Fine structure of mistletoe pollen. I. Eremolepidaceae, Lepidoceras, and Tupeia

1978 ◽  
Vol 56 (22) ◽  
pp. 2853-2864 ◽  
Author(s):  
Sylvia Feuer ◽  
Job Kuijt
Keyword(s):  
Electron Microscopy ◽  
Pollen Morphology ◽  
Spherical Shape ◽  
Oblate Spheroidal ◽  
Transmission Electron ◽  
Pollen Characters ◽  
The Family ◽  
Close Relationship ◽  
Relationship Of ◽  
The Relationship

An examination of pollen morphology and ultrastructure of Eremolepidaceae (Antidaphne, Ixidium, Eremolepis, Eubrachion) and Lepidoceras by light and scanning and transmission electron microscopy reveals a close relationship among the taxa. Pollen of Eremolepidaceae is typically echinate, tricolporate, and oblate-spheroidal. Eubrachion is unique within the family, exhibiting shallowly reticulate pollen. Ultrastructurally, all Eremolepidaceae exhibit a similar exine structure. The sculptural ektexinous elements (spines or 'muri') are never contiguous with the basal ektexine but rest on a thin granular zone. Pollen characters of Lepidoceras are particularly close to those of Ixidium and Eremolepis. The porate (por(or)ate) aperture type, completely spherical shape, and reduced granular ektexine of Lepidoceras pollen indicate an advanced position within the complex. The relationship of Tupeia to Eremolepidaceae is more obscure as pollen of the genus exhibits both eremolepidaceous (echinate sculpturing, shape in polar and equatorial views) as well as loranthaceous characters (simple apertures, ektexine organization). Palynologically Eremolepidaceae and related genera show no particular close relationship to Olacaceae or Santalaceae. Though Eremolepidaceae et al. do share a number of pollen features with Viscaceae (echinate sculpturing, compound apertures, exine organization) the strong nonpalynological differences between the two families suggest that these pollen features may have arisen independently.

Epitaxial Gold in Au/Si Eutectic Reaction and Epitaxial Aluminum Spikes in Al-1%Si/Ti-W/Si System

1988 ◽  
Vol 116 ◽  
Author(s):  
Peng-Heng Chang
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Epitaxial Growth ◽  
Orientation Relationship ◽  
Gold Film ◽  
Eutectic Reaction ◽  
Orientation Relationships ◽  
Transmission Electron ◽  
Relationship Of ◽  
The Relationship

AbstractEpitaxial regrowth of gold film on Si as a result of Au/Si eutectic reaction and epitaxial aluminum spikes forming at IC contacts during sintering have been investigated by transmission electron microscopy (TEM). For gold film on Si, three types of epitaxy were observed: (1) the crystal structures of the two lattices are exactly the same, (2) the two structures have the orientation relationship of Au(111)//Si(111) and Au[132]//Si[231] and (3) 20° misorientation from the relationship in (2). Two orientation relationships were observed in the case of Al spike in Si: (1) Al[011]//Si[123] and Al(200)//Si(11), (2) Al[001]//Si[112] and 2° misorientation between Al(200) and Si(111). Possible mechanisms are proposed to explained the observed epitaxial growth.

scholarly journals Taxonomical Investigation on Some Species of Genus Allium Based on the Pollen Morphology

2019 ◽  
pp. 1-10
Author(s):  
Mehdi Heidarian ◽  
Seyed Mohammad Mehdi Hamdi ◽  
Mohammad Mehdi Dehshiri ◽  
Taher Nejadsattari ◽  
Seyed Mohammad Masoumi
Keyword(s):  
Electron Microscopy ◽  
Pollen Morphology ◽  
Numerical Taxonomy ◽  
Morphological Characteristics ◽  
Pollen Grains ◽  
Pollen Grain ◽  
Wall Structure ◽  
Transmission Electron ◽  
Pollen Characters ◽  
Exine Ornamentation

Aims: The aim of this research was to investigate the morphological characteristics of the pollen grain of some species of genus Allium. Methodology: The pollen grains were examined by using Light Microscopy (LM), Scanning Electron Microscopy (SEM) and the pollen grains of one species under Transmission Electron Microscopy (TEM). Results: The pollen grains were oblate and medium in shape and size. The pollen ornamentation of exine surface, exine ornamentation on sulcus edge, lumina number in the exine surface and the state of pollen grain apex in the examined species were different. Semitectate and columellate ectexine with discontinuous endexine were seen in the pollen wall structure (sporoderm). The dendrogram obtained from the pollen characters in SEM observations by using the numerical taxonomy system (NTSYS) software placed the studied species in two types. Conclusion: Our palynological dendrogram can be used for segregation the sections and subgenera taxonomical levels in the studied species of genus Allium and confirmed the phylogram of the recent phylogenetic research.

