Abies guatemalensis Rehder, an endangered conifer endemic to Central American highlands, is ecologically vital in upper montane forests. It faces threats from habitat fragmentation, unsustainable logging, and illegal Christmas tree harvesting. While previous genetic studies on mature trees from eighteen populations showed high within-population diversity and limited among-population differentiation, the genetic impact of recent anthropogenic pressures on younger generations has yet to be discovered. Understanding these effects is crucial for developing effective conservation strategies for this vulnerable species. We sampled 170 young trees (< 15 years old) from seven populations across Guatemala. Seven microsatellite markers were used to analyse genetic diversity, population structure, and recent demographic history. Moderate levels of genetic diversity were observed within populations (mean Shannon diversity index = 4.97, mean Simpson's index = 0.51, mean allelic richness = 11.59, mean observed heterozygosity = 0.59). Although genetic structure broadly aligned with mountain corridors, substantial admixture patterns suggest historical connectivity across all populations. Most populations showed evidence of recent bottlenecks (p < 0.05) and inbreeding. The results suggest a potential decline in genetic diversity and increased population structuring (ΦST = 0.274, p < 0.01) over the past decades compared to the previous study on old trees. The observed genetic patterns indicate ongoing impacts of habitat fragmentation and anthropogenic pressures on A. guatemalensis. Conservation efforts should prioritise expanding effective population sizes and facilitating gene flow, particularly for isolated populations. While restoration efforts may be logistically easier within mountain ranges, genetic evidence suggests that increasing overall population connectivity could benefit this species. Management strategies should implement systematic seed collection protocols to maintain genetic diversity in future populations. These findings highlight the urgent need for conservation measures to preserve remaining genetic diversity and promote connectivity among A. guatemalensis populations.

• MeSH
• ekosystém * MeSH
• genetická variace * MeSH
• jedle * genetika   MeSH
• mikrosatelitní repetice * genetika   MeSH
• ohrožené druhy * MeSH
• populační genetika MeSH
• zachování přírodních zdrojů MeSH
• Publikační typ
• časopisecké články MeSH
• Geografické názvy
• Guatemala MeSH

During recent years, a new disease of Siberian fir (A. sibirica) emerged in Central Siberia, exhibiting symptoms of stem/branch deformation, cambium necrosis, and dieback of branches and twigs, the causal agent remaining unknown. The aim was to identify agent of the disease and to investigate its pathogenicity to A. sibirica and Norway spruce (Picea abies). Symptomatic tissues of fir were subjected to pure culture isolation of anticipated pathogen(s). Obtained isolates were subjected to molecular identification, phylogenetic analyses, and pathogenicity tests with A. sibirica saplings, and seeds and seedlings of A. sibirica and P. abies. The study demonstrated that, (i) most commonly isolated fungus from canker wounds of A. sibirica exhibited Acremonium-like anamorphs; (ii) phylogeny demonstrated that investigated fungi belong to genus Corinectria, but are genetically well separated from other worldwide known Corinectria spp.; (iii) one species of isolated fungi has the capacity to cause the disease and kill A. sibirica saplings and seedlings, but also seedlings of P. abies. Guidelines for future research were defined in order to generate needed information on species description, its origin and ecology, and estimation of potential risks upon the eventual invasion of the pathogen to new geographic areas, in particular of Europe.

• MeSH
• fylogeneze MeSH
• jedle mikrobiologie   MeSH
• mikroskopie elektronová rastrovací MeSH
• Nectria genetika   patogenita   ultrastruktura   MeSH
• nemoci rostlin mikrobiologie   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Geografické názvy
• Sibiř MeSH

