Fraxinus Ornus Research Articles

Exploring the diversity of native Lachancea thermotolerans strains isolated by sugary extracts from manna ash to modulate the flavour of sour beers

Exploring the diversity of native Lachancea thermotolerans strains isolated by sugary extracts from manna ash to modulate the flavour of sour beers

The Impact of Climate Variability on the Blooming of Fraxinus ornus ‘Globosa’ as a Component of Novi Sad’s (Serbia) Green Infrastructure

The Impact of Climate Variability on the Blooming of Fraxinus ornus ‘Globosa’ as a Component of Novi Sad’s (Serbia) Green Infrastructure

Evaluation of the Biological Activity of Manna Exudate, from Fraxinus ornus L., and Its Potential Use as Hydrogel Formulation in Dermatology and Cosmetology.

Manna, a well-known herbal drug has multiple traditional and pharmaceutical uses and the entire composition, sugar derivatives and polyphenols, gives rise to a very interesting bioactive complex with versatile therapeutic and benefic properties such as antioxidant and anti-inflammatory activities. The aim of this research was to investigate a F. ornus manna extract loaded in a pectin hydrogel as a synergic vehicle to evaluate the potential use of the complex for cosmetic and dermatological applications. In particular, the study set out to disclose manna properties as a wound healing agent with antimicrobial and reparative activity on infected tissues. Moreover, considering the correlation between antioxidant activity and antiaging potential, the extract was investigated in regard to the anti-elastase activity and skin whitening potential. The total phenolic content of each extract was also determined and a safe profile by in vitro cytotoxicity studies was verified. The hydrogel complex, containing the manna extract and pectin as the gelling agent, exhibited suitable properties in terms of pH (from 5.50 to 6.80), rheological behavior and ability of preserving the antioxidant activity of the manna exudate (around 10%). All the peculiarities that make the pectin hydrogels ideal systems for skin disease, as wound dressings and for antiaging cosmetic formulations.

Analysis of particulate matter (PM) trapped by four different plant species in an urban forest: Quantification and characterization

Urban forests provide a series of ecosystem services, as recognized from the European 2030 Forestry Strategy; among them, they have the ability to capture particulate matter (PM) from the atmosphere, retaining it on leaves surface. This study analyses the efficiency in PM capturing of four broadleaved species: Celtis australis, Fraxinus ornus, Morus alba and Tilia cordata, set in an experimental urban forest in the city of Reggio Emilia (Italy). The airborne particles have been quantitatively and qualitatively analysed through SEM/x-EDS. Furthermore, the role played by leaf micromorphology in the efficiency of these four species to intercept PM has been assessed. Considering the total average number of particles trapped and collected by leaves for three years (from 2019 to 2021), F. ornus showed the highest capture-capacity (5.0 ± 3.1 × 103 particles/mm2), collecting 49 % more particles than Celtis australis, 86 % more than Tilia cordata and 135 % more than Morus alba. Qualitative analyses on PM have found that the majority (from 68 % to 74 %) of total particles show a diameter lower than 2,5 μm. Leaf micromorphology proved to be important, however it was no possible to identify a micromorphological trait more influential than others in determining the ability of the species to capture PM. The particles trapped by leaves were mainly rich in non-toxic or low-toxic elements, but some of them can be considered potentially dangerous for human health and the environment for the presence of Ni, Cr and Ba. The PCA highlights as the principal source of pollution in this study seems to be the erosion soil, followed by vehicle traffic. These results can give useful knowledge to understand what the contribution of different plants species in PMs retention ability is, also identified as a regulation ecosystem service.

Net O2 exchange rates under dark and light conditions across different stem compartments.

Woody plants display some photosynthetic activity in stems, but the biological role of stem photosynthesis and the specific contributions of bark and wood to carbon uptake and oxygen evolution remain poorly understood. We aimed to elucidate the functional characteristics of chloroplasts in stems of different ages in Fraxinus ornus. Our investigation employed diverse experimental approaches, including microsensor technology to assess oxygen production rates in whole stem, bark, and wood separately. Additionally, we utilized fluorescence lifetime imaging microscopy (FLIM) to characterize the relative abundance of photosystems I and II (PSI : PSII chlorophyll ratio) in bark and wood. Our findings revealed light-induced increases in O2 production in whole stem, bark, and wood. We present the radial profile of O2 production in F. ornus stems, demonstrating the capability of stem chloroplasts to perform light-dependent electron transport. Younger stems exhibited higher light-induced O2 production and dark respiration rates than older ones. While bark emerged as the primary contributor to net O2 production under light conditions, our data underscored that wood chloroplasts are also photosynthetically active. The FLIM analysis unveiled a lower PSI abundance in wood than in bark, suggesting stem chloroplasts are not only active but also acclimate to the spectral composition of light reaching inner compartments.

