Micromorphological observations on lemma and palea surface of Bromus (Poaceae) in Iran

Phytotaxa ◽  
2021 ◽  
Vol 508 (1) ◽  
Author(s):  
SAMANEH MOSAFERI ◽  
MARYAM KESHAVARZI
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Cell Wall ◽  
Species Delimitation ◽  
Abaxial Surface ◽  
Ploidy Levels ◽  
The World ◽  
Close Relationship ◽  
Qualitative Characters ◽  
Scanning Electron

Bromus (Poaceae) includes more than 160 species of mesophytic and xerophytic grasses from temperate regions of the world, of which 39 occur in Iran. The genus is considered taxonomically problematic due to the occurrence of hybridization, variation in ploidy levels, and phenotypic plasticity. Moreover, morphological similarities make species delimitation difficult. It resulted in different taxonomic classifications proposed along the time. Thus, in order to contribute to a better understanding of the species of Bromus, 21 species from six different sections of Bromus occurring in Iran were evaluated micromorphologically. The abaxial surface of the lemma and palea of the lowermost florets were examined using Scanning Electron Microscopy (SEM). Twenty-three quantitative and qualitative characters were analysed using PAST software. Lemma characters such as shape of silica cells, cork cells, crown cells, outline of long cell wall, and long cell length, and palea characters such as shape of cork cells, silica cells, and outline of long cell wall were informative among species studied. In UPGMA clustering most species were aggregated according to the previously delimited sections demonstrating the taxonomic value of micromorphological features in the species studied. Two sections Bromus and Genea showed a close relationship whereas two sections Ceratochloa and Pnigma were placed in one cluster close to the cluster including section Boissiera. The only exception was B. japonicus which was resolved within cluster of sect. Genea, not in cluster of sect. Bromus.

Some small-sized Cosmarium (Conjugatophyceae, Desmidiales) from sphagnum bogs of Moscow Region

2013 ◽  
Vol 47 ◽  
pp. 13-20
Author(s):  
O. V. Anissimova
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Cell Wall ◽  
Moscow Region ◽  
Biological Station ◽  
Sphagnum Bogs ◽  
Different Seasons ◽  
Scanning Electron

Algae samples were collected during different seasons from 1997 to 2011 in two swamps located at Zvenigorod Biological Station in Moscow Region. There were found 25 Cosmarium species and varieties, 9 taxa of them being new to the region. Descriptions of the taxa were specified by observation of cell wall ornamentation with light and scanning electron microscopy. Original descriptions, photos and drawings of algae are presented.

Determination of cotton fiber maturity and linear density (fineness) by examination of fiber cross-sections. Part 2: A comparison optical and scanning electron microscopy

2014 ◽  
Vol 84 (18) ◽  
pp. 1939-1947 ◽  
Author(s):  
Geoffrey RS Naylor ◽  
Margaret Pate ◽  
Graham J Higgerson
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Cell Wall ◽  
Optical Microscopy ◽  
Cross Sections ◽  
Linear Density ◽  
Wall Area ◽  
Density Values ◽  
Fiber Maturity ◽  
Scanning Electron

Previous researchers established a set of reference cottons with known fiber maturity and linear density (fineness) values based on the analysis of a large number of individual transverse fiber cross-sections viewed under the optical microscope. Part 1 identified that the limited optical resolution of the captured images may be the source of a significant systematic error in the assigned values of cell wall area and hence fiber maturity and linear density values. In this paper the optical microscopy technique was implemented. Individual cross-sections were measured using this approach and also higher resolution and higher magnification images were obtained using scanning electron microscopy. It was found that the data obtained from optical microscopy were similar to the SEM data, with the perimeter being 2% smaller, the cell wall area being 6% larger and the maturity ratio values being 8% higher. It was concluded that the combined approach of utilizing SEM in conjunction with optical imaging is a useful approach for verifying and perhaps correcting the data obtained from optical imaging. Further the SEM images highlighted that the current experimental protocol does not adequately address the challenge of ensuring that the fibers are mounted normal to the plane of cutting the transverse cross-section. Modeling demonstrated that while maturity ratio values are relatively insensitive to this misalignment, measured cell wall area values and hence fiber linear density values will be overestimated. This may be the major source of error associated with the technique and warrants further attention in future studies.

scholarly journals Analysis of the type material of Achnanthes minutissima var. macrocephala (Bacillariophyta) and description of two new small capitate Achnanthidium species from Europe and the Himalaya

2019 ◽  
Vol 152 (2) ◽  
pp. 340-350
Author(s):  
Carlos E. Wetzel ◽  
Ingrid Jüttner ◽  
Smriti Gurung ◽  
Luc Ector
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Benthic Diatom ◽  
Original Material ◽  
Diatom Species ◽  
The World ◽  
Freshwater Habitats ◽  
The Himalaya ◽  
Scanning Electron ◽  
Achnanthes Minutissima

Background and aims – Two unknown benthic diatom species belonging to the genus Achnanthidium Kütz., and found in French and Nepalese freshwater habitats, were investigated. Both species are here described as new and compared with the original material of Achnanthes minutissima var. macrocephala Hust. [≡ Achnanthidium macrocephalum (Hust.) Round & Bukht.] from Indonesia. Methods – The morphology of three small and capitate Achnanthidium species was investigated using light microscopy (LM) and scanning electron microscopy (SEM). Key results – Achnanthidium coxianum sp. nov. (from the Himalaya) belongs to the group of species with hooked terminal raphe endings, while Achnanthidium peetersianum sp. nov. (from France) has variable terminal raphe endings which are usually slightly bent. Achnanthidium macrocephalum is a much rarer species and illustrations concerning its identity in the literature do not conform to the type studied here. Conclusions – The three species are similar in LM but clearly distinct in SEM. The shape of the areolae and terminal raphe endings separate the species. Achnanthidium macrocephalum has often been misidentified in studies from many areas of the world. It is similar to the new species in valve outline and in its small dimensions.

scholarly journals Serial Block-Face Scanning Electron Microscopy Reveals That Intercellular Nuclear Migration Occurs in Most Normal Tobacco Male Meiocytes

2021 ◽  
Vol 12 ◽  
Author(s):  
Sergey Mursalimov ◽  
Nobuhiko Ohno ◽  
Mami Matsumoto ◽  
Sergey Bayborodin ◽  
Elena Deineko
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Cell Wall ◽  
Three Dimensional ◽  
Nuclear Migration ◽  
Male Meiosis ◽  
Face Scanning ◽  
Block Face ◽  
Plant Meiosis ◽  
Scanning Electron

Serial block-face scanning electron microscopy (SBF-SEM) was used here to study tobacco male meiosis. Three-dimensional ultrastructural analyses revealed that intercellular nuclear migration (INM) occurs in 90–100% of tobacco meiocytes. At the very beginning of meiosis, every meiocyte connected with neighboring cells by more than 100 channels was capable of INM. At leptotene and zygotene, the nucleus in most tobacco meiocytes approached the cell wall and formed nuclear protuberances (NPs) that crossed the cell wall through the channels and extended into the cytoplasm of a neighboring cell. The separation of NPs from the migrating nuclei and micronuclei formation were not observed. In some cases, the NPs and nuclei of neighboring cells appeared apposed to each other, and the gap between their nuclear membranes became invisible. At pachytene, NPs retracted into their own cells. After that, the INM stopped. We consider INM a normal part of tobacco meiosis, but the reason for such behavior of nuclei is unclear. The results obtained by SBF-SEM suggest that there are still many unexplored features of plant meiosis hidden by limitations of common types of microscopy and that SBF-SEM can turn over a new leaf in plant meiosis research.

Four new Luticola taxa (Bacillariophyta) from Maritime Antarctica 

Phytotaxa ◽  
2014 ◽  
Vol 170 (3) ◽  
pp. 155 ◽  
Author(s):  
RALITSA ZIDAROVA ◽  
ZLATKO LEVKOV ◽  
BART VAN DE VIJVER
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
New Taxa ◽  
Similar Species ◽  
The South ◽  
Maritime Antarctica ◽  
World Data ◽  
The World ◽  
Scanning Electron

The paper describes four new Luticola taxa from the South Shetland Archipelago, Antarctica:  Luticola neglecta sp. nov., L. bogaertsiana sp. nov., L. contii sp. nov. and L. olegsakharovii sp. nov. All new taxa are studied using both light and scanning electron microscopy and compared to other morphologically similar species from (sub-)Antarctica and elsewhere in the world. Data on their ecology and biogeography are added. 

