303 resultados para NaCl 7.5%


Relevância:

80.00% 80.00%

Publicador:

Resumo:

Nd(C_8H_(11))Cl_2·3THF与不同烷基铝〔Et_3Al,i-Bu_3Al,HAl(i-Bu_2)〕组成的催化体系可催化丁二烯聚合。实验结果表明,催化剂活性取决于所用的烷基铝、铝钕比和催化剂用量,而溶剂对催化活性影响不大。聚合物的微观结构则不受烷基铝种类、溶剂、铬钕比和催化剂用量的影响,均可得到高顺式(97—98%)聚丁二烯。

Relevância:

80.00% 80.00%

Publicador:

Resumo:

交联型含磺化呋喃环聚醚复合膜对无机水溶液和有机水溶液具有很好的分离功能,其中日本东丽的PEC-1000反渗透复合膜对碱金属和碱土金属离子表现出特别高的截留率,巳用于工业规模的一级海水淡化。但这类膜材料的耐氧化氯解性尚不够理想,分离海水时,体系中需加入微量NaHSO_3之类还原剂。迄今,关于由糠醇(FA)均缩聚形成交联型含磺化呋喃环缩聚物的化学稳定性的研究仅有少量报道,而对于FA与三∈2-羟乙基

Relevância:

80.00% 80.00%

Publicador:

Resumo:

聚甲基丙烯酸酯类是被广泛应用于工业、建筑、医疗等方面的一类塑料。人们曾经用多种方法对这类材料进行过分析和研究。甲基丙烯酸甲酯(MMA)-甲基丙烯酸正丁酯(BMA)共聚物和均聚共混物的裂解色谱鉴别和定量测定已有报道,但这些方法比较烦琐,不易做准,有的还不完善。本文对聚甲基丙烯酸甲酯(PMMA)-聚甲基丙烯酸正丁酯(PBMA)共混物(简称共混物)和MMA-BMA无规共聚物(简称共聚物)进行了裂解色谱定量研究,探讨了采用回归分析作出的工作曲线的定量方法,以及

Relevância:

80.00% 80.00%

Publicador:

Resumo:

本文在蓖麻油聚氯酯/聚甲基丙烯酸甲酯交联共聚物体系中,加入不同含量的丙烯酸共聚,详细考察了氢键对力学性能、相容性及形态结构的影响。结果表明:丙烯酸含量为7.5%时,材料的相容性最差,微区尺寸在几十纳米,这时的增韧效果最好。丙烯酸含量在5%和lO%时相容性最佳。

Relevância:

80.00% 80.00%

Publicador:

Resumo:

本文采用平台和硝酸镁硝酸钯混合基体改进剂相结合的方法,使铬和锰的灰化温度从1200℃提高至1600℃,克服了大量钾、钠、钙、镁等共存元素的干扰,可直接测定样品中微量铬和锰。对于铬和锰的检出限分别为5.6×10~(-11)g和9×10~(-11)g,相对标准偏差分别为8.7%和7.5%,测定结果与等离子体发射光谱法结果一致。

Relevância:

80.00% 80.00%

Publicador:

Resumo:

Chinese mitten crab Eriocheir sinensis is one of the most important aquaculture crustacean species in China. A cDNA library was constructed from hemocytes of E. sinensis challenged with the mixture of Listonella anguillarum and Staphylococcus aureus, and randomly sequenced to collect genomic information and identify genes involved in immune defense response. Single-pass 5' sequencing of 10368 clones yielded 7535 high quality ESTs (Expressed Sequence Tags) and these ESTs were assembled into 2943 unigenes. BLAST analysis revealed that 1706 unigenes (58.0% of the total) or 4593 ESTs (61.0% of the total) were novel genes that had no significant matches to any protein sequences in the public databases. The rest 1237 unigenes; (42.0% of the total) were closely matched to the known genes or sequences deposited in public databases, which could be classed into 20 or 23 classifications according to "molecular function" or "biological process" respectively based on the Gene Ontology (GO). And 221 unigenes (7.5% of all 2943 unigenes, 17.9% of matched unigenes) or 969 ESTs (12.9% of all 7535 ESTs, 32.9% of matched ESTs) were identified to be immune genes. The relative higher proportion of immune-related genes in the present cDNA library than that in the normal library of E. sinensis and other crustaceans libraries, and the differences and changes in percentage and quantity of some key immune-related genes especially the immune inducible genes between two E. sinensis cDNA libraries may derive from the bacteria challenge to the Chinese mitten crab. The results provided a well-characterized EST resource for the genomics community, gene discovery especially for the identification of host-defense genes and pathways in crabs as well as other crustaceans. (C) 2009 Elsevier Ltd. All rights reserved.

