scholarly journals Woody charcoal with traces of pre-charring decay from the Late Oligocene (Chattian) of Norken (Westerwald, Rhineland-Palatinate, W Germany)

2020 ◽  
pp. 43-50
Author(s):  
Dieter Uhl ◽  
Michael Wuttke ◽  
André Jasper
Keyword(s):  
Cell Walls ◽  
Late Oligocene ◽  
Crown Fire ◽  
Deep Time ◽  
Surface Fire ◽  
Additional Information ◽  
Bordered Pits ◽  
Fungal Hyphae ◽  
Standing Trees ◽  
Different Diameters

A variety of traces of pre-charring decay are described from coniferous charcoals from the Norken locality, stratigraphically positioned within the Breitscheid Formation (Late Oligocene, Chattian) of the Westerwald area (Rhineland-Palatinate; W Germany). The traces include three-dimensionally preserved as well as collapsed fungal hyphae, collapsed filamentous structures (maybe related to ascomycetes), so-called shot-like holes of different diameters in cell walls of tracheids, as well as crater-like structures on the surface of tracheid walls. The latter occur on tracheids with bordered pits, in the direct vicinity of charred phloem (so far only rarely reported from pre-Quaternary charcoal). These observations, together with evidence that some of the charcoal fragments originated from wood that dried out prior to charring, point to a surface fire as the most likely source of the charcoal, although it cannot totally be ruled out that (partly) dead but still standing trees were affected during a crown fire. The data from the Late Oligocene of Norken provide further evidence that pre-Quaternary charcoal can be used as an additional, so far largely underutilized source for additional information about plant– microorganism interactions in deep time.

A modified resistance to compression (RtC) test for evaluation of natural fiber softness

2022 ◽  
pp. 004051752110694
Author(s):  
Hao Yu ◽  
Christopher Hurren ◽  
Xin Liu ◽  
Stuart Gordon ◽  
Xungai Wang
Keyword(s):  
Compression Test ◽  
Natural Fiber ◽  
Natural Fibers ◽  
Assessment Method ◽  
Fiber Types ◽  
New Approach ◽  
Additional Information ◽  
Significant Difference ◽  
Single Force ◽  
Different Diameters

Comfort is a key feature of any clothing that relates significantly to softness of the fiber, yarn and fabric from which is it constructed. A known softness assessment method for fibers is the resistance to compression test. This traditional test only provides a single force value for the resistance of a loose fiber sample using a fixed mass under compression. In this research, a modified resistance to compression test was introduced to show the effects of repeated compression, providing more information about the softness and resilience of selected fibers. Three different natural fiber types, including wool, cotton and alpaca were compared using this new approach. The results showed compression profiles were quite different for different fiber types as well as for the same fibers with different diameters. While the diameters of the wool and alpaca samples were similar (18.5 μm), the modified resistance to compression values were significantly higher for wool (with a peak value at 9.5 kPa compared to 2.1 kPa for alpaca). Cotton was different from wool and alpaca but showed a similar modified resistance to compression value (10.4 kPa) to wool. During cycles of compression, modified resistance to compression peak values decreased slightly and then tended to be constant. Even though the structures of wool, cotton and alpaca were quite different, there was no significant difference in the magnitude of decline in modified resistance to compression peak values. This means that the modified resistance to compression test is able to provide additional information on the resilience characteristics of different natural fibers, and can reveal the resistance behavior of fiber samples during cyclic compression.

scholarly journals Evaluating Potential Fire Behavior in Lodgepole Pine-Dominated Forests after a Mountain Pine Beetle Epidemic in North-Central Colorado

2011 ◽  
Vol 26 (3) ◽  
pp. 101-109 ◽  
Author(s):  
Jennifer G. Klutsch ◽  
Mike A. Battaglia ◽  
Daniel R. West ◽  
Sheryl L. Costello ◽  
José F. Negrón
Keyword(s):  
Mountain Pine Beetle ◽  
Tree Mortality ◽  
Lodgepole Pine ◽  
Fire Behavior ◽  
Crown Fire ◽  
Tree Species Composition ◽  
Surface Fire ◽  
Mountain Pine ◽  
Pine Beetle ◽  
Fuel Characteristics