High-Resolution Field Emission Scanning Electron Microscopy (FESEM) Imaging of Cellulose Microfibril Organization in Plant Primary Cell Walls

2017 ◽  
Vol 23 (5) ◽  
pp. 1048-1054 ◽  
Author(s):  
Yunzhen Zheng ◽  
Daniel J. Cosgrove ◽  
Gang Ning
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Cell Wall ◽  
High Resolution ◽  
Field Emission ◽  
Cell Walls ◽  
Cellulose Microfibrils ◽  
Critical Point Drying ◽  
Sputter Coating ◽  
Scanning Electron

AbstractWe have used field emission scanning electron microscopy (FESEM) to study the high-resolution organization of cellulose microfibrils in onion epidermal cell walls. We frequently found that conventional “rule of thumb” conditions for imaging of biological samples did not yield high-resolution images of cellulose organization and often resulted in artifacts or distortions of cell wall structure. Here we detail our method of one-step fixation and dehydration with 100% ethanol, followed by critical point drying, ultrathin iridium (Ir) sputter coating (3 s), and FESEM imaging at a moderate accelerating voltage (10 kV) with an In-lens detector. We compare results obtained with our improved protocol with images obtained with samples processed by conventional aldehyde fixation, graded dehydration, sputter coating with Au, Au/Pd, or carbon, and low-voltage FESEM imaging. The results demonstrated that our protocol is simpler, causes little artifact, and is more suitable for high-resolution imaging of cell wall cellulose microfibrils whereas such imaging is very challenging by conventional methods.

scholarly journals Palynological studies on some species of Anabasis L. (Amaranthaceae) from Iran

2016 ◽  
Vol 23 (2) ◽  
pp. 247-253 ◽  
Author(s):  
M. Assadi ◽  
S.M.M. Hamdi ◽  
F. Fajani
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Species Delimitation ◽  
Pollen Grains ◽  
Pollen Characters ◽  
Plant Taxon ◽  
Scanning Electron

The paper presents pollen micromorphology by scanning electron microscopy of seven Anabasis L. species namely, A. haussknechtii Bge., A. aphylla L., A. calcarea (Charif & Allen) Bokhari & Wendelbo, A. eugeniae Iljin, A. eriopoda (Shrernk) Volkens, A. annua Bge. and A. setifera Moq. from Iran. Pollen grains in all studied species are peripolyporate, spherical and are of two basic types based on pores diameter inner of holes. The study showed that the sculpturing of exine provides valuable characters in species delimitation, sometimes even for closely related ones. An artificial key based on pollen characters for seven species is provided.Bangladesh J. Plant Taxon. 23(2): 247-253, 2016 (December)

Observations on North American Gomphoneis. III. Gomphoneis septa comb.nov.

1986 ◽  
Vol 64 (11) ◽  
pp. 2764-2768 ◽  
Author(s):  
J. P. Kociolek ◽  
E. F. Stoermer ◽  
L. L. Bahls
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
North American ◽  
Size Range ◽  
Taxonomic Position ◽  
Apical Pore ◽  
Close Relationship ◽  
Ultrastructural Characteristics ◽  
Scanning Electron

The valvar ultrastructure of the diatom Gomphonema septum Mogh. was investigated with scanning electron microscopy and is discussed with regard to the taxonomic position of this species. Ultrastructural features include striae composed of double rows of puncta, presence of a narrow axial plate which is responsible for the image of longitudinal lines, and apical pore fields composed of pores dissimilar in appearance from the puncta. These and other ultrastructural characteristics point to a close relationship between G. septum and members of the genus Gomphoneis. A transfer of Gomphonema septum to Gomphoneis is proposed. Information supplemental to previous observations on the size range and variability of this species is presented.

Comparison of two new species of astogloia Bacillariophyceae) with other small members of section Ellipticae

Phytotaxa ◽  
2013 ◽  
Vol 126 (1) ◽  
pp. 1 ◽  
Author(s):  
CHIARA PENNESI ◽  
MICHEL POULIN ◽  
FRIEDEL HINZ ◽  
TIZIANA ROMAGNOLI ◽  
MARIO DE STEFANO ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
New Species ◽  
Geographical Distribution ◽  
New Taxa ◽  
Related Species ◽  
The World ◽  
Two New Species ◽  
Scanning Electron

In this study, seven Mastogloia species belonging of the section Ellipticae are morphologically described through scanning electron microscopy, including two new taxa M. matthaei and M. stellae. They were collected as epiphytes on seagrasses from several tropical (Indonesia), subtropical (Egypt, Greece, Republic of Malta, Turkey) and temperate (Slovenia, Italy) regions of the world. All these species show typical characters of the Hustedt’s section Ellipticae: elliptical valve outline, a flat valve surface and rounded apices. Moreover, this study provides novel information on the frustule ultrastructure and gives update of their current geographical distribution. Some nomenclatural inconsistencies have been resolved with the typification of M. ovulum and the related species, M. emarginata, from the original Miang Besar material in the Hustedt collection.

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