Drought legacies in mixed Mediterranean forests: Analysing the effects of structural overshoot, functional traits and site factors

Previous favorable climate conditions stimulate tree growth making some forests more vulnerable to hotter droughts. This so-called structural overshoot may contribute to forest dieback, but there is little evidence on its relative importance depending on site conditions and tree species because of limited field data. Here, we analyzed remote sensing (NDVI) and tree-ring width data to evaluate the impacts of the 2017 drought on canopy cover and growth in mixed Mediterranean forests (Fraxinus ornus, Quercus pubescens, Acer monspessulanum, Pinus pinaster) located in southern Italy. Legacy effects were assessed by calculating differences between observed and predicted basal area increment (BAI). Overall, the growth response of the study stands to the 2017 drought was contingent on site conditions and species characteristics. Most sites presented BAI and canopy cover reductions during the drought. Growth decline was followed by a quick recovery and positive legacy effects, particularly in the case of F. ornus. However, we found negative drought legacies in some species (e.g., Q. pubescens, A. monspessulanum) and sites. In those sites showing negative legacies, high growth rates prior to drought in response to previous wet winter-spring conditions may have predisposed trees to drought damage. Vice versa, the positive drought legacy found in some F. ornus site was linked to post-drought growth release due to Q. pubescens dieback and mortality. Therefore, we found evidences of structural drought overshoot, but it was restricted to specific sites and species. Our findings highlight the importance of considering site settings such as stand composition, pre-drought conditions and different tree species when studying structural overshoot. Droughts contribute to modify the composition and dynamics in mixed forests.

Metal concentrations in invasive Ailanthus altissima vs native Fraxinus ornus on ultramafic soils: Evidence for higher efficiency in Ni exclusion and adjustments to Mg and Ca imbalance

AbstractAilanthus altissima is one of the major invasive trees at a global scale. Despite numerous reports about its invasiveness in different habitats, so far it was not observed on harsh ultramafic soils and to colonize the vegetation of these outcrops. In this paper we show that the species can also spread in these habitats in the Mediterranean region and is able to cope with the severe anomalies of ultramafic soils. We sampled A. altissima in four ultramafic outcrops of central Italy and in control sites to unravel the behavior of this species toward the typically high soil concentrations of trace metals, such as Ni, Cr and Co, as well the imbalance of the Ca:Mg quotient. A similar sampling was performed for the native Fraxinus ornus that occurs naturally on a broad range of soils, including those from ultramafic rocks. Trace metal concentrations in leaves of both species were below toxicity thresholds, but A. altissima showed lower translocation and bioaccumulation factors (TF and BF, respectively) for Ni. Compared with F. ornus, the invasive species displayed higher leaf concentrations of Mg, thus suggesting a higher tolerance of potentially toxic levels of this element. Moreover, the higher TF and BF values for Ca in both control and serpentine populations suggested that A. altissima was more able to extract and accumulate this macronutrient in leaves in respect to F. ornus. Given the inherent deficiency of this element in ultramafic soils, efficient use of Ca could be a key trait contributing to the invasiveness of A. altissima on these soils.

Висшата флора на рида Венеца (Столова планина) над град Белоградчик (Северозападна България) и съдържащите се в нея лечебни растения

As a result of a field research performed of the vascular flora of the Venetsa Hill (Stolova mountain), which flora falls within the Balkan Foothill floristic region, there were 80 vascular species of 72 genera and 33 families established. Out of these 80 species, 38 were determined to be medicinal plants. Two species have been determined to be with Critical endangered (CR) status: Eranthis bulgaricus Stef. and Galanthus elwesii Hook. f. and one species was determined to be with category Vulnerable (VU): Melica altissima L. There are 10 tertiary relicts: Acer campestre L., A. monspessulanum L., Betula pendula Roth, Carpinus orientalis Mill., Corylus avellana L., Fraxinus ornus L., Syringa vulgaris L., Eranthis bulgaricus Stef., Pinus nigra subsp. pallasiana (Lamb.) Holmboe, Populus tremula L. One quaternary relict is Sternbergia colchiciflora Waldst. & Kit.

