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1.
利用扫描电镜(SEM)观察了吉祥草(Reineckia carnea)(铃兰科)的花部器官发生发育过程。吉祥草花被片、雄蕊的发生方式是由近轴端向远轴端发生的逆单向型(reversed unidirection),花发育后期花被片合生形成花被筒,花丝与之贴生。伴随花被片、雄蕊发生,三枚心皮也由近轴向远轴方向相继发生,随后彼此合生发育。花序顶部的花易发生花器官数目变异。结合早期花原基形态以及花器官数目变异情况分析,吉祥草的花被片与雄蕊可能是由共同原基分化而成。从花部器官发生式样和花被筒形成时间两方面比较吉祥草属、白穗花属和铃兰属的特征发现,三属中,铃兰属处于相对进化的位置,而白穗花属比吉祥草属更为原始。  相似文献   

2.
在海拔4300m地区,对18名移居汉族、24名世居藏族和21名高原红细胞增多症(HAPC)患者测定了2,3—二磷酸甘油酸(2,3—DPG)和肺通气功能,并进行了血气分析。结果显示:HAPC患者的全血和红细胞内2,3—DP6浓度均显著高于健康组,但世居、移居健康组之间无明显差异。HAPC组的红细胞2,3—DPG和Pdo_2呈显著负相关(r=—0.771,P<0.01),而在健康组无显著相关(r=—0.26,P>0.05)。HAPC组与健康组相比,pH、Pao_2和Sao_2降低,Paco_2和肺泡动脉氧分压差增高。HAPC病人P_(50)为3.75±0.66kPa,健康组为3.40±0.12kPa(P<0.05),P_(50)与2,3-DPG呈正相关(r=0.592,P<0.05)。HAPC组最大呼气中段流量和50%肺活量最大呼气量明显低于健康组(P<0.01)。本研究提示:①HAPC患者的低氧血症可能与血中2,3-DPG浓度过高有关;②轻度肺功能异常亦可促使红细胞进一步增多。  相似文献   

3.
渐危植物鹅掌楸的授粉率及花粉管生长   总被引:7,自引:0,他引:7  
对鹅掌楸Liriodendron chinense 3个自然居群连续3年直接统计落置柱头上的花粉量,其中 61.9%以上的柱头接受了花粉。每柱头上的平均花粉量为4.4~42.6粒,明显超过胚珠数2。授粉率是 结实率的6~8倍,鹅掌楸结实率低的主要原因可能不是由于花粉的限制。落置柱头的花粉几乎均可萌 发,少数花粉管穿过花柱道,经珠孔端进入胚囊,暗示花粉间存在着强烈的竞争。授粉率和柱头上的平 均花粉量与结实率呈正相关(R=0.77,R=0.69)。在柱头上人工授同株和异株的花粉,花粉管生长速 率看不出明显差异,到达胚珠的时间在48~60 h之间。花开花药未裂时柱头上落置较高比例的花粉, 由于先期到达柱头的花粉最有可能受精,表明鹅掌楸有异交为主的繁育系统。人工处理包括套袋、套网、去除花被片,其结实率大大降低,而去雄后的结实率接近自然传粉结实率支持了这一观点。  相似文献   

4.
应用细胞培养、3H-TdR和3H-Leucine掺入方法,观察血小板生长因子BB(Platelet-derivedGrowthFactorBB)对体外培养兔肺动脉平滑肌细胞DNA和蛋白质合成的影响。结果表明:(1)当PDGF-BB浓度为10ng/ml时,3H-TdR掺入值已较对照组显著增高(6262.5±412.9vs833.5±124.0,P<0.05);当PDGF-BB浓度为20ng/ml时,3H-Leucine掺入值亦较对照线显著增高(10212.8±638.3vs7340.3±1197.9,P<0.05)。(2)PDGF-BB浓度在5-25ng/ml范围内,3H-TdR,3H-Leucine掺入值与剂量直线相关(rDNA=0.97,rprot=0.90P<0.05)。说明PDGF-BB刺激体外培养兔肺动脉平滑肌细胞DNA和蛋白质合成。  相似文献   

