Fine Structure of Pollen Grain Ektexine of Maize, Teosinte and Tripsacum

Author(s):  
Umesh C. Banerjee ◽  
Elso S. Barghoorn

Using light microscope (LM) it was found very difficult to distinguish the ektexine (outer sculptured layer of exine) pattern of maize (Zea mays L.) pollen grains from that of its wild relatives teosinte (Euchlaena mexicana Schrad.) and tripsacum (Tripsacum spp.). At the magnifications obtained by LM, the pollen grain ektexine is faintly granular or netted. By the use of electron microscopy, however, it is possible to characterize their pollen ektexine patterns.For scanning electron microscopy (SEM) acetolysed pollen grains were used. After acetolysis the pollen samples were washed several times in glass-distilled water to remove traces of acids. Each sample was dispersed in a drop of distilled water placed on specimen holders.

2014 ◽  
Vol 50 (4) ◽  
pp. 583-584
Author(s):  
Józef Kocoń ◽  
Kazimierz Pliszka ◽  
Stanisław Muszyński

Pollen grain surface of <em>Vaccinium myrtillus</em> L. was analyzed by scanning electron microscopy. Pollen grains remain in tetrahedral tetrads. Grain surface is verrucose, consisting of thick, irregularly shaped muri, surrounding small, round or oval lumina. The surface of the muri is fissured, and minute papillae can also be noted.


2015 ◽  
Vol 57 (1) ◽  
pp. 149-160 ◽  
Author(s):  
Joanna Bykowska ◽  
Małgorzata Klimko

Abstract Pollen grains of Pinus mugo, P. sylvestris and P. ×rhaetica (= P. mugo × P. sylvestris) were examined by light and scanning electron microscopy. The pollen grains were bisaccate and monosulcate. The corpus-saccus attachment was distinct. The pollen corpus exine sculpture was verrucate-rugulate and deeply sculptured. The surface of the tectum was covered with small grana and it was perforate. The saccus sexine ornamentation was reticulate and irregularly perforate. The tectum surface characters in the proximal and distal view of the corpus and saccus were less variable and they did not provide good criteria to identify the species under study. However, some differences were observed in the size of elevation on the corpus between pollen grains of the same species and between the parental species. This study of the pollen grain morphology of the corpus and saccus provided some important new data.


Phytotaxa ◽  
2020 ◽  
Vol 458 (3) ◽  
pp. 183-194
Author(s):  
BRENDA Y. BEDOLLA-GARCÍA ◽  
MAYRA CASTRO-MORALES ◽  
CARLOS A. CULTID-MEDINA

The present study provides novel information about the pollen of Salvia assurgens. Pollen grains were collected and described based on their observed characters by light microscope and scanning electron microscopy. The species is distinguished from other Mexican salvias by having small pollen grains (14.2 × 18.2 µm), thin primary muri (0.2 µm thick), elongated primary lumina (1.03 µm long) and secondary lumina with relatively few perforations (9, range 5–14). Pollen characters are similar to those of the majority of American salvias. Regarding Mexican sages, there has been little palynological research, and only 23 species of 32 examined have been quantitatively studied. Standardization is needed in different aspects of palynological studies, especially in relation to measurement protocols and data analysis, as well as the increased use of scanning electron microscopy (SEM), since the majority of differences among species are provided by SEM microscope observation.


2021 ◽  
pp. 25-33
Author(s):  
Farag M. El-Mokasabi ◽  
Abdelbaset M. Asker ◽  
Raja M. El-Mabrouk

The micromorphological variation of the leaf and pollen grain characteristics in two species of Nicotiana was examined using a light microscope (LM) and scanning electron microscopy (SEM). These species are Nicotiana glauca R.C. Graham (wild species) and Nicotiana tabacum L. (cultivated species). The leaves are simple. The other leaf micromorphological features presented variation. The leaf architectural characteristics were also observed. Leaf venation is pinnate brochidodromous. The epidermal cell shape, on the abaxial leaf surface, is polygonal to irregular in Nicotiana glauca but it is so adaxially in all the two species the cells are irregular on both the epidermal layers. The anticlinal walls are either straight or sinuous. The leaves are amphistomatic. The stomata are commonly anomocytic to anisocytic. Foliar trichomes are glandular and non-glandular. Some of the foliar micromorphological characters as viewed under SEM were beneficial in species identification. The pollen shape is prolate with aperture tricolpate without opercula, the colpi shallow sunken with their ends acute. The exine sculpture is reticulate with granulate or granulate-microperforated to fine granulate and irregularly reticulate to perforate. Keywords: Leaf micromorphology- Pollen grains - Light microscope (LM); Scanning electron microscopy (SEM)- Nicotiana Solanaceae -Nicotianoideae.


Phytotaxa ◽  
2020 ◽  
Vol 458 (4) ◽  
pp. 242-256
Author(s):  
MEHDI HEIDARIAN ◽  
SEYED MOHAMMAD MAHDI HAMDI ◽  
MOHAMMAD MEHDI DEHSHIRI ◽  
TAHER NEJADSATTARI ◽  
SEYED MOHAMMAD MASOUMI

In this research, the pollen micromorphology of nine species belonging to Honorius, Loncomelos, Ornithogalum and Stellarioides are observed by LM (Light Microscopy), SEM (Scanning Electron Microscopy) and two species by TEM (Transmission Electron Microscopy). Lately, the phylogenetic studies have determined nineteen monophyletic genera in subfamily Ornithogaloideae (=tribe Ornithogaleae). Our results show that the pollen grains characters such as shape, size, exine ornamentation on equatorial surface, sulcus margin exine ornamentation, sulcus membrane ornamentation and lumina number on exine surface are varied among all studied genera. The dendrogram of palynological characters analyzed on LM and SEM observation by MVSP (Multi Variate Statistical Package) software partly supports the monophyletic genera. According to the obtained palynological dendrogram, Loncomelos arcuatum and Ornithogalum sintenisii are placed in one subtype. Based on the sporoderm structure (exine thickness and the endexine type), L. arcuatum differs from O. sintenisii. Finally, the palynological characters can be useful for clarifying the taxonomic relationship in this subfamily.


Author(s):  
Nakazo Watari ◽  
Yasuaki Hotta ◽  
Yoshio Mabuchi

It is very useful if we can observe the identical cell elements within the same sections by light microscopy (LM), transmission electron microscopy (TEM) and/or scanning electron microscopy (SEM) sequentially, because, the cell fine structure can not be indicated by LM, while the color is; on the other hand, the cell fine structure can be very easily observed by EM, although its color properties may not. However, there is one problem in that LM requires thick sections of over 1 μm, while EM needs very thin sections of under 100 nm. Recently, we have developed a new method to observe the same cell elements within the same plastic sections using both light and transmission (conventional or high-voltage) electron microscopes.In this paper, we have developed two new observation methods for the identical cell elements within the same sections, both plastic-embedded and paraffin-embedded, using light microscopy, transmission electron microscopy and/or scanning electron microscopy (Fig. 1).


Author(s):  
C. W. Kischer

The morphology of the fibroblasts changes markedly as the healing period from burn wounds progresses, through development of the hypertrophic scar, to resolution of the scar by a self-limiting process of maturation or therapeutic resolution. In addition, hypertrophic scars contain an increased cell proliferation largely made up of fibroblasts. This tremendous population of fibroblasts seems congruous with the abundance of collagen and ground substance. The fine structure of these cells should reflect some aspects of the metabolic activity necessary for production of the scar, and might presage the stage of maturation.A comparison of the fine structure of the fibroblasts from normal skin, different scar types, and granulation tissue has been made by transmission (TEM) and scanning electron microscopy (SEM).


Author(s):  
P. A. Madden ◽  
W. R. Anderson

The intestinal roundworm of swine is pinkish in color and about the diameter of a lead pencil. Adult worms, taken from parasitized swine, frequently were observed with macroscopic lesions on their cuticule. Those possessing such lesions were rinsed in distilled water, and cylindrical segments of the affected areas were removed. Some of the segments were fixed in buffered formalin before freeze-drying; others were freeze-dried immediately. Initially, specimens were quenched in liquid freon followed by immersion in liquid nitrogen. They were then placed in ampuoles in a freezer at −45C and sublimated by vacuum until dry. After the specimens appeared dry, the freezer was allowed to come to room temperature slowly while the vacuum was maintained. The dried specimens were attached to metal pegs with conductive silver paint and placed in a vacuum evaporator on a rotating tilting stage. They were then coated by evaporating an alloy of 20% palladium and 80% gold to a thickness of approximately 300 A°. The specimens were examined by secondary electron emmission in a scanning electron microscope.


Author(s):  
J. A. Traquair ◽  
E. G. Kokko

With the advent of improved dehydration techniques, scanning electron microscopy has become routine in anatomical studies of fungi. Fine structure of hyphae and spore surfaces has been illustrated for many hyphomycetes, and yet, the ultrastructure of the ubiquitous soil fungus, Geomyces pannorus (Link) Sigler & Carmichael has been neglected. This presentation shows that scanning and transmission electron microscopical data must be correlated in resolving septal structure and conidial release in G. pannorus.Although it is reported to be cellulolytic but not keratinolytic, G. pannorus is found on human skin, animals, birds, mushrooms, dung, roots, and frozen meat in addition to various organic soils. In fact, it readily adapts to growth at low temperatures.


Sign in / Sign up

Export Citation Format

Share Document