农杆菌介导的玉米自交系愈伤组织转化条件的优化

采用农杆菌介导法,将外源基因导入玉米骨干自交系掖515和掖502胚性愈伤组织并再生玉米植株。在农杆菌浸染玉米胚性愈伤组织过程中,采取真空渗入、部分酶解和超声波处理,可以显著提高转化率。农杆菌浸染玉米胚性愈伤组织时,在50kPa下真空渗入5min,掖515和掖502胚性愈伤组织的转化率分别从6.3％和4.5％提高到8．7％和7．8％。愈伤组织在农杆菌浸染前,以0．2％离析酶酶解10min,掖515和掖502胚性愈伤组织的转化率分别提高到8.3％和8．9％。在农杆菌浸染时,以功率100W超声波处理90-120s,掖515和掖502胚性愈伤组织的转化率最高可达9．1％和9．4％。     

兔眼越桔幼苗胚轴、子叶诱导再生植株

植物名称:兔眼越桔(Vaccinium ashei)材料类别:无菌苗胚轴、子叶。无菌苗培养:种子用70％酒精浸泡1分钟后,转移到10％的漂白精片过滤液中灭菌15分钟,再用无菌水冲洗三次,接种于0.5％琼脂上,培养温度为25～28℃,光强为2,000lx,每日光照16小时。培养3～4周后幼苗高约2～3cm,子叶绿色。于无菌条件下取子叶、胚轴(5～7mm)作为外植体进行诱导培养。     

一种鉴定金花茶人工杂交F_1代杂种苗的简易方法

本试验选用了两个以金花茶作父本的人工杂交组合F_1代实生苗,经根尖体细胞染色体观察鉴定四倍体杂种。一、云南野山茶(Camellia pitardii var.yunnanica六倍体)×金花茶(C.Chrysantha二倍体)。结果为:所获56株子叶和下胚轴为红色的F_1代杂种苗中,有55株(98.2％)是真正的四倍体杂种(X~2=0.0128,D.f.=1,0.95>p>0.90);所获50株子叶和下胚轴为黄白色的杂种苗中,有13株(26％)为真正四倍体杂种(X~2=27.38,D.f.=13,0.02>p>0.01)。二、云南山茶花(C.reticulata六倍体)×金花茶。结果为:在78株子叶和下胚轴为红色的杂交苗中,有77株(98.7％)为真正四倍体杂种(X~2=0.0128,D.f.=1,0.95>p>0.90);而在78株子叶及下胚轴为黄白色的杂种苗中,只有21株(26.9％)是真正四倍体杂种(X~2=41.65,D.f.=24,0.02>p>0.01) 在多数杂种实生苗中的这种红色素,是因种子直感现象而发生的父本金花茶的一种遗传性状。金花茶的另一特征——多子叶现象(3枚以上),则在一些F_1代杂种苗或杂种种子中表现得不明显。因此,利用F_1代杂种苗子叶和下胚轴所具有的红色特征,在杂种种子萌发期用来鉴别以金花茶为亲本的F_1代杂种的真伪,是一种简便、快速的、有发展前途的方法。     

菘蓝子叶和下胚轴的离体培养

植物名称:菘蓝(Isatis indigotica)。材料类别:子叶和下胚轴切段。培养条件:诱导分化与生长培养基为MS KT2mg/L(单位下同) NAA0.2;诱导生根培养基为B_5 NAA1 IAA1。培养温度25±2℃,每天光照10h,光照度为20001x。生长与分化情况:外植体培养7d后,切口处开始形成少量白色愈伤组织,10d后子叶切块开始分化出绿色的小芽;15d后下胚轴上也开始分化不定芽。20d后统计芽的诱导率为:子叶69.6％,下胚     

