Developmental comparison of leaf shape variation in three Chamaedorea species

Botany ◽  
2009 ◽  
Vol 87 (2) ◽  
pp. 210-221 ◽  
Author(s):  
Julia Nowak ◽  
Adam Nowak ◽  
Usher Posluszny

Compound palm leaf development is unique and consists of two processes. First, the primordial tissue folds through differential growth, forming plications. Second, these plications separate through an abscission-like process, forming leaflets. The second process of leaflet separation allows for the development of compound leaves. The question that this study addresses concerns the development of bifid leaves, as they do not form leaflets but only develop a cleft through an apical incision. The ideal genus to use for this study is Chamaedorea as it includes species with both pinnate and bifid leaves. Chamaedorea fragrans (Ruiz & Pav.) Mart. and Chamaedorea stolonifera H. Wendl. ex Hook. f. were chosen as the species with adult bifid leaves. Although Chamaedorea seifrizii Burret is a pinnate-leaved palm, its juvenile leaves are bifid. Scanning electron microscopy and light microscopy were used to study the development of bifid leaves. Our results indicate that neither of these bifid palms develop separation sites within the lamina, but rather the apical cleft develops through “late leaflet separation” or by an abscission-like process. In contrast, C. seifrizii juvenile leaves exhibit “early leaflet separation” when developing the apical cleft.

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):  
D. Johnson ◽  
P. Moriearty

Since several species of Schistosoma, or blood fluke, parasitize man, these trematodes have been subjected to extensive study. Light microscopy and conventional electron microscopy have yielded much information about the morphology of the various stages; however, scanning electron microscopy has been little utilized for this purpose. As the figures demonstrate, scanning microscopy is particularly helpful in studying at high resolution characteristics of surface structure, which are important in determining host-parasite relationships.


Author(s):  
D.R. Hill ◽  
J.R. McCurry ◽  
L.P. Elliott ◽  
G. Howard

Germination of Euonymous americanus in the laboratory has previously been unsuccessful. Ability to germinate Euonymous americanus. commonly known as the american strawberry bush, is important in that it represents a valuable food source for the white-tailed deer. Utilizing the knowledge that its seeds spend a period of time in the rumin fluid of deer during their dormant stage, we were successful in initiating germination. After a three month drying period, the seeds were placed in 25 ml of buffered rumin fluid, pH 8 at 40°C for 48 hrs anaerobically. They were then allowed to dry at room temperature for 24 hrs, placed on moistened filter paper and enclosed within an environmental chamber. Approximately four weeks later germination was detected and verified by scanning electron microscopy; light microscopy provided inadequate resolution. An important point to note in this procedure is that scarification, which was thought to be vital for germination, proved to be unnecessary for successful germination to occur. It is believed that germination was propagated by the secretion of enzymes or prescence of acids produced by microorganisms found in the rumin fluid since sterilized rumin failed to bring about germination.


2009 ◽  
Vol 18 (2) ◽  
pp. 191-195
Author(s):  
E.V. Soldatenko

The radula morphology and the anatomy of the copulatory apparatus in Kolhymorbis angarensis were examined using light microscopy, scanning electron microscopy (SEM) and histological methods. Kolhymorbis angarensis was shown to have the stylet and the penial sac with a glandular appendage (flagellum), the characteristics, previously unknown for any species of this genus. The significance of these findings for the taxonomy of the genus is discussed.


2010 ◽  
Vol 192 (7) ◽  
pp. 1751-1760 ◽  
Author(s):  
Esther Julián ◽  
Mónica Roldán ◽  
Alejandro Sánchez-Chardi ◽  
Oihane Astola ◽  
Gemma Agustí ◽  
...  

ABSTRACT The aggregation of mycobacterial cells in a definite order, forming microscopic structures that resemble cords, is known as cord formation, or cording, and is considered a virulence factor in the M ycobacterium tuberculosis complex and the species M ycobacterium marinum. In the 1950s, cording was related to a trehalose dimycolate lipid that, consequently, was named the cord factor. However, modern techniques of microbial genetics have revealed that cording can be affected by mutations in genes not directly involved in trehalose dimycolate biosynthesis. Therefore, questions such as “How does mycobacterial cord formation occur?” and “Which molecular factors play a role in cord formation?” remain unanswered. At present, one of the problems in cording studies is the correct interpretation of cording morphology. Using optical microscopy, it is sometimes difficult to distinguish between cording and clumping, which is a general property of mycobacteria due to their hydrophobic surfaces. In this work, we provide a new way to visualize cords in great detail using scanning electron microscopy, and we show the first scanning electron microscopy images of the ultrastructure of mycobacterial cords, making this technique the ideal tool for cording studies. This technique has enabled us to affirm that nonpathogenic mycobacteria also form microscopic cords. Finally, we demonstrate that a strong correlation exists between microscopic cords, rough colonial morphology, and increased persistence of mycobacteria inside macrophages.


1984 ◽  
Vol 32 (5) ◽  
pp. 561 ◽  
Author(s):  
PY Ladiges

The trichomes of Angophora and Eucalyptus are illustrated from scanning electron microscopy and light microscopy, and evolutionary trends are discussed. Bristle glands of Angophora and Eucalyptus subgen. Blakella and Corymbia are emergent oil glands of varying lengths. Emergent oil glands occur in all other Eucalyptus subgenera but they are most conspicuous in Blakella, Corymbia and Angophora, in which they are characterized by four cap cells each ornamented with micropapillae. Hairs in Angophora are unique, being multicellular; they are also uniseriate and scattered on the epidermis. In contrast, hairs in Eucalyptus are simple extensions, short or long, of the cells on the sides of or the cap cells of the emergent oil glands, and they are not homologous with those of Angophora. Eucalyptus setosa (subgen. Blakella) and E. brockwayi (subgen. Symphyomyrtus) are two exceptions, having unicellular hairs on the epidermis, not associated with oil glands. It is suggested that this is an ancestral condition (or secondary reversal to it).


Phytotaxa ◽  
2021 ◽  
Vol 502 (2) ◽  
pp. 191-207
Author(s):  
SHIVANI KASHYAP ◽  
CHANDAN KUMAR SAHU ◽  
ROHIT KUMAR VERMA ◽  
LAL BABU CHAUDHARY

Due to large size and enormous morphological plasticity, the taxonomy of the genus Astragalus is very complex and challenging. The identification and grouping of species chiefly based on macromorphological characters become sometimes difficult in the genus. In the present study, the micromorphology of the seeds of 30 species belonging to 14 sections of Astragalus from India has been examined applying scanning electron microscopy (SEM) along with light microscopy (LM) to evaluate their role in identification and classification. Attention was paid to colour, shape, size and surface of seeds. The overall size of the seeds ranges from 1.5–3.2 × 0.8–2.2 mm. The shape of the seeds is cordiform, deltoid, mitiform, orbicular, ovoid and reniform. The colour of seeds varies from brown to blackish-brown to black. Papillose, reticulate, ribbed, rugulate and stellate patterns were observed on the seed coat surface (spermoderm) among different species. The study reveals that the seed coat ornamentations have evolved differently among species and do not support the subgeneric and sectional divisions of the genus. However, they add an additional feature to the individual species, which may help in identification in combination with other macro-morphological features.


2012 ◽  
Vol 40 (1) ◽  
pp. 35 ◽  
Author(s):  
Hüseyin CILDIR ◽  
Ahmet KAHRAMAN ◽  
Musa DOGAN

In this study, the epidermal types and their distribution on dorsal and lateral petals, the trichome types and their density on sepals of Lathyrus chloranthus, L. digitatus, L. laxiflorus subsp. laxiflorus, L. roseus subsp. roseus, L. sativus, and L. tuberosus, belonging to sections Lathyrus, Lathyrostylis, Pratensis, and Orobon of the genus Lathyrus in Turkey were investigated using light microscopy (LM) and scanning electron microscopy (SEM), and the systematic significance of these characters was evaluated. These taxa, except L. sativus, are studied for the first time under aspects of the petal and sepal micromorphology. Three major epidermal types were recognized on the petal: tabular rugose striate cells (TRS), areolate cells with more or less striations (AS), and papillose conical striate cells (PCS). TRS and AS were further subdivided into three subtypes. TRS was found on the dorsal and lateral petals of L. chloranthus, L. sativus, and L. tuberosus: the dorsal petals of L. roseus subsp. roseus and the lateral petals of L. laxiflorus subsp. laxiflorus, while AS was present on the dorsal and lateral petals of L. digitatus and the lateral petals of L. roseus subsp. roseus. PCS was found only on the dorsal petals of L. digitatus. Three main types of trichomes on the sepal were observed: peltate glandular, capitate glandular, and nonglandular trichomes. The capitate glandular and nonglandular trichomes were further subdivided into three subtypes. The peltate glandular trichomes were present only in L. chloranthus, but absent in the others. The capitate glandular trichomes were found in L. chloranthus, L. laxiflorus subsp. laxiflorus, L. roseus subsp. roseus, and L. tuberosus. The nonglandular trichomes were always present in L. chloranthus and L. laxiflorus subsp. laxiflorus. The present results show that the petal and sepal micromorphology can be used in delimitation of the taxa based on petal and sepal micromorphology.


2017 ◽  
pp. 66
Author(s):  
Aída Carrillo-Ocampo ◽  
E.M. Engleman

With methods of light microscopy, histochemical staining and scanning electron microscopy, it was found that the ovule in the seed of Tigridia pavonia (Iridaceae) is anatropous, bitegmic, and crassinucellate. During development, the exotegmen is crushed and the endotegmen persists with tannins in the lumens and in the walls, which also react positively for lignin. The exotesta contains tannins and its outer walls are convex, thickened, and cuticularized. The mesotesta has multiple layers, accumulates abundant lipids, and forms a bulge in the chalaza. The cell walls of the endotesta collapse and accumulate tannins. In the chalaza, a hypostasal cushion contains tannins in the lumens and in the walls, which also react positively for lignin. At the micropylar end of the seed there is an operculum which consists of: a) a slightly crushed exotegmen, b) an endotegmen with cuticular thickenings that are concentric with respect to the micropyle, c) hemispherical deposists of cutin on the anticlinal walls of the endotegmen, and c) a thin layer of endosperm that covers the radicle. During its cellular stage of development, the endosperm has conspicuous transfer walls at the chalazal end next to the nucella. The embryo is small and has a conical cotyledon.


Author(s):  
Marina Macukanovic-Jocic ◽  
Snezana Jaric

Palynomorphological characteristics of Campanula lingulata, the Balkan-Carpathian endemic species growing in Serbia, have been investigated using light microscopy and scanning electron microscopy for the first time, in order to provide some information helpful for a better understanding of the taxonomic position of this species within the genus, as well as to contribute to the pollen atlas of Serbian apiflora. The pollen grains are radially symmetrical, isopolar, 3-zonoporate and medium-sized monads oblate-sphaeroidal in shape. Mean of the polar axis (P) is 27.6?1.9 ?m, while the average length of the equatorial axis (E) is 28.8?1.6 ?m. The apertures are operculate. The sculpturing pattern of the exine is microre?ticulate-microechinatae. The exine surface is covered with evenly distributed supratectal spinules of variable length and sparse granules. The longest supratectal spinules are 0.64?0.05 ?m in length and the smallest sculptural elements are less than 0.2 ?m high. The microechinae density per sample area of 5 ?m x 5 ?m averages 17.4?2.4.


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