Systematic relevance of the pollen morphology for the Rondeletia complex (Cinchonoideae, Rubiaceae)

2020 ◽  
Vol 194 (3) ◽  
pp. 290-307
Author(s):  
Alejandro Torres-Montúfar ◽  
Elia Ramírez-Arriaga ◽  
Enrique Martínez-Hernández ◽  
Helga Ochoterena
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Pollen Morphology ◽  
Morphological Characters ◽  
Palynological Data ◽  
Molecular Studies ◽  
Close Relationship ◽  
Relationship Of ◽  
Scanning Electron

Abstract Seventeen morphologically related genera have been considered as the Rondeletia complex, traditionally in Rondeletieae. Molecular studies agree that this is a polyphyletic group and some genera have been transferred to Guettardeae. Nevertheless, no solid morphological characters support this hypothesis. Our aim is to explore pollen morphology to see if this source of characters has systematic value. Our study uses light and scanning electron microscopy for 30 species of both tribes representing 14 genera. The most important characters are polar outline, endoaperture type and nexine discontinuities. Our results do not permit diagnosis of tribes, but they show that the genera formerly included in the Rondeletia complex, but now placed in Guettardeae, have nexine discontinuities in polar areas: endofissures (Rogiera) or endocracks (Arachnothryx complex: Arachnothryx-Gonzalagunia-Javorkaea-Renistipula). Palynological data also confirm a close relationship of Rondeletia with Stevensia, corroborating their synonymy, and of Arachnothryx with Gonzalagunia-Javorkaea-Renistipula, providing evidence of their close relationship. We conclude that pollen is a useful source of characters for supporting main lineages, but further research is still necessary for other genera, including Blepharidium, Machaonia, Mazaea and additional Rondeletia spp.

Behavior of Heavy Plastic Deformation of Cu-15Cr-0.1Zr In Situ Composite

2009 ◽  
Vol 79-82 ◽  
pp. 2191-2194
Author(s):  
Yan Li ◽  
Xiao Hong Chen ◽  
Ping Liu ◽  
Lin Hua Gao ◽  
Bao Hong Tian
Keyword(s):  
Electron Microscopy ◽  
Plastic Deformation ◽  
Cold Drawing ◽  
Degree Of Deformation ◽  
Transmission Electron ◽  
Fibrous Morphology ◽  
Two Phases ◽  
Relationship Of ◽  
The Relationship

The behavior of plastic deformation of Cu-15Cr-0.1Zr in-situ composite under different degree of cold drawing deformation was analyzed by using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results show that both Cu and Cr phases are elongated along cold drawn direction and appear a fibrous morphology; However, Cu phase shows a thread-like fibrous morphology and Cr phase shows a band-like fibrous morphology. The two phases have a coherent relationship of (111)Cu //(011)Cr; When the degree of deformation(ε)is equal to 6.43, the relationship shows// [111]Cu // [110]Cr //cold drawn direction. Furthermore, forming two different morphologies of Cu and Cr phases during cold drawing is also analyzed.

scholarly journals Pollen morphology of Quercus (subgenus Quercus, section Quercus) in Iran and its systematic implication

2012 ◽  
Vol 81 (1) ◽  
pp. 33-41 ◽  
Author(s):  
Parisa Panahi ◽  
Mohammad R. Pourmajidian ◽  
Asghar Fallah ◽  
Mehdi Pourhashemi
Keyword(s):  
Pollen Morphology ◽  
Morphological Characteristics ◽  
Pollen Grains ◽  
Structural Pattern ◽  
Pollen Characters ◽  
The Family ◽  
Pollen Shape ◽  
First Time ◽  
The Relationship ◽  
Systematic Implication