大别山五针松子叶和下胚轴离体培养成苗

植物名称:大别山五针松(Pinus dabeshanensis) 材料类别:子叶和下胚轴。种子冷水浸种24小时,剥去种壳,经0.1％升汞(8分钟)和70％酒精(0.5分钟)表面灭菌后,用无菌水冲洗5遍,接种到MS培养基上发芽。2周后,根长至0.5～1cm,剥去胚乳,切取子叶和下胚轴培养。培养条件:基本培养基为改良的MS(MS无机成分中NH_4NO_3浓度减低到1/4,KNO_3为1/2;有机成分改为VitB_1 0.4mg/L、甘氨酸2mg/L)和     

种子萌发出苗过程中胚轴的伸长和胚根的发展

在讲种子的萌发时,对胚各部分的发展变化,曾听到过如下的解释:胚轴发育成植物的主茎,胚根发展成植物的根系.这样说是否确切呢?下面谈谈与此有关的问题. 一株植物的主茎是否完全由胚轴发育而成的问题,了解了胚轴伸长的情况,就很容易得到答案.大家知道,双子叶植物种子胚中的胚轴以子叶为界可区分为两部分:子叶以下与胚根连接的部分叫下胚轴,从子叶着生位置以上至第一真叶着生处之间的部分叫上胚轴.单子叶植物常见的禾本科种子胚的胚轴则可区分为下胚轴(子叶即盾状体着生处以下与胚根连接的部分)、中胚轴(盾状体着生处以上至胚芽鞘着     

马铃薯实生苗子叶及下胚轴原生质体培养研究

用马铃薯普通栽培种（Ｓｏｌａｎｕｍ ｔｕｂｅｒｏｓｕｍ Ｌ．）３ 个品系的实生苗刚展开的子叶及下胚轴游离和培养原生质体。实验结果表明,子叶及下胚轴原生质体的分裂频率显著地高于经多次继代繁殖的试管苗顶部幼嫩叶片和茎尖的原生质体;在强连续光照下培养的实生苗,其原生质体的产量和质量都显著地高于弱光下培养的;在完全黑暗下培养的黄化实生苗不能游离出完整的原生质体;酶解前对子叶及下胚轴切段在酶液中进行真空渗透处理能显著地提高原生质体的产量,但此种处理对试管苗叶片无明显效果;下胚轴原生质体的产量显著地高于子叶,但在原生质体的质量方面,这两种组织间无明显的差异     

白皮松后期胚发育的研究

白皮松成熟胚的显著特点是苗端发达,胚苗端的H／D(高度与直径)比率平均为0.83, 有时达0.96,为松柏类植物所罕见。它的苗端可分为四个细胞区：顶端原始细胞、中央母细 胞、周缘组织和肋状分生组织区。在肋状分生组织与下胚轴的髓之间,有一过渡组织区。 从成熟胚的结构来看,松科成熟胚基本上可以分为3种类型：1．子叶特别发达,但下胚轴短; 2．下胚轴与根冠近等长; 3．下胚轴比较发达,白皮松就是这种类型。     

荞麦组织培养及高频植株再生体系的建立

通过对荞麦(Fagopyrum esculentum Moench)不同外植体、不同激素配比的比较研究,建立了荞麦离体培养高效植株再生体系。荞麦子叶切段在含2．0 mg/L 2,4-D和1．0 mg/L 6-BA的MS培养基上愈伤组织诱导率为89．6％,而下胚轴切段在含2．0 mg/L 2,4-D和1．0-2．0 mg/L 6-BA MS培养基上愈伤组织诱导率高达100％。在2．0 mg／L 6-BA、0．1 mg,L IAA和1 mg／L KT的MS培养基上通过愈伤组织间接分化或外植体直接分化形成不定芽。来自子叶和下胚轴的愈伤组织的分化率分别为42．5％和73．6％,下胚轴的分化率明显高于子叶。将生长状态良好的不定芽转至含1．0 mg/L IBA和0．5mg/L NAA的1/2 MS培养基上生根,生根率达到100％。再生植株移栽到盆土中,成活率达91．6％,并且生长状态和特征均表现正常。     

