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1.
The responses of rice to the second degree contamination of copper were studied by pot experiments under free-air CO2 enrichment (FACE) with 570 μmol ·mol^-1 of CO2. The results showed that the content of copper in rice leaves was reduced with the CO2 concentration reaching 570 μmol· mol^-1 and this happened more significantly under the second degree contamination of copper. Under FACE, activities of superoxide dismutase (SOD) enzyme in rice leaves treated by copper contamination were induced, whereas the contents of glutathione (GSH) and glutathione disulfide (GSSG) had no significant difference from the control. In the presence of ambient CO2, activities of SOD enzyme treated by copper pollution were suppressed during the whole rice growth, however, the contents of GSH and GSSG were induced at tillering and jointing stages, and then restored to the control levels in later growth under the second degree contamination of copper. With the rice growing, the content of malondialdehyde (MDA) rises continuously, but there had been no significant difference between the treatments at the same growth stage. Further studies are needed on the response mechanism of rice to Cu stress under elevated CO2.  相似文献   

2.
In pot experiments at Xichang,China,during 1989~1994,visual senescencesymptoms and associated changes in constituent contents and activities of leaves of fababean(Vicia faba L.)were compared in respones to flower removal.The leaves from upper,middle and lower positions were sampled six times during reproductive developmentphase.At 70 DAP flower removal had caused 37%~189% and 82%~197% increase ofgreen leaf area and green leaf dry weight per plant respectively.Flower removal led to asignificant increase in the chlorophyll,soluble sugar and protein contents and the catalaseactivity.The leaf cell relative electroconductivity of those plants was maintained at a lowerlevel,relative to the control,during the late growing stage.These results certainly impliedthat the leaves of flower removal plants were still fully functional at a very late growingstage,consequently the plants increased many new branches per plant.  相似文献   

3.
The ubiquitous occurrence of perfluorinated compounds (PFCs) in environmental samples has drawn much attention. Recent human exposure studies found relatively high perfluorooctane sulfonate (PFOS) concentrations in blood samples from several cities in China when compared with other countries. The objectives of the present study were: (1) to measure PFC concentrations and compositions in chicken egg samples from local markets in China; and (2) to conduct a preliminary human health risk assessment of egg consumption. Eight pooled egg samples from eight locations were analyzed for 11 PFCs. The results showed that close to 100% of the PFOS in the egg was distributed in egg yolk and PFOS was not detected in egg white (〈0.08 ng/g wet weight, w/w). Of the perfluoroalkylsulfonates, only PFOS was detected in all egg samples, while of the perfluoroalkylcarboxylates, perfluoroundecanoic acid (PFUnDA) was detected in all samples, followed by perfluorooctanoate (PFOA) (75% occurrence) and perfluorodecanoic acid (PFDA) (50% occurrence). PFOS concentrations in egg ranged from 45.0 to 86.9 ng/g w/w. The results suggested that current concentrations of PFOS in domestic chicken eggs are unlikely to cause immediate harm to Chinese populations.  相似文献   

4.
Gynogenetic diploid was induced in red crucian carp (RCC) (Carassius auratus Red Variety) eggs using UV-irradiated spermatozoa from blunt snout bream (B) (Megalobrama amblycephala) or from mirror carp (C) (Cyprinus carpio. L). Spermatozoa were genetically inactivated by an appropriate UV dosage, and then the maternal DNA was duplicated with cold shock at 0-4℃. When using the spermatozoa of B, the fertilization rate, hatching rate and survival at first feeding were 52.6±3.0 %, 23.6±4.1 % and 15.7±3.4 %, respectively, and the survival at first feeding was significantly higher than that (11.3±2.2%) when using the spermatozoa of C (Cyprinus carpio. L). According to the morphological characteristics, the chromosome number and the degree of gonadal development, gynogenetic RCC could be distinguished from the control hybrids of RCC♀× B♂. The individuals with red body color, 100 chromosomes and normal gonadal development were successful gynogenetic RCC, while the individuals with 124 or 148 chromosomes and delayed gonadal development were hybrids of (RCC× B). The triploid hybrids (RCC× B) (2 years old) were sterile, but the tetraploid hybrids (RCC× B) were sexually mature age of two. In the present study, compared to the spermatozoa of C, the advantages of spermatozoa of B as the activation source were that could increase the survival at first feeding of gynogenetic individuals and simplify the confirmation of gynogenetic status, which suggested that the sperm of B was an effective activation source for inducing gynogenesis in crucian carp.  相似文献   