Relevância:

80.00% 80.00%

Publicador:

Resumo:

Two photoperiodic responses, the development of sporophylls and hairs, have been quantified in sporophytes of the brown alga Undaria pinnatifida. In a final experiment, the algae were cultivated in outdoor, 2000-L seawater tanks in a greenhouse for up to 12 weeks, and daylength was regulated by automatic blinds mounted on top of the tanks. Vegetative young sporophytes were treated under short-day (SD; 8 h light per day) or long-day conditions (LD; 16 h light per day), at 12 h light per day or in a night-break regime (NB; 8 h light per day, 7.5 h dark, 1 h light, 7.5 h dark). The earliest sporophyll development was observed 6, 7 or 9 weeks under LD, NB or SD conditions, respectively. After 12 weeks the sporophylls were significantly longer and wider under LD or NB conditions than in the SD regime, and only half of the experimental algae had formed sporophylls under SD conditions, but all algae under LD or NB conditions. In a foregoing 7-week culture experiment performed in 300-L indoor tanks, enhanced sporophyll formation had also been observed under LD and not under SD conditions (NB omitted). In both experiments, blade elongation rates remained high until the end of the experiments in SD, but declined during sporophyll initiation in LD, NB or at 12 h light per day. Another difference caused by photoperiod was observed in regard to the development of surface hair spots which occurred in both experiments on the blades in LD, NB or at 12 h light per day with identical densities, but were completely lacking under SD conditions. It is concluded that U. pinnatifida is a facultatative long-day plant in regard to reproduction forming vigorously sporophylls in long days, and an obligate long-day plant in regard to hair formation.

Relevância:

80.00% 80.00%

Publicador:

Resumo:

Elemental sulfur and hydrogen sulfide emitted offshore of northeastern Taiwan known to local fishermen for generations, but never studied until recently, are found to have originated from a cluster of shallow (< 30 m depth) hydrothermal vents. Among the mounds is a massive 6 m high chimney with a diameter of 4 m at the base composed of almost pure sulfur and discharging hydrothermal fluid containing sulfur particles. The sulfur in the chimney has a delta(34)S= 1.1 parts per thousand that is isotopically lighter than seawater. A yellow smoker at shallow depths with such characteristics has never been reported on anywhere else in the world. Gas discharges from these vents are dominated by CO2 (> 92%) with small amounts of H2S. Helium isotopic ratios 7.5 times that of air indicate that these gases originate from the mantle. High temperature hydrothermal fluids have measured temperatures of 78-116 degrees C and pH (25 degrees C) values as low as 1.52, likely the lowest to be found in world records. Low temperature vents (30-65 degrees C) have higher pH values. Continuous temperature records from one vent show a close correlation with diumal tides, suggesting rapid circulation of the hydrothermal fluids. (c) 2005 Elsevier B.V. All rights reserved.

Relevância:

80.00% 80.00%

Publicador:

Resumo:

Helium, rieon and argon isotope compositions of fluid inclusions have been measured in hydrothermal sulfide samples from the TAG hydrothermal field at the Mid-Atlantic Ridge. Fluid-inclusion He-3/He-4 ratios are 2.2-13.3 times the air value (Ra), and with a mean of 7.2 Ra. Comparison with the local vent fluids (He-3/He-4=7.5-8.2 Ra) and mid-ocean ridge basalt values (He-3/He-4=6-11 Ra) shows that the variation range of He-3/He-4 ratios from sulfide-hosted fluid inclusions is significantly large. Values for Ne-20/Ne-22 are from 10.2 to 11.4, which are significantly higher than the atmospheric ratio (9.8). And fluid-inclusion Ar-40/Ar-36 ratios range from 287 to 359, which are close to the atmospheric values (295.5). These results indicate that the noble gases of fluid inclusions in hydrothermal sulfides are a mixture of mantle- and seawater-derived noble gases; the partial mantle-derived components of trapped hydrothermal fluids may be from the lower mantle; the helium of fluid inclusions is mainly from upper mantle; and the Ne and Ar components are mainly from seawater.

