Rot Type Research Articles

Substrate requirements of red-listed saproxylic invertebrates in Sweden

To evaluate which qualities of dead wood have the highest conservational value for invertebrates, substrate requirements were recorded for all 542 saproxylic (wood-living) red-listed invertebrates in Sweden. Preferred qualities of dead trees were described for each species in seven category variables: tree species, stage of decay, type of main stem, coarseness of stem, part of tree, light preference and microhabitat. For each quality we quantified the number of red-listed insect species using it and the number that are specific to the quality. The number of species associated with different tree genera ranged from five to 202. Species-rich genera had a higher proportion of monophagous species. To what extent different tree genera have faunas complementary to each other was also analysed. As the wood decays, the host range broadens and the flora of decay fungi will probably take over as the most important factor determining the saproxylic fauna. Because there are many different types of rot required by different invertebrates, an abundance of similar looking dead trees, logs and snags are probably needed. Some 59% of the invertebrate species can live in sun-exposed sites. Most of these are favoured when the forest burns and at least 29 of them are more strongly associated with fires. For the former category, leaving dead wood on clear cuts should be an effective way to increase the amount of breeding substrate. However, some species, especially those living in the last successional stages, are dependent on shaded sites. Hollow tree trunks are another important microhabitat; 64 of the 107 species living there are specialists. To maintain all saproxylic species we need a diversity of substrate types and management methods. Our data can help to decide how to optimize the conservation measures taken during forest operations.

STUDIES ON THE MICROBIAL DEGRADATION OF WATERLOGGED ARCHAEOLOGICAL WOOD FOUND IN SWEDEN

The degrading processes can, under special conditions, slow to a minimum. Environments which are waterlogged, such as lakes, seas, clay soils, and where the water-table is high, often become near-anaerobic and the activity of aggressive wood-decomposing microorganisms decreases dramatically. This is why, under these conditions, we can still find wooden objects which give us new information about the past. If we look 30 years back in time, we see that wood conservators and scientists concentrated for a long period on the hypothesis that the decomposition of waterlogged wooden material was of a chemical nature with hydrolytic reactions. It was in 1988, at the American Chemical Society congress in Los Angeles, that wood biologists first established that the degradation of waterlogged archaeological wood was caused mainly by microorganisms. In 1983, Holt and Nilsson made the first detailed description of wood attack by a bacterium [1]. By using a combination of light microscopy and transmission electron microscopy (TEM) it was possible to investigate and verify a new group of wood-decaying organisms, the tunnelling bacteria [2]. In the years which followed, two other wood-decaying bacteria were found: the cavitation bacteria and the erosion bacteria [3]. The use of new techniques like TEM and scanning electron microscopy (SEM), where the magnification is extremely high, was essential for these new discoveries. Since 1988 a number of archaeological wooden objects have been investigated under the microscope, and microbial attack has been observed in most cases. In dry wood, for example from the Pyramids, attack has mainly been due to fungi [4]. In waterlogged material, soft rot, tunnelling and erosion bacteria dominate [4-8]. The environmental history of wooden objects can be inferred from the results of microscopic observations. Basidiomycete fungi, like white rot and brown rot, require relatively high levels of oxygen for their wood-decaying activities, while soft rot, belonging to the group of ascomycetes and fungi imperfecti, can be active at lower concentrations. Some bacteria require only minimal amounts of oxygen. 'Bulverket' was a peculiar construction in the lake of Tingstdide Trask, Gotland, Sweden, from the early mediaeval period. Houses of wood were built on a construction of poles. Finds of dark-coloured poles led archaeologists to believe that the whole construction had been burned. However, microscopic examination showed that the dark colour was due to attack by soft rot fungi. It was also demonstrated that the house building material showed terrestrial decay forms associated with white and brown rot. Therefore the likely cause of destruction was rot and not fire. The foremast from the ship Vasa was broken, presumably during the wreck, and microscopic examination of wood samples taken next to the fracture revealed a special type of white rot. This white rot fungus grows in living trees and does not occur in aquatic environments. Therefore the wood used for the mast must have come from a tree attacked by white rot when being felled. The use of inferior wood indicates either that the shipwrights were poorly qualified, or that the building project was running out of time or money. In the current project, a great number of wood samples will be studied by light and electron microscopy and the microbial results will be related to environment, age and wood species to see if there is some relationship between the rate and type of decay. A large number of stratified wood fragments were obtained from different archaeological sites in Sweden through the cooperation of field archaeologists. The wood samples were from terrestrial and aquatic sites, including bogs, lake, sea, clay, sand and 'mediaeval deposits'. The age of the samples varies from 7000 BC to AD 1676 and different wood species are represented (mostly pine and oak). The wood samples were sectioned by hand with a razor blade, and stained with safranin or methylene blue in lactic acid. The sections were studied using polarized light. The use of light microscopy made it possible to identify different forms of attack (bacterial or fungal) and to assess the severity of attack. Earlier results [5-8] and preliminary results from this study show that erosion bacteria are responsible for most of the decay in waterlogged archaeological wood. A knowledge of the role of microbial decay in archaeological wood and the different forms of decay must be fundamental for the choice of conservation method.

