山丹不同居群花粉形态研究

为掌握山丹居群在孢粉学方面的遗传多样性,在扫描电子显微镜下对25个居群的山丹花粉进行了形态观察,结果表明:山丹花粉粒形态为单花粉粒,极面观为椭圆体,具单萌发沟。不同居群的花粉粒在大小、网眼直径、萌发沟宽、P/E值和外壁纹饰等方面存在不同程度的差异,且居群间花粉性状的变异大于居群内的变异,最大变异系数达25.52%。     

六个不同类型荞麦花花粉粒形态的电镜观察比较研究

对二倍体甜荞长花柱类型 (ES2 s)、二倍体甜荞短花柱类型 (ES2 S)、四倍体甜荞长花柱类型 (ES4s)、四倍体甜荞短花柱类型 (ES4S)、四倍体有翅细野荞 (GR4HI)、四倍体无翅细野荞 (GR4HO)等 6个不同荞麦类型花的花粉形态学进行了电镜观察。结果表明 :这些荞麦类型的花粉粒都是椭圆形 ,都有网状纹饰、3孔沟等特征。二倍体甜荞染色体加倍后形成的四倍体甜荞 ,相对于二倍体甜荞而言 ,花粉粒显著增大和明显变圆。无论二倍体还是四倍体甜荞 ,其长花柱型花的花粉粒都比其对应短花柱型花的花粉粒要小。尽管四倍体甜荞和四倍体细野荞在染色体数目和倍性上一样 ,但是它们在花粉粒的大小上有显著差异。四倍体细野荞有翅类型和无翅类型的花粉粒大小和形态差异不显著     

安徽特有植物安徽羽叶报春的繁殖生物学研究

本文分别从物候、繁育结构和传粉等方面研究了国家三级保护植物、安徽特有种--安徽羽叶报春(Primula merrilliana)的繁殖生物学特征。研究结果表明: (1) 安徽羽叶报春是典型的形态和功能意义上的花柱二型的二年生植物, 其始苗期为9月, 一直持续到第二年6月底或7月初死亡, 各居群长柱花植株比短柱花植株开花略早3–5 d; (2) 安徽羽叶报春的散孔型花粉显示其在报春花属中有重要的系统意义和进化意义。同时, 短柱花花粉量比长柱花少, 但其花粉直径是后者的1.78倍左右; (3) 长花柱的雌蕊长度是短花柱的1.64倍, 而且其柱头上的乳头状突起比短花柱上的长而稀; (4) 3个研究居群的P/O比都不相同, 我们发现花粉量比胚珠数量有更大的变异, 这可能与生境有关; (5) 安徽羽叶报春为异花授粉植物, 蓟马属(Thrips)昆虫为其重要的传粉者, 其同型花授粉可育性远比异型花授粉的高; (6) 其长、短柱型种子没有明显的形态差异, 多属不等边七面体, 少为其他多面体。据研究, 在小居群中两种花柱类型植株的比例失衡, 生境的破坏和伴生种的消失可能是导致安徽羽叶报春濒危的重要原因。     

中国独行菜属9种植物花粉形态扫描电镜观察

对中国产独行菜属9种植物的花粉微形态作了扫描电镜下的观察和研究。结果表明,花粉粒为超长球形或长球形,具三沟,外壁纹饰均为网状纹饰。根据外壁纹饰可分为3种类型：（1）网眼为不规则形状,网眼边缘常有刺突;（2）网眼为圆形或近圆形,网眼边缘较光滑;（3）网眼为多边形或不规则多边形,网眼边缘较光滑,偶有刺突。     

12种十字花科植物花粉形态研究

采用扫描电子显微镜对十字花科8属12种植物的花粉形态特征进行了观察分析.其中8种为首次报道.观察结果表明:4族8属12种十字花科植物花粉形态的一般特征为:花粉粒长球形至超长球形;极面观三裂圆形,少数四裂圆形;外壁纹饰为网状或细网状纹饰;三沟,偶四沟.12种植物的花粉可划分为5种类型:(1)花粉粒长球形,网状纹饰,三沟;(2)花粉粒超长球形,网状纹饰,三沟;(3)花粉粒长球形,细网状纹饰,三沟;(4)花粉粒超长球形,细网状纹饰,三沟;(5)花粉粒长球形,三或四沟,网状纹饰.十字花科花粉形态特征在不同族间、不同属间以及同属不同种间均没有明显规律,在十字花科分类过程中,不宜单独以花粉形态特征作为依据.     