Relevância:

80.00% 80.00%

Publicador:

Resumo:

Thirty-eight surficial deposit samples were collected from the equatorial North Pacific, and the natural thermoluminescence (TL) characteristics of both bulk and clay fraction samples ( < 2 mu m fractions) were studied by the FJ427 - Al automatic TL Dosimeter for the first time. With the measurements of clay mineral composition, element composition by XRD and ICP, the correlations between TL intensity and sedimentary environment proxies were analyzed, such as water depth, ratio of FeO to Fe2O3 contents, LOI, and major clay mineral concentration, and it was found the bulk sample's TL signal was stronger than the clay ones. Usually, increase in the clay components may result in the decrease of TL intensity. From the shape of TL curves, the pelagic sediments can be divided into two groups: the majority group has two glow peaks, in general, the first peak is broad and flat, but the second narrow and sharp; the minority group only has a single peak because the first is absent. The peak centers of TL curves are almost fixed, falling in the temperature sections 230 similar to 260 and 390 similar to 405 degrees C respectively. Lorentz model packed in the Origin 7.5 was chosen to deal with the TL curves. From the processing results, three parameters ( H, C and A), corresponding to the height, center, and kurtosis of TL curve, were obtained to describe the curve characteristics. The correlations between TL curve parameters and sedimentary environment proxies were also calculated. On the basis of the above work, the relationship between TL characteristics and sediment type, mineral composition, sedimentary environment of surface sediments was discussed in the study area, and a conclusion is: sediments from the environment of shallower water, higher organic contents and weaker reductivity have stronger TL signals.

Relevância:

80.00% 80.00%

Publicador:

Resumo:

AMS(14)C dating and grain-size analysis for Core PC-6, located in the middle of a mud area on the inner shelf of the East China Sea (ECS), were used to rebuild the Holocene history of the East Asian winter monsoon (EAWM). The 7.5-m core recorded the history of environmental changes during the postglacial transgression. The core's mud section (the upper 450 cm) has been formed mainly by suspended sediment delivered from the Yangtze River mouth by the ECS Winter Coastal Current (ECSWCC) since 7.6 kyr BP. Using a mathematical method called "grain size vs. standard deviatioW', we can divide the Core PC-6's grain-size distribution into two populations at about 28 mu m. The fine population (< 28 mu m) is considered to be transported by the ECSWCC as suspended loads. Content of the fine population changes little and represents a stable sedimentary environment in accord with the present situation. Thus, variation of mean grain-size from the fine population would reflect the strength of ECSWCC, which is mainly controlled by the East Asian winter monsoon. Abrupt increasing mean grain size in the mud section is inferred to be transported by sudden strengthened ECSWCC, which was caused by the strengthened EAWM. Thus, the high resolution mean grain-size variation might serve as a proxy for reconstruction of the EAWM. A good correlation between sunspot change and the mean grain-size of suspended fine population suggests that one of the primary controls on centennial- to decadal-scale changes of the EAWM in the past 8 ka is the variations of sun irradiance, i.e., the EAWM will increase in intensity when the number of sunspots decreases. Spectral analyses of the mean grain-size time series of Core PC-6 show statistically significant periodicities centering on 2463, 1368, 128, 106, 100, 88-91, 7678, and 70-72 years. The EAWM and the East Asian summer monsoon (EASM) agree with each other well on these cycles, and the East Asian Monsoon (EAM) and the Indian Monsoon also share in concurrent cycles in Holocene, which are in accord with the changes of the sun irradiance. (c) 2005 Elsevier B.V. All rights reserved.

