Decomposition of loblolly pine bark by soil- and root-inhabiting fungi

1970 ◽  
Vol 48 (10) ◽  
pp. 1787-1793 ◽  
Author(s):  
E. G. Kuhlman

A modified soil-block test was used to compare the bark-decomposing ability of various soil- and root-inhabiting fungi. Bark of Pinus taeda was highly resistant to decomposition by all 31 fungi tested. A brown-rot fungus, Lenzites saepiaria, caused the most weight loss, but weight losses due to decay by all fungi varied only from 3 to 15%. Isolates of Mucorales produced 3–8% weight losses from stem bark in 12 weeks. Available nutrients were used within 6 weeks; longer incubation resulted in little additional decomposition. Losses in weight from root bark and stem bark were similar, indicating little nutritional difference between these two substrates.Extraction of stem bark with ethanol or water before incubation with Fomes annosus, L. saepiaria, or Scytalidinun lignicola did not increase the amount of decomposition. This suggests that extractives in the bark may not be responsible for the slow rate of decay. Since autoclaving of the bark before incubation with the fungi enabled the fungi to cause more weight loss than did gas sterilization of the bark, the primary reason for the slow rate of decomposition by fungi is considered to be the complex molecular structure of the bark constituents.

1985 ◽  
Vol 15 (6) ◽  
pp. 1021-1024 ◽  
Author(s):  
T. J. Hall ◽  
Curt Leben

The effects of oxygen decay (weight loss) incited by Polyporuscompactus Overh. was studied using small fresh and dried wood blocks containing both sapwood and heartwood of similar radial position and age. A manifold was used to deliver hydrated gas mixtures of 1.0, 4.2, or 21% (ambient air) oxygen at constant pressure and continuous flow to jars containing inoculated or noninoculated blocks. Means (P = 0.05) for dry weight losses in inoculated blocks at 1.0, 4.2, and 21% oxygen were 3.3, 8.9, and 21.4%, respectively; losses may be comparable to decay by other white rot fungi using the soil-block procedure. Losses in noninoculated blocks at the above oxygen levels were 2.0, 4.6, and 7.0%, respectively. Differences in dry weight losses between fresh and dry blocks were found. In particular, losses in inoculated fresh blocks were significantly less than losses in inoculated dry blocks in ambient air. Native inhabitants occurring in fresh wood appear to interfere with the decay processes of P. compactus. Losses in noninoculated fresh blocks were significantly greater than in noninoculated dry blocks at 21% oxygen but not at 1.0 or 4.2% oxygen; losses were attributed to natural inhabitants in fresh wood.


Polymers ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 1511
Author(s):  
Roger M. Rowell

The wood preservation industry has depended on toxicity as a mechanism of effectiveness against decay fungi to extend the life of wood used in adverse conditions. An alternative to toxicity, however, is to study and understand the mechanism of fungal attack and stop it before it can start. Knowing that fungi need moisture for colonization, a new approach to wood preservation is to lower the cell wall moisture content below that needed for fungal attack. Acetylation chemistry is known to reduce the moisture content in the cell wall, and it was used to study moisture levels in the bulk cell wall and in the isolated cell wall polymers. Resistance to brown-rot was determined using a 12-week soil block test with Gloeophyllum trabeum. Weight loss was measured and an analysis of what was lost was determined.


Holzforschung ◽  
2004 ◽  
Vol 58 (2) ◽  
pp. 205-208 ◽  
Author(s):  
J. Simonsen ◽  
C. M. Freitag ◽  
A. Silva ◽  
J. J. Morrell

Abstract The effect of wood/plastic ratio and the presence of a boron compound on resistance to biodegradation of wood plastic composites (WPC's) by the brown rot fungus Gloeophyllum trabeum was investigated in a soil block exposure. Weight losses of all WPC's were generally lower than those of solid wood, even when only the wood component of the WPC was used in calculating weight loss. Higher wood content was associated with greater weight losses, suggesting that the plastic encapsulated wood at lower wood levels. Borates markedly reduced weight losses at all wood/plastic ratios. Weight losses tended to be slightly lower with a Na/Ca borate than with similar levels of zinc borate. Mechanical properties did not correlate well with weight losses under the conditions evaluated, but these effects may have been masked by moisture sorption. The causes and implications of these differences are discussed.