Abstract A mountain pine beetle outbreak in Colorado lodgepole pine forests has altered stand and fuel characteristics that affect potential fire behavior. Using the Fire and Fuels Extension to the Forest Vegetation Simulator, potential fire behavior was modeled for uninfested and mountain pine beetle-affected plots 7 years after outbreak initiation and 10 and 80% projected tree fall using measured and projected fuel and stand characteristics. Under 90th percentile weather conditions, uninfested plots exhibited proportionally more crown fire than infested plots. Plots predicted to have crown fire were composed mainly of nonhost conifer species and had a lower and more continuous canopy than infested plots. Where surface fire was predicted to occur, live lodgepole pine was the only conifer present, and plots had significantly lower tree mortality from fire than plots predicted to have crown fire. Mountain pine beetle-induced changes in stand and fuel characteristics resulted in increased intensity of surface fire behavior. Furthermore, with 80% infested tree fall, potential smoke production was predicted to be higher. Tree species composition of stands pre and postbark beetle outbreak is important when identifying mountain pine beetle-caused changes to potential fire behavior.

Exploring structural definitions of mycorrhizas, with emphasis on nutrient-exchange interfaces

2004 ◽  
Vol 82 (8) ◽  
pp. 1074-1088 ◽  
Author(s):  
R. Larry Peterson ◽  
Hugues B Massicotte
Keyword(s):  
Cell Wall ◽  
Plant Cell ◽  
Cell Walls ◽  
Plant Cell Wall ◽  
Structural Characteristics ◽  
Primary Cell ◽  
Fungal Cell ◽  
Symbiotic Associations ◽  
Nutrient Exchange ◽  
Fungal Hyphae

The roots or other subterranean organs of most plants develop symbioses, mycorrhizas, with fungal symbionts. Historically, mycorrhizas have been placed into seven categories based primarily on structural characteristics. A new category has been proposed for symbiotic associations of some leafy liverworts. An important feature of mycorrhizas is the interface involved in nutrient exchange between the symbionts. With the exception of ectomycorrhizas, in which fungal hyphae remain external to plant cell walls, all mycorrhizas are characterized by fungal hyphae breaching cell walls but remaining separated from the cell cytoplasm by a plant-derived membrane and an interfacial matrix that forms an apoplastic compartment. The chemical composition of the interfacial matrix varies in complexity. In arbuscular mycorrhizas (both Arum-type and Paris-type), molecules typical of plant primary cell walls (i.e., cellulose, pectins, β-1,3-glucans, hydroxyproline-rich glycoproteins) are present. In ericoid mycorrhizas, only rhamnogalacturonans occur in the interfacial matrix surrounding intracellular hyphal complexes. The matrix around intracellular hyphal complexes in orchid mycorrhizas lacks plant cell wall compounds until hyphae begin to senesce, then molecules similar to those found in primary cell walls are deposited. The interfacial matrix has not been studied in arbutoid mycorrhizas and ectendomycorrhizas. In ectomycorrhizas, the apoplastic interface consists of plant cell wall and fungal cell wall; alterations in these may enhance nutrient transfer. In all mycorrhizas, nutrients must pass into the symplast of both partners at some point, and therefore current research is exploring the nature of the opposing membranes, particularly in relation to phosphorus and sugar transporters.Key words: interface, apoplastic compartment, Hartig net, arbuscule, intracellular complex, nutrient exchange.

scholarly journals Microscopic Aspects of Silicon-Mediated Rice Resistance to Leaf Scald

2016 ◽  
Vol 106 (2) ◽  
pp. 132-141 ◽  
Author(s):  
Leonardo Araujo ◽  
Rayane Silva Paschoalino ◽  
Fabrício Ávila Rodrigues
Keyword(s):  
Cell Walls ◽  
Leaf Surface ◽  
Leaf Tissue ◽  
Phenylpropanoid Pathway ◽  
Microscopic Level ◽  
High Concentration ◽  
Great Abundance ◽  
Leaf Scald ◽  
X Ray ◽  
Fungal Hyphae