Kemijski sastav i antioksidativna aktivnost Fraxinus ornus L. i Fraxinus excelsior L.

In this work, the total content of phenolics, flavonoids, and phenolic acids in the leaves and bark extracts of <i>Fraxinus ornus</i> L. and <i>Fraxinus excelsior</i> L. was determined. In addition, the identification and quantification of phenolic acids was performed using the HPLC-DAD technique. Samples were tested for antioxidant activity using the ABTS and DPPH methods. Eight extract samples were prepared by Soxhlet and ultrasound extraction using 70 % ethanol as solvent. The content of phenolic compounds ranged from 7.59 for <i>F. ornus</i> to 88.93 mg GAE/g for <i>F. excelsior</i> in the bark extracts obtained by Soxhlet extraction. The highest content of total flavonoids in <i>F. ornus</i> and <i>F. excelsior</i> was found in the leaves extracts obtained by ultrasound extraction, which was 5.68 and 1.74 mg GAE/g extract, respectively. The results also showed that the highest content of total phenolic acids was found in <i>F. ornus</i> (105.33 mg CAE/g) and <i>F. excelsior</i> (97.97 mg CAE/g) in the bark extract obtained by Soxhlet extraction. The highest content of gallic acid (112.96 ± 1.32 mg g<sup>–1</sup> extracts) and chlorogenic acid (246.94 ± 0.82 mg g<sup>–1</sup> extracts) was found in the <i>F. ornus</i> bark extract obtained by ultrasound extraction. As for antioxidant activity, the bark extract obtained by Soxhlet extraction of <i>F. ornus</i> showed the best antioxidant activity by ABTS method with IC<sub>50</sub> value of 0.062 mg ml<sup>–1</sup>. The results of the DPPH method show that the leaves extract obtained by Soxhlet extraction had the best antioxidant activity for the <i>F. ornus</i> sample, with an IC<sub>50</sub> value of 0.23 mg ml<sup>–1</sup>.

Pestrost in pojavljanje domačih in tujerodnih drevesnih in grmovnih vrst na ploskvah nacionalne gozdne inventure v Sloveniji

In Slovenia, the National Forest Inventory (NFI) is used to monitor the state and development of forests at the national level. In this paper, we analysed the diversity of tree and shrub species and assessed the presence of non-native tree species in Slovenian forests. According to the literature, Slovenia hosts 71 autochthonous tree species, of which 60 were found among the trees measured on the 2 x 2 km NFI density plot grid. The highest average number of trees and shrubs, as well as the Shannon-Wiener index of species diversity, were observed in sample plots located in the Pre-Alpine Ecological Region (H’ = 0.85), while the lowest values were found in the Alpine Ecological Region (H’ = 0.58). The total growing stock of trees and shrubs in Slovenia is 330.7 m3/ha ± 2.1%, with the growing stock of small trees and shrubs (less than 10 cm DBH for trees and shrubs) estimated at 9.7 m3/ha ± 5.9%. Common beech (Fagus sylvatica) (31.9%) and Norway spruce (Picea abies) (28.2%) dominate the growing stock of tree and shrub species, while common hazel (Corylus avellana) (85.0%) represents the highest proportion of shrub species. Ten different non-native tree species were identified across 138 NFI plots, with the highest distributions in the Sub-Mediterranean and Pre-Pannonian Ecological Regions. Black locust (Robinia pseudoacacia) dominates the growing stock of non-native tree species. Among small trees (those with a DBH of less than 10 cm), common beech represents 32.4%, with Norway spruce and manna ash (Fraxinus ornus) each contributing more than 10.0%. The growing stock of small shrub species (shrubs with a DBH of less than 10 cm) is dominated by common hazel (Corylus avellana) with 78.3%, while more than 2% is also represented by cornel (Cornus mas), old man’s beard (Clematis vitalba) and elderberry (Sambucus nigra). The results show that the combination of a panel system, a large number of sample plots (3027) and an improved coding system enabled the first comprehensive and objective assessment of tree and shrub species diversity, as well as the presence of non-native species in Slovenian forests.