2021 ◽  
Vol 01 (01) ◽  
pp. 57-65
Author(s):  
Bala Muhammed ◽  

Spathodea campanulata Beauv. is an important plant widely used in traditional medicine for the treatment of hepatic disease. In the present study, we evaluate the phytochemical composition and hepatoprotective potential effect of the stem and root bark extracts of Spathodea companulata on dimethylnitrosamine (DEN) induced hepatic impairment in albino rats. Phytochemical compositions were analyzed using standard protocols. Forty-five male rats were grouped into 9 (A-I) of 5 rats each. Groups A-F were treated with stem bark extract, root bark extract, quercetin, DEN + stem bark extract, DEN + root bark extract, DEN + quercetin respectively while groups G-1 serve as control groups and were treated with corn oil only (Vehicle control), DEN only (Toxicant control), and distilled water (normal control) respectively. DEN was given at 25 mg/kg b.w., i.p on a weekly basis while all treatments were administered at 100 mg/kg BW orally for 60 days. Serum transaminase activities, body weight, and liver body weight ratio were evaluated. Results revealed the presence of alkaloids, cardiac glycoside, saponins, anthraquinone, steroids, and flavonoids in stem bark extract of Spathodea companulata, while the root bark contains cardiac glycoside, saponins, anthraquinonoid, steroids, and flavonoid. The DEN non-treated rat exhibited significant (p<0.05) weight loss and increase serum alanine transaminase (ALT) and aspartate transaminase (AST) activities when compared with the normal control. Treatment with stem and root bark extracts of Spathodea companulata significantly ameliorated the toxicant induce alterations in the transaminase activity and body weight loss when compared with the DEN nontreated rats. In conclusion, this study provides scientific validation of the use of this plant in traditional medicine for the management of hepatic disorders


Holzforschung ◽  
2010 ◽  
Vol 64 (5) ◽  
Author(s):  
Nathan S. Little ◽  
Tor P. Schultz ◽  
Darrel D. Nicholas

Abstract The soil block test is the most widely employed laboratory method for determination of biocide efficacy in North America. However, surprisingly little is known about the effect of different soil properties and soil amendments on fungal decay. Four soils with different textures and chemical properties were obtained and characterized. These soils, with and without pH amendments, were submitted to one soil block decay study using untreated southern pine wood and two brown-rot fungi. A second study examined the effect of adding water-soluble calcium chloride to soils, or directly to wood, on brown-rot decay. Based on the results of the first study with a limited number of soils, changes in the specified properties of the soil are suggested. Generally, fungal decay was reduced by raising the soil pH for acidic soils by hydrated lime as specified in the standards, or by adding water-soluble acidic calcium chloride to basic soils.


1980 ◽  
Vol 58 (1) ◽  
pp. 36-39 ◽  
Author(s):  
E. G. Kuhlman

Root segments of loblolly pine (Pinus taeda L.) were decayed by Heterobasidion annosum (Fr.) Bref. (=Fomes annosus (Fr.) Karst.) over a broad range of wood (33–317%) and soil (36–259%) moisture contents in modified soil-block tests. Maximum weight loss occurred at 50–286% wood moisture content. Decay was inhibited at wood moisture contents over 290%. Water moved rapidly into the root segments by capillarity, and some decay occurred within 2 weeks. Water uptake was faster in inoculated segments than in noninoculated segments at a soil moisture content of 172% of the 0.2 bar (1 bar = 100 kPa) moisture content.


Forests ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 785
Author(s):  
Congxun Huang ◽  
Guoqi Xu ◽  
Lihai Wang ◽  
Ping Zhang ◽  
Pengwei Zhao ◽  
...  

(1) Background: Wood decay is a serious issue that results from the presence of wood-destroying fungi and has a great influence on the international wood industry. The utilization of biological control methods offers good prospects for wood preservation. (2) Methods: The plate-screening experiment, the soil block test of the Chinese stand method (GB/T 13942.1), and the characterization of wood blocks were used to achieve biological control of brown rot and white rot. (3) Results: Through isolation, screening, and identification, the antagonistic bacterium Bacillus velezensis Nhw-B72 strain was obtained. In the plate-screening experiment, the inhibition zone diameter of Nhw-B72 for Gloeophyllum trabeum was 1.68 cm and that for Coriolus versicolor was 2.33 cm. After inhibition, the morphology of mycelia was distorted, malformed, and broken. In the soil block test, the average weight loss percentage of wood blocks in the control group was 61.66%. In the treatment group, the average weight loss percentage of the wood blocks with drying was 28.18% and that of the wood blocks without drying was 34.97%. (4) Conclusions: The strain has an obvious antagonistic effect on the wood-destroying fungi and the sterile fermentative liquid can effectively inhibit wood decay. In addition, compared to the drying of wood blocks, the air-drying of blocks after impregnation with the fermentative liquid had a better inhibition effect.