油橄榄下胚轴诱导完整植株

油橄榄离体茎培养出根已有报道,但无诱导完整植株的试验结果。我们以油橄榄下胚轴、子叶、胚根、嫩茎、茎尖和叶片等作为外植体进行了试验,除从茎尖诱导发生小植株外(待发表),在下胚轴上也已诱导出完整植株。从甘蓝下胚轴诱导发生小植株已有报道,本文就油橄榄下胚轴诱导完整植株作简要报道。油橄榄(Olea europaea L.)种子经消毒处理后,通过无菌培养得到无菌苗。在幼苗下胚轴伸长到2—3厘米时,在无菌条件下切除茎尖、子叶     

Photoregulation of seed germination of wild-type and of an aurea-mutant of tomato

Seed germination of an aurea mutant of tomato ( Lycopersicon esculentum Mill.) is promoted by continuous irradiation with red, far-red or long-wavelength far-red (758 nm) light as well as by cyclic irradiations (5 min red or 5 min far-red/25 min darkness). Far-red light applied immediately after each red does not change the germination behaviour. Seed germination of the isogenic wild-type, cv. UC-105, is promoted by continuous and cyclic red light while it is inhibited by continuous and cyclic far-red light and by continious 758 nm irradiation. Far-red irradiation reverses almost completely the promoting effect of red light. The promoting effect (in the aurea mutant) and the inhibitory effect (in the wild-type) of continuous far-red light do not show photon fluence rate dependency above 20 nmol m⁻² s⁻¹. It is concluded that phytochrome controls tomato seed germination throgh low energy responses in both the wild type and the au mutant. The promoting effect of continuous and cyclic far-red light in the au mutant can be attributed to a greater sensitivity to P_fr.     

六种藓类植物茎的比较解剖学研究

通过对6种藓类植物,即褶叶青藓(Brachythecium salebrosum(Web.et Mohr.)B.S.G.)、湿地匐灯藓(Plagiomnium acutum(Lindb.)Kop.)、侧枝匐灯藓(Plagiomnium maximoviczii(Lindb.)Kop.)、大凤尾藓(Fissidensnobilis Griff.)、大羽藓(Thuidium cymbifolium(Doz.et Molk.)B.S.G.)和大灰藓(Hypnum plumaeforme Wils.)嫩茎和老茎的石蜡切片和显微观察发现,同一藓类植株的嫩茎和老茎,茎结构稳定,不同种藓类植物茎横切面具有不同特征.植物体茎横切面形状、表层细胞的层数、细胞大小和细胞壁厚薄、皮层细胞大小和形状、中轴的有无以及比例等特征可以作为藓类植物的分科分类依据之一.     

Interconnection of parameters of regulation system of lipid peroxidation and of morphophysiological parameters of mouse liver

A complex analysis of seasonal fluctuations of the mean group parameters of the system of regulation of lipid peroxidation has been performed in liver of Balb/c mice. Association of lipid characteristics and morphophysiological parameters is studied in the Balb/c mouse liver. An inter-connection is revealed between the liver index and the amount of lysoforms of phospholipids, the scale and character of the interconnection differing essentially depending on proportion of phos-phatidylcholine in mouse liver phospholipids.     

History of the discovery of the mode of transmission of yellow fever virus

This essay documents and examines the historical circumstances and events surrounding the discovery of the mode of transmission of yellow fever virus in Cuba. Close scrutiny of the articles published by Walter Reed and his colleagues in 1900, 1901 and 1902 reveals their limitations as historic documents. Fortunately, other sources of information from that period survive in letters and documents written by individuals involved in the quest for the mode of transmission. Examination and comparison of those sources of information unveiled a fascinating story which reveals that misunderstandings engendered by published articles accorded merit where it was not fully due.     