This study investigated the effect of silicon (Si) on the potentiation of rice resistance against leaf scald at the microscopic level. Rice plants (‘Primavera’) were grown in a nutrient solution containing 0 (−Si) or 2 mM (+Si) Si. The foliar Si concentration of the +Si plants (3.6 dag/kg) increased in comparison with the −Si plants (0.3 dag/kg). An X-ray microanalysis revealed that the leaf tissue of +Si plants infected with Microdochium oryzae had higher peaks and deposition of insoluble Si than that of −Si plants. The high foliar Si concentration for the +Si plants reduced the expansion of leaf scald lesions. Scanning electron microscopy revealed that fungal hyphae and appressorium-like structures of M. oryzae were more abundant in the leaf surface of −Si plants relative to +Si plants. At both histopathological and ultrastructural levels, fungal hyphae grew abundantly into the leaf tissue of −Si plants. By contrast, rice cell walls were rarely degraded and fungal hyphae were often surrounded by amorphous granular material in the leaf tissue of +Si plants. Conidiophores emerged from stomata 36 h after fungal penetration, and conidia were noticed inside the leaf tissue of the −Si plants in great abundance. The collective results of the present study showed a high concentration and deposition of Si and a considerable deposition of phenolic-like compounds in the leaf tissue of +Si plants. These results indicate that the potentiation of the phenylpropanoid pathway in these plants supplied with Si was favorable for the increase in rice resistance to leaf scald.

Experimental modelling of crown fire initiation in open and closed shrubland systems

2014 ◽  
Vol 23 (4) ◽  
pp. 451 ◽  
Author(s):  
Watcharapong Tachajapong ◽  
Jesse Lozano ◽  
Shankar Mahalingam ◽  
David R. Weise
Keyword(s):  
Energy Transfer ◽  
Wind Speed ◽  
Wind Tunnel ◽  
Air Entrainment ◽  
Convective Heating ◽  
Crown Fire ◽  
Number Range ◽  
Surface Fire ◽  
Open Environment ◽  
Fire Initiation

The transition of surface fire to live shrub crown fuels was studied through a simplified laboratory experiment using an open-topped wind tunnel. Respective surface and crown fuels used were excelsior (shredded Populus tremuloides wood) and live chamise (Adenostoma fasciculatum, including branches and foliage). A high crown fuel bulk density of 6.8kgm–3 with a low crown fuel base height of 0.20m was selected to ensure successful crown fire initiation. Diagnostics included flame height and surface fire evolution. Experimental results were compared with similar experiments performed in an open environment, in which the side walls of the wind tunnel were removed. The effect of varying wind speed in the range 0–1.8ms–1, representing a Froude number range of 0–1.1, on crown fire initiation was investigated. The suppression of lateral entrainment due to wind tunnel walls influenced surface fire behaviour. When wind speed increased from 1.5 to 1.8ms–1, the rate of spread of surface fire and surface fire depth increased from 5.5 to 12.0cms–1 and 0.61 to 1.02m. As a result, the residence time of convective heating significantly increased from 16.0 to 24.0s and the hot gas temperature at the crown base increased from 994 to 1141K. The change in surface fire characteristics significantly affected the convective energy transfer process. Thus, the net energy transfer to the crown fuel increased so the propensity for crown fire initiation increased. In contrast, increasing wind speed decreased the tendency for crown fuel initiation in an open environment because of the cooling effect from fresh air entrainment via the lateral sides of surface fire.

