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1.
XU Huifeng JIN Yanming DENG Wei XU Kezhang WANG Zhen College of Agriculture Jilin Agricultural University Changchun P.R. China 《山地科学学报》2009,(3)
In order to reveal transpiration rates of wetland plants and its relationships to micro-meterological factors in a mountain valley wetland, relative humidity, air temperature, leaf temperature, soil temperature, photo flux density and transpiration rates were measured once two hours in a Carex meyeriana wetland of the Changbai Mountain valley in dry (July) and wet (September) of 2003, respectively. Results showed that the tendency of "decreasing after increasing" was obvious in wet season. However, a relati... 相似文献
2.
Abundance and production ofBranchiura sowerbyi (Oligochaeta: Tubificidae) in two typical shallow lakes (Hubei, China) 总被引:1,自引:0,他引:1
An April 1996 to March 1997 comparative study on the abundance and secondary production ofBranchiura sowerbyi Beddard, 1892 in two typical shallow lakes showed that in Houhu, an algae-dominated lake, the worm density (68 ind·m−2) peaked in July, biomass (1.930 g·m−2) peaked in June, while in Biandantang, a macrophyte-dominated lake, standing stock (density: 60 ind·m−2; biomass: 1.019 g·m−2 in wet weight) peaked in December. Secondary production of the animal in Houhu Lake was 3.413 g wet wt m−2 a−1, a little more than that (2.675 g wet wt m−2 a−1) in Biandantang Lake. Their turnover rates (P/B ratios) were 4.0 and 5.0, respectively.
Project (39600019 and 39430101) supported by NSFC. 相似文献
3.
1 Introduction It has been reported that habitat nutrient availability frequently limited plant growth and determined species dominance and abundance in natural communities (Miao et al., 2000). Nutrient availability is also a main regulator of aquatic primary production. Human-induced nutrient enrichment results in die-back of native vegetation and alteration of species dominance in various aquatic eco- systems (Miao et al., 2000; Green and Galatowitsch, 2002). Particularly, nutrient enrichm… 相似文献
4.
Impacts of soil fauna on litter decomposition at different succession stages of wetland in Sanjiang Plain, China 总被引:1,自引:0,他引:1
Litter decomposition is the key process in nutrient recycling and energy flow. The present study examined the impacts of soil
fauna on decomposition rates and nutrient fluxes at three succession stages of wetland in the Sanjiang Plain, China using
different mesh litterbags. The results show that in each succession stage of wetland, soil fauna can obviously increase litter
decomposition rates. The average contribution of whole soil fauna to litter mass loss was 35.35%. The more complex the soil
fauna group, the more significant the role of soil fauna. The average loss of three types of litter in the 4mm mesh litterbags
was 0.3–4.1 times that in 0.058mm ones. The decomposition function of soil fauna to litter mass changed with the wetland succession.
The average contribution of soil fauna to litter loss firstly decreased from 34.96% (Carex lasiocapa) to 32.94% (Carex meyeriana), then increased to 38.16% (Calamagrostics angustifolia). The contributions of soil fauna to litter decomposition rates vary according to the litter substrata, soil fauna communities
and seasons. Significant effects were respectively found in August and July on C. angustifolia and C. lasiocapa, while in June and August on C. meyeriana. Total carbon (TC), total nitrogen (TN) and total phosphorus (TP) contents and the C/N and C/P ratios of decaying litter
can be influenced by soil fauna. At different wetland succession stages, the effects of soil fauna on nutrient elements also
differ greatly, which shows the significant difference of influencing element types and degrees. Soil fauna communities strongly
influenced the TC and TP concentrations of C. meyeriana litter, and TP content of C. lasiocapa. Our results indicate that soil fauna have important effects on litter decomposition and this influence will vary with the
wetland succession and seasonal variation.
Foundation item: Under the auspices of State Key Development Program for Basic Research of China (No. 2009CB421103), Key Program
of National Natural Science Foundation of China (No. 40830535/D0101), Knowledge Innovation Programs of Chinese Academy of
Sciences (No. KZCX2-YW-BR-16, KSCX2-YW-N-46-06) 相似文献
5.