Postharvest rots of avocados: improved chemical control by using different application methods

Four methods of applying prochloraz to ‘Fuerte’ avocados postharvest were compared. These were: dipping, with and without a subsequent coating with polyethylene wax, ultra-low volume spray application followed by wax, and applying in wax. Prochloraz reduced rots best when applied as an ultra-low volume spray followed by waxing. It was also very effective when applied in wax. Dipping fruit in prochloraz increased the incidence of some types of rots. Waxing fruit without a prochloraz treatment reduced the incidence of internal and external stem end rots. This suggests that wax prevented stem end rot fungi from gaining entry to the fruit during packing.

Lignocellulolysis by ascomycetes (fungi) of a saltmarsh grass (smooth cordgrass).

Lignocellulose (LC) makes up greater than 70% of the mature shoots of the prodigiously photosynthetically productive saltmarsh grass Spartina alterniflora. Naturally decaying shoots of this cordgrass were examined by transmission electron microscopy (after high-pressure freezing and freeze-substitution) as a means of directly detecting lysis of the LC-rich tissues. Portions of the cordgrass were selected that contained ascomata (sexual reproductive structures) of only one of each of four species of fungi (Kingdom Fungi; Subdivision Ascomycotina): Phaeosphaeria spartinicola and Buergenerula spartinae from leaf blades, Phaeosphaeria spartinae from leaf sheaths, and Passeriniella obiones from naked stems. All four of the ascomycetes were LC-lytic. Phaeosphaeria spartinicola caused both thinning of LC-rich secondary walls of fiber cells from cell lumina outwards (type 2 soft rot, akin to white rot) and digestion extending from hyphae within longitudinal cavities in the secondary walls (type 1 soft rot). The other three species caused either one or the other type of soft rot. Bacterial erosion of cordgrass cells was found only in the samples of naked stems. Ascomycetous decomposers of standing-dead grasses may have potential for biotechnological applications involving alterations of lignocellulose or toxic polyphenolic substances.

Reliability of poly B-411, a polymeric anthraquinone-based dye, in determining the rot type caused by wood-inhabiting fungi

In both Basidiomycotina and Ascomycotina, Poly B-411 decolorization was an excellent indicator of the ability to cause white rot: 109 of the 110 isolates of brown rot fungi tested definitely did not decolorize Poly B-411, and 392 of the 401 mainly active isolates of white rot fungi decolorized Poly B-411. The Bavendamm (tannic acid) reaction was a less reliable test: of 74 white rot isolates examined that could not decay wood, 6 decolorized Poly B-411, but 19 gave positive Bavendamm reactions. Of 80 isolates of Ascomycotina and Deuteromycotina that do not cause white rot, only 4 decolorized Poly B-411, but 17 gave a positive Bavendamm test.

