中国连香树科的系统研究——Ⅱ.次生木质部的显微和超微结构

本文报道连香树木材解剖和扫描电镜研究结果,连香树木材特征较为原始,具导管和管胞,导管端壁斜、梯状穿孔板、具有超出穿孔板的三生螺旋加厚,管胞为原始的梯纹管胞,木纤维壁上具裂隙状纹孔,木薄壁组织离管型,星散状分布,木射线异型。     

四合木属四合木(蒺藜科)的木材解剖学研究

在光学显微镜和扫描电子显微镜下观察了蒺藜科四合木属四合木(Tetraena mongolica Maim.)木材结构.其导管分子直径小,管壁厚,分布密度高,分子短,端壁几乎水平,具单穿孔;管间纹孔为对列或互列的具缘纹孔;韧性纤维短、壁厚、壁上有较少的单纹孔;同型单列射线、分布密度高;轴向薄壁组织散生或傍导管生.这些表明四合木的木材解剖特征是与干旱环境条件是相适应的.     

中国木兰科香木莲和合果含笑木材解剖的初步研究

本文对中国木兰科的香木莲(Mangliaia aromatica Dandy)和合果含笑[Parami-chelia baillonii(Piene)]及其与邻近属的木材解剖特征进行了初步的研究。香木莲导管无螺纹加厚,无油脂细胞,无傍管薄壁组织,轴向木薄壁组织仅宽2—3列细胞,单列木射线多而高,多列射线主要为 Kribs 异形Ⅱ_A 型等特征都落入木莲属导管无螺纹,多列射线异形Ⅱ_A 型,无油细胞,轴向木薄壁组织2—6列等特征的幅度之内。合果含笑的单列木射线稀少至无,导管有螺纹加厚,有油细胞等特征。     

锦葵目蚬木属和柄翅果属的木材解剖学研究及其系统学意义

蚬木属(Excentrodendron H.T.Chang & R.H.Miau)与柄翅果属(Burretiodendron Rehder)的分离一直未得到广泛认同,二者在锦葵目中的系统地位也还不十分清楚.本文研究了柄翅果、元江柄翅果、滇桐和火绳树的木材解剖.柄翅果和元江柄翅果在木材解剖特征上非常相似,2～3个管孔组成径列复管孔,单管孔较多,导管分子无螺纹加厚,穿孔板单一,轴向薄壁组织稀少,射线异型IIB,单列射线少,多列射线常2～3列,具翅子树属型瓦形细胞;蚬木属单列射线罕见,瓦形细胞榴莲型,单列射线较高,木材解剖特征支持蚬木属和柄翅果属的分离;蚬木属和柄翅果属与滇桐属在木材解剖特征上差异显著,与火绳树属的差异也较明显,但与梧桐科翅子树属比较接近,与其它有关类群,如一担柴属、Luehea、Entelea以及Dombeyeae族等都有明显差异.     

广义锦葵科火绳树属4个种的枝条木材解剖及其分类学意义

研究了广义锦葵科火绳树属4个种枝条的木材解剖。火绳树属枝条为散孔至半环孔材,管孔主要为单管孔和2～3个管孔组成的径列复管孔;导管间纹孔式和射线导管间纹孔式互列、小;侵填体和螺纹加厚缺如。射线主要为单列射线,2～3列射线较多;射线细胞多为方形,射线组织主要为异型,边缘直立细胞常1行;射线组织稀为同型;鞘细胞和瓦形细胞缺如。轴向薄壁组织傍管和离管型,主要为带状。晶体丰富,主要在射线、纤维和薄壁组织中。研究的4个种可以通过枝条木材解剖特征加以区分。     

中国木兰科华盖木属的木材解剖和近缘属的关系

本文对最近在我国云南省西畴县热带雨林中发现的木兰科中的一个新的单种属——华盖木(Manglie-tastrum sinicum Law)的木材解剖特征进行首次报道:它具有较稀的管孔数目;单管孔占优势;导管侧壁具细螺纹加厚,底壁穿孔板横条数较多,为6—12枚,高达17枚;轴向薄壁组织轮界状,宽达9—12列细胞,还偶有稀疏傍管薄壁组织;木射线为Kribs异形ⅡA型,且在少数多列线中具略长的单列翼部分。这些解剖的,以及联系到外部形态特征,虽然和近缘的木莲属Manglietia Blume存在着一定的差别。但与本科其他各属比较,则又与“拟木莲属”(“Paramanglietia”Hu & Cheng)、香木兰属Aromadendron Blume、榻榔木属Talauma Juss.及木兰属Magnolia Linn.的多数种类,在木材构造中留存有较多的原始特征相类似。     

