N application rate increased the cottonseed protein content but decreased the cottonseed oil content. Based on the statistical analyses, an ecological model for predicting cottonseed protein and oil contents was established, taking cultivar, mean air temperature and solar radiation at bolling stage, and N application rate as the input parameters, being easy to be operated. The root mean square error (RMSE) of the prediction of cottonseed protein content and oil content by the model was 2.03% and 2.54%, respectively, showing a good predictability of the model.