Study on the ultrastructure and properties of gelatinous layer in poplar

2020 ◽  
Vol 56 (1) ◽  
pp. 415-427
Author(s):  
Rui Liang ◽  
Yu-Hui Zhu ◽  
Xu Yang ◽  
Jing-Shu Gao ◽  
Yao-Li Zhang ◽  
...  
Keyword(s):  
Gelatinous Layer

The nature of reaction wood. IV. Variations in cell wall organization of tension wood fibres

1955 ◽  
Vol 3 (2) ◽  
pp. 177 ◽  
Author(s):  
AB Wardrop ◽  
HE Dadswell
Keyword(s):  
Cell Wall ◽  
Tension Wood ◽  
Secondary Wall ◽  
Degree Of Crystallinity ◽  
Tropical Species ◽  
Normal Wood ◽  
Reaction Wood ◽  
Gelatinous Layer ◽  
Wood Fibres ◽  
Cell Wall Organization

The cell wall organization, the cell wall texture, and the degree of lignification of tension wood fibres have been investigated in a wide variety of temperate and tropical species. Following earlier work describing the cell wall structure of tension wood fibres, two additional types of cell wall organization have been observed. In one of these, the inner thick "gelatinous" layer which is typical of tension wood fibres exists in addition to the normal three-layered structure of the secondary wall; in the other only the outer layer of the secondary wall and the thick gelatinous layer are present. In all the tension wood examined the micellar orientation in the inner gelatinous layer has been shown to be nearly axial and the cellulose of this layer found to be in a highly crystalline state. A general argument is presented as to the meaning of differences in the degree, of crystallinity of cellulose. The high degree of crystallinity of cellulose in tension wood as compared with normal wood is attributed to a greater degree of lateral order in the crystalline regions of tension wood, whereas the paracrystalline phase is similar in both cases. The degree of lignification in tension wood fibres has been shown to be extremely variable. However, where the degree of tension wood development is marked as revealed by the thickness of the gelatinous layer the lack of lignification is also most marked. Severity of tension wood formation and lack of lignification have also been correlated with the incidence of irreversible collapse in tension wood. Such collapse can occur even when no whole fibres are present, e.g. in thin cross sections. Microscopic examination of collapsed samples of tension wood has led to the conclusion that the appearance of collapse in specimens containing tendon wood can often be attributed in part to excessive shrinkage associated with the development of fissures between cells, although true collapse does also occur. Possible explanations of the irreversible shrinkage and collapse of tension wood fibres are advanced.

scholarly journals On the detachment of the gelatinous layer in tension wood fiber

2005 ◽  
Vol 51 (3) ◽  
pp. 218-221 ◽  
Author(s):  
Bruno Clair ◽  
Bernard Thibaut ◽  
Junji Sugiyama
Keyword(s):  
Tension Wood ◽  
Wood Fiber ◽  
Gelatinous Layer

scholarly journals Structural analysis of the Pimelodus maculatus (Lacépède, 1803) embryogenesis (Siluriformes: Pimelodidae)

2011 ◽  
Vol 9 (3) ◽  
pp. 601-616 ◽  
Author(s):  
Hellen Buzollo ◽  
Rosicleire Veríssimo-Silveira ◽  
Isângela R. Oliveira-Almeida ◽  
Juliana S. Alexandre ◽  
Hélio T. Okuda ◽  
...  
Keyword(s):  
Embryonic Development ◽  
Cleavage Pattern ◽  
Posterior Intestine ◽  
Gelatinous Layer ◽  
Eyes Closed ◽  
Mean Diameter ◽  
Survival Studies ◽  
Otic Vesicles ◽  
Pimelodus Maculatus ◽  
Duration Of Development

