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Abstract: Living stumps reported in many tree species were the first, circumstantial evidence of root grafting. Although stump overgrowth has been extensively studied in various tree species, anatomical observations have mainly focused on the xylem part. Here, we investigated the xylem and phloem structure in living stumps of two conifer species: Norway spruce (Picea abies (L.) Karst.) and silver fir (Abies alba Mill.). The mechanism of wound closure was similar in the two species, however, there were differences in the structure of wound tissues in wood and bark. Immediately after the injury, a callus consisting of parenchymal cells was formed, followed by wound-wood with wide increments. In addition, the wood structure and morphology of tracheids were changed. Tracheids lost their typical elongated and tapering structure; instead, numerous crooked and forked tracheids were present. Traumatic resin canals were present in both species but were more abundant in P. abies, which also had normal resin canals. While the structure of the xylem growth rings eventually normalized in both species, the width of the annual xylem increments was diminished. In both species, the typical structure of annual phloem increment was lost in the non-collapsed phloem and sclereids were very abundant in the collapsed phloem. In A. alba, the collapsed phloem was rich in swollen parenchyma cells containing blue-stained contents, while in P. abies, numerous large traumatic resin canals were conspicuous. The study showed that similar patterns of vascular tissue restoration exist in A. alba and P. abies in response to tree felling. However, there are certain species-specific peculiarities in the wood and phloem anatomical response, which might affect long-term stump functioning and survival.
Keywords: wood physiology, phloem, xylem, Norway spruce, Picea abies, silver fir, Abies alba
Published in DiRROS: 03.12.2024; Views: 120; Downloads: 1382
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Abstract: International provenance trials of ecologically and economically important tree species are crucial to deciphering the influence of environmental factors and intraspecific variability on tree growth and performance under climate change to guide assisted gene flow and assisted migration of tree provenances and species. In this context, we compared inter-annual trends in tree-ring widths (carbon sequestration potential) and vessel characteristics (conductivity optimisation) of four beech provenances in two international provenance trials, one in Slovenia (Kamenski hrib, a core beech growing site) and one in Hungary (Bucsuta, a marginal beech site) in 2009–2019. We found different patterns of inter-annual variability in mean vessel area and tree-ring widths among provenances and sites, pointing to diverse genetic background and environmental influence on these two wood-anatomical traits. The average values of the vessel area varied less between provenances at Kamenski hrib than at Bucsuta. Weather conditions differently affected tree-ring width and mean vessel area. Furthermore, the length of the period of response of vessel area to the analysed weather conditions differed in summer and winter periods. The differences in the mean vessel area within the tree ring were more pronounced in the weather-wise extreme years, regardless of the provenance. Consistent with previous studies, we confirmed that site conditions affect the climate sensitivity of trees, which is more pronounced at marginal sites or in extreme years. The findings on how different environmental conditions affect the radial growth of young beech trees of different origin are very important for future forest management.
Keywords: Fagus sylvatica, quantitative wood anatomy, common gardens, intraspecific variation, juvenile period, weather conditions
Published in DiRROS: 03.12.2024; Views: 106; Downloads: 585
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Abstract: Soil mesofauna plays a key role in maintaining soil health by supporting the decomposition of organic matter, nutrient cycling and the maintenance of soil structure. In this study of Slovenian agricultural ecosystems, we used four modifications of the QBS index, a soil biological quality index based on soil mesofauna. We compared diversity in arable fields under different tillage intensities, a strawberry field and an orchard, managed with either organic or integrated pest management methods (IPM). The results show significant differences in the mesofaunal communities in the soil. Minimum tillage promoted higher biodiversity, especially of Collembola, compared to conventional tillage. In fruit production systems, the ratio of Collembola to Acarina differed from that of arable fields, skewing in favour of Collembola, possibly related to the use of copper-containing pesticides in organic orchards and systemic herbicides in IPM systems. The QBS index values for soil health varied considerably between systems. Only QBS modifications considering the abundances of organisms (QBS-ab and QBS-a) were able to distinguish between different system-management groups. This study provides insights into the limitations of the originally proposed QBS-ar index to discern the effects of farming intensity on the soil mesofaunal community. Results suggest that minimum tillage and organic management practices can promote healthier soil ecosystems, emphasizing the importance of sustainable soil management for the promotion of soil biodiversity. Future research should aim to incorporate a broader range of agricultural practices and assign fauna to a higher taxonomic rank to further explain the effects on soil mesofauna diversity.
Keywords: soil health, soil microarthropods, biodiversity, agroecosystems, tillage intensity, organic farming
Published in DiRROS: 03.12.2024; Views: 103; Downloads: 53
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Abstract: Background Research into the genetic diversity of honey bee (Apis mellifera L.) populations has become increasingly signifcant in recent decades, primarily due to population declines attributed to human activities and climate change. As a species of great importance, breeding programs that leverage understanding of genomic diversity could ofer solutions to mitigate these challenges. The objective of this study was to examine the genomic diversity and population structure of Carniolan honey bees (Apis mellifera carnica) using the Illumina SNP chip on a large honey bee sample collected from Central and South-Eastern European countries. The study also aims to ofer recommendations for future breeding programs
Keywords: honey bee, Carniolian honey bee, genomic diversity, diversity, population structure
Published in DiRROS: 02.12.2024; Views: 124; Downloads: 314
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Abstract: A study conducted in an unburned cork oak forest located in the Collo Massif (Skikda), northwestern Algeria, resulted in the capture of 385 beetles in 2015 and 545 beetles in 2016 at three sub-stations, using Barber pitfall traps. The study lasted three months, from April to June, over two consecutive years. Additionally, using the carpophores method on Fomes fomentarius (Linné) (Fries, 1849), a total of 3,017 beetle specimens were obtained in 2015 and 3,107 beetle specimens in 2016, observed over the same three-month period around the three unburned sub-stations (Oued Agouf, Ain Fegoum and El Maktoua). The first observation concerning the Erotylidae family is that they are poorly known in North Africa, including Algeria, where published data on this subject is scarce. This study also revealed the presence of the species Triplax melanocephala (Latreille, 1804), which is rarely observed in Algeria. This species was recorded on the tinder fungus Formes fomentarius, with 30 individuals and 71 individuals counted in the Barber pitfall traps.
Keywords: cork oak forest, Coleoptera, Erotylidae, Triplax melanocephala, tinder fungus, Formes fomentarius
Published in DiRROS: 29.11.2024; Views: 327; Downloads: 1311
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