Microscopie de la mycoflore des aiguilles de Sapin blanc (Abies alba). IV. Décomposition de la cuticule, de l'hypoderme et de l'épiderme

1989 ◽  
Vol 67 (3) ◽  
pp. 933-939 ◽  
Author(s):  
François Gourbière ◽  
Régis Pépin ◽  
Dominique Bernillon
Keyword(s):  
Cell Wall ◽  
Light And Electron Microscopy ◽  
Abies Alba ◽  
Soft Rot ◽  
Fungal Species ◽  
White Rot ◽  
Type I ◽  
Parenchyma Cells ◽  
Coniferous Needles ◽  
Stage 1

Degradation of protective tissues of coniferous needles (Abies alba Mill.) was examined by light and electron microscopy. Cuticle and hypodermis were destroyed at the beginning of the F1 stage, 1 year after needle fall. Hyphae from the superficial mycelium penetrated and colonized the cuticle, giving rise to numerous cavities throughout the cuticular layers. At the same time the cell wall of the hypodermis was invaded by soft rot fungi (type I) and hyphae grew within cavities within the secondary wall. During the F2 stage the epidermis was also destroyed by formation of cavities in the cell wall. At this time the remaining cuticle gave a typical wrinkled appearance to the needle surface. Hypotheses about the fungal species implicated in these activities are discussed. These processes do not affect residual cytoplasm of parenchyma cells and appear to be strongly different from white rot degradation of litter.

Degradation of the lignocellulose complex in wood

1995 ◽  
Vol 73 (S1) ◽  
pp. 999-1010 ◽  
Author(s):  
Robert A. Blanchette
Keyword(s):  
Cell Wall ◽  
White Rot Fungi ◽  
Brown Rot ◽  
Forest Products ◽  
Soft Rot ◽  
Cell Types ◽  
White Rot ◽  
Bacterial Degradation ◽  
White Rot Fungus ◽  
Type I

Degradation of the lignocellulose complex in wood varies depending on the microorganism causing decay. The degradative processes of white-, brown-, and soft-rot fungi as well as different forms of bacterial degradation are presented. Ultrastructural methods were used to elucidate cell-wall alterations that occurred during the various stages of decay. In wood inoculated with the white-rot fungus Ceriporiopsis subvermispora, changes in the cell wall, such as electron-dense zones after staining with uranyl acetate, were evident during incipient stages of decay. The ratio of syringyl:guaiacyl lignin of different woods, different cell types, and even the different layers within a cell wall influenced the type and extent of decay by white-rot fungi. Soft rots caused unique changes in the lignocellulose matrix. The type of wood substrate governed the form (type I or type II) of soft rot that occurred. Brown-rot fungi depolymerized cellulose early in the decay process and degraded cellulose without prior removal of lignin. Bacterial degradation was common in waterlogged woods and three forms, tunneling, erosion and cavitation, are discussed. In addition to an improved understanding of decay processes in living trees and forest products, knowledge of decomposition mechanisms is important to utilize effectively these microorganisms for new industrial bioprocessing technologies. Key words: biodegradation, white rot, brown rot, soft rot, bacterial degradation.

Resistance of hardwood vessels to degradation by white rot Basidiomycetes

1988 ◽  
Vol 66 (9) ◽  
pp. 1841-1847 ◽  
Author(s):  
Robert A. Blanchette ◽  
John R. Obst ◽  
John I. Hedges ◽  
Karen Weliky
Keyword(s):  
Cell Wall ◽  
Secondary Wall ◽  
White Rot ◽  
Fungal Decay ◽  
Acacia Koa ◽  
Monomer Composition ◽  
Lignin Removal ◽  
Vessel Elements ◽  
Parenchyma Cells ◽  
Unusual Type

White stringy rot, an unusual type of selective fungal decay, can be found in wood of some dicotyledonous angiosperms. Stages of advanced decay consist of a mass of vessel elements with only remnants of other cells adhering to the vessel walls. Degradation by various white rot Basidiomycetes causes loss of fibers, fiber tracheids, and parenchyma cells but not vessels. In wood of Acacia koa var. koa with a white pocket rot caused by Phellinus kawakamii, fibers and parenchyma cells were preferentially delignified. After extensive lignin removal the cellulose remaining in the secondary wall was degraded. Large vessel elements remained relatively intact after other cells were completely degraded. The resistance of vessels to degradation appears to be due to their high ligninxarbohydrate ratio, lignin monomer composition, and cell wall morphology.

scholarly journals Comparison of the Decay Behavior of Two White-Rot Fungi in Relation to Wood Type and Exposure Conditions

2020 ◽  
Vol 8 (12) ◽  
pp. 1931
Author(s):  
Ehsan Bari ◽  
Geoffrey Daniel ◽  
Nural Yilgor ◽  
Jong Sik Kim ◽  
Mohammad Ali Tajick-Ghanbary ◽  
...  
Keyword(s):  
Cell Wall ◽  
Moisture Content ◽  
Wood Species ◽  
White Rot Fungi ◽  
White Rot ◽  
High Mass ◽  
Type I ◽  
Oak Wood ◽  
Mass Losses ◽  
Decay Behavior