The toxic effects of benzo[α]pyrene (B[α]P) at different concentrations (0.1, 0.5, 1, 2.5 and 7.5 μgL−1) on scallop (Chlamy farreri) immune system were studied. The results showed that B[α]P had significant toxic effects on the haemocyte counts, neutral red uptake, phagocytosis, bacteriolytic and antibacterial
activity (P<0.05), while the seawater control and acetone control had no significant differences. The haemocyte counts, neutral red uptake,
phagocytosis and bacteriolytic activity in all B[α]P treatment groups as well as antibacterial activity in groups of 0.5, 1, 2.5 and 7.5 μgL−1 B[α]P decreased significantly (P<0.05). Some of these indices tended to be stable on the sixth day and others on the ninth day, and the indices showed clear
time- and concentration-response to B[α]P. Bacteriolytic activity in 0.1μgL−1 B[α]P treatment group and antibacterial activity in 0.1 μgL−1 and 0.5 μgL- B[α]P treatment groups increased at the beginning of exposure and reached their peaks on day 1 and day 6, respectively. Following
that, both activities decreased gradually and became stable after day 9. When all the indices reached stability, they were
significantly lower than those in control group (P<0.05), except for antibacterial activity in 0.1 μgL−1 B[α]P treatment group (P>0.05). Thus, B[α] has evident toxic effects on scallop immune system, which supports the view that a relationship exists between pollution
and immunomodulation in aquatic organisms. 相似文献
6.
1INTRODUCTIONPlant canaccumulatemercuryfromair,soilandwa-ter.Theconcentrationofmercuryinplantisaffectedbythesource,form ofmercury andthephysiology ofplant.Theconcentrationsofinorganicmercuryandor-ganicmercuryinvariousplantsaredifferent,sotheenvironmentalexposureofmercuryandthebiotopeofplantscanbereflected bytheconcentrationofmer-curyinplants.Wetlandplaysanimportantroleinthetransportandcycleofmercury(DRISCOLLetal.,1994),andisanimportantsourceofmethylmercury ofsomelakesandrivers(STLOUI… 相似文献
7.
The temporal dynamics of the biomass, as well as the carbon (C), nitrogen (N), phosphorus (P) concentrations and accumulation
contents, in aboveand below-ground vegetation components were determined in the alpine steppe vegetation of Northern Tibet
during the growing season of 2010. The highest levels of total biomass (311.68 g m−2), total C (115.95 g m−2), total N (2.60 g m−2), and total P (0.90 g m−2) accumulation contents were obtained in August in 2010. Further, biomass and nutrient stocks in the below-ground components
were higher than those of the above-ground components. The dominant species viz., Stipa purpurea and Carex moorcrofti had lower biomass and C, N, P accumulations than the companion species which including Oxytropis. spp., Artemisia capillaris Thunb., Aster tataricus L., and so on. 相似文献
8.
Effects of salinity, light and temperature on growth rates of two species of Gracilaria (Rhodophyta) 总被引:2,自引:0,他引:2
Effects of temperature, salinity and light intensity on growth rates of Gracilaria lichenoides and G. tenuistipitata var. liui Zhang et Xia were tested. Eight to ten levels of each factor were first tested separately. The best growth rate was obtained
under the conditions of 32°C, 30 and 240 μmol/(m2·s) for G. lichenoides, and 24°C, 20 and 200 μmol/(m2·s) for G. tenuistipitata, respectively. Then a uniform design was used to evaluate the optimal combinations of the three factors. The best conditions
for the highest daily specific growth rates (% increase in wet weight) are determined to be 31.30°C, 32.10, and 287.23 μmol/(m2·s) for G. lichenoides (16.26%/d), and 25.38°C, 21.10, and 229.07 μmol/(m2·s) for G. tenuistipitata (14.83%/d), respectively.
Supported by the 908 Special Program (908-02-04-07), the National Basic Research Program of China (973 Program, No. 2006CB400608),
and K. C. Wong Magna Fund in Ningbo University 相似文献
9.
CARBON DYNAMICS OF WETLAND IN THE SANJIANG PLAIN 总被引:2,自引:0,他引:2
SONG Chang-chun WANG Yi-yong WANG Yue-si YAN Bai-xing WANG De-xuan ZHAO Zhi-chun LOU Yan-jing 《中国地理科学(英文版)》2003,13(3):228-231
1INTRODUCTIONWetlandsplayanimportant roleintheprocessofcar-bonstorage.Thetotalcarbonstoredindifferentkindsofwetlandsisabout15%-35%ofthetotalcarboninthegloballandsoils(POSTetal.,1982;GORHAM,1991).Inaddition,wetlandsaresignificantnaturalsources fortheatmospheric CH4 (MOORE,1994).It isestimatedthatabout110×1012gCH4 originates fromanaerobicdecompositioninthenaturalwetlands,CH4 emission fromthenaturalwetlandsis15%-30%oftheglobalCH4 emission andtheCH4 emission from thepeat land at hi… 相似文献
10.