Botryosphaeriaceae Species Associated with Stem Canker, Shoot Blight and Dieback of Fraxinus ornus in Italy

A severe dieback of flowering ash (Fraxinus ornus L.) has been observed in north-central Italy in the last decades. Symptoms include typical sunken, light-brown cankers on the stem and branches; vascular discoloration; tip and shoot dieback; and foliage necroses. The disease was more evident at the beginning of the growing season, and more severe on young regeneration. Six Botryosphaeriaceae species were consistently isolated from symptomatic plant tissues: Botryosphaeria dothidea, Diplodia fraxini, Diplodia subglobosa, Dothiorella iberica, Dothiorella omnivora and Neofusicoccum parvum. B. dothidea and D. fraxini expressed higher aggressiveness and showed a widespread incidence, being the species most frequently associated with cankers; the other four species were less virulent and more erratic, occurring mainly on succulent branch tips and foliage. Isolates were characterized using morphological and molecular approaches (colony/conidial phenotyping and rDNA-ITS genotyping). Phylogenetic analysis provided congruent phylogenies depicting the relationships of the six taxa with the most closely related conspecifics. Pathogenicity tests on 2-year-old seedlings confirmed the higher virulence of B. dothidea and D. fraxini. Extensive, multi-year field surveys at different sites supported the hypothesis that climatic vagaries, mainly heat, water and drought stresses, impaired tree health and vigor, facilitating infection and pervasive colonization by these Botryosphaeriaceae species. Environmental stressors are thus the key factor bringing the six fungal pathogens together in a multitrophic interaction with F. ornus in a novel, lethal fashion.

Impact of two new non-conventional yeasts, Candidaoleophila and Starmerella lactis-condensi, isolated from sugar-rich substrates, on Frappato wine aroma

The interest of non-Saccharomyces yeasts in wine fermentation increased constantly in last years. This study reports for the first time the enological potential of two strains Starmerella lactis-condensi MN412 and Candida oleophila YS209. In an innovative way, these strains were used in winemaking to improve floral and fruity aroma of Frappato red wine, which has not been explored. The enological performances of the two non-Saccharomyces strains were compared to a wine strain of Starmerella bacillaris, namely Cz3, previously characterized in winemaking conditions. In these three cases, the non-Saccharomyces strain was sequentially inoculated with S. cerevisiae wine strain NF213, used as control. The St. lactis-condensi MN412 was isolated from Sicilian manna, a sugar-rich matrix, extracted from Fraxinus angustifolia trees (Oleaceae). The strain C. oleophila YS209 was isolated from honey by-products. Microbiological counts showed the ability of MN412 and YS209 to maintain high counts up to 6 days of alcoholic fermentation. Regarding chemical parameters, Cz3 showed the highest glycerol production. Analysis of VOCs revealed that the trials with non-Saccharomyces yeasts were characterized by a higher concentration of esters that contributed positively to the fruity aroma of the wines. The sensory analysis confirmed that the use of MN412 and YS209 impacted positively the final wines in terms of fruity and floral intensity, respectively, while did not generate sensory defects. In conclusion, non-conventional yeasts represent strategy to improve floral-fruity freshness of wine aroma and sugar-rich matrices such as manna ash and honey might represent novel ecological niches as source of potential oenological yeast.

Using stomatal conductance capacity during water stress as a tool for tree species selection for urban stormwater control systems

Improving our understanding of how different tree species function in urban stormwater management systems is important, as tree pits may provide a temporary reservoir for stormwater and as trees have the potential to actively reduce stormwater runoff by transpiration. While urban tree planting pits are increasingly used for short-term water storage during stormwater runoff events, this storage can have negative effects on both tree vitality and water removal capacity, since stress from waterlogging result in stomatal closure. However, sensitivity to water stress varies by species. It is therefore important to determine which tree species can maintain long-term vitality and continued transpiration even under water stress, and thus are suitable for such locations. Here, we studied how nine different tree species, varying in expected tolerance to water stress, were affected by short-term and seasonal waterlogging, in a greenhouse experiment. The seedlings (Magnolia x loebneri, Tilia tomentosa, and Sorbus torminalis – low water logging tolerance; Cercidiphyllum japonicum, Rhamnus cathartica, and Fraxinus ornus – medium water logging tolerance; Quercus palustris, Acer saccharinum, and Fraxinus pennsylvanica – high water logging tolerance) were exposed to two days, five days and seasonal waterlogging. The treatments reflected best practice (optimal), suboptimal and total lack of tree pit drainage, using Swedish standards. Stomatal conductance and leaf water potential were determined regularly over a period of 71 days, and morphological adjustments were registered. Four of the species were affected already after two days of waterlogging, with reduced stomatal conductance either during the waterlogging or immediately after, and only the most waterlogging tolerant species were unaffected by the five-day treatment. However, all plants survived waterlogging for almost 30 days before the estimated permanent wilting was reached in some plants. We suggest that tree species selection for stormwater management systems should consider the species’ capacity to maintain high stomatal conductance during waterlogging, as there were clear differences between species. The effectiveness of the selected species could have an important impact on the stormwater management capacity of cities, as well as on other aspects of ecosystem service delivery from urban trees.

Biochemical Characterization and Fuel Properties of Endemic Taurus Flowering Ash (Fraxinus ornus subsp. cilicica) Bark from Turkey

Taurus flowering ash (Fraxinus ornus subsp. cilicica) is an endemic tree species in Turkey. The bark of the species was characterized for summative chemical composition, the monomeric composition of polysaccharides, phenolic content, in vitro and ex vivo antioxidant properties of hydrophilic extracts, the composition of lipophilic extractives and suberin, and thermal degradation. The bark has an elevated ash content (17%), primarily composed of calcium, and a noteworthy extractive content (38.9%), predominantly of hydrophilic compounds. The antioxidant activity of the bark extracts is moderate, with an IC50 value of 40 μg/mL and an EC50 value of 230 μg/mL by DPPH and TBARS methods. The lipophilic extractives principally contain fatty acids and diterpenoids. The suberin content is low (1%) and composed primarily of ω-hydroxy acids with 9,10,18 trihydroxyoctadecanoic acid as the major suberin monomer. The lignin content is low (9.8%), and polysaccharides represent 33%. The ignition temperature of the bark is 190 °C, the burnout temperature is 653 °C, and the activation energy in combustion is 29 kJ mol−1. A biorefinery concept was developed considering the bark’s chemical and thermal characteristics to convert approximately 90% of the bark mass into valuable chemicals, extracts, functional materials, and additives.

Radial growth, wood anatomical traits and remote sensing indexes reflect different impacts of drought on Mediterranean forests

Drought reduces canopy cover, productivity and tree growth in forests. However, there is still little knowledge on how drought affects coupling between canopy greenness assessed by remote sensing and hydraulic conductivity detected by wood anatomy. This combination could improve the understanding of forest response to climate change. Thus, we investigated the impacts of a hot drought, which occurred in summer 2017, on radial growth, earlywood hydraulic diameter (Dh), a proxy of conductivity, and several remote-sensing indices in mixed Mediterranean hardwood forests (Quercus pubescens Willd. – Fraxinus ornus L.). In general, growth showed a higher coherence among trees and a higher responsiveness to climate. Growth decreased during the drought year, particularly for Q. pubescens, which showed high defoliation and dieback intensity. Both species showed a decline of Dh in 2018 after the drought and subsequent warm winter conditions. We found positive relationships between Dh and remote-sensing data for Q. pubescens in some of these vulnerable sites, where (i) growth was constrained by dry spring-summer conditions and (ii) Dh and growth covaried. These findings indicate a high variability among sites and tree species in their responses to drought considering earlywood anatomy, growth canopy cover and water content. However, some common patterns emerge such as links between potential hydraulic conductivity (Dh), tree cover and Dh-growth covariation in the most impacted sites. Further, F. ornus seem to perform better in terms of growth under drought conditions, showing less mortality and dieback than Q. pubescens. Future studies could explore how water transport and changes in canopy cover respond to dry and warm conditions and if that covariation indicates vulnerability to drought.

Pathogenic fungi and oomycetes causing dieback on Fraxinus species in the Mediterranean climate change hotspot region