Relevância:

80.00% 80.00%

Publicador:

Resumo:

作为大陆向大洋的过渡带,由于享有得天独厚的沉积环境,具有独特的构造特征以及与黑潮主流之间的密切关系,一直以来,冲绳海槽都是中外学者研究的重点靶区。2005年5月,由我国与法国联合主持的IMAGES 航次在台湾东北海域获取MD05-2908柱状岩芯(24º48.04′N,122 º29.35′E,水深为1275米),该柱状岩芯为一34.17米长高质量的连续沉积记录,岩性以深灰色粘土质粉砂为主,含水量较高,粘性、可塑性强,含有数层厚度不等的夹层。岩芯年龄模式依据17个AMS 14C定年数据建立,岩芯底部年代约6.8ka,为中全新世以来的沉积。在实验室对样品按照2cm的间隔进行分割后分别进行了粒度分析、粘土矿物提取与测试、碎屑矿物提取与鉴定、常微量元素和稀土元素分析等实验。 粒度分析结果显示,MD05-2908岩芯沉积物粒度垂向上总体比较均一,以细颗粒的粘土与粉砂质为主,但不同层位也稍有差别,表现为底部层位粒度较粗,含砂量较高,说明底部沉积环境比较复杂。粘土粒级(<2µm)矿物主要由四种粘土矿物和少量石英、长石碎屑组成。其中,粘土矿物相对含量变化中,伊利石(~68%)与绿泥石(~17%)构成主要成分,含有蒙皂石(~10%)和高岭石(~5%)。结合台湾东北外海表层沉积物的研究,利用粘土矿物伊利石/蒙皂石和绿泥石/高岭石比值得出岩芯粘土矿物主要为陆源碎屑粘土矿物,其源岩主要为台湾中央山脉的变质岩与台湾东部的沉积岩。重矿物分析共选取了41个层位,对63~250μm粒级的样品在实体镜和偏光显微镜下进行鉴定,结果显示,岩芯重矿物主要由绿泥石(29%)、普通角闪石(22%)、白云石(10%)、黑云母(8%)、绿帘石(7%)、白云母(7%)、褐铁矿(5%)等组成。稳定矿物少,矿物成熟度低。碎屑矿物风化程度低,磨蚀不明显,分选较差,表明沉积物来自于近源,后期改造作用不明显。常量元素分析结果表明,SiO2 、Al2O3和Fe2O3是岩芯沉积物中的最主要组分,这三种组分占沉积物总量的82%左右。 整个岩芯自下而上各常量组分变化不大,其平均值与东海陆架沉积物基本接近。微量元素变化比较明显, Ba、Cr、Cu、Zn元素的含量比东海陆架沉积物中的含量要高,而Sr的含量明显低于东海陆架。对常微量元素的R型因子分析表明,常量元素SiO2、Al2O3、Fe2O3、MgO和K2O,微量元素Cr、Cu、Ni、Zn、Pb、Rb和Mn可代表陆源物质;常量元素CaO和微量元素Sr、Ba可代表生物源物质。岩芯沉积物以陆源物质为主,生源物质的贡献起次要作用。岩芯沉积物中稀土元素总量平均为169.87×10-6,并且轻稀土含量均高于重稀土,LREE/HREE平均值为10.14,表明了轻稀土对稀土总量的贡献远高于重稀土,沉积物富集轻稀土,反映了沉积物的陆源特征。 岩芯MD05-2908中全新世以来平均5m/ka的高沉积速率主要源于丰富的物质供应和适宜的沉积环境。岩芯细粒级沉积物中,地球化学特征表明沉积物主要来源于陆源碎屑物质,粘土矿物特征与台湾东部陆源物质相同;粗粒级沉积物中,重矿物含量及矿物特征也表明岩芯沉积物粗颗粒组分主要来自于近源沉积。台湾宜兰境内的兰阳溪每年携带约一千万吨冲积物入海成为研究区重要的物质来源。由于受到黑潮的强烈影响,逆时针涡流及底层反向流的存在是岩芯高沉积速率重要控制因素。因此,利用动力分选的粉砂组分可以用来示踪古洋流强度,结果显示,6.8ka以来黑潮的强弱波动频繁,并表现出一定的旋回性变化,频谱分析表明,其具有的千年尺度周期(1500a)、百年尺度周期(604a、242a、192a、153a、133a)与十年尺度周期(22a)的周期性变化均与太阳辐射量变化有密切关系,因此,黑潮的强弱变化在大背景上是由太阳活动所控制的。 根据测年资料可以识别出岩芯存在5期快速堆积事件,这与区域性降水增加有关,降雨量增加导致陆源物质输入的增加。另外,岩芯位于大陆斜坡区,附近存在有三支海底峡谷,并且地震活动频繁,沉积在宜兰陆架及东海陆架处的浅海沉积物由于受到地震、风暴等活动的影响而受扰动崩塌、因重力作用而向低处输送,产生二次侵蚀并经由海底峡谷搬运到冲绳海槽南段堆积,使得沉积环境更为复杂,但同时也为冲绳海槽提供了丰富的物质供应。