The diet rich in fruits and vegetables reduces the risk of metabolic syndrome, including diabetes development by various mechanisms of action, mainly due to the presence of polyphenolic compounds. Extracts from different conifer species are known to be a rich source of various polyphenols. In the present study we elucidated the in vitro mechanism of anti-diabetic activity of silver fir (Abies alba) wood and bark extracts and compared their activity to non-coniferous sweet chestnut wood extract and standardized maritime pine bark extract. Extracts and lignans were tested for their inhibitory activity of enzymes involved in the regulation of blood glucose in vitro. The ability of extracts to protect against oxidative stress in high glucose environment was tested on mouse myoblast cell line. Silver fir wood and bark extracts were shown to be effective inhibitors of α-glucosidase, α-amylase and dipeptidyl peptidase 4, three enzymes involved in the regulation of blood glucose levels. Coniferous extracts also showed protection against oxidative stress generated in high glucose environment. Lignans, particularly pinoresinol diglucoside, isolariciresinol and secolariciresinol were shown to be important contributors of antihyperglycemic activity through inhibition of dipeptidyl peptidase 4. This corroborates previously published in vivo results on blood glucose level obtained with silver fir wood extract and supports the use of silver fir wood and bark extracts as food supplements or functional foods in borderline diabetes.

• MeSH
• alfa-amylasy antagonisté a inhibitory   MeSH
• alfa-glukosidasy metabolismus   MeSH
• buněčné linie MeSH
• dipeptidylpeptidasa 4 metabolismus   MeSH
• dřevo chemie   MeSH
• hypoglykemika izolace a purifikace   farmakologie   MeSH
• inhibitory dipeptidylpeptidasy 4 izolace a purifikace   farmakologie   MeSH
• inhibitory glykosidových hydrolas izolace a purifikace   farmakologie   MeSH
• jedle chemie   MeSH
• krevní glukóza účinky léků   MeSH
• kůra rostlin chemie   MeSH
• lidé MeSH
• myši MeSH
• oxidační stres účinky léků   MeSH
• rostlinné extrakty izolace a purifikace   farmakologie   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

Although plants are often exposed to atmospheric nanoparticles (NPs), the mechanism of NP deposition and their effects on physiology and metabolism, and particularly in combination with other stressors, are not yet understood. Exploring interactions between stressors is particularly important for understanding plant responses in urban environments where elevated temperatures can be associated with air pollution. Accordingly, 3-year-old spruce seedlings were exposed for 2 weeks to aerial cadmium oxide (CdO) NPs of environmentally relevant size (8-62 nm) and concentration (2 × 105 cm-3). While half the seedlings were initially acclimated to high temperature (35 °C) and vapour pressure deficit (VPD; 2.81 kPa), the second half of the plants were left under non-stressed conditions (20 °C, 0.58 kPa). Atomic absorption spectrometry was used to determine Cd content in needles, while gas and liquid chromatography was used to determine changes in primary and secondary metabolites. Photosynthesis-related processes were explored with gas-exchange and chlorophyll fluorescence systems. Our work supports the hypothesis that atmospheric CdO NPs penetrate into leaves but high temperature and VPD reduce such penetration due to stomatal closure. The hypothesis that atmospheric CdO NPs influences physiological and metabolic processes in plants was also confirmed. This impact strengthens with increasing time of exposure. Finally, we found evidence that plants acclimated to stress conditions have different sensitivity to CdO NPs compared to plants not so acclimated. These findings have important consequences for understanding impacts of global warming on plants and indicates that although the effects of elevated temperatures can be deleterious, this may limit other forms of plant stress associated with air pollution.

• MeSH
• aklimatizace fyziologie   MeSH
• borovice MeSH
• fotosyntéza fyziologie   MeSH
• globální oteplování MeSH
• jedle MeSH
• látky znečišťující vzduch toxicita   MeSH
• látky znečišťující životní prostředí metabolismus   MeSH
• listy rostlin účinky léků   MeSH
• nanočástice toxicita   MeSH
• oxidy toxicita   MeSH
• semenáček účinky léků   MeSH
• sloučeniny kadmia toxicita   MeSH
• smrk účinky léků   fyziologie   MeSH
• teplota * MeSH
• vysoká teplota MeSH
• Publikační typ
• časopisecké články MeSH