Interactions between a fungal endophyte and gametophyte cells in Psilotum nudum

1981 ◽  
Vol 59 (5) ◽  
pp. 711-720 ◽  
Author(s):  
R. L. Peterson ◽  
Melanie J. Howarth ◽  
Dean P. Whittier
Keyword(s):  
Energy Source ◽  
Endophytic Fungus ◽  
Cell Walls ◽  
Fungal Endophyte ◽  
Hyphal Cell ◽  
Cell Organelles ◽  
Host Cytoplasm ◽  
Psilotum Nudum ◽  
Parenchyma Cells ◽  
Fungal Hyphae

Mature Psilotum gametophytes found in greenhouse pots containing plants of Hoya, Philodendron, Aspidistra, or Diffenbachia were processed for microscopy. An endophytic fungus was abundant in the rhizoids and in most cortical parenchyma cells except at the growing apices. Although the fungus has not been identified, it is an aseptate fungus with coarse hyphae which occasionally form vesicles. Endophytic fungal hyphae store quantities of lipid which appear to be released into the host cytoplasm upon fungal degeneration. This lipid and the remnants of hyphal cell walls may be used as an energy source by the achlorophyllous gametophyte. Gametophyte cell organelles, including the nucleus, appear to degenerate after fungal breakdown, and the cells presumably die. Although reinfection of cells containing degenerated hyphae was found, it was not particularly common.

ANALYSIS OF CAMBIUM AND DIFFERENTIATING VESSEL ELEMENTS IN KALOPANAX PICTUS USING RESIN CAST REPLICAS

IAWA Journal ◽  
2001 ◽  
Vol 22 (1) ◽  
pp. 15-28 ◽  
Author(s):  
Peter Kitin ◽  
Yuzou Sano ◽  
Ryo Funada
Keyword(s):  
Organic Material ◽  
Cell Walls ◽  
Three Dimensional ◽  
Wall Material ◽  
Acidic Solutions ◽  
Kalopanax Pictus ◽  
Bordered Pits ◽  
Vessel Elements ◽  
Cambial Cells ◽  
Perforation Plates

A resin-casting method with subsequent scanning electron microscopy (SEM) was used to examine the three-dimensional (3-D) shapes of cells and the cell walls of cambium and differentiating xylem. Glutaraldehyde- fixed and dehydrated specimens were embedded in polystyrene and then organic material was removed by digestion with acidic solutions or enzymes. The acidic solutions used for treatment were sulphuric acid and a mixture of acetic acid and hydrogen peroxide and the enzymes used for treatment were pectinase and cellulase, with a final treatment with sodium hypochlorite. Both methods could be used for studies of the differentiation of cambial cells; however, digestion with enzymes allowed better preservation of the 3-D organisation of the tissue. Negative replicas of inner surfaces of cell walls of differentiating vessel elements revealed the sequential stages of the development of bordered pits and perforation plates. Future bordered pits at the early stages of the differentiation of cell walls were demarcated by the accumulation of organic material between adjacent pit membranes. Subsequent deposition of cell wall material resulted in formation of pit cavities and the rims of perforation plates.

scholarly journals Cladophialophora bantiana brain abscess masquerading cerebral tuberculoma in an immunocompetent host

2014 ◽  
Vol 21 (1) ◽  
pp. 75-79 ◽  
Author(s):  
Amit Agrawal ◽  
Vissa Shanthi ◽  
K.V. Murali Mohan ◽  
Kishor V. Hegde ◽  
Umamaheshwar Reddy V.
Keyword(s):  
Brain Abscess ◽  
Cell Walls ◽  
Fungal Infections ◽  
Surgical Excision ◽  
Immunocompetent Host ◽  
Neutrophilic Infiltrate ◽  
Fungal Hyphae ◽  
The Right ◽  
Thalamic Region ◽  
Cerebral Tuberculoma