Relevância:

80.00% 80.00%

Publicador:

Resumo:

沿海工农业生产的快速发展和人类活动对近海生态系统产生了很大影响,大量化肥的使用和工业污水、生活污水的排放导致近海环境污染,海水富营养化,赤潮频发。另外,由于近海养殖活动的迅猛发展以及养殖的不规范和不科学性导致近海生态系统结构和功能改变,一方面加重了海水富营养化,另一方面养殖动植物病害经常发生,严重影响了海产品的质量和效益。 大型海藻是海区重要的初级生产者,生命周期长、生长快,能通过光合作用吸收固定水体的C、N、P等营养物质来合成自身,同时增加水体溶解氧。因此,大型海藻被称为海洋环境中的生物过滤器。另外,由于大型藻类自身营养成分的复杂性和与藻共生的微生物多样性,大型海藻还可对生态系统中的浮游生物和微生物产生直接和间接影响。 在海洋环境,尤其是海水养殖水体环境存在着两个主要问题:海水富营养化和病源微生物控制,本文针对海洋环境中存在的这两个问题进行了探索研究。 以大型经济藻种长心卡帕藻(Kappaphycus alvarezzi)作为实验材料,分别在实验室内、室外藻类处理系统和海湾养殖现场三种条件下,进行藻类去除海水氮磷的一次性实验、半连续实验和连续实验,研究了其对海水中无机氮、无机磷的吸收速率和去除能力,初步评估了其生态价值。 构建了一种半封闭海域富营养化治理模式,以长心卡帕藻为实验材料,研究了其去除海水富营养化的能力,主要结果如下: (1)室内实验研究发现,长心卡帕藻对氮、磷的吸收速率随底物浓度升高而升高。在氮磷比为10:1,温度28℃条件下,氮浓度为50μmol • L-1时,藻对氮、磷的吸收速率达到最大,分别为0.93µmol • g-1(FW)• h-1和0.072µmol • g-1(FW)• h-1。 (2)人工修建的藻类养殖系统中进行的长心卡帕藻去除氮、磷的半连续实验,结果表明该藻具有连续去除海水DIN、DIP的能力。只要保持足够的底物浓度,长心卡帕藻对无机氮、无机磷的吸收速率达到最大,分别为0.3µmol • g-1(FW) • h-1和0.03µmol • g-1(FW)• h-1。但是对氮磷的吸收速率较室内实验有所降低。 (3)自然条件下,通过调查黎安海湾水质情况发现,长心卡帕藻具有较大的生态效益。在整个海湾大面积养殖卡帕藻,通过收获藻体,每年大约可以从海水中带走33吨氮素,7.5吨磷素。由于在海湾长心卡帕藻的作用,全年海湾水质保持在1-2级国家海水质量标准,产生了明显的生态效益。 另外,我们对大型藻类浒苔(Ulva clathrata)吸收氮磷和抑制鳗弧菌(Vibrio anguillarum)的效果进行了初步探索,结果表明:浒苔不仅对培养系统内无机氮和磷具有明显的去除作用,而且在异养细菌总量没有降低的情况下,对鳗弧菌有显著抑制作用,该抑制作用还受到水体中氮磷营养盐浓度的影响。在10g • L-1海藻的条件下,鳗弧菌以105-107 cfu • mL-1接入2天后,无论是否添加外源氮磷,鳗弧菌密度降到10 cfu • mL-1以下,鳗弧菌去除率几乎达到100%。实验数据还显示,添加氮磷营养盐可以增强浒苔对鳗弧菌的抑制作用,但没有降低其中的异养菌群数量,系统内异养细菌总量均维持在较高水平。进一步研究表明,培养浒苔24h后的海水,也对鳗弧菌65#产生抑制作用,这说明浒苔代谢释放到水体中某种化学成分或与藻共栖的微生物对鳗弧菌生长产生了抑制。