Fungal wood decay strategies are influenced by several factors, such as wood species, moisture content, and temperature. This study aims to evaluate wood degradation characteristics of spruce, beech, and oak after exposure to the white-rot fungi Pleurotusostreatus and Trametesversicolor. Both fungi caused high mass losses in beech wood, while spruce and oak wood were more resistant to decay. The moisture content values of the decayed wood correlated with the mass losses for all three wood species and incubation periods. Combined microscopic and chemical studies indicated that the two fungi differed in their decay behavior. While T. versicolor produced a decay pattern (cell wall erosion) typical of white-rot fungi in all wood species, P. ostreatus caused cell wall erosion in spruce and beech and soft-rot type I (cavity formation) decay in oak wood. These observations suggest that P. ostreatus may have the capacity to produce a wider range of enzymes/radicals triggered by the chemical composition of wood cell walls and/or local compositional variability within the cell wall.

Microscopie de la mycoflore des aiguilles de sapin (Abies alba). II. Lophodermium piceae

1986 ◽  
Vol 64 (1) ◽  
pp. 102-107 ◽  
Author(s):  
François Gourbière ◽  
Régis Pépin ◽  
Dominique Bernillon
Keyword(s):  
Electron Microscopy ◽  
Cell Wall ◽  
Light And Electron Microscopy ◽  
Abies Alba ◽  
Living Cells

Colonization of Abies alba Mill, needles by Lophodermium piceae (Fckl.) Höhn. (Ascomycetes, Hypodermataceae) was studied by light and electron microscopy. Internal mycelium is at first extracellular and invades all the tissues of the needle; thereafter hyphae may penetrate all cells. Cytoplasm and walls of living cells (parenchyma, phloem, cellulosic transfusion tissues) are then lysed. Hyphae also invade thick-walled and lignified cells (epidermis, hypodermis, xylem, tracheids, and fibers of transfusion tissues) without major degradation of the cell wall. Ascomatal development is intraepidermic. Colonization of the needles is limited by black areas (the diaphragms), the structure of which is described. Lophodermium piceae is a primary saprophyte. Needles are colonized during senescence but ascomata appear only on fallen needles. There are about 230 ascomata per gram of needles. The ecology of this fungus is compared with that of Thysanophora penicillioides (Roum.) Kendrick on Abies needles and with that of Lophodermium pinastri (Schrad.) Chev. on Pinus needles.

Performance of waterborne copper/organic wood preservatives in an AWPA E14 soft-rot laboratory soil bed test using modified soil

Holzforschung ◽  
2017 ◽  
Vol 71 (9) ◽  
pp. 759-763 ◽  
Author(s):  
Darrel Nicholas
Keyword(s):  
Treated Wood ◽  
Soft Rot ◽  
Major Effect ◽  
White Rot ◽  
Equivalent Efficacy ◽  
Particulate Copper ◽  
Neutral Soil ◽  
Commercial Copper ◽  
Organic Formulations ◽  
Better Than

AbstractSoil chemistry is known to have a major effect on the degradation of treated wood by basidiomycete fungi in laboratory and exterior ground-contact exposures. However, this topic received little attention from a soft-rot (SR) decay perspective. In the present paper, laboratory SR tests were performed with two different types of forest soils, which were also modified. Test samples, made ofPinus glabra(Walt.) (pine) were treated with four commercial copper/organic waterborne preservatives. In addition, soluble or particulate copper and the organic co-biocides quarternary ammonia compound or tebuconazole, were individually examined. After 19 months of soil bed exposure, moderate to severe degradation was observed in all treated samples in both soils. Surprisingly, microscopic examination showed minimal SR decay. Samples in the neutral soil had extensive tunneling bacterial deterioration and the best performance was observed with both copper/quaternary commercial formulations. Samples in the acidic soil appeared to have some white-rot and bacterial deterioration and all four commercial copper/organic formulations showed good statistically equivalent efficacy. For samples treated with only copper, the particulate copper samples performed statistically equivalent or slightly better than amine copper, while samples treated with only the organic quarternary or tebuconazole performed poorly in both soils.

scholarly journals OPTIMALISASI PRODUKSI ENZIM KITINASE PADA ISOLAT JAMUR KITINOLITIK DARI SAMPEL TANAH RIZOSFER

2018 ◽  
Vol 3 (01) ◽  
pp. 62-69
Author(s):  
Eka Corneliyawati ◽  
Massora Massora ◽  
Khikmah Khikmah ◽  
As’ad Syamsul Arifin
Keyword(s):  
Biological Control ◽  
Cell Wall ◽  
Rhizosphere Soil ◽  
Plant Root ◽  
Optimal Growth ◽  
Chitinase Activity ◽  
Fungal Species ◽  
Plant Roots ◽  
Chitinase Production