Genetic association studies in forest trees would greatly benefit from information on the response of trees to environmental stressors over time, which can be provided by dendroecological analysis. Here, we jointly analysed dendroecological and genetic data of surviving silver fir trees to explore the genetic basis of their response to the iconic stress episode of the 1970s and 1980s that led to large-scale forest dieback in Central Europe and has been attributed to air pollution. Specifically, we derived dendrophenotypic measures from 190 trees in the Bavarian Forest that characterize the resistance, resilience and recovery during this growth depression, and in the drought year in 1976. By focusing on relative growth changes of trees and by standardizing the dendrophenotypes within stands, we accounted for variation introduced by micro- and macroscale environmental differences. We associated the dendrophenotypes with single nucleotide polymorphisms (SNPs) in candidate genes using general linear models (GLMs) and the machine learning algorithm random forest with subsequent feature selection. Most trees at our study sites experienced a severe growth decline from 1974 until the mid-1980s with minimum values during the drought year. Fifteen genes were associated with the dendrophenotypes, including genes linked to photosynthesis and drought stress. With our study, we show that dendrophenotypes can be a powerful resource for genetic association studies that permit to account for micro- and macroenvironmental variation when data are derived from natural populations. We call for a wider collaboration of dendroecologists and forest geneticists to integrate individual tree-level dendrophenotypes in genetic association studies.

• MeSH
• ekologie MeSH
• fyziologická adaptace genetika   MeSH
• fyziologický stres genetika   MeSH
• genetické asociační studie MeSH
• genotyp MeSH
• jedle genetika   růst a vývoj   MeSH
• jednonukleotidový polymorfismus genetika   MeSH
• období sucha MeSH
• podnebí MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Dead wood represents an important pool of organic matter in forests and is one of the sources of soil formation. It has been shown to harbour diverse communities of bacteria, but their roles in this habitat are still poorly understood. Here, we describe the bacterial communities in the dead wood of Abies alba, Picea abies and Fagus sylvatica in a temperate natural forest in Central Europe. An analysis of environmental factors showed that decomposing time along with pH and water content was the strongest drivers of community composition. Bacterial biomass positively correlated with N content and increased with decomposition along with the concurrent decrease in the fungal/bacterial biomass ratio. Rhizobiales and Acidobacteriales were abundant bacterial orders throughout the whole decay process, but many bacterial taxa were specific either for young (<15 years) or old dead wood. During early decomposition, bacterial genera able to fix N2 and to use simple C1 compounds (e.g. Yersinia and Methylomonas) were frequent, while wood in advanced decay was rich in taxa typical of forest soils (e.g. Bradyrhizobium and Rhodoplanes). Although the bacterial contribution to dead wood turnover remains unclear, the community composition appears to reflect the changing conditions of the substrate and suggests broad metabolic capacities of its members.

• MeSH
• Bacteria klasifikace   genetika   izolace a purifikace   MeSH
• biodiverzita MeSH
• biomasa MeSH
• buk (rod) mikrobiologie   MeSH
• dřevo mikrobiologie   MeSH
• ekosystém MeSH
• houby klasifikace   genetika   izolace a purifikace   MeSH
• jedle mikrobiologie   MeSH
• lesy MeSH
• mikrobiota genetika   MeSH
• půda chemie   MeSH
• půdní mikrobiologie MeSH
• smrk mikrobiologie   MeSH
• stromy mikrobiologie   MeSH
• Publikační typ
• časopisecké články MeSH
• Geografické názvy
• Evropa MeSH