Diffuse cavity formation in soft rot of pine

A new type of soft rot of southern pine longitudinal tracheids is described. In this type, soft-rot cavities form by diffuse degradation of the S2 cell wall layer by hyphae growing within the cell wall. Cavity formation is diffuse and irregular as opposed to the restricted, periodic cavity formation typical of type 1 soft rot. Proboscis hyphae are small (diameter 0.6 to 0.9 μm) and rapidly autolyse. These proboscis hyphae are not easily recognizable with light microscopy, especially at later stages of decay, but require transmission electron microscopy to confirm their presence. This may be an alternative interpretation of the type 2 soft rot of softwoods described previously as being caused by lumenal hyphae through an intact S3. Chemical analysis of pine test blocks revealed a greater loss of glucose and an increase of galactose with diffuse type 1 species compared to typical type 1 soft rot species. The term “diffuse type 1” is suggested to describe this soft rot.

Microbial routes to aromatic aldehydes

Three routes were explored for their potential to produce the aromatic aldehydes benzaldehyde, p-hydroxybenzaldehyde, and vanillin, which are important flavor components. The first was to exploit organisms which degrade aromatic amino acids via the cinnamate pathway. Trichosporon beigelii was selected and good evidence collected that benzaldehyde was a degradative intermediate. While accumulation of benzoic acid from phenylalanine or cinnamic acid was demonstrated, the aldehyde was not accumulated under any of the conditions examined due to the very high activity of benzaldehyde dehydrogenase. An analogous situation appeared to exist with ferulic acid, from which only vanillic acid was accumulated. Using fungi of the white rot type, reduction of benzoic acid and vanillic acid to benzaldehyde and vanillin was achieved, but rates were low and yields poor due to further reduction to the alcohol. The third and most successful route was microbial conversion of aromatic amino acids to the corresponding phenylpyruvic acids, which were then readily converted to the aldehyde with mild base. A range of organisms were identified which, under appropriate conditions, were effective producers of phenylpyruvic acids. Proteus vulgaris in particular, transformed phenylalanine, tyrosine, or methoxytyrosine into the corresponding phenylpyruvic acids, which could then be converted to benzaldehyde, p-hydroxy-benzaldehyde, and vanillin respectively. The overall process as optimized for benzaldehyde was rapid, relatively simple, and high-yielding.

Detection and properties of plasmid-like DNA in isolates from nine anastomosis and intraspecific groups of Rhizoctonia solani

Summary: Plasmid-like DNA (plDNA) was found in 48 out of 114 field isolates of Rhizoctonia solani. These 48 isolates were distributed as follows among the nine anastomosis groups (AG) and intraspecific groups (ISG) recognized among Japanese isolates of R. solani: 0 in AG-1 (sasakii type), 1 in AG-1 (web-blight type), 0 in AG-2-1, 11 in AG-2-2 (rush type), 10 in AG-2-2 (root rot type), 10 in AG-3,8 in AG-4,4 in AG-5 and 4 in AG-6. Each isolate carried one, two or three plDNAs identified by gel electrophoresis. Electron microscopic analysis revealed that all these plDNAs were linear molecules. The sequence homology among plDNAs found in representative isolates was examined by Southern blot analysis, using nick-translated plDNAs as probes. Considerable sequence homology was observed among plDNAs obtained from isolates within the same AG and ISG. The plDNAs occurring in the isolates of AG-2-2 were classified into two groups on the basis of the sequence homology.

Characterization of Pseudomonas maltophilia Isolates from Fleece Rot

A total of 286 isolates of Pseudomonas maltophilia was collected from sheep exhibiting brown or yellowish fleece rot and from fly-strike lesions. Enzyme activities for 10 of the isolates were examined by plate tests and with the API ZYM system and compared with the enzymatic profile of a human type strain of P. maltophilia. The fact that ovine isolates of P. maltophilia are biochemically similar to pathogenic human strains suggests there may be an association between this organism and the brown to yellow type of fleece rot.