5.
A number of specimens recently collected from the Early Permian Shanxi Formation of Wuda, Inner Mongolia demonstrate that the leafy shoot and strobilus of Tingia unita sp. nov. are both sprouting from a common stem, and consequently improve our understanding of the whole plant mor- phology of this enigmatic taxon of the Cathaysian flora. The strobili are cylinder-like, 1.7-2.5 cm in diameter and over 20 cm in length, with a basal stalk 7―8 mm in width and about 7 cm long. Sporophylls are verticillate, with approximately 8-10 in a whorl. On the adaxial side of each sporophyll a sporangium is attached. The strobilus is heterosporous and the microspores are of the Punctatisporites type. Large leaves vary from linear to oblong with entire lateral margins but are slightly lobed at the apex. Small leaves are generally the same as the large leaves but much narrower. The whole plant is probably a small arborescent tree with leafy shoots and strobili forming a crown, rather than a water plant with larger leaves floating on the surface of the water as previously understood. Features of the new species are in favor of the close affinity between Tingia Halle and Noeg- gerathiales, and accordingly the affinity of Noeg- gerathiales to Progymnospermophyta.  相似文献   

6.
The identification and characterization of the phosphate preservation of the spherical microfossils in the Ediacaran Doushantuo time and the Early Cambrian has long been controversial.Modern artificial simulation experiments of phosphate animal eggs can provide scientific evidence to settle the aforementioned disputes.This experiment simulated environmental changes to observe the early morphological changes of the Bluntnose black bream eggs(Megalobrama amblycephala).It was found that the eggs can show a different morphology in the phosphate environment and that these eggs exhibited considerable morphological variations under different conditions.Thus,those eggs cannot be ascribed to the same species based only on the features.The experimental results are expected to provide a useful reference for the identification of phosphatized microfossils and provide a more empirical basis for their genesis.  相似文献   

7.
Weng'an phosphates of the Precambrian Doushantuo Formation, Guizhou (southwestern China) preserve a large number of exquisite biological structures, which are mostly micro-spherical and represent seaweeds, acritarchs and developing eggs related to various groups of metazoans. Here is a report of a variety of developing eggs and larvae, which are most probably of Cnidarian affinity. The eggs examined in the study are composed of early cleavage embryos and two-layered gastrulae. The early cleavage embryos are radial and total cleavage with equal-size blastomeres. The gastrulae mostly bear a large archenteron, which is filled with yolk-degrading organic matter. Ovoid to fusiform planula-like larvae identified in thin sections under light microscope are mostly mouthless and their gastrovascular cavity is filled with possible yolk-degrading organic matter. They are likely representatives of non-feeding larva. The uncommon planula-like structures are hollow, with each having a mouth-like structure on its narrow end. We interpret them as feeding larva. Study of these embryos with possible Cnidarian affinities shed new insight on the origin of metazoans.  相似文献   

8.
The eastern Xing’an-Mongolian (Xing-Meng) Orogenic Belt (XMOB) is one of the important areas of porphyry copper (Cu)-molybdenum (Mo) deposits in China. However, studies on the exact ages of mineralization and their geodynamic significance are very limited. In this study, granodioritic rocks from the Duobaoshan Cu deposit and Daheishan Mo deposit were selected to make zircon SHRIMP U-Pb analyses in order to constrain their mineralization ages. Geochronological data indicate that two episodes of mineralization took place in the Duobaoshan Cu deposits. The granodiorite related to the Duobaoshan porphyry Cu deposit was formed in the Early Paleozoic with zircon U-Pb age of 485±8 Ma, whereas the granodiorites related to the Sankuanggou skarn-type Cu deposit were emplaced in the Jurassic with zircon U-Pb ages of 176±3 and 177±3 Ma. In the Daheishan area of Jilin Province, the emplacement age of the granodiorite porphyry related to the porphyry Mo deposit was dated at 170±3 Ma, and the unmineralized monzogranite at 178±3 Ma. Therefore, two episodes of Cu-Mo mineralization were developed in the eastern XMOB, at ~485 Ma and ~175 Ma, respectively. Based on the geological history and spatial-temporal distribution of the granitoids in northeastern (NE) China, it is proposed that the Duobaoshan Cu deposit was related to the collision of the Xing’an and Erguna blocks in the Early Paleozoic, and the Sankuanggou Cu and Daheishan Mo deposits were related to subduction of the Paleo-Pacific plate during the Jurassic.  相似文献   