Liang Yanling 《中国海洋湖沼学报》1984,2(1):102-108
Branchiura sowerbyi in the Donghu Lake (Wuhan, China) completes its life cycle in one year. Its production rates were 6.7 g m−2 yr−1 (wet weight) during the period from April 1962 to May 1963 and 8.6g m−2 yr−1 during the period from August 1963 to August 1964. The standing stocks in corresponding periods were 1.9g m−2 (wet weight) and 1.1g m−2, and theP/B ratios were 3.6 and 7.8. Based on the standing stock during 1973–1975, an evaluation of recent productin levels ofB. sowerbyi in Donghu Lake has also been made (i.e. 5.7–33.5g m−2 yr−1). 相似文献
11.
A feeding trial was conducted in a recirculating water system to investigate the effects of dietary protein levels on growth,
feed utilization, hepatosomatic index and liver lipid deposition of juvenile red snapper, Lutjanus argentimaculatus (average initial wet weight 8.0 ± 0.39 g and total length 3.14 ± 0.3 cm). In the experiment, six fishmeal-based diets were
formulated to contain various protein levels (20% to 45% in 5% increments), with dietary energy ranging from 2210.7kJ lOOg
to 2250.2kJlOOg dry matter. The protein to energy ratios of diets ranged from 8.58 mg protein kJ−1 to 20.03 mg protein kJ−1. Diets were fed for 90d to triplicate groups of fish stocked in 0.128m3 seawater tanks, 25 individuals each. The daily ration of 2% wet body weight was offered to the fish thrice a day. The fish
at the end of the study had more than ten-fold (77.0g) increase in weight compared to the initial (8.0g). Fish fed diets of
40% and 45% protein produced significantly (P<0.05) higher weight gain of 77.2g and 76.5g, and specific growth rate (SGR) of 2.65% and 2.62% than those of 67.0 g and 68.3g,
and 2.49% and 2.51% of the other diets. The broken-line regression of SGR against dietary protein level yielded an optimum
dietary protein requirement of 42.6% (Y=−1.6295 + 0.1114 X
2,P<0.05). Survival remained 100% among groups. Feed conversion ratio decreased from 0.45 for fish fed 20% dietary protein to
0.35 for fish fed 45% dietary protein. Nitrogen intake increased with an increase in dietary protein, which in turn resulted
in an increase in nitrogen gain of fish whole body. Fish fed 40% and 45% protein diets showed higher (P<0.05) nitrogen gain (0.27g and 0.26g) than those (0.23g and 025g) fed all other diets. Gross energy intake (GEI) in fish
fed 45% protein was lower (600.67kJ) than that (607.97 kJ) of 40% protein diet, though the differences were not statistically
significant (P>0.05); GEI ranging from 677.31 kJ to 663.20 kJ at remaining four diets (20% to 35% protein) did not appear to differ significantly
(P>0.05). The highest energy gain of 518.33 kJ was obtained with fish fed 40% protein, resulting in the highest energy retention
efficiency of 85.26%. The hepatosomatic index of fish fed diets of 20%, 25%, 30% and 35% protein were significantly (P<0.05) higher (2.09% to 2.57%) than those (1.44% and 1.41%) of fish fed diets containing 40% and 45% protein. Liver lipid
contents decreased from 8.72% to 7.0% in fish fed dietary protein of 20% to 45% in 5% increments. Results suggest that the
diet containing 40% to 42.6% protein with a P/E ratio of 17.6 mg protein kJ−1 is required for good growth of L. argentimaculatus weighing between 8.0 g and 85.2 g under the culture conditions of the present study. 相似文献
12.
When cultured under certain environmental conditions (25°C, light intensity 80 μmol/m2·s, LD 12/12, in enriched seawater medium with 7×10−4 mol/L NO3−N, 1.56×10−4 mol/L, PO4−P and supplements of other elements like Mn, Fe, I, etc.), male and female gametophytes ofU. pinnatifida kept growing vegetatively and propagated fast at average daily fresh weight increase rate of about 20%. The empirical formulaG
m=G
o·3m was established to estimate the output of vegetative gametophytes. Vigorous vegetative gametophyte cells began to form reproductive
structures (oogonium and spermatangium, when the temperature was lower than 25°C and other environmental factors were kept
optimal. The sufficient supply of gametophyte cells provided enough seeds for raisingUndaria sporelings on production scale. Controlled cross-breeding experiments using selected male and female gametophyte clones which
increase their cell number by mitosis instead of meiosis were also carried out in vitro. Juvenile sporophytes from the cross-breeding
had almost the same length and width increase rates as those of the control. The fact that vegetative gametophytes can be
purposely selected, propagated quickly, cross-bred, with the resulting sporophytes having almost the same characteristics
leads to a new way to select desiredUndaria strains for long time use without losing the desired economic characteristics.
Contribution No. 2696 from the Institute of Oceanology, Chinese Academy of Sciences.
Supported by National Natural Science Foundation of China. 相似文献
13.
Introduction Agriculture, which is the dominant sector in the mountains, is generally stagnant. Degradation of the natural resource base has contributed to an increase in frequency and intensity of landslides, gully formation, soil erosion, declining soil fertility, reduced per capita availability and fragmentation of land, and reduced flow of water for irrigation. This has led to steady decline in crop yields (5~30 %) or stagnation that caused food shortages at varying degrees among mountain … 相似文献
14.
Prepared in this experiment were six groups of diets, i.e. VC0, VC1, VC2, VC3, VC4 and VC5 with the contents of vitamin C (VCmg(100 g)−1 diet) of 0, 100, 200, 400, 800, and 1200 respectively. It was found that vitamin C increased the concentrations of immunoglobulin-like
(IgG-like, IgA-like and IgM-like) substances in the serum of Penaeus chinensis after a feeding period of 3 weeks. The differences among groups were significant (P<0.01), but there was no difference in the contents of complement3-like and complement4-like substances in the serum (P>0.05). Phenoloxidase (PO) activity in the serum of VC3 group shrimps was higher than that of VC0 and other groups, but no
significant difference was observed between VC0 group and other groups. Furthermore, bactericidal activity of the serum to
Vibrio parahaemolyticus in shrimps fed with the VC1 diet was higher than that in the other groups (P<0.01), while no difference was demonstrated among all groups for the bactericidal activity to Vibrio alginolyticus (P>0.05). It is, therefore, suggested that vitamin C (100–400 mg(100 g)−1 diets) could be used as an immunostimulant of P. chinensis. 相似文献
15.
Net primary productivity and species diversity of herbaceous vegetation of banj-oak (Quercus leucotrichophora A.Camus) forest in Kumaun Himalaya,India were analyzed.Across different growth forms (tall forbs,short forbs,cushion and spreading forbs,grasses),short forbs were most dominant component during rainy season (IVI=152) and winter season (IVI=167) and grasses during the winter season (IVI=148).Maximum above-ground production occurred during rainy season (132.5 g m-2) and minimum during winter season (2.8 g m-2).Below-ground production was maximum (85.9 g m-2) during winter season and minimum (14.9 g m-2) during summer season.Annual net shoot production was 150 g m-2 and below-ground production was 138 g m-2.Of the total input 61 % was channeled to above-ground parts and 39% to below-ground parts. 相似文献
16.
The process-oriented model Forest-DNDC describing biogeochemical cycling of C and N and GHGs (greenhouse gases) fluxes (CO2, NO and N2O) in forest ecosystems was applied to simulate carbon sequestration and GHGs emissions in Abies fabric forest of the Gongga Mountains at southeastern edge of the Tibetan Plateau. The results indicated that the simulated gross primary production (GPP) of Abies fabric forest was strongly affected by temperature. The annual total GPP was 24,245.3 kg C ha^-1 yr^-1 for 2005 and 26,318.8 kg C ha^-1 yr^-1 for 2006, respectively. The annual total net primary production (NPP) was 5,935.5 and 4,882.2 kg C ha^-1 yr^-1 for 2005 and 2006, and the annual total net ecosystem production (NEP) was 4,815.4 and 3,512.8 kg C ha^-1 yr^-1 for 2005 and 2006, respectively. The simulated seasonal variation in CO2 emissions generally followed the seasonal variations in temperature and precipitation. The annual total CO2 emissions were 3,109.0 and 4,821.0 kg C ha^-1 yr^-1 for 2005 and 2006, the simulated annual total N2O emissions from forest soil were 1.47 and 1.36 kg N ha^-1 yr^-1 for 2005 and 2006, and the annual total NO emissions were 0.09 and o.12 kg N ha^-1 yr^-1 for 2005 and 2006, respectively. 相似文献
17.
