-We investigated the species richness and composition of mycorrhizal fungi naturally colonizing one-and two-year-old Pinus sylvestris L. seedlings from four bare-root nurseries in Poland. We hypothesized that both edaphic factors and seedling age would affect ectomycorrhizal (ECM) community structure. We assessed the relative abundance of mycorrhizal morphotypes and distinguished ECM fungi present on root tips using RFLP (restriction fragment length polymorphism) of the ITS (internal transcribed spacer) of fungal rDNA. Most of the RFLP types were identified by comparing RFLP patterns with reference data obtained from regional sporocarps and isolates of ectendomycorrhizal species. Samples of unidentified RFLP types and representatives of suilloid RFLP patterns were sequenced and compared with available sequences. Overall, we identified 13 fungal species, with species richness varying from two to eight species among nurseries. The dominant species in each examined nursery were Wilcoxina mikolae and Thelephora terrestris. Suilloid fungi were also abundant in most of the nurseries. S. variegatus was the most frequent suilloid species among the nurseries. Seedling age affected the relative abundance of ECM species to some extent. Principal component analysis (PCA) revealed a lack of apparent correlations between the relative abundances of species and edaphic factors. Factors that may contribute to the maintenance of ECM community structure are discussed.forest nursery / mycorrhiza / ITS-RFLP / Scots pine Résumé -Associations mycorhiziennes des semis de pin sylvestre (Pinus sylvestris L.) en pépinière en Pologne. Nous avons étudié la richesse spécifique et la composition des champignons mycorhiziens colonisant naturellement des semis de Pinus sylvestris L. âgés de un et deux ans dans quatre pépinières de production de plants à racines nues en Pologne. Nous avons fait l'hypothèse que ensemble les facteurs édaphiques et l'âge des semis affecteraient la structure de la communauté ectomycorhizienne (ECM). Nous avons déterminé l'abondance relative des morphotypes mycorhiziens et distingué les champignons ECM présents dans les pointes racinaires en utilisant RFLP de ITS de l'ADNr fongique. La plupart des types RFLP ont été identifiés en comparant les modèles RFLP avec des données de référence obtenues de sporocarpes régionaux et isolés d'espèces ectoendomycorhiziennes. Des échantillons de types RFLP non identifiés et de modèles représentatifs de suilloides RFLP ont été séquencés et comparés avec les séquences disponibles. Globalement, nous avons identifié 13 espèces fongiques, avec une richesse spécifique variant de deux à huit espèces parmi les pépinières. Dans chaque pépinière étudiée, les espèces dominantes étaient Wilcoxina mikolae et Thelephora terrestris. Les champignons suilloides étaient aussi abondants dans la plupart des pépinières. S. variegatus était l'espèce suilloide la plus fréquente parmi les pépinières. L'âge des semis affecte dans une certaine mesure l'abondance relative des espèces ECM. Une analy...

We report the effects of pine and oak litter on species composition and diversity of mycorrhizal fungi colonizing 2-year-old Pinus sylvestris L. seedlings grown in a bare-root nursery in Lithuania. A layer of pine or oak litter was placed on the surface of the nursery bed soil to mimic natural litter cover. Oak litter amendment appeared to be most favorable for seedling survival, with a 73% survival rate, in contrast to the untreated mineral bed soil (44%). The concentrations of total N, P, K, Ca, and Mg were higher in oak growth medium than in pine growth medium. Relative to the control (pH 6.1), the pH was lower in pine growth medium (5.8) and higher in oak growth medium (6.3). There were also twofold and threefold increases in the C content of growth medium with the addition of pine and oak litter, respectively. Among seven mycorrhizal morphotypes, eight different mycorrhizal taxa were identified: Suillus luteus, Suillus variegatus, Wilcoxina mikolae, a Tuber sp., a Tomentella sp., Cenococcum geophilum, Amphinema byssoides, and one unidentified ectomycorrhizal symbiont. Forest litter addition affected the relative abundance of mycorrhizal symbionts more than their overall representation. This was more pronounced for pine litter than for oak litter, with 40% and 25% increases in the abundance of suilloid mycorrhizae, respectively. Our findings provide preliminary evidence that changes in the supply of organic matter through litter manipulation may have far-reaching effects on the chemistry of soil, thus influencing the growth and survival of Scots pine seedlings and their mycorrhizal communities.In the boreal zone, Scots pine (Pinus sylvestris L.) is widely planted for reforestation and afforestation of marginally economic agricultural land (25,26). For example, in Lithuania 76.4 million seedlings are planted each year; approximately 20% of these are Scots pine (36). An important factor in the performance of outplanted conifers is the association of plant roots with ectomycorrhizal (ECM) fungi (7, 37). ECM fungi are essential for nutrient acquisition and plant protection against root pathogens and drought stress (51). Pinus species are dependent on symbiosis to develop optimally under natural conditions (40).ECM fungi naturally established in nurseries are diverse, and their establishment depends on several factors, including host species relationships, sylvicultural practices, and nursery conditions (11, 35). Early differences in ECM colonization of tree seedlings may affect their performance after outplanting to forest sites (30). The application of forest litter to nurserygrown seedlings can be useful in enhancing ECM colonization and the field performance of outplanted seedlings (8, 47).In forest nurseries, attempts have been made to use various germination media instead of mineral soils. The Dunemann system of nursery practice demonstrated that spruce needles are a good medium for raising conifer seedlings (24). A series of experiments following the Dunemann scheme showed that germination, growth, and sur...

No abstract

We investigated the species richness and composition of ectomycorrhizal (EM) fungi colonizing Pinus sylvestris L. seedlings naturally regenerating in boreal forest, in three different microhabitats: on forest ground, on decaying stumps, and within moss layer on erratic boulders. We tested the hypothesis that habitat differences would affect the composition of the EM community of regenerating pine seedlings. In total, 16 EM species were detected, from which none occurred on seedlings growing in all three microhabitats. Piloderma croceum and Cenococcum geophilum were common for seedlings growing in forest ground and on boulders, while Tricholoma aestuans and Suillus luteus were shared between seedlings growing on forest ground and decaying stumps. EM species richness and composition were strikingly different between seedlings regenerating in different microhabitats. Results are discussed as a function of dispersal and niche differentiation of EM fungi.

The Covid-19 pandemic caused serious turbulences in most aspects of humans activities. Due to the need to address the epidemic developments at extreme scales, ranging from the entire population of the country down to the level of individual citizens, a construction of adequate mathematical models faces substantial difficulties caused by lacking knowledge of the mechanisms driving transmission of the infections and the very nature of the resulting disease. Therefore, in modeling Covid-19 and its effects, a shift from the knowledge-intensive systems paradigm to the data-intensive one is needed. The current paper is devoted to the architecture of ProME, a data-intensive system for forecasting the Covid-19 and decision making support needed to mitigate the pandemics effects. The system has been constructed to address the mentioned challenges and to allow further relatively easy adaptations to the dynamically changing situation. The system is mainly based on open-source solutions so can be reproduced whenever similar challenges occur.

No abstract