Monika Małecka

Changes in nitrogen level and mycorrhizal structure of Scots pine seedlings inoculated with Thelephora terrestris

Abstract• We investigated the influence of Thelephora terrestris, an ectomycorrhizal fungus, on the concentration of nitrogen in needles of Pinus sylvestris L. seedlings and their mycorrhizal structure within four seasons of growth.• Seedlings were grown in four treatments: (I) inoculated + 0.030 g N, (II) inoculated + 0.045 g N, (III non-inoculated + 0.030 g N, (IV) non-inoculated + 0.045 g N under laboratory conditions and later planted in post-agricultural land.• For inoculated treatments, statistically significant differences in N concentration of needles were observed for two- and four-year-old seedlings. The number of ectomycorrhizae and concentration of N in needles were negatively correlated. After four seasons of growth the greatest numbers of ectomycorrhizae were present on seedlings from treatment II, and the smallest on seedlings from treatment IV.• Two-year-old seedlings had been colonized by at least six different fungal taxa, i.e. Cenococcum geophilum, Hebeloma crustuliniforme, Rhizopogon sp., Suillus bovinus, Thelephora terrestris and a non-identified one. Treatments I and II were dominated by the ectomycorrhizae of T. terrestris and their number was significantly greater than in treatments III or TV. On four-year-old seedlings ectomycorrhizae of T. terrestris were dominated in all treatments, while ectomycorrhizae of Hebeloma sp. were not found.Résumé• L’influence du champignon ectomycorhizien Thelephora terrestris sur la concentration en azote dans les aiguilles de semis de pin sylvestre et sur la structure mycorhizienne des plants a été suivie durant quatre saisons de croissance.• Les semis ont été cultivés sous quatre traitements : (I) inoculé + 0,030 g N, (II) inoculés + 0,045 g N, (III non inoculés + 0,030 g N, (IV) non inoculés + 0,045 g N, dans les conditions du laboratoire avant d’être plantés sur le terrain.• Dans les traitements d’inoculés, des différences significatives ont été observées dans la concentration des aiguilles en azote pour les semis de deux et quatre ans. Le nombre de mycorhizes et la concentration des aiguilles en azote étaient corrélés négativement. Après quatre saisons de croissance, le plus grand nombre de mycorhizes a été obtenu dans le traitement II et le plus petit dans le traitement IV• Les semis de deux ans avaient été colonisés par au moins six taxons différents de champignon : Cenococcum geophilum, Hebeloma crustuliniforme, Rhizopogon sp., Suillus bovinus, Thelephora terrestris et un autre taxon indéterminé. Dans les traitements I et II, les ectomycorhizes de T. terrestris dominaient et leur nombre était plus élevé que dans les traitements III et IV Pour les semis de quatre ans, les ectomycorhizes de T. terrestris dominaient dans tous les traitements, tandis que celles de Hebeloma sp. étaient absentes.

Characterisation of some Phlebiopsis gigantea isolates with respect to enzymatic activity and decay of Norway spruce wood

Abstract The activity of cellulase, peroxidase, phosphatase and dehydrogenase enzymes, together with the content of protocatechuic and vanillic acids, in samples of Norway spruce wood inoculated with 17 different isolates of Phlebiopsis gigantea was measured. The same isolates were used to compare decay activity in samples of Norway spruce wood after incubation for 3 and 6 months. Significant differences in enzyme activity and phenol production were found between aerial mycelium overgrowing the wood sample and the underlying wood. These differences indicated that the nature of the fungal mycelium appears to change depending on whether it is in contact with wood. After 6 months, highly extensive decomposition of the wood was shown by two British isolates. The results confirm a large difference in P. gigantea inoculum among isolates in natural conditions and reinforce the need for constant evaluation of the most active isolates to use in preparations for biocontrol: a problem for both users and registration bodies.

Evaluating the persistence of Phlebiopsis gigantea (Fr.: Fr.) Jülich mycelium and fruiting bodies in pine stumps after root-rot protection treatments

Ocena występowania grzybni i owocników Phlebiopsis gigantea (Fr.: Fr.) Jülich w pniakach sosnowych po wykonaniu zabiegu ochronnego przed hubą korzeni Evaluating the persistence of Phlebiopsis gigantea (Fr.: Fr.) Jülich mycelium and fruiting bodies in pine stumps after root-rot protection treatments Commercial preparations Rotstop and PgSuspension, used in Scandinavia and the United Kingdom, are EU-licensed biocontrol agents against root rot that contain isolates of the fungus Phlebiopsis gigantea. The composition of these two products differs from that of PgIBL, previously use in Poland, hence the need to verify their effectiveness under Polish site and stand conditions. Stumps were treated with the commercial products and subsequently checked after one year for the persistence of mycelia and fruiting bodies. Molecular methods were used on the mycelia present in the stumps to confirm that their genetic identity was consistent with fungal isolates from the preparations. Treatments with EU-licensed preparations gave satisfactory results - in about 70-80% of the stumps mycelia were present under the bark. Inoculation with Rotstop preparations was most effective during autumn 2008 (effectiveness of 82%), while PgSuspension application was most effective during spring 2008 (effectiveness of 77%). The development of the mycelia in pine stumps from the two preparations investigated (containing preserved dormant spores) was similar to that of preparation PgIBL (formulated from living mycelium within a growing medium), in terms of their relative effectiveness measured as the percentage of stumps supporting under-bark mycelia (which ranged between 70-90%, depending on the treatment term).

Pine sawdust as stimulator of the microbial community in post-arable afforested soil

ABSTRACT Sawdust and wood residues are considered to be stimulators of microbiological change in soil and could be used in post-arable sites designed for afforestation. In this study, we discuss changes in bacteria numbers within selected groups in relation to soil type (arable and forest) and method of sawdust application. Sawdust was spread along planting rows and mixed with the soil or put directly under roots of planted seedlings. Applying sawdust under the roots increased the number of cellulolytic bacteria in all experimental treatments. On post-arable soil, adding sawdust in rows increased the number of copiotrophic bacteria and reduced the number of fluorescent bacteria and actinomycetes (ACT). In control forest soils, the number of copiotrophic, oligotrophic and spore-forming bacteria decreased simultaneously with increased ACT in all treatments. The number of fluorescent bacteria increased when sawdust was applied on forest sites under planted trees and decreased when sawdust was spread in planting rows. Oligotrophic bacteria also decreased in the latter case. We present a list of bacteria identified by DNA – 16S rRNA gene sequences. Adding sawdust to arable soils significantly changed the quantitative and qualitative composition of microbial communities.

Decay indices for evaluating wood decomposition activity

The goal of the current study was to evaluate the efficiency of Norway spruce wood decomposition by the saprotrophic fungus Phlebiopsis gigantea (Fr.) Jülich. We identified the following indices as reliable measures of wood decay: decay acceleration index (DAI), final decay index (FD), and decay intensity index (DI). DAI was used to assess acceleration and deceleration of spruce wood loss, FD to estimate the final wood decay, and DI to evaluate the ability of the fungus to decompose wood, taking into consideration changes in mycelial activity over time. We tested the hypothesis that the wood decay activity of any fungus can be evaluated more objectively when: (i) several isolates of the tested fungus are assessed simultaneously, (ii) tests are performed for at least two time-points, and (iii) samples vary in wood density. Allowing a three-month period for wood decomposition was inadequate for reliable assessment of the wood decay ability of P. gigantea. Conversely, six months after inoculation, the tested isolates showed significant differences in their ability to generate dry wood loss, which depended on wood density. In view of these results, the DAI, FD, and DI indices are practical tools for assessing fungal activity to predict wood loss.

Antrodia gossypium, Phlebiopsis gigantea and Heterobasidion parviporum: in vitro growth and Norway spruce wood block decay

ABSTRACT Polymerase chain reaction-amplified and sequenced isolates of Antrodia gossypium, Phlebiopsis gigantea and Heterobasidion parviporum from decaying Norway spruce wood blocks after three and six months, which exhibited linear growth, were investigated. P. gigantea strains showed the fastest growth, whereas A. gossypium growth was five times slower. The differences between the mean daily increment of A. gossypium and the other examined isolates (except Hp2) were statistically significant. There were also significant differences in wood decay between densities over time. These results were confirmed by the decay acceleration index (DAI) and decay activity index, which were positively correlated with wood density regardless of the fungus species. The registered P. gigantea strains (Rotstop and PG Suspension) exhibited a strong decomposition ability (28% after six months); the weight loss caused by A. gossypium after six months of decay (15.2%) was similar to the results of P. gigantea (GB) after just three months (13.2%). All tested H. parviporum isolates showed rather rapid growth and equally strong wood decay (20–25%) compared to those of P. gigantea. DAI showed that A. gossypium may significantly contribute to wood decomposition over time, particularly in less dense wood samples. The use of both saprotrophs as biological agents against root pathogens is discussed.

Influence of resting and pine sawdust application on chemical changes in post-agricultural soil and the ectomycorrhizal community of growing Scots pine saplings

Abstract Changes in chemical compounds and in ectomycorrhizal structure were determined for Scots pine growing on post agricultural soil lying fallow for 3, 6 and 15 years, after amendment with pine sawdust. Soil without any amendments was used as the control treatment. Comparing the ectomycorrhizal structure 15 years after the application of pine sawdust revealed no significant differences in abundance or species richness between soil with and without organic enrichment. The results showed that the ectomycorrhizal status depends on soil conditions (soil pH, nitrogen content), which remain unaffected by saw dust application. In all treatments, the most frequently occurring ectomycorrhizae genera were Dermocybe, Hebeloma, Suillus, Tomentella and Tricholoma. Two species (Paxillus involutus, Amanita muscaria) were specific to the control plots that lay fallow for 15 years.

Chemical composition of soils on post-agricultural and forest sites before and after sawdust addition against the background of weather elements

Abstract We analysed changes in soil chemical properties (pH, C:N, N, P, K, Ca, Na) inside two forest areas chosen for renewal (Lubartów A and B) and within one post-agricultural site (Świerczyna) designated for afforestation with Scots pine. The experimental plots were located in areas known as persistent cockchafer grub spots. The Lubartów A site was not fenced and showed signs of wild boar activity. Analyses were carried out in the autumn of 2011 and spring 2012, prior to pine sawdust application to the soil and before tree planting, respectively, and again one year later in May 2013. Precipitation as well as air and soil temperatures were recorded throughout the experimental period. We found that soil temperature and humidity, determined by changes in weather, differences in soil chemical properties between forest and agricultural sites as well as sawdust treatments differentially affected soil reaction, C:N ratios and nutrient content. In the unfenced area (Lubartów A), the content of nutrient forms available to plants decreased no more under sawdust treatment than under control conditions. In the remaining areas, sawdust treatment caused an increase or no change in soil concentrations of the investigated nutrients. Under suitable temperature and humidity conditions, sawdust can represent a significant source of energy-rich compounds promoting diversified edaphone activity, which appears to be the main reason for changes in soil nutrient content.