5.
渐危植物鹅掌揪的授粉率及花粉管生长   总被引:6,自引:0,他引:6  
对鹅掌揪Liriodendronchinense3个自然居群连续3个直接统计落置柱头上的花粉量,其中结实率在6-8倍,鹅掌揪结实率低的主要原因可能不是由于花粉的限制,落置柱头的花粉几乎均可萌发,少数花粉管穿过花柱道,经珠孔端进入胚囊,暗示花粉间存在的强烈的竞争,授粉率和柱头上的平均花粉量与结实率呈正相关(R=0.77,R=0.69)在柱头上人工授同株和异株的花粉,花粉管生长速率看不出明显差异,到达  相似文献   

6.
在海拔4300地区,对18名移居汉族、24名世居藏族和21名高原红细胞增多症(HAPC)患者测定了2,3-二磷酸甘油酸(2,3-DPG)和肺通气功能,并进行了血气分析。结果显示:HAPC患者的全血和红细胞内2,3-DPG深度均显著高于健康组,但世居、移居健康组之间无明显差异。HAPC组的红细胞2,3-DPG和Pao2呈显著负相关(r=-0.771,P<0.01),而在健康组无显著相关(r=-0\2  相似文献   

7.
山东四种草本植物的核型研究   总被引:5,自引:2,他引:3  
杨德奎   《广西植物》1998,18(1):41-44
本文对山东4种草本植物进行了染色体研究。结果表明:阿尔泰狗哇花(Heteropappusal taicus(Wild)Navopokr)的染色体数目为2n=36,核型公式为K(2n)=36=36m,核型“1A”型;求米草(Oplismenusundulatifolius(Arduino)RoemetSchult)的染色体数目为2n=12,核型公式为K(2n)=12=8m+4sm,核型“2A”型;红秋葵(Hibiscuscocineus(Medic)Walt)的染色体数目为2n=38,核型公式为K(2n)=38=14m+22sm+2st,核型“2B”型;蟋蟀草(Eleusineindica(L)Gaertn)的染色体数目为2n=18,核型公式为k(2n)=18=16m+2sm,核型“2A”型。  相似文献   

8.
七种药用植物的染色体研究   总被引:4,自引:1,他引:4  
杨德奎  周俊英   《广西植物》1998,18(2):115-118
对山东7种药用植物的染色体进行了研究。结果表明:田旋花(ConvolvulusarvensisL)的染色体数目为2n=78;蜜柑草(PhylanthusmatsumuraeHavata)的染色体数目为n=88;挂红灯(PhysalisalkekengiLvarfrancheti(Mast)Makino)的染色体数目为2n=24,核型公式为K(2n)=24=2m+18sm+2st+2st(sat),核型“2A”型;无剌曼陀罗(DaturastramoniumLvarinermis(Jacq)SchinzetThel)的染色体数目为2n=24,核型公式为K(2n)=24=20m+4sm,核型“1B”型;决明(CasiatoraL)的染色体数目为2n=26,核型公式为K(2n)=26=24m+2sm,核型“1A”型;荔枝草(SalviaplebeiaRBr)的染色体数目为2n=16,核型公式为K(2n)=16=6m+10sm,核型“2A”型;车前(PlantagoasiaticaL)的染色体数目为2n=36,核型公式为K(2n)=36=32m+4sm,核型“1A”型。  相似文献   

9.
阴山荠属和泡果荠属受试种类的染色体数目是:柔毛阴山荠(Y.henryi(Oliv.)Y.H.Zhang)2n=12,叉毛阴山荠(Y.furcatopilosa(Kuan)Y.H.Zhang)2n=12,双牌泡果荠(H.shuangpaiensisZ.Y.Li)2n=44,黟县泡果齐(H.yicianensisY.H.Zhang)2n=42,双牌泡果(H.pardoxa(Hance)Y.H.Zhan  相似文献   

10.
对欧洲及地中海地区燕麦草复合体27个居群的等位酸电泳调查表明,燕麦草复合体维持比较高的等位酶多样性(He=0.447,A=3.29),亚种间遗传分化较小(G(ST)=0.053);在四个亚种内,也维持着比较高的多样性(He:0.325—0.533),各亚种内的基因多样度主要存在于居群之内,居群间分化较小.四倍体的基因多样性高于二倍体的.燕麦草复合体内居群间基因流较高,表明燕麦草繁育方式主要为风媒远交.对Nei氏标准遗传距离的UPGMA聚类结果表明,四倍体是从二倍体有鳞茎的ssP.baeticum中产生的.  相似文献   

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It has now been over twenty years since a novel herpesviral genome was identified in Kaposi's sarcoma biopsies. Since then, the cumulative research effort by molecular biologists, virologists, clinicians, and epidemiologists alike has led to the extensive characterization of this tumor virus, Kaposi's sarcoma-associated herpesvirus(KSHV; also known as human herpesvirus 8(HHV-8)), and its associated diseases. Here we review the current knowledge of KSHV biology and pathogenesis, with a particular emphasis on new and exciting advances in the field of epigenetics. We also discuss the development and practicality of various cell culture and animal model systems to study KSHV replication and pathogenesis.  相似文献   

16.
Comprises species occurring mostly in subtidal habitats in tropical, subtropical and warm-temperate areas of the world. An analysis of the type species, V. spiralis (Sonder) Lamouroux ex J. Agardh, a species from Australia, establishes basic characters for distinguishing species in the genus. These characters are (1) branching patterns of thalli, (2) flat blades that may be spiralled on their axis, (3) width of the blade, (4) primary or secondary derivation of sterile and fertile branchlets and (5) position of sterile and fertile branchlets on the thalli. Application of the latter two characters provides an important basic method for separation of species into three major groups. Osmundaria , a genus known only in southern Australia, was studied in relation to Vidalia , and its separation from the Vidalia assemblage is not accepted. Species of Vidalia therefore are transferred to the older genus name, Osmundaria. Two new species, Osmundaria papenfussii and Osmundaria oliveae are described from Natal. Confusion in the usage of the epithet, Vidalia fimbriala Brown ex Turner has been clarified, and Vidalia gregaria Falkenberg, described as an epiphyte on Osmundaria pro/ifera Lamouroux, is revealed to be young branches of the host, Osmundaria prolifera.  相似文献   

17.
Fifteen chromosome counts of six Artemisia taxa and one species of each of the genera Brachanthemum, Hippolytia, Kaschgaria, Lepidolopsis and Turaniphytum are reported from Kazakhstan. Three of them are new reports, two are not consistent with previous counts and the remainder are confirmations of very scarce (one to four) earlier records. All the populations studied have the same basic chromosome number, x = 9, with ploidy levels ranging from 2x to 6x. Some correlations between ploidy level, morphological characters and distribution are noted.  相似文献   

18.
肝癌中HBV和HCV基因和抗原的分布及意义   总被引:1,自引:0,他引:1  
采用原位分子杂交方法检测HCV RNA及HBV X基因;采用免疫组织化学方法研究HCV核心抗原,非结构区C33c抗原及HBxAg在肝细胞肝癌中的定位及分布.结果表明(1)HCV RNA、HBV X基因在肝细胞肝癌组织检出率分别为40%(55/136)和82%(112/136).HCV RNA定位于癌细胞的胞浆内,阳性细胞呈散在、灶状及弥漫分布三种形式;HBV X基因在肝癌细胞中的分布呈胞浆型、核型及核浆型,阳性细胞也呈上述三种分布形式;(2)HCV C33c抗原、核心抗原在肝细胞肝癌中的阳性率为81%(133/164)及86%(141/164).C33c抗原定位于癌细胞及肝细胞的胞浆内;核心抗原既定位于癌细胞核中,又可定位于胞浆中.C33c抗原阳性细胞以灶状分布为主;而核心抗原阳性细  相似文献   

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For a plant selection model with frequency-independent viabilities, fertilities and selfing rates, it is shown that apart from global fixation, for certain parameter combinations a protected polymorphism and facultative fixation (either allele may become fixed according to initial frequencies) may both occur. Facultative fixation requires different selling rates for the dominant and recessive type. Protection of the polymorphism requires resource allocation for male and female function. In this connection the problem of purely genetically caused population extinction is discussed.
For general frequency dependence and regular segregation, the chances for establishment of a completely recessive gene are compared to those of a completely dominant gene. It is proven that the process of establishment of the recessive gene, despite a fitness advantage, may be considerably endangered by drift effects if random mating prevails. The recessive gene may reach the same effectivity in establishment as a dominant gene, only if the recessive homozygote mates exclusively with its own type during the period of establishment.  相似文献   

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