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1.
AN ADDITIONAL ULTRASTRUCTURAL COMPONENT OF FLAGELLA   总被引:6,自引:6,他引:0       下载免费PDF全文
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2.
Frond members belonging to the monostelic seed fern genus Heterangium have been found in Pennsylvanian age coal balls collected in the Illinois Basin. Petioles bear small pinnae below a dichotomy which produced a bipartite frond. Pinnules of the Sphenopteris obtusiloba type are borne on secondary pinnae. The anatomy of each pinna order and the pinnules is described.  相似文献   

3.
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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植物标本采集标签计算机印制数据系统陈涛,陈都,吴德邻(中国科学院华南植物研究所,广州510650)ANINTRODUCTIONTOTHEDATASYSTEMFORCOMPUTER-AIDEDLABELPREPARATIONOFSPECIMENCOLL...  相似文献   

5.
Eggert , Donald A. (Southern Illinois U., Carbondale.) Studies of Palerzoic ferns: The frond of Ankyropteris glabra. Amer. Jour. Bot. 50(4): 379–387. Illus. 1963—The major features of the frond of A. glabra are described on the basis of preserved parts found in Middle Pennsylvanian coal ball material from Illinois. The frond is planated and has well-developed foliar laminae. Primary pinnae arise from the petiole in 2 alternating series, and secondary pinnae arise in a similar fashion from the primary pinnae. Foliar laminae occur on the secondary pinnae and have dichotomous venation. The xylem of the petiole has a diupsilon configuration in the lower part of the axis, while higher in the petiole the xylem forms a strand resembling that of the European species A. westfaliensis. The xylem strands of the primary pinnae arise from the adaxial antennae of the petiolar vascular strand as somewhat C-shapcd bodies and develop antennae and become H-shaped at higher levels. A gap occurs in the antenna of the petiole vascular system above the level of departure of the primary pinna trace. Terete vascular strands occur in the secondary pinna axes which arise from the adaxial antennae of the xylem of the primary pinnae. The foliar laminae are relatively thin, have an irregular outline, and their histology is like that found in many living ferns. The frond of A. glabra illustrates that leaf evolution had progressed in at least one species of the coenopterid family Zygopteridaceae to the extent that an essentially 2-dimensional frond of modern aspect, and with well-developed foliar laminae, was present by Middle Pennsylvanian time.  相似文献   

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黄芪复合体(豆科)核型研究补充材料   总被引:3,自引:0,他引:3  
朱相云   《广西植物》1996,16(1):61-63
本文首次报道了民和黄芪的染色体数目及核型。发现该种与黄芪复合体其它类群的染色体数目相同,但核型有别,其核型公式为2n=16=8m(2SAT)+8sm。这种核型变异与它的形态变异一致。在黄芪复合体内,每一类群的染色体至少具1对随体,且附着在最后1对染色体的短臂上(除蒙古黄芪具2对随体外),而Toh(1971)报道采自Kyungi和Mt.Harla膜荚黄芪和高山膜荚黄芪(新拟)的染色体不具随体,可能观察有误。  相似文献   

8.
The stem, rachides, and pinnae of Archaeopteris macilenta, formerly considered to be a fern of Devonian age, comprise a branch system in which the ultimate divisions heretofore referred to as pinnules are the leaves. The primary vascular system of the “frond” is a lobed siphonostele from which leaf traces arise in a spiral sequence. The anatomy of the “rachis” and of the “pinnae” is shown to be similar to that of the stem, Callixylon, which bore these “fronds.” Branching, epidermal pattern and stomates are described for the spirally arranged leaves (fertile pinnules). Attachment and dehiscence of sporangia as well as their stomates are reported. Archaeopteris is retained in the Class Progymnospermopsida which includes plants with gymnospermous anatomy and pteridophytic reproduction. It is suggested that Actinopodium, Svalbardia and Siderella are related closely to Archaeopteris and that this group of genera shows evolutionary stages in webbing of leaves and planation of branch systems. The opportunities for ontogenetic studies of the arborescent genus Archaeopteris are pointed out.  相似文献   

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以2个雄器大多围生、少数侧生的苎麻疫霉菌株与1个雄器侧生、偶有围生的恶疫霉菌株为材料,采用真菌核糖体基因转录间隔区(ITS)通用引物,PCR扩增3个供试菌株核糖体基因的ITS1和ITS2,并对PCR产物进行了克隆和序列分析。结果是苎麻疫霉的ITS1和ITS2分别由206和453个碱基组成, 而恶疫霉则分别由218和415个碱基组成。2个供试苎麻疫霉菌株的ITS1和ITS2的碱基序列同源性均分别为100%。苎麻疫霉和恶疫霉ITS1同源性为74.9%,其中中间区域40bp-164bp之间在两种间变异丰富,同源性只有59.4%,而1bp-39bp和165bp-239bp两区域的同源性分别为92.3%和92.1%; ITS2在两种疫霉菌间的同源性为71.0%。结果表明苎麻疫霉和恶疫霉ITS的碱基序列有明显差异。上述结果提示,ITS区域碱基序列可区分苎麻疫霉和恶疫霉。  相似文献   