Heterogeneity of the yeast flora in the breeding sites of cactophilic Drosophila

Yeasts were isolated from 278 rots in cladodes and basal stems of Opuntia stricta sampled over 15 months at one locality. The most common yeast species among 370 nonidentical isolates representing 20 species were Candida sonorensis (27% of isolates) and Pichia cactophila (24%). These species generally were present in all months and throughout the area sampled. Other relatively common species (3–9% of alt isolates) had much more restricted distributions in both time and space. The mean number of yeast species per rot was 1.27 ± 0.082, and no yeasts were isolated from 20% of the rots sampled. Significant differences among months or seasons in average number of yeast species per rot were due primarily to lower numbers in the summer and winter months, while differences among rot types resulted mainly from a higher number in the longer persisting basal stem rots. Both hierarchical diversity analysis and analysis of the distributions of the 10 most common yeast species showed temporal effects (month or season) to be the major component contributing to heterogeneity, while microgeographic effects and rot type also were significant. The seasonal and microgeographic heterogeneity are interpreted in terms of longer persisting rots in part of the locality providing a reservoir for yeast species through the winter and are discussed in relation to the maintenance of genetic variation in cactophilic Drosophila that utilize the rots as feeding and breeding sites.

DNA base sequence homology in Rhizoctonia solani Kuehn I. Genetic relatedness within anastomosis group 1.

DNA base sequence homology among AG-2 group isolates of Rhizoctonia solani was investigated on the basis of DNA-DNA reassociation kinetics, and the genetic relationship among pathological types was examined. DNA homology value among isolates within each single type was 100.3% with the winter crops type (II), 98.1% with the rush type (IIIB) and 100.1% with the root rot type (IV). Comparatively high values of DNA homology ranging from 68.6 to 71.5% were observed between rush type isolates and root rot type isolates, both belonging to AG-2-2. DNA homology values of winter crops type isolates of AG-2-1 with rush type isolates of AG-2-2 was 37.6 to 40.1%, and 43.5 to 49.4% with root rot type isolates of AG-2-2. These results suggested that each pathological type in AG-2 is genetically homogenous, and that between the rush type and the root rot type of AG-2-2 there is a small but significant partial heterogeneity. AG-2-1 and AG-2-2 may form genetically distinct groups.

Influence of soil on wood-degradation and fruit body formation by parasites and saprophytes among wood-destroying basidiomycetous fungi

Formation of soil mycelium enables the fungal mycelium to amend the nutrient-deficient wood substrate actively by enclosing macronutrients from soil. Supposition to formation of a soil mycelium proved the resistance of the fungus to competitive substrate microorganisms. This resistance is absent in pathogenic, but wide-spread in saprophytic wood-decay fungi. Consequently, production of soil mycelium was restricted to saprophytic fungi. Saprophytes of the white-rot type are superior to brown-cubical rot type fungi in forming soil mycelium and utilizing soil nutrients. However, rich soils stimulate a more limited degree of wood degradation and yield increase of basidiocarps in parasitic fungi, too, that fail to produce a soil mycelium. It is concluded that uptake of soil nutrients turns out in two different ways, via an actively absorbing soil mycelium and via passive nutrient diffusion from soil into the substrate wood.

A comparison of DNA base compositions among anastomosis groups in Rhizoctonia solani Kuehn.