中国蓼科萹蓄属植物花粉形态及其分类意义

利用扫描电镜研究了中国萹蓄属(Polygonum) 13种、1变种、1变型植物的花粉形态.结果表明,中国萹蓄属植物的花粉粒为长球形或超长球形,具三孔沟,外壁纹饰可分为4种类型(1)花粉粒表面具细网状纹饰;(2)花粉粒表面具颗粒纹饰;(3)花粉粒表面仅两端具颗粒纹饰,其余部分光滑;(4)花粉粒表面仅沟间区两端肩部光滑,其余部分具颗粒纹饰.根据花粉形态类型,结合该属植物的习性、叶柄基部及花柄上关节的有无、花柱和柱头的数目以及瘦果形态等特征,参照前人的研究处理意见,将中国萹蓄属植物划分为4个组,即小灌木组section Fruticulosae (Boiss.) F.Z.Li et Y.T.Hou,stat.& comb.nov.、萹蓄组section Polygonum、丝茎萹蓄组section Pseudomollia Boiss.和铁马鞭组section Plebeia Tzvel..     

国产爵床科山牵牛属6种、叉柱花属和老鼠簕属各1种植物的花粉形态

报道了国产爵床科Acanthaceae山牵牛属Thunbergia(山牵牛亚科Thunbergioideae)6种、叉柱花属Staurogyne(瘤子草亚科Nelsonioideae)和老鼠簕属Acanthus(老鼠簕亚科Acanthoideae)各1种植物在扫描电镜下的花粉形态。山牵牛属植物的花粉粒为圆球形,均具螺旋状萌发孔,外壁纹饰以光滑或颗粒状为主,偶具棒状突起。具螺旋状萌发孔被认为是该科独特而较原始的花粉特征。叉柱花属的花粉粒为圆球形,具3孔沟,外壁平滑。老鼠簕属的花粉粒为长球形,具3沟,外壁具细网状纹饰或具小穿孔。花粉形态特征支持传统上将上述3属置于3个不同亚科的处理。     

中国木犀科花粉形态研究

本文利用扫描电子显微镜和光学显微镜研究国产的木犀科花粉共11属、26种。根据花粉粒大小和外壁纹饰本科花粉可分为两个主要类型:第一类型为花粉粒较大,外壁网状纹饰粗;第二类型为花粉粒较小,外壁网状纹饰细。从花粉形态特征看本科花粉第一类型类似于金缕梅科的蜡瓣花属 Corylopsis;第一类型类似于金缕梅科的金缕梅属 Hamamclis 和木属Loropetalum。     