Abstract Phaeohyphomycosis is a term that collectively describes fungal infections caused by moulds and yeasts that have brown-pigmented cell walls (due to the presence of melanin). We report a case of 45 year female who had multiple coalescing lesions in the right basal ganglionic and thalamic region. Based on the imaging and investigation findings a diagnosis of cerebral tuberculoma was suspected. Histopathology of the excised specimen showed brown colored fungal hyphae surrounded by neutrophilic infiltrate. A diagnosis of phaeohyphomycosis caused by Cladophialophora bantiana was made and accordingly antifungal treatment was started. Brain abscess caused by Cladophialophora bantiana in an immunocompetent host is relatively uncommon and usually associated with overall high mortality. The best outcomes have been reported in patients who receive both surgical excision of the abscess followed by systemic antifungal therapy. In view of its rarity of these lesions preoperative diagnosis is difficult particularly in an immunocompetent host and absence of other risk factors.

scholarly journals Conifer tracheids resolve conflicting structural requirements: Data, hypotheses, questions

2017 ◽  
Vol 11 (1) ◽  
pp. 123-141
Author(s):  
Sherwin Carlquist
Keyword(s):  
Mechanical Strength ◽  
Cell Walls ◽  
Surface Relief ◽  
Anatomical Structure ◽  
Structural Requirements ◽  
Wall Strength ◽  
Pit Membrane ◽  
Bordered Pits ◽  
Cool Temperate ◽  
Solid Cell

The nature of conduction involves movement of a liquid (under tension or pressure) through a solid (cell walls necessary to direct the liquid and provide mechanical strength). The numerous consequences of the liquid/solid nature of the conductive interface in plants can be viewed as a series of conflicting requirements that are resolved by various mechanisms. For example, the types of mechanical strength conferred by thicker cell walls (latewood) run counter to optimal conduction (earlywood). Conflict resolution situations are examined with light microscopy and SEM to show in detail not merely conflicting requirements but the various types of resolution in various conifers. Abies is presented as exemplary of a cool temperate conifer with numerous aspects to earlywood/latewood structure. Tropical conifers (Araucaria) present different compromises; the riparian conifer Dacrydium guillauminii has only earlywood; the parasitic conifer Parasitaxus has only latewood. Particular conifers have only some of the features by which latewood differs from earlywood. Cell dimorphism is only one aspect of resolution of conflicting requirements; others include modifications in pit size, shape, and density; the nature of the pit membrane; the nature of the pit cavity, pit border and pit aperture; and surface relief (warty layer) of the tracheid wall. The invention of coniferous bordered pits involves a circular shape, so that tension on the margo strands is equal, and thus the pit can be closed. These factors and margo pore maximization necessitate expending a large amount of space to pits in earlywood, the strength of which is thereby lessened and must be compensated by greater wall strength in latewood. The paper concludes with a series of twenty features which represent resolutions of conflicting requirements in terms of anatomical structure. Wood physiological literature is integrated with the anatomical observations.

scholarly journals The sporophyte of the Paleogene liverwort Frullania varians Caspary

Fossil Record ◽  
2012 ◽  
Vol 15 (2) ◽  
pp. 115-120 ◽  
Author(s):  
J. Heinrichs ◽  
M. von Konrat ◽  
H. Grabenhorst ◽  
A. R. Schmidt
Keyword(s):  
Cell Walls ◽  
Internal Layer ◽  
Late Oligocene ◽  
Capsule Wall ◽  
Layer Cell ◽  
First Time ◽  
Upper Third

We document the sporophyte of the extinct <i>Frullania varians</i> based on an inclusion in Late Oligocene Bitterfeld amber from Germany. The sporophyte consists of a short, ca. 45 µm thick seta that exceeds the perianth only slightly; the elongate-ovate, acute valves of the opened capsule are about 225 µm long, curved backwards and consist of an epidermal and an internal layer. Cell walls of both layers possess nodulose trigones. Several trumpet-shaped, unispiral elaters are fixed to the upper third of the internal valve layer. They have a length of ca. 150 µm and a diameter of 15–18 µm. A subglobose structure of 19 µm diameter is interpreted as a degraded spore. Fossil elaters and spores as well as capsule wall details of Frullaniaceae are described for the first time. <br><br> doi:<a href="http://dx.doi.org/10.1002/mmng.201200009" target="_blank">10.1002/mmng.201200009</a>

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