Base composition of DNAs of 30 isolates of Rhizoctonia solani Kuhn was compared. The relationships between the base composition of DNA and each anastomosis group or cultural type were investigated. The range of guanine plus cytosine (GC) content of R. solani DNA was 40.9 to 49.3 mole%, and its average was 45.3 mole%. The GC contents of the isolates within each anastomosis group were almost same. Little difference of GC content was observed between the sasakii type (IA) and the web-blight type (IB) in AG-1. Furthermore GC contents of the rush type (IIIB) and the root rot type (IV) in AG-2-2, were quite similar. While a significant difference was observed between the potato type (IV) in AG-3 and the root rot type (IV). AG-1 showed the highest GC content (avg. 48.8 mole%) among all of the anastomosis groups, followed by AG-4 (avg. 47.3 mole%), AG-3 (avg. 47.1 mole%), AG-5 (avg. 45.2mole%), AG-2-2 (avg. 44.6 mole%), AG-2-1 (avg. 43.7 mole%), AG-6 (avg. 41.8 mole%) and AG-BI (avg. 41.4 mole%). These results suggest that each anastomosis group must be regarded as a genetically independent unit.

Influence of soil on wood‐degradation and fruit body formation by parasites and saprophytes among wood‐destroying basidiomycetous fungi

Formation of soil mycelium enables the fungal mycelium to amend the nutrient-deficient wood substrate actively by enclosing macronutrients from soil. Supposition to formation of a soil mycelium proved the resistance of the fungus to competitive substrate microorganisms. This resistance is absent in pathogenic, but wide-spread in saprophytic wood-decay fungi. Consequently, production of soil mycelium was restricted to saprophytic fungi. Saprophytes of the white-rot type are superior to brown-cubical rot type fungi in forming soil mycelium and utilizing soil nutrients. However, rich soils stimulate a more limited degree of wood degradation and yield increase of basidiocarps in parasitic fungi, too, that fail to produce a soil mycelium. It is concluded that uptake of soil nutrients turns out in two different ways, via an actively absorbing soil mycelium and via passive nutrient diffusion from soil into the substrate wood.

A study of progressive stages of discoloration and decay in Malus using scanning electron microscopy

Scanning electron microscopy has elucidated the roles of microorganisms during various stages of discoloration and decay in living apple trees Malussylvestris Mill. Disks were removed sequentially at 30-cm intervals up the tree from the bases of decayed trunks into clear sapwood from ten 20- to 30-year-old (Red Delicious) apple trees variously affected by internal decay. Evidence for a microbial succession and morphological changes in cell constituents was observed. Bacteria, yeasts, and other nonhymenomycetes (e.g., Cytospora spp.) appeared to be primary colonists of discolored tissues, which altered cell wall components, and degraded wound-initiated vessel plugs. Basidiomycetous hyphae were observed only in tissues where amorphous vessel deposits had been degraded by pioneer microorganisms. Associations of secondary bacteria and yeasts with wood-destroying hymenomycetes, indicating a mutualistic existence, were frequent. Decay was of the white rot type with numerous crystalline structures observed in regions of advanced decay.

Nia vibrissa — a marine white rot fungus

The gasteromycete, Nia vibrissa , was isolated from wood submerged in the sea and its growth and ability to degrade wood was examined using the light and scanning electron microscopes. Basidiocarps developed on submerged and unsubmerged wood. The surface of the basidiocarps was composed of hook-like uncinate hyphae which may aid dispersal. When cultured on different wood species N. vibrissa caused a pattern of wood decay characteristic of the white rot type. Wood decay enzyme assays confirmed the observational diagnosis. The white rot type of attack exhibited by N. vibrissa represents a previously undocumented form of wood degradation by a marine fungus.

Specificity in vitamin requirement among anastomosis groups of Rhizoctonia solani Kuehn.