Relevância:

80.00% 80.00%

Publicador:

Resumo:

本研究应用显带技术和荧光原位杂交(Fluorescence in situ hybridization,FISH)技术,鉴定了牡蛎的染色体;应用FISH方法定位了一系列的重复序列和大分子的P1克隆DNA;制备了染色体特异性探针。应用FISH特异性探针成功地鉴定了长牡蛎的三体10。结果如下:1.分析了G带和C带在美洲牡蛎染色体上的分布。G带在每一条染色体上的带型不同,某些染色体间(如第1对和第4对染色体,第7对和第9对染色体)的带型差别不是很明显。G带型容易受染色体收缩程度的影响。C带型重复性较好,染色体带型较清楚,分布在染色体的端粒区域和着丝粒区域。G带和C带带型能够用来鉴定牡蛎的染色体,但是重复性低和带型差异不显著,并不适合常规的染色体鉴定。2.早期胚胎和担轮幼虫制备的染色体适合于FISH分析。染色体制备方法重复性好,可适用于其它贝类的染色体制备。3.研究了重复序列基因--rDNA的定位:1)18S-5.8S rDNA在研究的五种巨蛎属Crassostrea牡蛎均只有一个位 点。太平洋种(C.gigas,C. ariakensis和C. plicatula)中,杂交信号位于最短的染色体一第10对染色体长臂的端粒区域,在大西洋种(C. virginica和C. rhizophorae)中,同一序列定位在第2对染色体短臂的端粒区域。2)18S-28S rDNA在两种蛤中有两个位点。rDNA探针定位在侏儒蛤(Mulinis Lateralis)的第15对和第19对染色体的端粒区域,同一序列定位在硬壳蛤(Mercenaria mercenaria)的第10对染色体的长臂和第12对染色体短臂的端粒区域。信号强度在两对染色体之间有差异。 3)5s rDNA位于美洲牡蛎的第5对染色体的短臂上靠近着丝粒区域和第6 对染色体的短臂的中间区域。信号强度在两对染色体之间没有显著差异。5S rDNA探针可以作为鉴定和识别第5对和第6对染色体的特异性探针。4.研究了一些重复序列的定位1)两个短的重复序列1G8,1P2均产生很强的荧光信号分布在美洲牡蛎所有的染色体上。在低严谨条件下,这些序列均产生很强的信号散布在所有的染色体上。在高严谨条件下,信号强度大大减弱,但是信号仍散布在所有的染色体上。这些重复序列散布在美洲牡蛎的整个基因组中。2)高度重复序列Cgl70产生的信号分布在长牡蛎的7对染色体的着丝粒区域,没有发现间区信号。在第1对,第2对,第4对和第7对染色体上的荧光信号强且稳定。在第5对,第8对和第10对染色体上的信号相对弱且不稳定。在剩余的染色体上(第3对,第6对和第9对染色体)没有检测到荧光信号。结果表明此卫星序列是一个着丝粒卫星序列。