Holzforschung ◽  
2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Liselotte De Ligne ◽  
Jan Van den Bulcke ◽  
Jan M. Baetens ◽  
Bernard De Baets ◽  
Gang Wang ◽  
...  

AbstractThe effect of fungicidal components in wood has been known for ages, yet there is no method to assess the impact of such components on the durability of a wood species, as compared to other material characteristics that influence decay. In this paper, the importance of fungicidal effects on the natural durability of 10 wood species is assessed in relation to other decay-influencing factors with a new test, the so-called ‘paste test’. By comparing results from this test with the ‘mini-block test’, on both heartwood and leached sapwood, insight is gained into the significance of fungicidal components on the one hand and other material characteristics on the other hand. The durability of species such as Prunus avium was attributed mainly to fungicidal components. For species such as Pterocarpus soyauxii, durability seemed to be an effect of both fungicidal components and moisture-regulating components, while the latter seemed to be of main importance in regulating the decay of Aucoumea klaineana and Entandrophragma cylindricum. Wood-anatomical features, such as the parenchyma content (in case of brown rot fungi) and the vessel-fiber ratio, possibly affect degradation as well. This work shows that fungicidal components are not always of major importance for the durability of a wood species. The authors hereby emphasize the importance of moisture-regulating components and wood anatomy on the durability of wood.


2009 ◽  
Vol 69 (1) ◽  
pp. 34-38 ◽  
Author(s):  
C. R. Hankey

Treatments to induce weight loss for the obese patient centre on the achievement of negative energy balance. This objective can theoretically be attained by interventions designed to achieve a reduction in energy intake and/or an increase in energy expenditure. Such ‘lifestyle interventions’ usually comprise one or more of the following strategies: dietary modification; behaviour change; increases in physical activity. These interventions are advocated as first treatment steps in algorithms recommended by current clinical obesity guidelines. Medication and surgical treatments are potentially available to those unable to implement ‘lifestyle interventions’ effectively by achieving losses of between 5 kg and 10 kg. It is accepted that the minimum of 5% weight loss is required to achieve clinically-meaningful benefits. Dietary treatments differ widely. Successful weight loss is most often associated with quantification of energy intake rather than macronutrient composition. Most dietary intervention studies secure a weight loss of between 5 kg and 10 kg after intervention for 6 months, with gradual weight regain at 1 year where weight changes are 3–4 kg below the starting weight. Some dietary interventions when evaluated at 2 and 4 years post intervention report the effects of weight maintenance rather than weight loss. Specific anti-obesity medications are effective adjuncts to weight loss, in most cases doubling the weight loss of those given dietary advice only. Greater physical activity alone increases energy expenditure by insufficient amounts to facilitate clinically-important weight losses, but is useful for weight maintenance. Weight losses of between half and three-quarters of excess body weight are seen at 10 years post intervention with bariatric surgery, making this arguably the most effective weight-loss treatment.


Author(s):  
Thomas S. K. ◽  
George E. ◽  
Kunjumon M. ◽  
Thankamani I.

Alstonia venenata R. Br. belonging to the family Apocynaceae is a tall evergreen shrub distributed throughout Peninsular India. Stem-bark, root-bark, fruits and leaves are used by many tribal communities and also in Ayurveda. The study investigates the phytochemical composition of hexane, butanol, methanol and water extracts of Alstonia venenata fruits and flowers as well as the TLC profile of hexane extracts of fruits and flowers. Quantitative data of the wet and dry weight, yields from different solvent fractions and percentage yields were noted. The phytochemical analysis revealed the presence of secondary metabolites such as alkaloids, steroids, terpenoids, saponins, flavonoids, tannins and phenolic compounds from the various extracts. Alkaloids were present in all the fractions tested. Methanol extracts of fruits and flowers showed the presence of major phytoconstituents. TLC profile of hexane extracts of fruits and flowers were developed using anisaldehyde sulphuric acid/ceric sulphate (steroids/terpenoids) and Dragendorff’s spray reagents (alkaloids). Petroleum ether: Chloroform: Methanol (5: 4.5: 0.5) showed good resolution for the hexane extracts of fruit and flower when treated with Dragendorff’s spray reagent. Petroleum ether: Chloroform (1:1) was best for the hexane exacts of flowers and fruits when sprayed with ceric sulphate spray reagent


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