Physiological characteristics of various species of strains of carboxydobacteria

Seven strains of aerobic carbon monoxide-oxidizing bacteria (carboxydebacteria) when growing on CO as sole source of carbon and energy had doubling times which ranged from 12–42 h. The activity profiles obtained after discontinuous sucrose density gradient centrifugation indicated that the CO-oxidizing enzymes are soluble and the hydrogenases are membrane-bound in all strains examined. The CO-oxidizing enzymes of Pseudomonas carboxydohydrogena, Pseudomonas carboxydoflava, Comamonas compransoris, and the so far unidentified strains OM2, OM3, and OM4 had a molecular weight of 230,000; that of Achromobacter carboxydus amounted to 170,000. The molecular weights of the CO-oxidizing and H₂-oxidizing enzymes turned out to be identical. The cell sonicates were shown to catalyze the oxidation of both CO and H₂ with methylene blue, thionine, phenazine methosulfate, toluylene blue, dichlorophenolindophenol, cytochrome c or ferricyanide as electron acceptors. Methyl viologen, benzyl viologen, FAD⁺, FMN⁺, and NAD(P)⁺ were not reduced. The spectrum of electron acceptors was identical for all strains tested. Neither free formate, hydrogen nor oxygen gas were involved in the CO-oxidation reaction. Methylene blue was reduced by CO at a 1:1 molar ratio. The results indicate that CO-oxidation by carboxydobacteria is catalyzed by identical or similar enzymes and that the reaction obeys the equation CO+H₂OCO₂+2H⁺+2e^- as previously shown for Pseudomonas carboxydovorans.Dedicated to Otto Kandler remembering almost three decades of enjoyable cooperation     

Modulation of allostery of pyruvate kinase by shifting of an ensemble of microstates

Since the introduction of the concepts of allostery about four decades ago, much advancement has been made in elucidating the structure-function correlation in allostery. However, there are still a number of issues that remain unresolved. In this review we used mammalian pyruvate kinase (PK) as a model system to understand the role of protein dynamics in modulating cooperativity. PK has a triosephosphate isomerase (TIM)(α/β)₈ barrel structural motif. PK is an ideal system to address basic questions regarding regulatory mechanisms about this common (α/β)₈ structural motif. The simplest model accounting for all of the solution thermodynamic and kinetic data on ligand-enzyme interactions involves two conformational states, inactive E^T and active E^R. These conformational states are represented by domain movements. Further studies provide the first evidence for a differential effect of ligand binding on the dynamics of the structural elements, not major secondary structural changes. These data are consistent with our model that allosteric regulation of PK is the consequence of perturbation of the distribution of an ensemble of states in which the inactive E^T and active E^R represent the two extreme end states. Sequence differences and ligands can modulate the distribution of states leading to alterations of functions. The future work includes: defining the network of functionally connected residues; elucidating the chemical principles governing the sequence differences which affect functions; and probing the nature of mutations on the stability of the secondary structural elements, which in turn modulate allostery.     

真菌类遗传学分析的知识结构教学

本文以认知结构理论为指导,讨论了真菌类遗传分析与高等动植物遗传分析的内在联系,认为利用这种内在联系进行教学可收到好的效果并说明了作者的具体教学过程。 Abstract:In the paper, the relationship between genetic analysis of Fungi and genetic analysis of high animal and plant was discussed.A good results were obtained when we adopted this method in the teaching.     

（鱼句）亚科花（鱼骨）型鱼类骨骼系统的比较

对我国花型Hemibarbuspattern鱼类作了骨骼系统比较,结果表明,此类型鱼类脑颅较长,副蝶骨平直或稍弯曲,眶蝶骨腹纵嵴发达(铜鱼Coreius septentrionalis例外),下颞窝和咽突中等大,基枕骨后突发达;脑颅中的上筛骨的后突、侧筛骨的外筛突,蝶耳骨的外突、上耳骨的后突、围眶骨和后颞窝等均有明显的差异;咽颅中的舌颌骨、尾舌骨、鳃盖骨和下咽齿的列数等又有显著的区别;附肢骨骼中的腰带骨、脊椎骨中的复合神经骨和第4椎骨腹侧的悬器等也有不同之处。据此,这些差异和区别可作为属间或种间的分类依据。