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1.
本文报道发现于内蒙古乌达煤田早二叠世太原组顶部火山凝灰岩层中的莲座蕨类植物一新种Eoangiopteris congestus sp. nov.,标本包含有机连生的辉木型茎干,栉羊齿型营养羽片和始莲座蕨型繁殖羽片。其中营养羽片为三次羽状复叶,末二次和末次羽片均为线形,小羽片栉羊齿型,卵圆形,中脉下延,侧脉分叉一次,属于东方栉羊齿Pecopteris orientalis (Schenk) Potonié类型。繁殖小羽片与营养小羽片同形;两侧对称的聚合囊成单列分布在中脉两侧,排列拥挤,由6–8个孢子囊组成,通过一个薄壁组织构成的聚合囊托与叶片相连;孢子囊呈纺锤形,无环带;孢子囊面向外的壁2–3层细胞厚,面向内的壁厚度仅1层细胞。原位孢子为三缝孢,椭圆形至圆形,表面具小刺状纹饰,可与分散孢子属Apiculatisporites对比。当前始莲座蕨属植物的发现代表其在华夏植物群目前最早的化石记录。此外,这些两侧对称的聚合囊明显区别于以往报道中与东方栉羊齿叶型化石连生的辐射对称聚合囊类型(星囊蕨Asterotheca),表明在古植物学研究中一种化石羽片类型可能对应多种繁殖器官类型。  相似文献   

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Pecopteris lativenosa Halle是栉羊齿属中羽叶形态变化十分显著的一个种。作者在详细观察的基础上,尝试性地运用定量统计和方差分析方法判定该植物具有代表性的各项特征,提出了普遍存在的5种小羽片类型、6种末次羽片类型和2种末二次羽片类型,以及各类型小羽片、末次羽片、末二次羽片和末三次羽片的空间分布关系,并以此为依据绘制了Pecopteris lativenosa Halle三次羽状复叶复原图。这一复原图能够解释以往发现的Pecopteris lativenosa Halle标本所属类型。  相似文献   

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至少二次羽状复叶,叶轴粗达2厘米,以30—35°角二歧分枝,表面凹凸不平,具明显的纵纹。末次羽片互生,披针形至线形,长度可达10厘米以上,基部宽约2.5厘米,渐尖,顶端钝,轴亦具纵纹。在轴二歧分枝点以下的羽片,排列稀疏;二歧分枝点以上多叶的区域,排列紧挤;相互覆盖,与末二级羽轴成40—45°角。小羽片互生或亚对生,以锐角斜生于羽轴,菱形或亚圆形,菱形前端分裂成2—3个圆形裂片,每个裂片顶端具2—3个圆齿,基部收缩呈楔形;小羽片向羽片末端渐变成长椭圆形,在羽片末端由3—4枚狭长的裂片联合成一深裂的顶小羽片。羽片基部下行第一小羽片着生于羽片与羽轴夹角处,分裂形式似现代银杏,中间一深裂将小羽片分为二瓣,每瓣再分裂一次,每一裂片顶端具圆齿;上行基部第一小羽片亦较大,分裂形式与下行第一小羽片同,其大部常盖在羽轴上。叶脉扇  相似文献   

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晚泥盆世是植物叶片形态复杂化进程中的一个重要时期,前裸子、种子、似真蕨和楔叶这四类植物都独立演化出了片化的大型叶。本文研究浙江长兴上泥盆统(法门阶)五通组的几种羽状复叶植物(3属4种),包括Sphenopteris(楔羊齿),Rhodea(须羊齿)和Triphyllopteris(三裂羊齿)。它们大多具二次羽状复叶,小羽片具有不同程度、数目和形状的裂片。这里明确Rhodea的晚泥盆世起源,并给出Triphyllopteris的最早化石记录。这些植物的分类尚不清楚,但为大型叶尤其是复叶的早期演化提供了新证据。  相似文献   

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晚泥盆世是植物叶片形态复杂化进程中的一个重要时期,前裸子、种子、似真蕨和楔叶这四类植物都独立演化出了片化的大型叶。本文研究浙江长兴上泥盆统(法门阶)五通组的几种羽状复叶植物(3属4种),包括Sphenopteris(楔羊齿),Rhodea(须羊齿)和Triphyllopteris(三裂羊齿)。它们大多具二次羽状复叶,小羽片具有不同程度、数目和形状的裂片。这里明确Rhodea的晚泥盆世起源,并给出Triphyllopteris的最早化石记录。这些植物的分类尚不清楚,但为大型叶尤其是复叶的早期演化提供了新证据。  相似文献   