The fish embryonic development comprises the events between the egg fertilization up to larvae hatching, being useful for the identification of viable eggs in productivity and survival studies as well as in raising experiments of several species. The goal of the present study was to characterize the embryonic development of Pimelodus maculatus (Siluriformes; Pimelodidae). The embryogenesis was typical of teleosteans, but with differences in relation to other species such as duration of development, type of blastocoel, moment of somite segmentation among others. Six stages of embryonic development were defined: zygote, cleavage, blastula, gastrula, organogenesis (divided in phases: early segmentation and late segmentation) and hatching with a period of incubation equal to 13 hours at 29 ºC and 17 hours at 25 ºC. The extruded oocytes presented a mean diameter of 812 µm before and 1066 µm after hydration. When fertilized, they presented a yellowish coloration and a gelatinous layer surrounding the chorion. The cleavage pattern is described as: 2; 4; 8 (4x2); 16 (4x4); 32 (4x8) and 64 (2x4x8) blastomeres up to morula phase (+64 cells). It was also possible to observe at this phase, the beginning of the formation of the yolk syncyctial layer (YSL). Afterwards, the blastula and gastrula stages followed. The end of gastrula was characterized by the formation of the yolk plug. Subsequently, the differentiation between cephalic and caudal regions began, along with the embryo elongation, structuring of optic, Kupffer's and otic vesicles besides a previously unidentified structure in the yolk syncyctial layer. The end of this stage is typified by the tail detachment. The late segmentation phase was distinguished by a free tail, presence of more than 30 somites, optic and otic vesicles, development of posterior intestine, pigmentation of cephalic and caudal regions of yolk sac and embryo growth. The recently-hatched larvae presented a primordial digestive tract, quite evident and pigmented eyes, closed mouth, encephalic vesicles and a mean length of 3410 µm.

scholarly journals Relationship Between Growth Stress, Mechanical-Physical Properties and Proportion of Fibre with Gelatinous Layer in Chestnut (Castanea Sativa Mill.)

Holzforschung ◽  
2003 ◽  
Vol 57 (2) ◽  
pp. 189-195 ◽  
Author(s):  
B. Clair ◽  
J. Ruelle ◽  
B. Thibaut
Keyword(s):  
Physical Properties ◽  
Castanea Sativa ◽  
Wood Properties ◽  
Growth Stress ◽  
Gelatinous Layer ◽  
Basic Model ◽  
Mechanical And Physical Properties ◽  
Castanea Sativa Mill ◽  
Chestnut Wood

Summary A range of mechanical and physical properties were determined for 96 specimens of chestnut wood and for wood types ranging from compression to tension wood; tests included (1) growth stress, (2) longitudinal Young's modulus in green and air-dried states (3) shrinkage in longitudinal and tangential directions. Anatomical observations permitted determination of the proportion of fibres with a gelatinous layer. The influence of these atypical fibres on macroscopic wood properties is examined and discussed. A basic model is proposed to determine their properties in theoretically isolated conditions.

Pyrenocarpous lichens (except Trypetheliaceae) in Rondônia

2013 ◽  
Vol 45 (6) ◽  
pp. 763-785 ◽  
Author(s):  
André APTROOT ◽  
Marcela Eugenia da Silva CÁCERES
Keyword(s):  
New Species ◽  
Ground Level ◽  
Gelatinous Layer ◽  
Lichen Diversity ◽  
The Poor ◽  
Pyrenocarpous Lichens ◽  
Dense Forest ◽  
Rich Flora ◽  
Crustose Lichens ◽  
First Time