The influence of vitamins on the growth of hyphal anastomosis groups of Rhizoctonia solani Kuhn, AG-1 (IA, sasakii type), AG-1 (IB, web-blight type), AG-2-1 (winter crop type), AG-2-2 (IIIB, rush type), AG-2-2 (IV, root rot type), AG-3 (potato type), AG-4 (praticola type), and AG-5, were studied. All isolates of AG-2-2 (IIIB), AG-2-2 (IV), and AG-5 barely grew in the medium without thiamine hydrochloride, and showed 10∼20-fold growth at 10-5M thiamine, i.e. these groups are thiamine auxotrophic. The stimulating effect of thiamine was slight at 10-10M and obvious at 10-9M, and the mycelial dry weights at 10-8 or 10-7M were almost the same at 10-5M. The need for thiamine is a specific character of the group, not of the isolate. Most of AG-2-1, AG-2-2 (IIIB), AG-2-2 (IV) and AG-5 isolates had their growth somewhat stimulated with 10-5M of calcium pantothenate, but were not auxotrophic. There were two isolates of AG-2-1 that might be Ca-pantothenate auxotrophic. Some isolates had stimulated their growth with biotin, folic acid, p-aminobenzoic acid, inositol, nicotinic acid, pyridoxine hydrochloride, and riboflavin, but were not auxotrophic. The need for these vitamins is a character of the isolate, not of the group.

Light and electron microscope studies on cell wall breakdown in American elm xylem tissues infected with Dutch elm disease

Seven years (1970–1977) of comparative light and electron microscope studies show that extensive cell wall disruption and breakdown occur consistently in elm xylem tissues infected by Ceratocystis ulmi (Buism.) C. Moreau. These alterations, noticeable even in incipient infection, can be related to the severity of wilting development and occur in association with the presence of an unbound osmiophilic material containing fine fibrillar material, dense particles of approximately 15 nm, and multilamellate structures. Masses of unbound osmiophilic material in host walls and walled fungal cells with which it is sometimes continuous are highly and exclusively labeled following injection of [6-3H]thymidine.The presence of osmiophilic material in host walls and the interrelation between the two was further established by examining stereoscopic pairs of prints taken at various angles with a goniometer. This type of cell wall breakdown seems difficult to relate to other known types of wood rots. Further discussion on the possible nature and origin of the osmiophilic material is presented.

Influence of slit plastic mulches and nitrogen fertilization rates on potato yield and quality

Clear and black slit plastic mulches had little effect on tuber yields when compared with unmulched controls during two growing seasons. Mulching films significantly increased the incidence of pinkeye, caused byPseudomonas spp. and varius types of soft rot in 1974 but not in 1975. The incidence of tuber greening was higher than normal both years due to inability to hill with mulch films in place. Under these conditions, black plastic reduced the incidence of greening. Significant yield responses were observed for an increase in nitrogen fertilization rate from 100 (45.36 kg) to 140 (63.5 kg) but not from 140 to 180 1b, (81.65 kg) N/A. Plastic mulches did not affect the nitrogen response. Higher post-harvest inorganic soil nitrogen levels were found under both mulches compared with unmulched controls.

Notes on Wood-Rotting Hymenomycetes in New Mexico

One hundred and ninety species of wood-rotting Basidiomycetes in the series Hymenomycetes of the subclass Homobasidiomycetes are reported from New Mexico. Data on substratum relationships and types of rot are given. This paper records 190 species of wood-rotting Basidiomycetes col­ lected in New Mexico by the authors in 1967, 1968, and 1972. Notes concerning habitat, type of rot, and unusual characteristics are pre­ sented. Collecting was confined primarily to coniferous forest zones from the pinyon-juniper woodland upward through the ponderosa pine forest, Douglas fir forest, and spruce-fir forest zones as defined by Little (1950). These zones extend approximately from 4,500 to 12,000 ft. in elevation. The highest locality represented in our collecting sta­ tions is the summit of the Sandia Mts., at 10,678 ft. The major sub­ strata were Pinus ponderosa Laws. (ponderosa pine), Pseudotsuga menziesii (Mirb.) Franco (Douglas fir), Abies concolor (Gord. et Glend.) Lindl. (white fir), Populus tremuloides Michx. (quaking as­ pen), Pinus edulis Engelm. (pinyon), and Quercus gambelii Nutt. (Gambel oak). The dates and locations for collections cited are as fol­ lows: