Search the repository

A+ | A- | | SLO | ENG

Abstract: Climate change will affect radial growth patterns of trees, which will result in different forest productivity, wood properties, and timber quality. While many studies have been published on xylem phenology and anatomy lately, little is known about the phenology of earlywood and latewood formation, also in relation to cambial phenology. Even less information is available for phloem. Here, we examined year-to-year variability of the transition dates from earlywood to latewood and from early phloem to late phloem in Norway spruce (Picea abies) from three temperate sites, two in Slovenia and one in the Czech Republic. Data on xylem and phloem formation were collected during 2009-2011. Sensitivity analysis was performed to determine the specific contribution of growth rate and duration on wood and phloem production, separately for early and late formed parts. We found significant differences in the transition date from earlywood to latewood between the selected sites, but not between growth seasons in trees from the same site. It occurred in the first week of July at PAN and MEN and more than two weeks later at RAJ. The duration of earlywood formation was longer than that of latewood formation; from 31.4 days at PAN to 61.3 days at RAJ. In phloem, we found differences in transition date from early phloem to late phloem also between the analysed growth seasons; from 2.5 weeks at PAN to 4 weeks at RAJ Compared to the transition from earlywood to latewood the transition from early phloem to late phloem occurred 25-64 days earlier. There was no significant relationship between the onset of cambial cell production and the transition dates. The findings are important to better understand the inter-annual variability of these phenological events in spruce from three contrasting temperate sites, and how it is reflected in xylem and phloem anatomy.
Keywords: Picea abies, xylem formation, phloem formation, cambium, tracheid, sieve cell, conifer, temperate environment
Published in DiRROS: 22.03.2021; Views: 1120; Downloads: 822
Full text (1,27 MB)
This document has many files! More...

Abstract: Dothistroma septosporum, the primary causal agent of Dothistroma needle blight, is one of the most significant foliar pathogens of pine worldwide. Its wide host and environmental ranges have led to its global success as a pathogen and severe economic damage to pine forests in many regions. This comprehensive global population study elucidated the historical migration pathways of the pathogen to reveal the Eurasian origin of the fungus. When over 3800 isolates were examined, three major population clusters were revealed: North America, Western Europe, and Eastern Europe, with distinct subclusters in the highly diverse Eastern European cluster. Modeling of historical scenarios using approximate Bayesian computation revealed the North American cluster was derived from an ancestral population in Eurasia. The Northeastern European subcluster was shown to be ancestral to all other European clusters and subclusters. The Turkish subcluster diverged first, followed by the Central European subcluster, then the Western European cluster, which has subsequently spread to much of the Southern Hemisphere. All clusters and subclusters contained both mating-types of the fungus, indicating the potential for sexual reproduction, although asexual reproduction remained the primary mode of reproduction. The study strongly suggests the native range of D. septosporum to be in Eastern Europe (i.e., the Baltic and Western Russia) and Western Asia.
Keywords: Mycosphaerella pini, biogeography, ABC, DNB, global spread, introduction pathways, invasive pathogen, global spread
Published in DiRROS: 09.02.2021; Views: 1226; Downloads: 776
Full text (2,27 MB)
This document has many files! More...

Keywords: nacionalna gozdna inventura, definicija gozda, raba zemljišč, gozdovi, negozdne površine
Published in DiRROS: 14.01.2021; Views: 1328; Downloads: 0

Keywords: Poplar, Willow, Black Walnut, Black Locust, international commission, FAO, national report, questionnaire, genetics, forest protection, legislation, categorisation, forest products, ecology, Slovenia
Published in DiRROS: 11.12.2020; Views: 1319; Downloads: 411
Full text (624,71 KB)

Abstract: Background. Food allergy is an increasing public health issue and the commonest cause of life-threatening anaphylactic reactions. Conventional allergy tests assess for the presence of allergen-specific IgE, significantly overestimating the rate of true clinical allergy resulting in over-diagnosis and adverse impact on health-related quality of life. Objective. To undertake initial validation and assessment of a novel diagnostic tool, the mast cell activation test (MAT). Methods. Primary human mast cells (hMCs) were generated from peripheral blood precursors, and sensitized using patient sera and then incubated with allergen. Mast cell degranulation was assessed by flow cytometry and mediator release. We compared the diagnostic performance of MAT to existing diagnostic tools to assess in a cohort of peanut-sensitized individuals undergoing double-blind, placebo-controlled challenge. Results. hMCs sensitized with sera from peanut, grass pollen and hymenoptera- (wasp venom) allergic patients demonstrated allergen-specific and dose-dependent degranulation by both expression of surface activation markers (CD63 and CD107a) and functional assays (prostaglandins D2 and ß-hexosaminidase release). In this cohort of peanut-sensitized individuals, MAT was found to have superior discrimination performance compared to other testing modalities including component-resolved diagnostics and basophil activation test. Using functional principle component analysis, we identified 5 clusters or patterns of reactivity in the resulting dose-response curves, which at preliminary analysis corresponded to the reaction phenotypes seen at challenge. Conclusion. MAT is a robust tool which may confer superior diagnostic performance compared to existing allergy diagnostics, and may be useful to explore differences in effector cell function between basophils and mast cells during allergic reactions.
Keywords: allergy and immunology -- diagnosis, anaphylaxis, immunologic tests, mast cells, food hypersensitivity, basophil activation test, BAT, mast cell activation test
Published in DiRROS: 30.11.2020; Views: 1668; Downloads: 1572
Full text (3,30 MB)
This document has many files! More...