ANTIFUNGAL ACTIVITY OF ORGANIC ACIDS AND THEIR IMPACT ON WOOD DECAY RESISTANCE

Organic acids are present in many bio-based chemicals suggested as active ingredients for wood preservative formulations, but their effects in wood have not been studied. However, an understanding of their effect in wood is necessary. The aim of this study was to determine the antifungal and wood-preserving activities in vitro of acetic, formic, and propionic acids against the wood-decaying fungi Coniophora puteana, Rhodonia (Poria) placenta, Gloeophyullum trabeum, and Trametes versicolor. Mixes of these three acids were also tested for possible synergetic effects. All the acids and mixtures showed antifungal activity against the pure cultures of wood-decaying fungi. Propionic acid by itself had the best performance, inhibiting at 1 g/L concentration the growth of all the decay fungi by 99-100%. Despite the antifungal activity of the organic acids, the pine sapwood specimens treated with 3% and 6% acid solutions and exposed to decay by C. Puteana and G. trabeum did not differ significantly from the untreated pine. Leaching of the sapwood specimens caused an incremental mass loss of the sapwood specimens. In addition, the leached specimens had a lower mass than the specimens before the acid impregnation, indicating that they were damaged by the acidic chemicals. The presence and acidity of organic acids in wood-derived bio0-based chemicals need to be assessed before they are used as wood preservatives. 

Antifungal activity of chemicals derived from forestry side streams

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Morphological and ecophysiological root and leaf traits in ectomycorrhizal, arbuscular-mycorrhizal and non-mycorrhizal Alnus incana seedlings

Background and aims The aim was to assess possible benefits or drawbacks of arbuscular-mycorrhizal (AM) and ectomycorrhizal (EM) colonisation compared to no mycorrhizas (NM) in seedlings of the same host species. Eight broadleaf species were tested for mycorrhiza formation. Grey alder (Alnus incana) and four fungal species were selected for further experiments. Methods Grey alder seedlings were inoculated with AM fungi Rhizophagus intraradices and Glomus hoi or EM fungi Paxillus involutus plus an ascomycete isolated from Alnus roots or mock-inoculated (NM). Results EM formed in 70% of root tips and AM in 30% of root length. AM plants were smaller than EM and NM, but their specific root length (SRL) and specific leaf area (SLA) were highest. Net photosynthesis, stomatal conductance and shoot water potential did not differ between treatments. Foliar Ca, K, Mg, Mn, N, P and S concentrations (mg g−1) were highest in AM plants. However, total foliar contents (mg per plant) were lowest in AM plants, except for P, K and Zn. Conclusions The larger SRL and SLA suggest more efficient resource usage in AM plants, even though these were smaller than EM and NM plants. Grey alder is proposed as a new model species for comparisons between mycorrhiza types in cold climates.Peer reviewe

Field Quality Control of Spectral Solar Irradiance Measurements by Comparison with Broadband Measurements

Measurement of solar spectral irradiance is required in an increasingly wide variety of technical applications, such as atmospheric studies, health, and solar energy, among others. The solar spectral irradiance at ground level has a strong dependence on many atmospheric parameters. In addition, spectroradiometer optics and detectors have high sensitivity. Because of this, it is necessary to compare with a reference instrumentation or light source to verify the quality of measurements. A simple and realistic test for validating solar spectral irradiance measurements is presented in this study. This methodology is applicable for a specific spectral range inside the broadband range from 280 to 4000 nm under cloudless sky conditions. The method compares solar spectral irradiance measurements with both predictions of clear-sky solar spectral irradiance and measurements of broadband instruments such as pyrheliometers. For the spectral estimation, a free atmospheric transmittance simulation code with the air mass calculation as the mean parameter was used. The spectral direct normal irradiance (Gbl) measurements of two different spectroradiometers were tested at Plataforma Solar de Almería, Spain. The results are presented in this article. Although only Gbl measurements were considered in this study, the same methodology can be applied to the other solar irradiance componentsThis research was funded by the Chilean Corporación de Fomento de la Producción (CORFO), grant number 17BPE3-83761, and 7PTECES-75830 under the framework of the project “AtaMoS TeC,” by the ANID grant number ANID/FONDAP/15110019 (SERC-Chile) and ANID/ FONDECYT-INITIATION/11190289, funded by the Spanish Education and Competitivity Ministry and co-financed by the European Regional Development Fund grant number ENE2017-83790-C3- 1,2,3 and by the Spanish Ministry of Science and Innovation and co-financed by the European Regional Development Fund grant reference PID2020-118239RJ-I00 (MAPVSpain) Special thanks to Antonio Campos (PSA, Spain) for his support during this wor

Does severe soil drought have after-effects on arbuscular and ectomycorrhizal root colonisation and plant nutrition?

Background and aims Arbuscular (AM) and ectomycorrhizas (EM) predominate in different soils. We hypothesise that also climatic factors affect directly their relative success and AM fungi (AMF) generally tolerate drought better than EM fungi (EMF). Here we tested the colonisation rates of soil-borne AMF and EMF after soil drought treatments. Methods Forest and meadow soils were mixed to include AMF and EMF propagules. There were three soil treatments: soil moisture corresponding to 60% (control) or 10% in mass of maximum water retention, or air-dry. The bait plants were EM-forming silver birch (Betula pendula), dual-mycorrhiza forming grey alder (Alnus incana) and AM-forming white clover (Trifolium repens). After re-watering, bait plants were sown and grown in a growth chamber in favourable conditions. This way, hostplant responses to drought were eliminated. Results Previous soil drought decreased EM colonisation in alder. The spore formation by AMF in clover was negatively affected after the most severe soil drought treatment, suggesting slightly retarded AM formation. Soluble soil potassium concentrations were lower in drought-treated soils and this was reflected in birch foliar concentrations. Conclusions The results provide some support to the hypothesised better drought tolerance of AMF than EMF propagules but further studies in milder drought and in other plant-fungus combinations are needed.201

Analysis of Green Wood Preservation Chemicals

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Are arbuscular-mycorrhizal Alnus incana seedlings more resistant to drought than ectomycorrhizal and nonmycorrhizal ones?

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Activity of Spent Coffee Ground Cinnamates against Wood-decaying Fungi in vitro

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Characterisation, recovery and activity of hydrophobic compounds in Norway spruce log soaking pit water

Norway spruce log soaking water (SLSW) is considered a waste in the plywood and veneer industry but has not been characterised, and its possible uses remain unexplored. The purpose of this study is to characterise and test the possibility of using SLSW in wood preservative formulations. First, the SLSW was characterised, and the presence of carbohydrates in the log soaking water was reduced with a hydrophobic adsorbent to reduce the nutrient availability for fungi in the liquids. Then, the feasibility of using SLSW and the sugar free SLSW (denoted later as EHC solution) as wood preservatives was studied by testing their antifungal and antioxidant activities and performing a mini-block test against Schizophyllum commune, Trametes versicolor, Fibroporia vaillantii and Gloeophyllum trabeum. Several phenolic compounds were found in the SLSW. This water also had high antioxidant activity at 1000 mg/L before and after carbohydrate removal but no antifungal activity. Its impregnation in wood caused a slight reduction in mass loss of the Pinus sylvestris specimens but had no effect on the Fagus sylvatica specimens when exposed against Schizophyllum commune, Trametes versicolor, Fibroporia vaillantii and Gloeophyllum trabeum. The SLSW as a wood preservative is invalid, even after partial carbohydrate removal. However, due to the presence of wood constituents, SLSW could be a resource for other uses requiring high antioxidant activity but specific applications need further investigation