12.
以2个雄器大多围生、少数侧生的苎麻疫霉菌株与1个雄器侧生、偶有围生的恶疫霉菌株为材料,采用真菌核糖体基因转录间隔区(ITS)通用引物,PCR扩增3个供试菌株核糖体基因的ITS1和ITS2,并对PCR产物进行了克隆和序列分析。结果是苎麻疫霉的ITS1和ITS2分别由206和453个碱基组成,而恶疫霉则分别由218和415个碱基组成。2个供试苎麻疫霉菌株的ITS1和ITS2的碱基序列同源性均分别为100%。苎麻疫霉和恶疫霉ITS1同源性为74.9%,其中中间区域40bp-164bp之间在两种间变异丰富,同源性只有59.4%,而1bp-39bp和165bp-239bp两区域的同源性分别为92.3%和92.1%;ITS2在两种疫霉菌间的同源性为71.0%。结果表明苎麻疫霉和恶疫霉ITS的碱基序列有明显差异。上述结果提示,ITS区域碱基序列可区分苎麻疫霉和恶疫霉。  相似文献   

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Modern birds have extremely short tail skeletons relative to Archaeopteryx and nonavialian theropod dinosaurs. Long- and short-tailed birds also differ in the conformation of main tail feathers making up the flight surface: frond shaped in Archaeopteryx and fan shaped in extant fliers. Mechanisms of tail fanning were evaluated by electromyography in freely flying pigeons and turkeys and by electrical stimulation of caudal muscles in anesthetized birds. Results from these experiments reveal that the pygostyle, rectrices, rectricial bulbs, and bulbi rectricium musculature form a specialized fanning mechanism. Contrary to previous models, our data support the interpretation that the bulbi rectricium independently controls tail fanning; other muscles are neither capable of nor necessary for significant rectricial abduction. This bulb mechanism permits rapid changes in tail span, thereby allowing the exploitation of a wide range of lift forces. Isolation of the bulbs on the pygostyle effectively decouples tail fanning from fan movement, which is governed by the remaining caudal muscles. The tail of Archaeopteryx, however, differs from this arrangement in several important respects. Archaeopteryx probably had a limited range of lift forces and tight coupling between vertebral and rectricial movement. This would have made the tail of this primitive flier better suited to stabilization than maneuverability. The capacity to significantly alter lift and manipulate the flight surface without distortion may have been two factors favoring tail shortening and pygostyle development during avian evolution.  相似文献   

15.
黄燮才   《广西植物》1982,(2):80-80
<正> 假木通(Stephanotis chunii Tsiang)隶属于萝摩科(Asclepiadaceae)黑曼藤属(Stephanotis Thou.),为我国特有的藤状灌木植物,现仅见于广西的大瑶山、十万大山和广东的鼎湖山。1936年蒋英教授发表假木通新种时,没有看见果的标本,最近从金秀县(大瑶山)采集到假木通的果实标本,现补充记载如下,以供参考。 假木通(中国高等植物图鉴)大补药、十全大补、瑶佬药、藤列别、铜列(广西金秀瑶语)  相似文献   

16.
Abstract
Final-instar larvae, pupae and adults of Cestrinus trivialis Erichson from south Queensland are described and illustrated. Characters are given which allow the species to be separated from Gonocephalum macleayi (Blackburn), Pterohelaeus darlingensis Carter, and P. alternatus Pascoe.  相似文献   

17.
The discovery of pedunculate specimens of pollen organ Dolerotheca in close association with Myeloxylon-type pinnae and Alethopteris-type pinnules provides evidence for the reconstruction of a petrified medullosan frond and the attachment of the microsporangiate fructification. Specimens of Dolerotheca villosa and D. formosa from Middle and Upper Pennsylvanian age strata of North America are borne on slender peduncles with anatomical features and vascularization identical to those of some level in a Myeloxylon-Alethopteris-type frond. Reconstruction of the frond reveals a large, repeatedly dichotomising organ that bears penultimate pinnae and ultimate pinnules in a pinnate arrangement. Examination of pinnules on the surface of coal ball material indicates that they conform to the compression genus Alethopteris. Identical numbers and arrangement of vascular bundles together with identical anatomical features and multicellular hairs indicate that the Dolerotheca campanulum is borne in the position of a penultimate pinna. A reconstruction of the frond with a proposed polled organ attachment is included.  相似文献   

18.
SUCKLING AN ADDITIONAL PUP TO WEANING IN THE NEW ZEALAND FUR SEAL   总被引:1,自引:1,他引:0  
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19.
潜山盆地位于大别山东南侧,呈北东-南西向狭长分布。这里下第三系发育,化石丰富,尤其是近十余年来,大量古新世哺乳动物化石的陆续报道,引起了地层古生物学者极大的兴趣。1980年10月,安徽省地质矿产局区域地质调查队四分队和笔者分别在盆地东侧的桐城县龙头树、朱桥、大苏庄和古井附近的痘姆组中采获两层叶肢介化石,并有丰富的介形类共生。这个发现,对于早第三纪叶肢介化石的分布和中国陆相古新世地层的划分对比都有重要意义。潜山盆地早第三纪红层自下而上划分为望  相似文献   

20.
Pododimeria, containing the brown-spored species P. gallica and P. andina, is expanded to include species with hyaline as well as brown ascospores. Two new hyalodidymous taxa, P. juniperi and P. gelatinosa, are added to the genus. Species of Pododimeria occur as ectocommensals on living shoots of Cupressaceae or Podocarpaceae. Although the superficial mycelium may extend into the labyrinthine chambers enclosed by the imbricated scale leaves of the host, it does not penetrate the cuticle. The tiny, black, subglobose, uniloculate ascocarps taper basally to stromatic stipes. The bitunicate asci are interspersed with pseudoparaphyses composed of broad, irregularly shaped cells that readily break apart. The thick, brown to bluish-green ascocarp wall of P. juniperi has a broad equatorial band of prosenchymatous cells. The ascocarp wall of P. gelatinosa is composed uniformly of subhyaline, gelatinous pseudoparenchymatous cells covered by a dark, amorphous crust.  相似文献   

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