For the first time, pollen morphology of 9 (4 spp. and 5 subspp.) taxa representing lobed leaved oaks of Iran in the family of Fagaceae has been examined and illustrated using light microscopy and scanning electron microscopy of acetolysed material. Detailed pollen morphological characteristics are given for <em>Quercus</em> section. The pollen grains are single, isopolar, radially symmetrical, tricolpate, tricolporoidate or tricolporate. Pollens were studied to show all possible characteristics like shape, size, apertures, wall thickness, etc., with special reference to the specific features of each pollen type such as structural, sculptural and suprasculptural patterns. There is considerable variation in pollen morphology between taxa so that, three types of pollen shape, five types of structural pattern, two types of sculptural pattern, five types of suprasculptural pattern and three types of perfora distribution are defined. Furthermore, the relationship between pollen morphology and taxonomy is discussed. Overall, pollen characters are shown to be a useful and informative tool for assessing taxonomic position within <em>Quercus</em> section in Iran.

Eocronartium muscicola: a basidiomycetous moss parasite exploiting gametophytic transfer cells

1988 ◽  
Vol 66 (4) ◽  
pp. 762-770 ◽  
Author(s):  
E. W. A. Boehm ◽  
D. J. McLaughlin
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Transfer Cells ◽  
Transmission Electron ◽  
Host Parasite ◽  
Relationship Of ◽  
The Relationship ◽  
Gain Access ◽  
Scanning Electron

The host–parasite interface in Eocronartium muscicola, Auriculariales sensu lato, was examined histologically for 6 of the 21 reported moss hosts, using light microscopy, scanning electron microscopy, and transmission electron microscopy. A unique mode of fungal biotrophy was encountered in 5 of the 6 mosses analyzed, in which E. muscicola exploits gametophytic host transfer cells concomitant with varying degrees of supplantation of the moss sporophyte. Basidiocarps are restricted in these mosses to postfertilized archegonia, in which they are seen to associate with the sporophyte foot region, where they gain access to the host transfer cell nutritional interface. Basidiocarp ontogeny is presented as it relates to the development of the host–parasite interface. The relationship of E. muscicola to other simple-septate auricularioid taxa and the the Uredinales is discussed.

Observations on the variation in pollen morphology of Palmae and its significance

1986 ◽  
Vol 64 (12) ◽  
pp. 3079-3090 ◽  
Author(s):  
I. K. Ferguson
Keyword(s):  
Electron Microscopy ◽  
Pollen Morphology ◽  
Electron Microscope Study ◽  
Extensive Study ◽  
Fossil Pollen ◽  
Transmission Electron ◽  
Pollen Characters ◽  
Exine Ornamentation ◽  
Structural Differences ◽  
Scanning Electron

Study of the pollen morphology of the Palmae by using scanning electron microscopy and transmission electron microscopy shows that there is more remarkable variation and parallelism in pollen characters, especially exine ornamentation and stratification, than has been demonstrated previously. The pollen of Arenga borneensis has gemmate exine ornamentation and closely resembles that of species of the closely related Caryota (Caryoteae) as well as Iriartea and Dictyocaryum (Iriarteae). Some species of Pinanga (Areceae), Korthalsia, and Daemonorops (Calameae) have pollen which can only be separated from the A. borneensis type by careful electron microscope study. Other species of Arenga have spiny pollen with a smooth foot layer, which resemble Wallichia (Caryoteae) and other Caryota species. Catoblastus, Wettinia, and Socratea (Iriarteae) have similar characteristic pollen with columellate spines interspersed with dense scabrate ornamentation. Again, species of Pinanga and Korthalsia have superficially similar pollen, as do the genera Mauritia, Mauritiella, and Lepidocaryum (Lepidocaryeae). However, these groups can be distinguished by structural differences of the spines. Very similar tectate, perforate pollen with supratectal spines occur in genera which have small differences in apertures but are widely separated taxonomically. These include Pinanga, Nypa, Salacca (Calameae), and Ravenea (Ceroxyleae). In view of this variation and parallelism it is suggested that there is a need for caution in assigning fossil pollen to extant genera until a much more detailed and extensive study of palm pollen morphology is carried out.