9.
At 1.0?4.0 GPa and 1123?1473 K and under oxygen fugacity-controlled conditions (Ni+NiO, Fe+Fe3O4, Fe+FeO and Mo+MoO2 buffers), a YJ-3000t Model six-anvil solid high-pressure apparatus and a Sarltron-1260 Impedance/Gain-Phase analyzer were employed to conduct an in situ measurement of the electrical conductivity of single crystal olivine. Experimental results showed that: (1) within the range of experimentally selected frequencies (103?106 Hz), the electrical conductivity of the sample is of great dependence on the frequency; (2) with the rise of temperature (T), the electrical conductivity (σ) will increase, and the Arrenhius linear relationship is established between lgσ and 1/T; (3) under the control of oxygen buffer Fe+Fe3O4, with the rise of pressure, the electrical conductivity tends to decrease whereas the activation enthalpy and independent-of-temperature preexponential factor tend to increase, with the activation energy and activation volume of the sample estimated at (1.25±0.08) eV and (0.105±0.025) cm3/mol, respectively; (4) under given pressure and temperature conditions, the electrical conductivity tends to increase whereas the activation energy tends to decrease with increasing oxygen fugacity; and (5) the mechanism of electrical conduction of small polarons can provide insight into the behavior of electrical conduction of olivine under high pressure and high temperature.  相似文献   

10.
The newly emerged adult females of Schistocerca gregaria were separated and kept in the rearing conditions without males to examine the detailed developmental characteristic of the no mating females and carefully observed the developmental progress of non-fertilised eggs laid by virgin females. The results showed that the females kept without males survived in average 43 d, i.e. 58% of the life span of mated controls, and laid correspondingly fewer egg pods. The size of egg batches, the weight of eggs, and their content of ecdysteroids were normal but the hatch rate was reduced to 18.27%. Blocks of early embryogenesis (58.43%) and hatching failures (23.29%) were the major causes of death. Moreover, most of the hatched insects died during the postembryonic development and only a few females reached the adult stage. All insects that developed until the penultimate or last larval instar or reached the adult stage were females.  相似文献   

11.
Among entomopathogenic fungi the Entomophthor- ales plays an important role in natural control of insect pests through induction of epizootics in insect popula-tions[1—3]. Since most species of the fungal group are 4 - characteristic with their special capability of actively dis-charging conidia to favor infection and dissemination in host populations, they are ideal targets for epizootiologi-cal study, being considered as important microbial control agents. Currently, 66 species …  相似文献   

12.
The effect of carboxymethytl pachymaram (CMP) on the function of dendritic cells(DCs) derived from spleens of hepatitis B virus transgenic mice are studied in vitro. The phenotypes of DCs are tested by flow cytometry (FCM), cytokines measured by ELISA. The expression of DCs’ phenotypes in HBV transgenic mice are low (CD80+CD11c+:59.12±11.53 vs 9.60±4.53, p<0.01; CD80+ MHC-II+: 44.86±12.31 vs 9.80±5.72, p<0.01, normal mice vs HBV transgenic mice), the ability of DCs stimulating T lymphocytes proliferation decreases (0.37±0.11 vs 0.20±0.11, p<0.05, normal mice vs HBV transgenic mice), levels of IL-12 and IFN-γ decrease whereas the level of IL-10 increases; CMP can enhance DCs’ ability of stimulating T lymphocytes proliferation, facilitate the secretion of IL-12 and IFN-γ, inhibit the secretion of IL-10, thus up regulates DCs function. The results show a good prospective use of CMP on the treatment of chronic hepatitis B. Biography: HOU Anji (1963–), male, Ph.D. candidate, Associate professor, research direction: clinical virology.  相似文献   

13.
The relaxation of the highly vibrationally excited CO (v = 1–8) by CO2 is studied by timeresolved Fourier transform infrared emission spectroscopy (TR FTIR). 193 nm laser photolysis of the mixture of CHBr3 with O2 generates the highly vibrationally excited CO(v) molecules. TR FTIR records the intense infrared emission of CO(v→v-1). The vibrational populations of each level of CO(v) have been determined by the method of spectral simulation. Based on the evolution of the time resolved populations and the differential method, 8 energy transfer rate constants of CO(v = 1–8) to CO2 molecules areobtained: (5.7±0.1), (5.9±0.1), (5.2±0.2), (3.4±0.2), (2.4±0.3), (2.2±0.4), (2.0±0.4) and (1.8±0.6) (1014 cm3 · molecule−1 · s−1), respectively. A two-channel energy transfer model can explain the feature of the quenching of CO(v) by CO2. For the lower vibrational states of CO, the vibrational energy transfers preferentially to the u3 mode of CO2 For the higher levels, the major quenching channel changes to the vibrational energy exchange between CO(v→v-1) and the u1 mode of CO2.  相似文献   

14.
A new artificial diet for the diamondback moth,Plutella Xylostella (L), had been selected out successfully. The diet contained the following constituents: soybean powder, wheat germ, wheat bran powder, brewer's yeast and other constituents. So far, the diamondback moth had been reared on this artificial diet for 25 generations and still mantained its normal biological characteristics. Under 25±1 C and 60%–75%RH with 12 h PH, the results of rearing the diamondback moth on the diet as follows: egg hatch, 81.3%–94.7%; survival from eggs to pupae, 55.0%–76.7%; pupal survival, 79.7%–100%; adult emergence, 80%–100%; fecundity 94.7–144. 4 eggs/♀; pupal weight, 90.4–110.8 mg/20 pupae; average days to adult: ♀, 10.2; ♂ 13.1. The diet is not only simpler on the constituents but also have better rearing results and more rearing generations. Li Guanghong: born in June 1965, Ph.D. graduate student. Current research interest is in entomo logical physiology Supported by the State Eighth Five-Year-Plan  相似文献   

15.
Effect of quercetin on HeLa cell system of cervical cancer was studied by methods of MTT and Annexin V-FITC/PI. The results show that quercetin has functions of inhibiting breeding of HeLa cells and inducing apoptosis of the cells. The total apoptosis rate is positively proportional to reaction duration and concentration of quercetin used. The maximum apoptosis rate being (88.76±2.35)% was obtained when the concentration was 50.0 μmol/L and the cells were treated with quercetin for 72 hours. Based on establishing a model of tumor of cervical cancer transplanted into nude mice, quercetin of different concentrations was injected into abdominal cavity of nude mice and situation of tumor growth was reviewed. The result showed that with quercetin concent'ration increasing from 0 to 100.0 μmol/L, the transplantation volume and weight of the tumors decreased from (279.59±70.58) mm^3 and (0.145±0.019) g to (128.72±36.12) mm^3 and (0.089± 0.019) g respectively, while apoptosis rate of the transplanted tumor increased from (9.63±1.85)% to (34,98±0.47)%, which proved that quercetin inhibited increment of volume and weight of transplanted tumor in nude mice bodies.  相似文献   

16.
Cadmium-metallothionein (Cd-MT) of Pteria penguin was used to immunize domestic rabbit in order to obtain polyclonal antibody against Cd-MT. Using the anti-Cd-MT antibody, a method of indirect non-competitive enzyme-linked immunosorbent assay (non-competitive ELISA) was established to detect shellfish Cd-MT. In this case, the minimum detectable concentration of P. penguin Cd-MT was (4.563±0.051) ng/mL. The linear range of detection was 9.75-2.0×104 ng/mL. Intra-assay relative standard deviation (RSD) was less than 11.6%, and inter-assay RSD less than 6.7%. The recovery rates ranged from 83.7% to 119.0%. The polyclonal antibody against Cd-MT of P. penguin can also be used to detect MT of other four types of shellfish. In the crude extracts from different organs of P. penguin, the MT concentrations determined by this method matched well with the concentrations of cadmium detected by the atomic absorption spectroscopy.  相似文献   

17.
Outcrossing rate in a natural population of Caldesia grandis was estimated by the dominant random amplified polymorphism DNA (RAPD) marker using 10 open-pollinated progeny arrays of 24 individuals. The multilocus outcrossing rate estimated based on all 25 RAPD loci was 0.872 ±0.033 and the single-locus outcrossing rate was 0.795 ±0.032. Multilocus estimates did not differ significantly from the single-locus estimates. The fixation index, F, in the progeny estimated from RAPD data was -0.142 ±0.000. The estimates of multilocus outcrossing rates (t_m) and single-locus outcrossing rates (t_s) obtained from MLDT clearly indicate that outcrossing is predominant in the open-pollinated C. grandis population. An empirical analysis suggests that 15 should be the minimum number of dominant marker loci necessary to achieve robust estimates of t_m.  相似文献   

18.
Biosorption of Cu(Ⅱ) and Pb(Ⅱ) by Auricularia polytricha   总被引:1,自引:0,他引:1  
For searching biological material for heavy metal removal of waste-water, using macrofungus Auricularia polytricha as biosorbent for Cu^2+ and Pb^2+ removal was investigated. After shaking and biosorbing Cu^2+ and Pb^2+ in solution by biosorbents, the filtrates were tested by AAS and the adsorbed quantity of Cu^2+ and Pb^2+ was calculated. The biosorbents were effective in removal of Cu^2+ and Pb^2+ on the biosorbents that showed a high- est value around pH 5-6. The biosorption rate of Cu^2+ and Pb^2+ on A. polytricha biomass decreased with increasing the initial concentration of Cu^2+ and Pb^2+ in the medium. The biosorption of Cu^2+ and Pb^2+ on the biomasses follows pseudo-second order kinetics. The determined maximum biosorption capacities presented by the fungus biomass were 3.34 and 13.03 mg·g^-1 dry weight for Cu^2+ and Pb^2+, respectively by the biosorption equilibrium with Langmuir adsorption isotherm. According to the whole data analysis in each experiment of studying Cu^2+ and Pb^2+ biosorption including condition factors and adsorption isotherm, the adsorbed capacity of Pb^2+ by A. polytricha biomass was bigger than Cu^2+. The biosorption by A. polytricha was most effective when pH 5-6. The biosorbents are suitable for low Cu^2+ and Pb^2+ concentration waste-water, especially for Pb^2+ removal.  相似文献   

19.
In situ U-Pb dating of xenotime by laser ablation (LA)-ICP-MS   总被引:1,自引:0,他引:1  
Xenotime is an ideal mineral for U-Th-Pb isotopic dating because of its relatively high U and Th contents, but typically low concentration of common Pb. These characteristics, and the fact that it is widespread throughout various types of rocks, suggest that the U-Th-Pb dating of xenotime has broad applications. Studies of U-Pb dating on xenotime by ion microprobe (such as SHRIMP) have increased in recent years, whereas studies by laser ablation (LA)-ICP-MS are still rare. In this study, we developed a technique for U-Pb dating of xenotime using the 193 nm ArF laser-ablation system and Agilent 7500a Q-ICP-MS. To evaluate the reliability of our method, a xenotime standard, BS-1, was analyzed and calibrated against another xenotime standard, MG-1. The weighted mean 206 Pb/ 238 U ages of 510.1 ± 5.2 Ma (2 n = 21), 509.8 ± 4.3 Ma (2 n = 21) and 510.0 ± 4.6 Ma (2 n = 21) were obtained using beam diameters of 16, 24 and 32 m, respectively. These ages are identical to those determined by ID-TIMS method (weighted mean 206 Pb/ 238 U age of 508.8 ± 1.4 Ma), which supports the reliability of our LA-ICP-MS method. We also analyzed xenotimes in leucogranites from South Tibet and granites from Xihuashan in southern China, and obtained accurate and precise ages. Nevertheless, we observed systematic differences in Pb/U fractionation among xenotime, monazite and zircon. The matrix-effect resulted in either under-correction or over-correction of fractionation, and thus led to inaccurate ages. Thus, a matrix-matched material is required for U-Pb dating of xenotime by LA-ICP-MS.  相似文献   

20.
0 IntroductionAsgue-br-eclaaptseudl acrat acraatcatr ianctc l,ud aems ocnogrte xwh,incuhcl,e acro ratnexdcataract and nuclear cataract are more i mportant .Cortex cataract is different from nuclear cataract inoccurring,developing and clinic display,evenin his-tology. The pathogenesis of age-related cataract hasnot been perfectly described.But it has been verifiedthat thereis alayer oflens epithelial cells (LECs) un-der vertebrates’lens anterior capsule, which is i m-portant in maintaining t…  相似文献   

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