在美洲牡蛎的染色体上没有检测到荧光信号,表明了这个着丝粒卫星序列在这两种牡蛎中的分布存在着显著的差异。3)脊椎动物端粒序列(TTAGGG)n的FISH信号局限在四种双壳贝类(美洲牡蛎,the mangrove oyster,硬壳蛤,侏儒蛤)所有染色体的端粒区域,没有发现间区信号的存在。研究结果与已报道的研究结果表明脊椎动物端粒序列或许存在于所有双壳贝类的染色体末端。双壳贝类是目前研究过的唯一含有脊椎动物端粒序列DNA的无脊椎动物。4)研究了RAPD探针在美洲牡蛎染色体上的定位。大多数RAPD探针产生了多个信号散布在间期细胞核和所有的染色体上。引物OPX-03,OPX-04,OPX—06,OPG-02,OPM—04,OPM-11,0PS-02制备的探针在适宜的条件下产生特异性荧光 信号,分布在牡蛎的特定的染色体上。PCR特异性带产生的探针OPX—06—310和0PG-02—300产生了特异性的荧光信号:OPX—06—310产生的信号位于第5对染色体的短臂的近端粒区域,0PG—02—300探针定位到第3对染色体的短臂上。这两个探针是鉴定美洲牡蛎单条染色体的特异性探针。5.研究了大分子Pl克隆DNA(插入片断为80~100 kb)在美洲牡蛎染色体上的定位。Pl克隆DNA通过切口平移方法标记digoxigenin—11-dUTP用作FISH的探针。Cot-1 DNA作为竞争剂有效地抑制了Pl克隆序列中的重复序列产生的信号。杂交信号用fluorescein标记的anti—digoxigenin抗体来检测,用两层抗体rabbit-anti-sheep抗体和FITC anti—rabbit抗体来扩增信号。9个P1探针成功地定位在特定的染色体上。46—1探针杂交到第1对染色体的长臂靠近着丝粒区域;47-10探针定位到第2对染色体的长臂近端粒区域;Cvpl和48-13两探针定位到第3对染色体上:Cvpl位于短臂的端粒区域,48-13探针位于长臂的近着丝粒区域;48—10探针杂交到第4对染色体的长臂上;48-1探针杂交到第5对染色体长臂的近着丝粒区域;49-11探针位于第7对染色体长臂上;探针49-10和44-11位于第8对染色体长臂上。同时我们成功地将2个P1探针杂交到同一染色体分裂相中,进一步确定了Pl探针在美洲牡蛎染色体 上的定位。6.应用18S-28S rDNA探针成功地鉴定出长牡蛎非整倍体中的三体10。经鉴定AF-35,AF-39和AF-3三体家系属于三体10家系。rDNA探针分布在三条染色体上,即多出的一条染色体为染色体10。相应地在间期细胞核上有三个信号出现。AF-34和AF-36家系不属于三体10家系。rDNA探针分布在两条染色体上,相应地在间期细胞核上有两个信号出现。FISH和染色体特异性探针为非整倍体的鉴定提供了一个快速准确可靠的方法和途径。

Relevância:

80.00% 80.00%

Publicador:

Resumo:

潮汐汊道是砂质海岸常见的沉积地貌单元,是海岸带与内陆架的重要组成部分,其作为港口航道、旅游、海水养殖等方面的资源的重要性早已被认识;但是,潮汐汊道的沉积动力行为、浅海物质循环与通量、全球变化的区域响应等方面的研究尚未充分开展。月湖是山东半岛东北角的一个小型的泻湖--潮汐汊道系统,已有4000年的历史,具有很高的科研、经济、生态、休闲旅游价值。历史上的月湖是比较稳定的,1979之后,由于人为活动的影响,月湖的物理环境和生态环境质量呈恶化趋势。研究月湖的沉积与水动力现状,分析其变化的地貌动力学原因,有助于理解小型潮汐汊道系统的沉积动力行为,重视海带海湾在全球物质循环中的作用,具有现实和理论的意义。1998年冬季和1999年夏季,在月湖进行了为期各一月的野外工作,采集了131个表层底质沉积样和9个岩芯,获得了冬夏各29天的潮位记录,观测了口门大小潮期间的潮位、潮流,并采集了同步的悬移质水样。在实验室分析测定了沉积物的粒度、颗粒态有机碳含量和~(210)Pb放射性活度,进行了粒径趋势分析和沉积速率估算。对潮位和潮流进行了调和分析,从湾内潮位记录推算出口门的干道垂线平均流速和断面平均流速,并计算了口门的推移质和悬移质的输运能力。在此基础上,结合历史资料(地形图、航片、前人的研究成果等),探讨了月湖的沉积物平衡、汊道稳定性、流不对称性、口门P-A关系等问题。另外,对于海岸带的海湾--泻湖系统在全球碳通量与碳循环过程中的作用进行了讨论。月湖是一个小而浅的潮汐汊道系统,面积4.94km~2,平均水深不足1m,无常年性淡水径流汇入。集水盆地属于低山丘陵地貌,面积15.2km~2。月湖表层沉积物以细颗粒物质为主,从岸到湖心逐渐变细,泥和砂质泥占湾内面积的40%以上;表层沉积物的平均粒径与沉积物类型有比较好的对应关系。~(210)Pb数据分析表明,湖心的沉积速率高达18.2mmyr~(-1),而湖区大部沉积速率在2-5mmyr~(-1)。从岩芯的垂向粒度变化所反映的信息来看,湖区的沉积速率大约是5-10mmyr~(-1)。朋湖的沉积物主要来自流域的坡面侵蚀、湖岸侵蚀、风尘沉降、生物物质、涨湖流带入的悬移质和推移质;整修湖区的沉积通量为10000-22000tyr~(-1)。粒径趋势分析表明,月湖的湾顶(西部与北部)、涨潮三角洲和湖心等地貌单元是沉积的优势区域。月湖的潮汐属不规则半日潮,潮差小,日不等现象明显,冬夏两季有显著差异;平均潮差0.50m,平均涨潮历时5小时19分,平均落潮历时7小时5分,平均纳潮量2.0 * 10~6 m~3。月湖口门的潮流是不规则半日潮流,涨急、落争流速可达1.0ms~(-1)以上;口门憩流时刻正对应湾内的高/低潮时,是典型的驻波。月湖的潮流具有独特的不对称性,口门的干道垂线平均流速的主要模式为落潮流速大于涨潮流速、且落潮历时长于涨潮历时,而断面平均流速以涨潮流优势型占微弱优势。这种现象出现的原因是月湖的不规则潮汐特征,以及口门的形态与潮位的特殊对应关系。其他潮汐汊道可能也存在类似的现象。月湖所处海域的波浪作用并不强烈,沿岸输沙强度较小。实测悬浮体浓度较低,在10~0-10~1 mg L~(-1)左右。用口门干道垂线平均流速计算,月湖的悬移质和推移质净输运均为向外海输出,悬移质的输运量不到推移质的1/10。但是,从沉积物平衡的角度分析,涨潮流带入的悬移质和推移质可能是月湖湾内沉积物的重要来源。人类活动对月湖的沉积过程可能有重大影响。从平均大潮纳潮量与沿岸毛输沙量的比值来看,月湖应属于稳定性相当好的潮汐汊道系统;如果仅考虑口门的形态及主干道的通畅性,这一判断是可以接受的。可以认为,月湖当前的物理系统是脆弱而稳定的,但其生态系统的稳定性和自适能力已经遭到了严重破坏。月湖湖心的颗粒态有机碳通量为0.34kgm~(-2)yr~(-1)。推而广之,仅就有机碳通量而言,整个黄、渤海沿岸的小型海湾具有和黄、渤海陆架泥区相同的数量级。因此,在碳循环研究中应充分注意海岸带海湾的贡献。均衡状态下的潮汐汊道系统,它的纳潮量与口门面积之间的确存在某种稳定的P-A关系。传统方法得出的P-A关系有其固有的不准确性。应用沉积动力学方法,每个潮汐汊道的P-A关系都受涨落潮历时、断面平均流速、口门形态(面积和宽深比)、纳潮量、淡水径流量、沿岸毛输沙量和沉积物粒度等因素的控制,对于上述因素的每一种组合,都有对应的均衡态P-A关系。均衡态潮汐汊道的P-A关系的指数应在1.15左右。