Improving our understanding of the potential of forest adaptation is an urgent task in the light of predicted climate change. Long-term alternatives for susceptible yet economically important tree species such as Norway spruce (Picea abies) are required, if the frequency and intensity of summer droughts will continue to increase. Although Silver fir (Abies alba) and Douglas fir (Pseudotsuga menziesii) have both been described as drought-tolerant species, our understanding of their growth responses to drought extremes is still limited. Here, we use a dendroecological approach to assess the resistance, resilience, and recovery of these important central Europe to conifer species the exceptional droughts in 1976 and 2003. A total of 270 trees per species were sampled in 18 managed mixed-species stands along an altitudinal gradient (400-1200 m a.s.l.) at the western slopes of the southern and central Black Forest in southwest Germany. While radial growth in all species responded similarly to the 1976 drought, Norway spruce was least resistant and resilient to the 2003 summer drought. Silver fir showed the overall highest resistance to drought, similarly to Douglas fir, which exhibited the widest growth rings. Silver fir trees from lower elevations were more drought prone than trees at higher elevations. Douglas fir and Norway spruce, however, revealed lower drought resilience at higher altitudes. Although the 1976 and 2003 drought extremes were quite different, Douglas fir maintained consistently the highest radial growth. Although our study did not examine population-level responses, it clearly indicates that Silver fir and Douglas fir are generally more resistant and resilient to previous drought extremes and are therefore suitable alternatives to Norway spruce; Silver fir more so at higher altitudes. Cultivating these species instead of Norway spruce will contribute to maintaining a high level of productivity across many Central European mountain forests under future climate change.

• MeSH
• fyziologická adaptace MeSH
• jedle fyziologie   MeSH
• klimatické změny MeSH
• lesy MeSH
• období sucha * MeSH
• Pseudotsuga fyziologie   MeSH
• smrk fyziologie   MeSH
• Publikační typ
• časopisecké články MeSH
• Geografické názvy
• Evropa MeSH
• Německo MeSH
• Norsko MeSH

BACKGROUND: Somatic embryogenesis in conifer species has great potential for the forestry industry. Hence, a number of methods have been developed for their efficient and rapid propagation through somatic embryogenesis. Although information is available regarding the previous process-mediated generation of embryogenic cells to form somatic embryos, there is a dearth of information in the literature on the detailed structure of these clusters. METHODOLOGY/PRINCIPAL FINDINGS: The main aim of this study was to provide a more detailed structure of the embryogenic tissue clusters obtained through the in vitro propagation of the Norway spruce (Picea abies (L.) Karst.). We primarily focused on the growth of early somatic embryos (ESEs). The data on ESE growth suggested that there may be clear distinctions between their inner and outer regions. Therefore, we selected ESEs collected on the 56th day after sub-cultivation to dissect the homogeneity of the ESE clusters. Two colourimetric assays (acetocarmine and fluorescein diacetate/propidium iodide staining) and one metabolic assay based on the use of 2,3,5-triphenyltetrazolium chloride uncovered large differences in the metabolic activity inside the cluster. Next, we performed nuclear magnetic resonance measurements. The ESE cluster seemed to be compactly aggregated during the first four weeks of cultivation; thereafter, the difference between the 1H nuclei concentration in the inner and outer clusters was more evident. There were clear differences in the visual appearance of embryos from the outer and inner regions. Finally, a cluster was divided into six parts (three each from the inner and the outer regions of the embryo) to determine their growth and viability. The innermost embryos (centripetally towards the cluster centre) could grow after sub-cultivation but exhibited the slowest rate and required the longest time to reach the common growth rate. To confirm our hypothesis on the organisation of the ESE cluster, we investigated the effect of cluster orientation on the cultivation medium and the influence of the change of the cluster's three-dimensional orientation on its development. Maintaining the same position when transferring ESEs into new cultivation medium seemed to be necessary because changes in the orientation significantly affected ESE growth. CONCLUSIONS AND SIGNIFICANCE: This work illustrated the possible inner organisation of ESEs. The outer layer of ESEs is formed by individual somatic embryos with high metabolic activity (and with high demands for nutrients, oxygen and water), while an embryonal group is directed outside of the ESE cluster. Somatic embryos with depressed metabolic activity were localised in the inner regions, where these embryonic tissues probably have a very important transport function.