AbstractThe following new species of pyrenocarpous lichens are described from Rondônia: Agonimia tenuiloba: corticolous, thallus with minute flabellate lobes developing goniocysts; ascomata smooth, grey, ellipsoidal; ascospores densely muriform, 30–50(–76)×20–35 µm. Anisomeridium lateriticum: saxicolous; conidiomata sessile, pyriform, ostiole with brown and hyaline septate setae; conidia simple to 1-septate, 8–11×2·0–2·5 µm. Anisomeridium triseptatum: corticolous, ascomata with lateral ostioles; ascospores (1–)3-septate, 25–30×7·5–10·0 µm, often with gelatinous appendages. Mycomicrothelia megaspora: ascospores ornamented, 1-septate, (27–)29–35(–40)×8–12 µm, often with a gelatinous layer 6–15 µm thick. Porina linearispora: corticolous; thallus green, shiny; ascomata immersed, 0·2–0·3 mm; ascospores filiform, (7–)9(–13)-septate, 75–90×1·5–2·0 µm. Porina maxispora: corticolous; thallus green, matt; ascomata immersed, 0·5–0·7 mm; ascospores filiform, (17–)23–35-septate, 95–110×4·5–5·5 µm. Porina novemseptatoides: saxicolous; thallus very thin, brown, glossy; ascomata superficial, 0·1–0·2 mm; ascospores fusiform, (7–)9-septate, 21–24×4·5–5·0 µm, with a c. 5 µm thick gelatinous layer. Porina termitophila: terricolous; thallus greyish green; ascomata emergent, 0·15–0·20 mm; ascospores fusiform, 1–3-septate, 13–15×2·5–3·0 µm. Pyrenula bispora: corticolous, thallus whitish, ascomata dispersed; hamathecium inspersed; ascospores 2 per ascus, muriform, 55–75×19–23 µm. Pyrenula leptaleoides: corticolous; thallus green to pale brown; ascomata deeply immersed in bark, with long necks fused in joint ostioles visible as brown dots on the surface; ascospores 23–27×8–11 µm, with rather angular lumina. Pyrenula rhomboidea: corticolous; thallus olive-brown; ascomata single, immersed; ascospores irregularly uniseriate, clavate-rhomboidal, 11–13×3·5–4·0 µm.A key is provided to all species of pyrenocarpous lichens (except Trypetheliaceae) found in Rondônia. Nearly all species are new reports for Rondônia. Aspidothelium glabrum, Pyrenula leucotrypa and P. micheneri are newly reported for South America. The usually foliicolous Strigula nitidula is reported for the first time from bark.The high lichen diversity is explained by the poor soils, supporting an only moderately dense forest where enough light can reach the tree trunks at ground level to support a rich flora of crustose lichens usually confined to the upper trunks.

CHARACTERISTICS OF TROCHODENDRON ARALIOIDES TENSION WOOD FORMED AT DIFFERENT INCLINATION ANGLES

IAWA Journal ◽  
2013 ◽  
Vol 34 (3) ◽  
pp. 273-284 ◽  
Author(s):  
Tokiko Hiraiwa ◽  
Tatsuya Toyoizumi ◽  
Futoshi Ishiguri ◽  
Kazuya Iizuka ◽  
Shinso Yokota ◽  
...  
Keyword(s):  
Tension Wood ◽  
Growth Promotion ◽  
Growth Stress ◽  
Aperture Angle ◽  
Wall Structure ◽  
Cellulose Content ◽  
Klason Lignin ◽  
Glucose Content ◽  
Gelatinous Layer ◽  
Inclination Angles

To assess the characteristics of tension wood (TW) in Trochodendron aralioides Sieb. et Zucc., seedling stems were artificially inclined at angles of 30° (TW- 30), 50° (TW-50), and 70° (TW-70) from the vertical. At all angles, the growth promotion was pronounced on the upper side of the inclined stems, where excessive tensile growth stress was observed. A gelatinous layer (G-layer) formed in the tracheids of TW. The cell wall structure of the tracheids in TW was S1 + G. The G-layer had a small pit aperture angle <10°. TW-50 showed larger tensile growth stress, a thicker G-layer area, and a smaller pit aperture angle of the Glayer than TW-30 and TW-70. Lower levels of Klason lignin and hemicellulose and higher levels of α-cellulose content were observed in TW-50. In addition, an increase in glucose content and a decrease in xylose content in holocellulose were observed in TW-50. Therefore, it can be concluded that the degree of TW varied with different inclination angles.

The nature of reaction wood. VI. The reaction anatomy of seedlings of woody perennials.

1962 ◽  
Vol 10 (2) ◽  
pp. 93 ◽  
Author(s):  
G Scurfield ◽  
AB Wardrop
Keyword(s):  
Fibre Length ◽  
Structural Features ◽  
Age Difference ◽  
Reaction Wood ◽  
Lower Side ◽  
Electron Microscopic ◽  
Cortical Cells ◽  
Gelatinous Layer ◽  
Ray Cells ◽  
Electron Microscopes