国产爵床科芦莉花族植物的花粉形态

报道了国产爵床科Acanthaceae芦莉花族Ruellieae芦莉花亚族Ruelliinae 2属7种、假杜鹃亚族Barlerinae 1属3种和马蓝亚族Strobilanthinae 16属34种植物扫描电镜下的花粉形态.芦莉花亚族的地皮消属Pararuellia和喜花草属Eranthemum的花粉均为圆球形,具3孔或3孔沟,外壁为不同的网状结构; 假杜鹃亚族的假杜鹃属Barleria的花粉为长球形,具3孔沟,外壁亦为网状结构;马蓝亚族植物(包含广义的马蓝属Strobilanthes s.l.)花粉形态多样,结构复杂.依据花粉萌发孔和外壁纹饰特征,可将马蓝亚族16属植物和上述两亚族3属植物的花粉形态归纳成3大类型: 1. 具3孔类型.其中又有(1)外壁具网状纹饰者,见于地皮消属; (2)外壁具芽胞状纹饰者,见于黄猄草属Championella; (3)外壁具刺状(棒状)纹饰者,见于南一笼鸡属Paragutzlaffia、叉花草属Diflugossa和假蓝属Pteroptychia.2. 具3孔沟及具3孔沟与假沟类型(肋条带型).其中又有(1)具3孔沟和网状纹饰者,见于喜花草属和假杜鹃属; (2)具刺状(棒状)纹饰者,见于南一笼鸡属、叉花草属和假蓝属; (3)具3孔沟与假沟,外壁纹饰具节隔、肋条带状或网状,网眼纵向排列成行,网眼内有细网纹者,见于耳叶马蓝属Perilepta、马蓝属Pteracanthus(大部分)、金足草属Goldfussia、紫云菜属Strobilanthes(部分)和合页草属Sympagis; (4)具3孔沟与假沟类型,肋条带状,但不具节隔,外壁纹饰网状,网眼不成行或不明显纵向排列,网内无细网纹者,见于尖蕊花属Aechmanthera、板蓝属Baphicacanthus、马蓝属(部分)和糯米香属Semnostachya; (5)具双脊及细网状纹饰者,见于环毛紫云菜Strobilanthes cycla.3. 具(4-)5孔沟及假沟类型(肋条带型),外壁具网状或拟网状纹饰,见于腺背蓝属Adenacanthus.另外兰嵌马蓝属Parachampionella、山一笼鸡属Gutzlaffia和肖笼鸡属Tarphochlamys的花粉有无萌发孔尚不清楚,有待进一步研究.综上所述,芦莉花族植物的花粉形态具有较高的多样性,是重要的分类性状.利用花粉形态特征能较好地区分高级分类群如亚科、族以及亚族,有时也有助于阐明类群之间的相互关系,甚至也能用于区分属、种和阐明其关系.     

国产爵床科鳞花草族1属、穿心莲族2属和爵床族8属植物的花粉形态

报道了中国爵床科Acanthaceae爵床亚科Ruellioideae鳞花草族Lepidagathideae 1属、穿心莲族Andrographideae 2属和爵床族Justicieae 8属共14种植物的花粉形态。根据花粉萌发孔类型和外壁纹饰特征,可将这些植物的花粉归为4个类型: (1)具3孔沟,外壁具网状纹饰。该类型见于色萼花属Chroesthes (采自广西样品)和穿心莲属Andrographis植物。(2)具3孔沟及假沟(肋条带型)类型,外壁具网状纹饰,网眼纵向排列成行,网眼内有细网纹。该类型见于色萼花属(采自云南样品)和鳔冠花属Cystacanthus。(3)具3孔沟,沟两侧各有1条假沟,外壁具网状纹饰。该类型见于瑞丽山壳骨Pseuderanthemum shweliense、狗肝菜属Dicliptera和驳骨草属Gendarussa植物。(4)具2孔沟,沟两侧具斑块。该类型见于山壳骨属Pseuderanthemum 1种、纤穗爵床属Leptostachya、鳄嘴花属Clinacanthus、鸭嘴花属Adhatoda、杜根藤属Calophanoides和野靛棵属Mananthes植物。     

Curcuminoids as inhibitors of thioredoxin reductase: A receptor based pharmacophore study with distance mapping of the active site

Curcumin is the yellow pigment of turmeric that interacts irreversibly forming an adduct with thioredoxin reductase (TrxR), an enzyme responsible for redox control of cell and defence against oxidative stress. Docking at both the active sites of TrxR was performed to compare the potency of three naturally occurring curcuminoids, namely curcumin, demethoxy curcumin and bis-demethoxy curcumin. Results show that active sites of TrxR occur at the junction of E and F chains. Volume and area of both cavities is predicted. It has been concluded by distance mapping of the most active conformations that Se atom of catalytic residue SeCYS498, is at a distance of 3.56 from C13 of demethoxy curcumin at the E chain active site, whereas C13 carbon atom forms adduct with Se atom of SeCys 498. We report that at least one methoxy group in curcuminoids is necessary for interation with catalytic residues of thioredoxin. Pharmacophore of both active sites of the TrxR receptor for curcumin and demethoxy curcumin molecules has been drawn and proposed for design and synthesis of most probable potent antiproliferative synthetic drugs.     

A Unique Protease Cleavage Site Predicted in the Spike Protein of the Novel Pneumonia Coronavirus (2019-nCoV) Potentially Related to Viral Transmissibility

正Dear Editor,In December 2019, a novel human coronavirus caused an epidemic of severe pneumonia(Coronavirus Disease 2019,COVID-19) in Wuhan, Hubei, China(Wu et al. 2020; Zhu et al. 2020). So far, this virus has spread to all areas of China and even to other countries. The epidemic has caused 67,102 confirmed infections with 1526 fatal cases     

Comparative morphology of the carpel in the Liliaceae: Hewardieae, Petrosavieae, and Tricyrteae

The young pistils in the melanthioid tribes, Hewardieae, Petrosavieae and Tricyrteae, are uniformly tricarpellate and syncarpous. They lack raphide idioblasts. All are multiovulate, with bitegmic ovules. The Petrosavieae are marked by the presence of septal glands and incomplete syncarpy. Tepals and stamens adhere to the ovary in the Hewardieae and the Petrosavieae but not in the Tricyrteae. Two vascular bundles occur in the stamens of the Hewartlieae and Tricyrtis latifolia. Ventral bundles in the upper part of the ovary of the Hewardieae are continuous with compound septal bundles and placental bundles in the lower part. Putative ventral bundles occur in the alternate position in the Tricyrteae and putative placental bundles in the opposite. position in the Petrosavieae. The dichtomously branched stigma in each carpel of the Tricyrteae is supplied by a bifurcated dorsal bundle.     

Entwicklungsgeschichte und Ultrastruktur von Pollenkitt und Exine bei nahe verwandten entomophilen und anemophilen Angiospermensippen derAlismataceae,Liliaceae, Juncaceae,Cyperaceae, Poaceae undAraceae

Some closely related members of the monocotyledonous familiesAlismataceae, Liliaceae, Juncaceae, Cyperaceae, Poaceae andAraceae with variable modes of pollination (insect- and wind-pollination) were studied in relation to the ultrastructure of pollenkitt and exine (amount, consistency and distribution of pollenkitt on the surface of pollen grains). The character syndromes of pollen cementing in entomophilous, anemophilous and intermediate (ambophilous or amphiphilous) monocotyledons are the same in principal as in dicotyledons. Comparing present with former results one can summarize: 1) The pollenkitt is always produced in the same manner by the anther tapetum in all angiosperm sub-classes. 2) The variable stickiness of entomophilous and anemophilous pollen always depends on the particular distribution and consistency of the pollenkitt, but not its amount on the pollen surface. 3) The mostly dry and powdery pollen of anemophilous plants always contains a variable amount of inactive pollenkitt in its exine cavities. 4) A step-by step change of the pollen cementing syndrome can be observed from entomophily towards anemophily. 5) From the omnipresence of pollenkitt in all wind-pollinated angiosperms studied one can conclude that the ancestors of anemophilous angiosperms probably have been zoophilous (i.e. entomophilous) throughout.

     

Identification and Characterization of the First Equine Parainfluenza Virus 5

正Dear Editor,Parainfluenza virus 5 (PIV5), known as canine parainfluenza virus in the veterinary field, is a negative-sense,nonsegmented, single-stranded RNA virus belonging to the Paramyxoviridae family (Chen 2018). The virus was first reported in primary monkey kidney cells in 1954 (Hsiung1972), then it has been frequently discovered in various     

Pathogenic Characterization and Full Length Genome Sequence of a Reassortant Infectious Bursal Disease Virus Newly Isolated in Pakistan

<正>Dear Editor,Infectious bursal disease (IBD) is one of the most important diseases of the poultry. The IBD virus (IBDV), a nonenveloped virus belonging to the Birnaviridae family with a genome consisting of two segments of double-stranded RNA (segments A and B), targets B lymphocytes of bursa of Fabricious leading to immunosuppression. In Pakistan,poultry farming is the second biggest industry and IBD is the second biggest disease threating the poultry sector.However, there is limited genome information of IBDV