• MeSH
• jedle účinky léků   růst a vývoj   MeSH
• rostlinné proteiny metabolismus   MeSH
• smrk účinky léků   růst a vývoj   metabolismus   MeSH
• tetrazoliové soli farmakologie   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Geografické názvy
• Norsko MeSH

Silice z jedle sibiřské (Abies sibirica Ledeb.) patří mezi látky s potenciálním využitím v prevenci a terapii orálních kandidóz. Proto cílem práce byla formulace, příprava a hodnocení orálního gelu obsahujícího 0,3 % této silice. Jako gelotvorná látka byl použit Carbopol 974P NF v 1% koncentraci, řada vzorků byla navíc stabilizována přísadou polysorbátu 80 (0,1–0,5 %). K úpravě chuťových vlastností sloužil xylitol v koncentraci 10 % nebo 20 %. Na základě mikroskopického hodnocení (průměrná velikost kapek silice, stupeň disperzity) ihned po přípravě a po šestiměsíčním uchovávání bylo zjištěno, že optimální koncentrace polysorbátu 80 je 0,3 %. Z výsledků experimentu rovněž vyplývá, že xylitol představuje nejen pomocnou látku upravující organoleptické vlastnosti přípravku, ale jeho použití umožňuje významným způsobem ovlivnit kvalitativní parametry a stabilitu. Klíčová slova: jedle sibiřská • silice • orální gel • xylitol • stabilita

Essential oil of the Siberian fir (Abies sibirica Ledeb.) ranks among the substances with potential use in prevention and treatment of oral candidiasis. Therefore, the aim of the study was the formulation, preparation and evaluation of an oral gel containing 0.3% of this essential oil. Carbopol 974P NF in 1% concentration was used as the gelling agent, some samples were additionally stabilized by an addition of polysorbate 80 (0.1–0.5%). Xylitol in concentrations of 10% or 20% was added with the aim to modify the taste properties of the gel. Following microscopic evaluation (mean oil droplet size, degree of dispersity) immediately after preparation and after 6-month storage, it has been found that the optimal concentration of polysorbate 80 is 0.3%. The results of the experiment also demonstrated that xylitol was not only an excipient adjusting the organoleptic properties of the preparation – its use enabled significant improvement of the quality parameters and stability. Keywords: Siberian fir • essential oil • oral gel • xylitol • stability

• Klíčová slova
• silice, orální gel,
• MeSH
• akryláty MeSH
• gely normy   MeSH
• jedle * MeSH
• lidé MeSH
• oleje prchavé * MeSH
• orální kandidóza * farmakoterapie   prevence a kontrola   MeSH
• polysorbáty MeSH
• pomocné látky MeSH
• příprava léků * metody   statistika a číselné údaje   MeSH
• řízení kvality MeSH
• stabilita léku MeSH
• xylitol * normy   MeSH
• Check Tag
• lidé MeSH

Silver fir is one of the most productive and ecologically valuable native European tree species, however, it has been experiencing decline which has periodically occurred over its natural range. This paper aims to investigate the recent climate-growth relationships of silver fir (Abies alba Mill.) and its temporal change along the course of its life. Long-term tree-ring databases, as well as records on climate, atmospheric SO2, NO3 and acid concentrations from four different regions in the Western Carpathians were used. The results provide clear evidence of significant increase of silver fir's radial increment over the entire Western Carpathian area since 1970-1980. The results indicated that the most probable factors behind the rapid recovery of tree radial increment were reductions in emissions of NO3 and SO2, alongside a significant increase in mean June, July and April temperatures.

• MeSH
• dusičnany analýza   MeSH
• ekologie MeSH
• jedle růst a vývoj   MeSH
• klimatické změny MeSH
• látky znečišťující vzduch analýza   MeSH
• monitorování životního prostředí MeSH
• oxid siřičitý analýza   MeSH
• podnebí MeSH
• teplota MeSH
• znečištění ovzduší statistika a číselné údaje   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH