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1.
广西英罗湾红树植物幼苗矿质元素含量初步研究   总被引:5,自引:2,他引:3  
梁士楚  李瑞棠  梁发英   《广西植物》1996,16(4):363-366
木榄、秋茄、红海榄、白骨壤和桐花树幼苗是广西英罗湾红树林幼苗库中的主要成分。对这5种幼苗的N、P、K、Na和Cl进行了测定,结果表明:(1)Cl和Na的含量较高;(2)Cl和Na、Cl和K以及N和P含量之间存在着显著的相关性;(3)N的富集系数较高。  相似文献   

2.
应用逆转录-聚合酶链反应(RT-PCR)技术,从HCV感染者血清中扩增编码HCV病毒蛋白酶的NS2-NS3cDNA片段,在其5′和3′端分别引入EcoRⅠ和XbaⅠ限制性内切酶位点,定向克隆至真核表达载体pcDNA3,构建重组载体pcDNA-NS23,重组表达载体经限制性内切酶消化鉴定.用SP6和T7通用引物对目的基因片断进行序列分析.序列同源性分析结果表明,与HCV-J、HC-C2有高度的同源性,与HCV-1、HCV-J6、HCV-J8同源性差,提示所克隆的基因属HCVⅡ型.该区内重要的功能位点如Zn2+依赖性金属蛋白酶催化中心、丝氨酸蛋白酶催化中心等均高度保守  相似文献   

3.
红树林是海岸重要生态关键区, 在维护生物多样性和沿海地区生态安全等方面发挥着重要作用。红海榄(Rhizophora stylosa)是我国红树林生态系统的建群种之一。为了揭示红海榄次生木质部解剖特征可塑性的生态适应意义, 该文测定了海南省东寨港红树林自然保护区6个红海榄种群18个采样点的土壤理化性质, 应用显微镜和电镜详细观测了各采样点生长的18株红海榄植株次生木质部的形态解剖特征, 并测量了红海榄次生木质部的数量解剖特征。不同样地的红海榄次生木质部都具有纤维状导管和环管管胞、螺旋雕纹和附物、生长轮、薄壁细胞(含淀粉粒)等结构。这些特化结构具有生态适应意义, 在潮间带高盐生境中能促进水分输导的安全性。不同生境中红海榄次生木质部数量解剖特征可塑性大, 利用逐步回归分析方法分析了土壤理化因子与红海榄次生木质部数量特征的关系。结果表明: 土壤全盐含量、土壤Mn2+含量、土壤Na+含量、土壤Cl-含量、土壤Ca2+含量、土壤有机质含量、土壤全磷含量和土壤pH值对次生木质部数量特征的影响达到极显著水平, 不同样地红海榄次生木质部数量特征的变化是红海榄适应异质生境的结果。  相似文献   

4.
稻田CH4和N2O的排放及养萍和施肥的影响   总被引:56,自引:10,他引:56  
用箱法对我国东北稻田CH4和N2O排放进行观测研究表明,东北稻田的CH4排放通量比南方稻田小,平均日排放通量和生长季节排放总量分别为0.07和7.4g·m-2.稻田淹水期几乎没有N2O的净排放,但在非淹水期内却有大量N2O排放(平均通量59μgN2O·m-2·h-1).稻田养萍和施肥明显促进CH4和N2O排放.稻田CH4和N2O排放之间存在消长关系.制定稻田温室气体减排技术措施时应充分注意这一关系.  相似文献   

5.
红树植物秋茄和红海榄叶片元素含量及季节动态的比较研究   总被引:10,自引:0,他引:10  
王文卿  林鹏 《生态学报》2001,21(8):1233-1238
研究了福建九龙江口秋茄(Kandelia candel L.)和红海榄(Rhizophora stylosa G.)成熟叶片N、P、K、Na、Ca、Mg和CI等元素含量的季节变化和元素间的关系。结果表明秋茄和红海榄同为红树科树种,生境相同且同属拒盐植物,但在元素积累及季节变化模式上存在较大差别。秋茄和红海榄叶片高盐分和Ca含量及低K/Na比,这是我们对盐渍生境的一种适应。秋茄无机渗透调节剂(主要指K^ 、Na^ 、Ca^2 、Mg^2 和CI^-)含量夏季高于冬季,而红海榄与之完全相反。秋茄能够通过主动积累有机渗透调节剂来适应低温,而红海榄不能。对秋茄和红海缆抗寒机制进行了讨论。  相似文献   

6.
长白山北坡不同土壤N2O和CH4排放的初步研究   总被引:20,自引:0,他引:20  
用箱法技术原位测定了长白山北坡不同土壤(苔原土、生草森林土、棕色针叶林土和暗棕色森林土)6—8月间的N2O和CH4排放.结果表明,这些土壤既是N2O的源,又同时是CH4的汇.N2O通量变化于6.17—12.33μg·m-2·h-3之间(平均9.37μg·m-2·h-1),CH4通量为-85.63—-7.58μg·m-2·h-1(平均-41.45μg·m-3·h-1),并观察到在N2O排放和CH4吸收之间有着相互消长关系.实验室培养实验表明,最大反硝化作用活性存在于土壤上层(0—6cm);不同土壤的反硝化作用活性明显不同.山地暗棕色森林土的CH4吸收作用也主要发生在土壤的上层(0—12cm).  相似文献   

7.
神经元缺氧复氧损伤时氧自由基的毒性作用及其机制*   总被引:2,自引:0,他引:2  
在原代分离培养Wistar乳鼠大脑皮质神经元上研究了缺氧复氧损伤(H/R)对神经细胞乳酸脱氢酶(LDH),漏出率,死亡率和脂质过氧化物含量的影响,并选用一氧化氮(NO)合酶抑制剂L-NG-硝基-精氨酸(L-NNA)巯基供体N-乙酰半胱氨酸(NAC)和超氧化物歧化酶(Cu,Zn-SOD)三种自由基清除剂进行预保护等方法来探讨机制。结果表明 H/R损伤引起LDH漏出率,细胞死亡率和脂过氧化物含量极显著  相似文献   

8.
神经元缺氧复氧损伤时氧自由基的毒性作用及其机制   总被引:3,自引:0,他引:3  
在原代分离培养Wistar乳鼠大脑皮质神经元上研究了缺氧复氧损伤(H/R)对神经细胞乳酸脱氢酶(LDH),漏出率,死亡率和脂质过氧化物含量的影响,并选用一氧化氮(NO)合酶抑制剂L-NG-硝基-精氨酸(L-NNA)巯基供体N-乙酰半胱氨酸(NAC)和超氧化物歧化酶(Cu,Zn-SOD)三种自由基清除剂进行预保护等方法来探讨机制。结果表明 H/R损伤引起LDH漏出率,细胞死亡率和脂过氧化物含量极显著  相似文献   

9.
氢醌和双氰胺对种稻土壤N2O和CH4排放的影响   总被引:14,自引:1,他引:13  
通过盆栽试验,研究了脲酶抑制剂氢醌(HQ)、硝化抑制剂双氰胺(DCD)及二者的组合(HQ+DCD)对种稻土壤N2O和CH4排放的影响.结果表明,在未施麦秸粉时,所有施抑制剂的处理均较单施尿素的能显著减少水稻生长期供试土壤N2O和CH4的排放.特别是HQ+DCD处理,其N2O和CH4排放总量分别约为对照的1/3和1/2.而在施麦秸粉后,该处理的N2O排放总量为对照的1/2,但CH4排放总量却较少差别.不论是N2O还是CH4的排放总量,施麦秸粉的都比未施的高出1倍和更多.因此,单从土壤源温室气体排放的角度看,将未腐熟的有机物料与尿素共施,并不是一种适宜的施肥制度.供试土壤的N2O排放通量,与水稻植株的NO-3N含量和土表水层中的矿质N量分别呈显著的指数正相关和线性正相关;CH4的排放通量则与水稻植株的生长量和土表水层中的矿质N量呈显著的线性负相关.在N2O与CH4的排放间,未施麦秸粉时存在着定量的相互消长关系;施麦秸粉后,虽同样存在所述关系,但难以定量化.  相似文献   

10.
本文采用抗原捕捉ELISA方法检测了HCV感染者血清中抗-HCVIgG抗体轻链Κ和λ的比值,发现所检测的抗HCV-NS4、抗HCV-CP1和抗HCV-CP2抗体轻链的表达呈现明显的偏斜,65例抗HCV阳性者中63例(占96.9%),至少一种抗HCV抗体К/λ偏离了正常1∶1的比值,尤以λ链较多,分别占65.6%、89.9%和70.2%,但任何一个HCV感染者血清抗-HCV抗体既可能是Κ链占优势,也  相似文献   

11.
The aim of this report has been to present results concerning analytical quality controls of Hg analysis of fish and sediment, analyses of Fe, Ca, total-P, K, pH, alkalinity, conductivity, colour and hardness (Ca + Mg) of lake water samples. Despite the fact that these are standard parameters in many regular water control programs, there are major differences in the reliability with which these parameters can be determined. The focus here is on an overall inter-laboratory comparison between the parameters. Six laboratories have been involved in the analysis. Selected results: pH gives the lowest (average) relative standard deviation (error), about 2 %; conductivity gives an error of about 5–7 %; alkalinity yields an average error of as much as 13–25 %, which is the largest among the parameters studied here; colour also gives a high error, 9–15 %; hardness gives a relative standard deviation of about 6–7 %. Of the other parameters (i. e., Hg, Fe, Ca and P), Hg gives the best reliability and Fe and P the lowest. To have knowledge of the reliability of the analytical data is of paramount importance in most control programs and research projects.  相似文献   

12.
Summary Concentration of N, P, K, Ca, Mg and S in summer groundnut crop was higher than in kharif while Zn, Fe, Mn and Cu contents were higher in summer crop. Kernel's N, P and Zn; Leaflet's Ca and Mn; Stem's K and Fe; Root's S and Cu and Petiole's Mg contents were highest. Shell's N, P, K, Mg, S, Zn and Cu; Kernel's Ca, Fe and Mn contents were the least. N, P, K, S, Zn and Cu concentrations decreased linearly as the crop grew. Ca, Mg, Fe and Mn concentrations did not display any distinct pattern. Ca concentration was positively correlated with pod yield in both the seasons.  相似文献   

13.
The cell has been represented as a charged liquid drop. Contrary to the DLVO-theory, the effect of the surface potential upon the value of the interfacial tension of the cell membrane has also been taken into consideration. The cell membrane has visco-elastic properties and its constituents may move against each other. Cell movement is caused by the appearance of a small number of the electrically charged constituents of the cell membrane on the leading edge of the cell. This produces a local decrease in the surface tension and the cell membrane expansion. At the moment of contact between two cells proton transfers occur between the strongly negatively charged microvilli of one cell and the body of the other, analogous to a condenser breakdown. This, through the effect on the surface tension, causes contact inhibition of movement. The distribution of the proton dissociable groups modifies the interaction between the cells (differentiation) and between the cell and the substratum (adhesion). Adsorption of the charged compounds at the surface of the cell membrane, decreasing the surface potential and increasing the surface tension, causes the phenomena of chemotaxis, phagocytosis and pinocytosis. Cell division, considered in the terms of the surface energy, requires an adequate supply of considerable quantities of energy inversely proportional to the surface potential value. In case of a reduction of the distance between the cells, their surface potential and the energetic barrier of the cell division processes increases, and causes contact inhibition of cell division. Due to their high charge, division of neoplastic cells is inhibited much later than division of normal cells, or is completely ininhibited due to geometric conditions. Fusion of the cell membrane in the intra-cellular and intercellular processes is a reverse process in relation to the cell division.  相似文献   

14.
15.
Acute and chronic toxicity tests for malathion, diazinon, copper (Cu), mercury (Hg), lead (Pb), zinc (Zn), nickel (Ni), and iron (Fe) were conducted. Mortalities ofBarilius vagra andCyprinus carpio (common carp) were variable but LC50-96 hr were similar for pesticides. AdultB. vagra seem to be more sensitive to malathion than juvenile carp. Both juvenile carp and adultB. vagra were extremely sensitive to diazinon. Long-term exposure to pesticides modified morphology and behavior. The LC50-96 values for Cu, Hg, and Pb were 0.3, 0.16, and 0.44, respectively, for smaller fish and 1.0, 0.77, and 1.33, respectively, for larger fish. Replicate LC50 values for Zn, Ni, and Fe were somewhat variable, and for these metals, the size of the fish seemed to affect response because LC50 values increased as fish size increased. Cooper, Pb, Zn, and Fe residues following exposure to sublethal concentrations of these metals for 15 d were significantly greater in whole juvenile common carp than in controls.  相似文献   

16.
The effect of age and gender on major, minor, and trace element contents in the intact rib bone of 80 relatively healthy 15–55-year-old women and men was investigated. Contents or upper limit of contents of 16 chemical elements in the rib bone were determined by inductively coupled plasma atomic emission spectrometry (ICP-AES). Mean values (M?±?SΕΜ) for the mass fraction of Ba, Ca, Cu, Fe, K, Li, Mg, Na, P, S, Sr, and Zn (milligram per kilogram of dry bone) were as follows: 2.54?±?0.16, 171,400?±?4,050, 1.35?±?0.22, 140?±?11, 1,874?±?71, 0.049?±?0.011, 2,139?±?38, 5,378?±?88, 75,140?±?1,660, 1,881?±?51, 291?±?20, and 92.8?±?1.5, respectively. The upper limits of contents of Al, B, Mn, and V were <7.20, <0.65, <0.36, and <0.03, respectively. Statistically significant tendency for the Ca, Mg, and P content to decrease with age was found in the human rib bone, regardless of gender. The mass fraction of Fe in the male rib bone increases with age. It was shown that higher Ca, Mg, Na, P, and Sr mass fractions as well as lower Fe content were typical of female ribs as compared to those in male ribs.  相似文献   

17.
18.
The sieve-element plastids of 69 species of theCaryophyllales were investigated by transmission electron microscopy. All contained the specific subtype-P3 plastids characterized by a peripheral ring of protein filaments. The presence or absence of an additional central protein crystal and their shape being either polygonal or globular as well as the average sizes of the sieve-element plastids are useful features in the characterization of some families.—Barbeuia contains sieve-element plastids that confirm its placement within thePhytolaccaceae. Lyallia differs fromHectorella by including small starch grains in their sieve-element plastids, which otherwise by their globular crystals negate a closer connection to theCaryophyllaceae. The lack of a central protein crystal in its form-P3fs plastids placesMicrotea best within theChenopodiaceae. Sarcobatus, a so far uncontested member of theChenopodiaceae, contains form-P3cf plastids, i.e., including a central crystal not found elsewhere in this family.Telephium andCorrigiola, shifted back and forth betweenMolluginaceae andCaryophyllaceae, have form-P3cf(s) plastids with a polygonal crystal which favor their placement within theCaryophyllaceae.  相似文献   

19.
A review is presented of issues relevant to the definition, measurement, and classification of stimuli, situations, and environments. Problems such as the lack of adequate definitions of concepts, error and bias in measurement procedures, confusion between measurement of a concept and measurement of its behavioral effects, and the lack of agreement among alternative measures are emphasized. It is suggested that concepts be defined in terms of objective characteristics while allowing for the study of the transactional relationship between organism and environment. The work of the ethologists in defining stimuli while studying their relationship to different organismic states and situational contexts is emphasized in this regard. Following Brunswik, it is also suggested that wherever possible there be a representative sampling of variables in natural settings. Note from the editors: From time to time, Human Ecology will publish a review article. Our first in this series is a review by a psychologist of basic definitional and conceptual problems in environmental studies.This paper was prepared while the author was a Visiting Research Fellow at the Educational Testing Service. The support of ETS and my colleagues in the Division of Psychological Studies is gratefully acknowledged. The review was also supported in part by a grant from the Rutgers University Research Council.  相似文献   

20.
The translocation of the radionuclides of Co, Zn, Se, Rb, Y, Tc, and Re into red and green fruits, flesh, seeds, rind, calyxes, flower, leaves, and stems via the root of the tomato plant at two different growth stages was studied by a multitracer technique. The contents (%/g) of Co, Zn, Se, and Y in the roots were the highest among the organs, but only small amounts of them were translocated into the aerial parts after 5 d cultivation with a multitracer. In contrast, Rb, Tc, and Re showed rapid translocation into the stems and leaves from the root. In the plants cultivated for 95 d with a multitracer, Zn, Se, and Rb distributed in all of the organs, Co in the organs except for flowers, and Y, Tc, and Re in the limited organs. The translocation ratio of the elements for the edible part of the plants cultivated for 95 d decreased in the order of Rb>Zn>Co≈Se>Tc≈Y>Re. The transfer factor of the elements for tomato fruit was determined to be in the range of 10−5–10−2. The characteristic translocation behavior of the elements gives us fundamental information on the assessment of pollutant uptake by the tomato plant.  相似文献   

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