scholarly journals Spinnerets and silk-producing system of Segestria senoculata (Araneae, Araneomorphae, Segestriidae)

2016 ◽  
Vol 48 (3) ◽  
pp. 388 ◽  
Author(s):  
S. Karschová ◽  
J. Hajer

The spinning apparatus and silk of <em>Segestria senoculata</em> were studied with the use of scanning electron microscopy and light microscopy, which confirmed the presence of four categories of spigots connected with four types of spinning glands (<em>i.e</em>., <em>Glandulae ampullaceae major, Glandulae ampullaceae minor, Glandulae piriformes and Glandulae pseudaciniformes</em>). New data about the morphology of spinnerets and spigots were obtained for both the adults and nymphal stages of both sexes. For the first time the silken threads of retreats, signal threads and attachment discs of the members of <em>Segestria</em> were subjected to a detailed SEM study. The data resulting from studying the spinning apparatus of <em>S. senoculata</em> was compared to current knowledge of the silk producing systems of families belonging to the Dysderoidea superfamily. Silks that are emitted from spigots in the course of retreat construction are not (similarly to the other dysderoids) processed by the spider’s legs during the subsequent process of hardening. Apart from the major ampullate glands/spigots, segestriids also possess developed minor ampullate glands. Minor ampullate threads are used by <em>S. senoculata</em> spiders when making their signal threads.

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.


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.


1994 ◽  
Vol 6 (2) ◽  
pp. 215-222 ◽  
Author(s):  
Marek R. Lipinski ◽  
M. Deon Durholtz

It appears that squid statoliths cannot yet be regarded as accurate an ageing tool as fish otoliths. Statoliths from the same pair, prepared differently for viewing and counting increments, were compared. Increment counts do not imply age in days, because this was not validated. One statolith from each pair was examined by light microscopy (LM) after preparation following a new method. The other was viewed by Scanning Electron microscopy (SEM) with a modified etching solution. Shape of each statolith was similar when compared by multiple regression analysis (11 variables, n=53). There was a weak but significant difference between sexes (statoliths of females were slightly larger). All other differences were insignificant. Microscopic observation and increment counts of increments were successfully carried out for 37 pairs of statoliths. Significant differences between two independent counts were found for the LM method, but no significant differences were found between two independent SEM counts. Counts were significantly different when interpreted by both LM and SEM, probably because of poor resolution in the LM readings and over-resolution (growth layers prominent and numerous) in those read by SEM. Recommendations are made on how ageing studies, based on statoliths, should be structured and the results evaluated.


Phytotaxa ◽  
2015 ◽  
Vol 207 (1) ◽  
pp. 135 ◽  
Author(s):  
Giovanni Raul Bogota ◽  
Carina Hoorn ◽  
Wim Star ◽  
Rob Langelaan ◽  
Hannah Banks ◽  
...  

Sabinaria magnifica is so far the only known species in the recently discovered tropical palm genus Sabinaria (Arecaceae). Here we present a complete description of the pollen morphology of this palm species based on light microscopy (LM), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). We also made SEM-based comparisons of Sabinaria with other genera within the tribe Cryosophileae. Pollen grains of Sabinaria magnifica resemble the other genera in the heteropolar, slightly asymmetric monads, and the monosulcate and tectate exine with perforate surface. Nevertheless, there are some clear differences with Thrinax, Chelyocarpus and Cryosophila in terms of aperture and exine. S. magnifica differs from its closest relative, Itaya amicorum, in the exine structure. This study shows that a combination of microscope techniques is essential for the identification of different genera within the Cryosophileae and may also be a necessary when working with other palynologically less distinct palm genera. 


1988 ◽  
Vol 66 (5) ◽  
pp. 829-838 ◽  
Author(s):  
M. J. Hodson ◽  
A. G. Sangster

Silica deposition in the lower glume, lemma, and palea of wheat (Triticum aestivum L. cv. Highbury) was investigated using scanning electron microscopy and light microscopy. Silica was present in the outer walls of all the epidermal cells including prickles and papillae of the glume and lemma awns. The glume and the lemma were similar in epidermal silica deposition pattern, both having numerous silicified short trichomes and papillae on inner and outer surfaces. Epidermal long cells and short cells were also silicified. Macrohairs were restricted to isolated areas in these bracts, particularly on the inner surfaces just beneath the awns. The palea was a thin membranous structure differing markedly from the other two bracts. Most of the palea is pressed between the caryopsis and the next floret, and both surfaces are almost devoid of trichomes in these areas. However, at the apex and margins of the palea, macrohairs and papillae were abundant. The results are discussed with respect to possible taxonomic, anatomical, medical, and archaeological implications.


2010 ◽  
Vol 55 (1) ◽  
Author(s):  
Zhu Ming ◽  
Li Zhang ◽  
Luping Zhang

AbstractMonodontella giraffae Yorke et Maplestone, 1926 was collected from the biliary duct of liver of a dead giraffe, Giraffa camelopardalis (Linnaeus) from the Tianjin Zoo, Tianjin, China. A redescription of this species was made using light microscopy and scanning electron microscopy (SEM). The lateral alae and the detailed structures of the spicules and genital cone were observed for the first time by SEM. The taxonomic status of the genus is discussed.


2002 ◽  
Vol 13 (3) ◽  
pp. 170-174 ◽  
Author(s):  
Luciane R.R S. Costa ◽  
Ii-Sei Watanabe ◽  
Márcia C. Kronka ◽  
Marcelo C.P. Silva

The dentin structure of non-erupted human deciduous mandibular and maxillary central and lateral incisor teeth was studied employing light and scanning electron microscopy. For light microscopy, nitric-acid-demineralized and ground sections were used. The sections were stained by hematoxylin-eosin, picrosirius and azo-carmim methods, and ground specimens were prepared using a carborundum disk mounted in a handpiece. For SEM study, teeth were frozen in liquid nitrogen and fractured at longitudinal and transversal directions. Structurally, demineralization and ground methods revealed tubules with primary and secondary curvatures, canaliculi, giant tubules, interglobular dentin, predentin, and intertubular dentin. Scanning electron microscopy showed three-dimensional aspects of dentinal tubules, canaliculi, peritubular dentin, intertubular dentin, and predentin. This study contributes to knowledge about dentin morphology showing characteristics of teeth not yet submitted to mastication stress.


Weed Science ◽  
1978 ◽  
Vol 26 (6) ◽  
pp. 619-625 ◽  
Author(s):  
R. E. Hoagland ◽  
R. N. Paul

A comparative scanning electron microscopy (SEM) study was performed on the surfaces of seeds and coleoptiles of several conspecific rice(Oryza sativaL.) varieties including the weed red rice and several cultivars: Mochi-Gommi and LA-110 (medium grained); Starbonnet, Labelle, and Bluebelle (long grained). Seed surfaces of red rice, LA-110 and Mochi-Gommi possessed trichomes that were more numerous at the seed apex than on other seed parts. Red rice also exhibited a large central awn extending from the seed apex. This awn had spines along its axis and numerous spines at its apical end. These characteristics were absent in the other varieties. No significant differences were noted in the seed-surface tubercles and in the quantity or structure of wax on the seed surface in all six samples. The coleoptiles of all samples had several similarities: the stomata were arranged in parallel rows on both the adaxial and abaxial surfaces, the epicuticular wax structure on both surfaces was rodlet, prickle hairs were found on the adaxial coleoptile surface (but absent on abaxial), spines were present on the edge of the apical end (older portion) and decreased in number toward the basal end (younger portion), and two types of papillae (based on size and shape) were present on both the adaxial and abaxial surfaces. Although there were varietal differences among developing coleoptiles on a macroscopic scale, significant morphological differences were not discernible at the SEM level.


Zootaxa ◽  
2007 ◽  
Vol 1559 (1) ◽  
pp. 31-57 ◽  
Author(s):  
THIAGO DA SILVA PAIVA ◽  
INÁCIO DOMINGOS DA SILVA-NETO

A population of the rare species Strongylidium pseudocrassum Wang and Nie, 1935, was discovered from a lagoon in the northern region of Rio de Janeiro, Brazil, and its morphology was investigated through protargol-impregnation, scanning electron microscopy and in vivo observations. Morphogenetic events of cell division and physiological reorganization were described for the first time to this species. It was found that S. pseudocrassum has the ventral cirral rows organized in the same manner as Pseudouroleptus caudatus Hemberger, 1985. However two independent primordia VI, one for the proter and other for the opisthe, are generated intrakinetally from the rightmost ventral cirral row. In addition, dorsal kineties replicate entirely “de novo” and do not fragment. Based on the data obtained, the genus Strongylidium was redefined and the species currently assigned to it were classified into five groups according to current knowledge on their ciliature and the combination S. lentum (Biernacka, 1963) nov. comb. is proposed.


2012 ◽  
Vol 60 (3) ◽  
pp. 260 ◽  
Author(s):  
Andrew H. Thornhill ◽  
Geoff S. Hope ◽  
Lyn A. Craven ◽  
Michael D. Crisp

Pollen morphology of 44 genera and 101 species from the Myrtaceae tribes Kanieae, Myrteae and Tristanieae was surveyed using scanning electron microscopy (SEM) and light microscopy (LM). Most Myrteae pollen were brevicolpate and granulate, which is unique within Myrtaceae, and these are most likely ancestral characters for this tribe. Two main pollen types were observed in tribe Kanieae, one form being with syncolpate colpi and a distinctive granulate exine, and the other with parasyncolpate colpi and a less ornamented exine. Genera Tristania and Thaleropia of tribe Tristanieae produce the smallest pollen in Myrtaceae, whereas Octamyrtus of tribe Myrteae produces the largest pollen observed in Myrtaceae.


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