The rhizosphere is the zone of soil surrounding a plant root where plant roots, soil and the soil biota interact with each other. Chitinolytic fungi has been effectively used in biological control agens. The chitinase activity causes lysis of the fungi cell wall pathogen. The aim of the research was to find optimization of activity chitinase enzyme from rhizosphere soil was conducted in vitro. Optimal growth chitinase production for TKR3 fungi isolate were concentration of chitin 0,2% (b/v), pH 5,5, temperature 30ºC, agitation 150 rpm and incubation time at four days. The optimum yield of chitinase production is influenced by fungal species and environmental conditions.

scholarly journals Evaluation of Compressive Strength of Decayed Wood in Magnolia obovata

2010 ◽  
Vol 36 (2) ◽  
pp. 81-85
Author(s):  
Kahoru Matsumoto ◽  
Futoshi Ishiguri ◽  
Kazuya Iizuka ◽  
Shinso Yokota ◽  
Naoto Habu ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Early Stage ◽  
White Rot Fungi ◽  
Brown Rot ◽  
Soft Rot ◽  
White Rot ◽  
Chemical Components ◽  
Cellulose Content ◽  
Magnolia Obovata ◽  
Weight Loss Ratio

To obtain the basic information needed to estimate the degree of decay from compressive strength measured using a Fractometer (CS), relationships between CS and the contents of chemical components were analyzed for Magnolia wood decayed by three types fungi (brown rot, white rot, and soft rot fungi) at various decay levels. Weight loss ratio was significantly, negatively correlated with CS in woods decayed by brown rot and white rot fungi. In addition, a relatively high correlation coefficient was recognized between CS and holocellulose or α-cellulose content, except for wood decayed by soft rot fungus. The results obtained showed that Fractometer can detect the decrease of CS at relatively early stage of decay.

scholarly journals Changes in structure of red pepper (Capsicum annuum L.) seedlings shoots under aluminum stress conditions

2012 ◽  
Vol 60 (1) ◽  
pp. 85-93 ◽  
Author(s):  
Agata Konarska
Keyword(s):  
Cell Wall ◽  
Capsicum Annuum ◽  
Red Pepper ◽  
Outer Cell ◽  
Aluminum Stress ◽  
Water Culture ◽  
Anatomical Features ◽  
Parenchyma Cells ◽  
Al Treatment ◽  
Outer Cell Wall

The seedlings of the red pepper (<i>Capsicum annuum</i> L.) cv. Trapez grown in water culture for a period of 14 days with Al (0, 10, 20 and 40 mg·dm<sup>-3</sup> AlCl<sub>3</sub>·6 H<sub>2</sub>O). Some morphological and anatomical features of red pepper shoots were analyzed. Reduction in height and diameter of stems as well as decrease in fresh mass of shoots were observed after Al-treatment. In the hypocotyl the thickness of cortex parenchyma layer and the size of their cells were reduced. The aluminum treatment resulted in the increased in thickness of the epidermis outer cell wall. Under Al stress in the cotrex and the central cylinder parenchyma cells were present numerous enlarge plastids which contained large grains of starch and dark little bodies which were possible aluminum deposits. They weren`t observed in control seedlings.

Morphological changes in putrefactive anaerobe 3679 (Clostridium sporogenes) induced by sorbate, hydrochloric acid, and nitrite

1989 ◽  
Vol 35 (3) ◽  
pp. 388-398 ◽  
Author(s):  
Irene E. Ronning ◽  
Hilmer A. Frank
Keyword(s):  
Cell Wall ◽  
Hydrochloric Acid ◽  
Growth Regulation ◽  
Morphological Changes ◽  
Light And Electron Microscopy ◽  
Normal Growth ◽  
Outer Wall ◽  
Exponential Growth Phase ◽  
Clostridium Sporogenes ◽  
Cellular Debris

Putrefactive anaerobe 3679 (Clostridium sporogenes), a gram-positive bacterium, was examined by light and electron microscopy during normal growth and in a medium containing sorbate (50 mM, pH 6.5), hydrochloric acid (pH of medium adjusted from 7 to 5 with HCl), or nitrite (1 mM, pH 7). During the early exponential growth phase, untreated cells were filamentous and nonseptate, but became septate later and divided when the culture entered the stationary phase. Untreated short and filamentous cells had a double-layered cell wall. Sorbate-treated cells were usually filamentous and nonseptate, but with distorted shapes characterized by numerous bends and bulges. Septation, when present, resulted in minicells. The inner cell wall appeared to be thickened and the outer wall was absent in many areas. Acid-treated cells were similar to sorbate-treated cells but contained septa. Considerable cellular debris was present in the suspension. Nitrite-treated cells were also filamentous, bent, and bulged but the cell wall appeared normal. Considerable cellular debris was also present in suspensions of nitrite-treated cells. Changes in morphology are discussed in relation to possible mechanisms of cell growth regulation and the inhibitory action of sorbate, acid, and nitrite.Key words: putrefactive anaerobe 3679, sorbate, hydrochloric acid, nitrite.

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