8种木本旱生植物的木质部解剖学特性研究

从生态学角度对8种旱生植物木材的次生木质部结构进行了对比研究.结果表明,8树种次生木质部结构的共同特点为:生长轮分界明显(霸王和四合木的年轮有时不连续),半环孔材,单穿孔,导管壁间纹孔互列,木纤维无横隔膜,联合傍管轴向薄壁组织丰富,导管壁上呈现螺纹加厚,都具有异型射线;它们主要差异在于射线和导管的数量化指标:四合木异型射线1~2列,霸王、白刺、沙冬青和胡枝子射线2~5列,柽柳、柠条和花棒大型射线4~10列;导管分子长度和纤维长度在树种间和同一树种个体间差异较明显.四合木和沙冬青导管频率较大,导管管孔较小,因此Vulnerability和Mesomorphy值也较小,更能适应干旱环境.     

扁担木叶片和次生木质部解剖和水分生理特征的可塑性

基于叶片和次生木质部解剖特征及水分生理指标观测,研究了淮北相山不同群落中扁担木的表型可塑性.结果表明,扁担木叶片结构表现出中生特点：叶为异面叶,较薄,角质层不甚发达,气孔密度较小.次生木质部表现出旱生特点：导管频率和复孔率较高,导管分子短而窄,纤维很短,射线很低.扁担木叶片、次生木质部的解剖和水分生理特征均表现出一定的可塑性,其可塑性指数高低顺序为次生木质部解剖特征（0.24）＞水分生理特征（0.19）＞叶片解剖特征（0.18）.与侧柏林和混交林相比,灌丛中扁担木个体对干旱生境有一定的适应能力,表现在次生木质部导管分子短,导管频率高,单孔率低,木纤维短,射线矮小,具有较大的相对输导率和较小的脆性指数;叶片水势、组织含水量、自由水含量较低,叶面积、比叶面积较小,而束缚水含量、束缚水自由水比值较高.扁担木的解剖和生理可塑性,使之能忍受群落演替早期的干旱生境,更好地适应演替后期的中生环境,从而成为广布种和混交林中的优势种.     

人工纯林和混交林中南酸枣木材解剖特性的比较分析

对林龄为25 a的南酸枣[Choerospondias axillaris (Roxb. ) Burtt et Hill]纯林、南酸枣-马尾松(Pinus massoniana Lamb. )混交林和南酸枣-杉木[Cunninghamia lanceolata (Lamb. ) Hook. ]混交林中南酸枣木材的解剖特性进行了比较分析.测定结果表明,在25 a的树龄内,南酸枣-马尾松混交林、南酸枣-杉木混交林和南酸枣纯林中南酸枣木材纤维的长度分别为0.843～1.401、0.858～1.489和0.873～1.347 mm,宽度分别为19.28～23.58、19.34～22.34和19.76～25.26 μm,长宽比分别为39.70～62.04、39.20～63.96和40.60～59.34;随树龄的增加,纯林和混交林中南酸枣木材纤维的长度、宽度及长宽比均逐渐增加,且不同林分间的差异逐渐达到显著水平,并以南酸枣-杉木混交林中南酸枣木材纤维的长度和长宽比最大、宽度最小.3种林分中南酸枣木材的导管组织比量、纤维组织比量和木射线组织比量分别为16.1%～16.7%、64.7%～65.2%和12.9%～13.4%,以南酸枣-杉木混交林中南酸枣木材导管组织比量和纤维组织比量最大,但差异均不显著;仅纯林的木材轴向薄壁组织比量(5.8%)显著高于混交林(5.1%和5.2%).随树龄的增加,3种林分中南酸枣木材微纤丝角均逐渐减小,南酸枣-马尾松混交林、南酸枣-杉木混交林和南酸枣纯林中南酸枣木材微纤丝角分别为23.33°～16.82°、 23.20°～16.36°和23.34°～17.41°, 且仅在树龄16～25 a阶段,混交林中的南酸枣木材微纤丝角显著小于纯林, 其中又以南酸枣-杉木混交林中的南酸枣木材微纤丝角最小.研究结果显示,南酸枣-杉木混交林中南酸枣木材的解剖特性总体上最优,在南酸枣木材品质定向培育过程中宜选择杉木作为伴生树种.     

海桑属红树植物次生木质部解剖特征极其对潮间带生境的适应

通过光学显微镜和扫描电子显微镜详细观察了相似生境条件下生长的海桑属(Sonneratia)植物以及低、高潮位生长的海桑(S. caseolaris)和杯萼海桑(S. alba)次生木质部的形态特征,应用Lasersharp软件测量了其次生木质部的数量特征.结果表明:海桑属植物次生木质部形态特征的特化是与潮间带生境相适应的,能在水分胁迫的生境中,有效地协调水分输导的有效性和安全性.其特化结构主要包括:1)宽、窄导管并存,2)管孔密度较大,复孔率高,3)存在纤维状导管、形状不规则的导管和少量环管管胞,4)螺旋雕纹、附物纹孔、管壁具疣等许多导管壁的微观结构,有利于水分输导的安全性,5)射线细胞和分隔木纤维内的淀粉粒是渗透调节的物质基础,有利于促进水分上升,6)薄的纤维壁厚和宽的纤维腔径有利于水分的贮存,7)具胶质纤维.相似生境条件下生长的海桑属植物次生木质部数量特征的测量结果表明海桑和拟海桑水分输导效率高,但水分输导安全性差,而杯萼海桑水分输导效率低,但其输导安全性高.与高潮位生长的海桑和杯萼海桑相比,低潮位生长的海桑和杯萼海桑次生木质部导管分子更加"小型化"(有更小的导管分子长度、管孔弦向直径、管孔面积),有更高的导管聚合度和管孔密度,数量特征随生境不同的种内变动有利于海桑和杯萼海桑提高水分输导的安全性,但海桑和杯萼海桑输导安全性的获得是以牺牲水分输导的有效性为前提的.与生长在高潮位生境的海桑和杯萼海桑相比,低潮位生境生长的海桑和杯萼海桑的木材结构有更小的管孔面积,更厚的纤维壁,更低的导管比率和射线比率,更高的纤维比率,胶质纤维分布均匀且数量增加,这些特征有利于低潮位生境生长的海桑和杯萼海桑提高木材的韧性和强度,增强抗风浪冲击的能力.     

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     

Similar aerosol emission rates and viral loads in upper respiratory tracts for COVID-19 patients with Delta and Omicron variant infection

Highlights
1 Aerosol emission rates of Delta or Omicron patients were similar.
2 Viral loads in upper respiratory tract of Alpha, Delta and Omicron patients were similar.
3 Viral loads in upper respiratory tract of vaccinated or unvaccinated Delta patients had no difference.     

Recombinant human interferon-α1b inhibits SARS-CoV-2 better than interferon-α2b in vitro

Highlights
1) A comprehensive evaluation method for anti-SARS-CoV-2 drugs was established based on RT-qPCR, TCID₅₀ method, and immunofluorescence.
2) A significant antiviral effect of rHuIFN-α1b was shown with EC₅₀=0.12 IU/mL in Vero cells and EC₅₀=0.52 IU/mL in Calu-3 cells, which was better than rHuIFN-α2b (EC₅₀=0.25 IU/mL in Vero cells and EC₅₀=2.48 IU/mL in Calu-3 cells).
3) rHuIFN-α1b has a good potential in the application of anti-COVID-19 therapy.     

Continued antigenic variation of highly pathogenic avian influenza A (H7N9) virus in laying hens in China, 2020–2021

Highlights
1. 13 strains of H7N9 viruses from laying hens in 2020 and 2021 were identified.
2. H7N9 viruses in China comprised at least 11 genotypes.
3. H7N9 viruses are high pathogenic in chickens, not in ducks.
4. The most H7N9 viruses cross-reacted poorly with H7-Re3 antiserum.
5. The H7-Re3 vaccine was unable to prevent H7N9 infection.