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植株高达60厘米,根状茎直立或斜升,顶端密被黑褐色、全缘、披针形鳞片,鳞片边缘有棕色狭边。叶丛生,叶柄长约20—25厘米,禾杆色,初被黑褐色先端卷曲的披针形鳞片,后逐渐脱落;叶片长圆形,长30—40厘米,宽20—25厘米,基部圆形,先端渐尖,3回羽裂;羽片10—12对,斜向上,互生,基部一对较大,柄长约1厘米,卵状披针形,长约16厘米,宽约10厘米,2回羽裂,小羽片约10对,基部上侧小羽片与叶轴平  相似文献   

7.
吴秀元  王军 《古生物学报》2004,43(4):489-501
记述的两种新植物分别来自秦岭地区的凤县和镇安县。产于凤县草凉驿红花铺草凉驿组的Adiantites honghuapuensis sp.nov.,至少二次羽状复叶,羽片线形,以宽角着生于羽轴上;小羽片椭圆形,羽片基部的小羽片偶尔分裂为2—3个裂片。小羽片基部收缩,有短柄或以较宽的基部着生于羽轴上,扇状脉。另一产自镇安县茅坪东山梁二峪河组的Qinlingopteris orientalis gen.et sp.nov.,其特征是二次羽状复叶,末二级羽轴与末级羽轴夹角较小,大约30^#左右。小羽片亚对生,长卵形或亚圆形,顶端较窄,中部较宽,基部较狭并具短柄;叶脉扇状;羽轴上具间小羽片,间小羽片与正常小羽片等形同大。草凉驿组的地质时代大致为纳缪尔期至维斯发早期,而二峪河组则为早石炭世维宪期。  相似文献   

8.
黑龙江鸡西早白垩世穆棱组真蕨类植物一新种   总被引:5,自引:0,他引:5  
杨小菊 《古生物学报》2002,41(2):259-265
描述似里白属一新种—Gleichenitesjixiensissp .nov .。新种的叶为二次羽状 ,末次羽片与羽轴成70°—80°角 ,线形 ,互生。小羽片数目达 40对以上 ,以 6 0°— 90°角从小羽轴上伸出 ,互生 ,线形至长三角形。叶片为厚纸质。中脉明显 ,侧脉两歧分叉。生殖羽片与营养羽片同形 ,略小 ,孢子囊群生于小羽片背面 ,位于中脉两侧每组叶脉的前一支脉上 ,无囊群盖 ,由 8个近乎无柄的孢子囊聚合成圆形的囊群 ,孢子囊环带横生。该种的外部形态特征与化石属的GleichenitesporsildiiSeward和现代里白属的Hicriopterislaevissima (Christ)Ching较为相似。  相似文献   

9.
在开展苏铁Cycas revoluta形态特征观测中,发现一株苏铁根蘖苗有5片羽片生长异常,其中一片比其他正常羽片长且中脉出现分叉(即一羽多脉现象),另外4片基部两两贴生。另一株苏铁的小孢子叶球生长奇特,其顶部为莲座状,形似大孢子叶球。这两种异常现象为苏铁类植物的系统分类与演化研究提供了新资料。  相似文献   

10.
本文报道了鄂西荆门-当阳盆地晚三叠世九里岗组几种丁菲羊齿(Thinnfeldia)植物,即雅致丁菲羊齿[(新种)Thinnfeldia elegans(sp.nov.)]、南漳丁菲羊齿[(新种)Thinnfeldiananzhangensis(sp.nov.)]、远安丁菲羊齿[(新种)Thinnfeldia yuaanancnsis(sp.nov.)],并对九里岗组植物群的性质进行了扼要的讨论,初步认为该植物群具有我国南、北晚三叠世两个植物群的过渡性质。  相似文献   

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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.
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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  相似文献   

17.
<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  相似文献   

18.
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.  相似文献   

19.
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.  相似文献   

20.
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.  相似文献   

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