TEM Studies of Cement Hydration

1986 ◽  
Vol 85 ◽  
Author(s):  
G. W. Groves
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Cement Hydration ◽  
Cement Ratio ◽  
Water Cement Ratio ◽  
Effect Of Water ◽  
Transmission Electron ◽  
Detailed Evaluation ◽  
Relationship Of ◽  
The Relationship

ABSTRACTThe application of transmission electron microscopy to the study of the early stages of hydration C3S and the microstructure of very mature C3 S paste is reported. In the former case the effect of water-cement ratio appears to be very important. In the latter, a detailed evaluation of the microstructures of inner C-S-H, outer C-S-H and CH is possible and the relationship of these to models of cement hydration is discussed.

scholarly journals Areca Palm Necrotic Ringspot Virus, Classified Within a Recently Proposed Genus Arepavirus of the Family Potyviridae, Is Associated With Necrotic Ringspot Disease in Areca Palm

2019 ◽  
Vol 109 (5) ◽  
pp. 887-894 ◽  
Author(s):  
Ke Yang ◽  
Wentao Shen ◽  
Ye Li ◽  
Zengping Li ◽  
Weiguo Miao ◽  
...  
Keyword(s):  
Close Association ◽  
Taxonomic Status ◽  
Ringspot Virus ◽  
Viral Agent ◽  
Transmission Electron ◽  
The Family ◽  
Areca Catechu ◽  
Close Relationship ◽  
Small Rna Deep Sequencing ◽  
Relationship Of

Areca palm (Areca catechu), one of the two most important commercial crops in Hainan, China, has been severely damaged by a variety of pathogens and insects. Here, we report a new disease, tentatively referred to as areca palm necrotic ringspot disease (ANRSD), which is highly epidemic in the main growing regions in Hainan. Transmission electron microscopy observation and small RNA deep sequencing revealed the existence of a viral agent of the family Potyviridae in a diseased areca palm plant (XC1). The virus was tentatively named areca palm necrotic ringspot virus (ANRSV). Subsequently, the positive-sense single-stranded genome of ANRSV isolate XC1 was completely determined. The genome annotation revealed the existence of two cysteine proteinases in tandem (HC-Pro1 and HC-Pro2) in the genomic 5′ terminus of ANRSV. Sequence comparison and phylogenetic analysis suggested the taxonomic classification of ANRSV into the recently proposed genus Arepavirus in the family Potyviridae. Given the close relationship of ANRSV with another newly reported arepavirus (areca palm necrotic spindle-spot virus), the exact taxonomic status of ANRSV needs to be further investigated. In this study, a reverse transcription polymerase chain reaction assay for ANRSV-specific detection was developed and a close association between ANRSV and ANRSD was found.

scholarly journals Pollen Morphology and Anatomy of Cornelian Cherry (Cornus mas L.) Cultivars

HortScience ◽  
2009 ◽  
Vol 44 (2) ◽  
pp. 519-522 ◽  
Author(s):  
Cevriye Mert
Keyword(s):  
Electron Microscopy ◽  
Pollen Morphology ◽  
Pollen Grains ◽  
Pollen Grain ◽  
Prolate Spheroidal ◽  
Normal Appearance ◽  
Cornelian Cherry ◽  
Oblate Spheroidal ◽  
Cornus Mas ◽  
Transmission Electron

Morphology and ultrastructure of pollen grain were described for six cornelian cherry (Cornus mas L.) cultivars (Degirmendere, Erkenci Degirmendere, İri Bardak, Yuvarlak Bardak, Uzun Memeli, and Bugur) using light microscopy and both scanning and transmission electron microscopy. Pollen grains of cornelian cherry cultivars are trizonocolporate, the germinal furrow extending almost the full length of the grain axis. Pollen grain length for the studied cultivars ranged from 23.63 to 25.13 μm. Two different pollen shapes were observed: oblate spheroidal and prolate spheroidal. Significant changes in various layers of the pollen wall are as follows: the thickness of the intine: 233.1 to 406.4 nm, exine: 510.2 to 842.7 nm, and total wall 851.4 to 1175.8 nm. Percentages of abnormal pollen grains ranged from 3.9% to 27.6% among the cultivars. Abnormal pollen grains were categorized as: 1) shrunken pollen grains of abnormal appearance with little cytoplasm; 2) pollen grains of normal appearance with little or no cytoplasm; and 3) shrunken, abnormal pollen grains of elliptical shape with a colpate-type aperture.

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