The abundance and biomass of benthic heterotrophic bacteria were investigated for the 4 typical sampling stations in the northern
muddy part of Jiaozhou Bay, estuary of the Dagu River, raft culturing and nearby areas of Huangdao in March, June, August
and December, 2002. The abundance and biomass range from 0.98×107 to 16.87×107 cells g−1 sediment and 0.45 to 7.08 μg C g−1 sediment, respectively. Correlation analysis showed that heterotrophic bacterial abundance and biomass are significantly
correlated to water temperature (R=0.79 and 0.83, respectively,P<0.01). 相似文献
18.
KANG Kyoung Ho 《中国海洋大学学报(英文版)》2009,8(3):265-269
Trumpet shell, Charonia sauliae, is an endangered and valuable species, but its artificial propagation protocol has not been successfully established. To
estimate the possibility of cryopreservation for larvae of C. sauliae, which is a potential preparation for its artificial reproduction and further research, in this study a protocol for the
cryopreservation of veliger larvae of trumpet shell was optimized. Through a two-step cryopreservation procedure, four kinds
of cryoprotectants (ethylene glycol, 1, 2-propanediol, dimethyl sulfoxide and glycerol) were employed at three concentrations
(1.0, 1.5 and 2.0 molL−1) respectively and survival rates of larvae were determined after a storage of 1h. The larvae frozen with these four cryoprotectants
after 1 h storage were cultured, and then survival rates were determined at 24, 72 and 120 h after thawing. Dimethyl sulfoxide
at a concentration of 1.5 molL−1 showed the best protective effect in all experiments (p<0.05). And survival rates of larvae frozen with dimethyl sulfoxide were determined after 1, 7 and 15 d of storage. The survival
rates of larvae frozen with 1.5 molL−1 dimethyl sulfoxide after 1 h, 1 d, 7 d and 15 d of storage were 80.77% ±7.51%, 80.34% ±11.28%, 83.10% ±9.14% and 77.23% ±6.22%
respectively. No significant differences in survival rates of larvae frozen with dimethyl sulfoxide were observed after various
storage periods (p>0.05). 相似文献
19.
The effects of several nutritional factors on the growth and eicosapentaenoic acid (EPA) production of diatom Nitzschia laevis were studied. 4 LDM (quadrupled concentration of the nutrient salt) was the optimal concentration of nutrient salt for the
growth and EPA production of N. laevis. The growth of N. laevis was inhibited when the glucose concentration was either lower than 10 gL−1 or higher than 15 gL−1. Both sodium nitrate and urea were good nitrogen sources for the growth and EPA production, while ammonium chloride seriously
decreased the dry cell weight (DW) and the EPA content. Silicate seriously influenced the growth of N. laevis. The maximum DW of 2.34 gL−1 was obtained in the presence of 150 mgL−1 Na2SiO3·9H2O. The EPA content remained almost the same when the silicate concentration was lower than 150 mgL−1; however, higher silicate concentrations resulted in a steady decrease of EPA content. Low medium salinity (⩽29) did not
seem to influence the DW of N. laevis, and high salinity resulted in a decrease of DW. The highest EPA content (4.08%) and yield (110 mgL−1) were observed at the salinity of 36 and 29, respectively. 相似文献
20.
Effects of hypoxia on dopamine concentration and the immune response of White Shrimp (Litopenaeus vannamei) 总被引:1,自引:0,他引:1
Effects of hypoxia on the dopamine concentration and the immune response of White Shrimp Litopenaeus vannamei were studied. The results showed that hypoxia had significant effects on the concentration of dopamine (DA) in the haemolymph,
haemocyte count, phenoloxidase activity, phagocytic activity of haemocytes and bacteriolytic and antibacterial activity in
the haemolymph (P<0.05). The concentration of the dopamine in haemolymph reached its maximum in the 3.0 and 1.5 mg L−1 DO groups at 12 h and 6 h, and then returned to normal after 24 h and 12 h, respectively. All immune parameters decreased
with the reduction of dissolved oxygen. Total haemocyte count (THC), the hyaline cells and semi-granular cells in the 3.0
mg L−1 DO group became stable after 12 h, while granular cells did so after 24 h. The THC and different haemocyte count (DHC) in
the 1.5 mg L−1 DO group became stable after 24 h. Phenoloxidase activity and bacteriolytic activity in the 3.0 and 1.5 mg L−1 DO groups reached their stable levels after 24 h and 12 h respectively, while phagocytic activity and antibacterial activity
became stable after 24 and 12, and 36 and 24 h, respectively. It was also indicated that the changes of dopamine concentrations
in haemolymph, haemocyte count and phenoloxidase activity were obviously related to the exposure time under hypoxic conditions. 相似文献