The reaction anatomy of the stems of seedlings of A 1 species of hroad-leaved trees was examined. The reaction was induced by bending the stems at right angles or growing the plants horizontally. As a result of greater cambial activity on the upper side such stems developed a structural asymmetry characterized by enhanced xylem and phloem development. The structural features of the lower side were similar to those of stems grown vertically. The xylem on the upper side contained fewer vessels, more fibres, and fewer medullary rays than that on the lower side of the same stem. "Gelatinous" layers developed within the reaction fibres as well as in fibres of the phloem. Vessels, medullary ray cells, and parenchyma cells were often compressed and sometimes obliterated. Reaction fibres showed reduced wall pitting and tended to retain their contents until they lay relatively deep within the stem. There were no differences in fibre length between upper and lower sides of the stem, but comparisons were probably confounded with an age difference. Cortical cells and, in species where they occurred, canals were compressed on that side of the stem. Such cortical cells were not only smaller in cross section than those on the lower side, but were also shorter in length. This was also a feature of medullary ray cells. There was a greater accumulation of tannins in phloem and cortex on the upper side of the stem. The structure of reaction fibres was examined in ultraviolet, polarizing, and electron microscopes. In the first of these, the "gelatinous" layer was seen to consist of a series of concentric bands convoluted towards the cell lumen, the bands containing radial striations. The polarizing microscope showed that the innermost part of the wall possessed some birefringence. Both convolutions and birefringence tended to disappear as the cells matured; staining with Congo red became less intense. The heterogeneity of the "gelatinous" layer was confirmed by electron microscopic examination. The results are discussed in connection with the gravimorphic responses of displaced stems, the altered patterns of lignification, and the development of growth stresses in such stems.

scholarly journals Localization of xyloglucan epitopes in the gelatinous layer of developing and mature gelatinous fibers of European aspen (Populus tremula L.) tension wood

BioResources ◽  
2019 ◽  
Vol 14 (4) ◽  
pp. 7675-7686
Author(s):  
Jong Sik Kim ◽  
Geoffrey Daniel
Keyword(s):  
Tension Wood ◽  
Developmental Changes ◽  
Immunogold Localization ◽  
Gelatinous Layer ◽  
Gelatinous Fibers ◽  
Transmission Electron ◽  
European Aspen ◽  
Innermost Layer ◽  
Specific Localization ◽  
Populus Spp

There is controversy concerning the presence of xyloglucans in gelatinous (G) layers of Populus spp. tension wood, particularly in mature G-fibers. Transmission electron microscopy (TEM) immunogold localization combined with LM15 antibody (recognizes XXXG-motif of xyloglucans, heptasaccharide) was used to investigate the distribution of xyloglucan epitopes in both transverse and radial sections of P. tremula tension wood. Results provided clear evidence for the presence of xyloglucans in both mature and developing G-layers. Developmental decrease of LM15 epitope localization in G-layers was also detected during G-fiber maturation. High magnification TEM observations showed specific localization of LM15 epitopes on newly synthesized cellulose macrofibrils present in the innermost layer of developing G-layers adjacent to the cell lumen, suggesting linkage between xyloglucans and cellulose macrofibrils. Possible mechanisms were discussed for developmental changes of xyloglucan with respect to the different results reported in the literature.

HPMC- A Marvel Polymer for Pharmaceutical Industry-Patent review

2021 ◽  
Vol 15 ◽  
Author(s):  
Kumar Guarve ◽  
Priyanka Kriplani
Keyword(s):  
Methyl Cellulose ◽  
Dosage Forms ◽  
Delivery Systems ◽  
Gelatinous Layer ◽  
Dispersing Agent ◽  
Patent Review ◽  
Film Forming ◽  
Cellulosic Polymer ◽  
Hydrophilic Gel ◽  
Polymer Erosion

: At the present time, designing of defined release dosage forms, either controlled, sustained, modified, are gaining much importance. For the development of such delivery systems, proper blend of polymers is required, so that drug release occurs by polymer erosion, swelling, diffusion/dissolution. HPMC (hydroxypropyl methyl cellulose) is the most commonly used cellulosic polymer available in various grades to develop such types of systems. Depending upon the molecular weight and viscosity chosen, it can be applied for emulsification, adhesion, bonding, thickening, suspension, film forming and gelation. It consists of polymeric units linked together, which retain water, thereby acting as an excellent hydrophilic gel-forming polymer. It generally hydrates on the outer surface to form a gelatinous layer. It swells, expands upon contact with water and releases the drug in a predetermined manner initially and then forms a viscous gel to control the release further. The objective of the present review is to overview the recent patents and articles of HPMC, its properties, grades and its use in various drug delivery systems and as a binder, dispersing agent, bioavailability enhancer and as capsule forming material have been identified and reviewed.

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