Environmental changes are occurring on a global scale, but their effects are most pronounced in climate change hotspot zones, such as the Mediterranean basin. Within this area Italy, extending from its southern coasts in the core of the Mediterranean Sea to its northernmost pre-Alpine and Alpine regions, is characterized by a variety of climatic conditions and vegetation types. Surveys conducted in 2018–2022 in forest formations of Central-Northern Italy revealed that the enhanced warming trend and irregular distribution of precipitations are strongly impacting the health of Fraxinus species, with some pathogenic fungi and oomycetes being important contributing factors to the decline of the three main ash species growing there: common ash (Fraxinus excelsior), flowering ash (Fraxinus ornus), and narrow-leaved ash (Fraxinus angustifolia). Isolation from symptomatic plant material collected countrywide under different site conditions and pathogenicity tests revealed a complex phytopathological framework, with several pathogenic species in addition to Hymenoscyphus fraxineus involved with a prominent role in the ash dieback etiology. Key microbial taxa included the fungal and oomycete pathogens Botryosphaeria dothidea, Diplodia fraxini, Diplodia subglobosa, Phytophthora acerina, and Phytophthora plurivora. The disease impact was higher on sites where ash trees grew under environmental stress (i.e., areas characterized by mild dry winters, hot summers with intense and prolonged drought) and exhibited reduced vigor, also as a consequence of anthropogenic interference (i.e., silvicultural management and fires). The identified causative agents are emerging pathogens that thrive under warmer conditions, their impact in the investigated areas being prevalent compared to H. fraxineus, which appears to be restricted on the Italian peninsula to the cooler and wetter valleys of the Alps and Central-Northern Apennines.

Vegetation dynamics and land-use change at the Neolithic lakeshore settlement site of Ploča Mičov Grad, Lake Ohrid, North Macedonia

Detailed knowledge about the interactions between vegetation, climate and land use during the Mesolithic and Neolithic, at the transition from foraging to farming, is still scarce in the Balkans. Here we present a palaeoecological study combining pollen, spores and charcoal found in sedimentary cores from Lake Ohrid, Ploča Mičov Grad, North Macedonia, with a particular focus on the vegetation dynamics during the Late Glacial-Holocene and the Mesolithic-Neolithic transitions. Our record begins at ca. 13,500 cal bp (11,550 cal bc) when partially open vegetation, consisting mainly of Pinus, Abies and deciduous Quercus tree stands grew on the hilly flanks of the bay of Ploča. From 12,650 cal bp (cal 10,700 bc), herbs dominated the record until the onset of the Holocene (ca. 11,700 cal bp; 9750 cal bc), when increasing temperatures led to the establishment of pine-deciduous oak forests including Alnus, Fraxinus ornus, Tilia, Ulmus and Abies. These forests persisted until 7,500 cal bp (cal 5550 bc), when deforestation started due to Neolithic land use. This first phase of Neolithic activities in the Ploča Mičov Grad area precedes the earliest archaeological structures so far recorded by almost 1,000 years. Our data suggest two phases of human land use between 7,500 and 6,300 cal bp (5550–4350 cal bc), when high values of Cerealia type pollen and other cultural indicators indicate intense arable and pastoral farming activities. Once human activities decreased, forests were able to re-establish quickly (within 100–250 years), although the composition changed with disturbance-adapted Ostrya type (mostly Ostrya carpinifolia) and Fagus becoming more important. We conclude that forests were resilient to early human disturbance, despite intensive land use and logging activities gradually leading to forest composition changes. Many of these composition changes can still be seen today, suggesting the legacy of Neolithic farmers is still present in today’s landscape.

Tree tracking: species selection and traceability for sustainable and biodiversity-friendly urban reforestation

The current climate change and increasing climate variability represent a serious global challenge that demands urgent responses. Among the multiple actions that should be taken, afforestation and reforestation are the most common strategies. The current paper aims to assess the potential of tree species to be used in urban forestry in the Po Plain ecoregional province (Northern Italy) using DNA barcoding approach for plant traceability and ecophysiological indexes (shade, drought and waterlogging) for plant selection. DNA barcoding markers results showed a 55.5% of success, but the power of discrimination increased to 94.5% when considering only the autochthonous ecoregional species pool. Concerning ecophysiological markers, Fagus sylvatica, Abies alba, Picea abies and Taxus baccata were very shade-tolerant. The best performing trees concerning drought tolerance were oak species (Quercus ilex, Q. pubescens and Q. cerris), pines (Pinus pinea, P. nigra and P. sylvestris) and Fraxinus ornus. Only a few tree species (Salix alba, Alnus glutinosa, Populus nigra and Prunus padus) showed high tolerance to waterlogging. The combination of both approaches makes it possible to select the most suitable species, based on eco-pedological and microclimatic conditions, and to trace their identity along the entire supply chain, from nursery to planting, for urban forestry.

Analysis of chosen growth and reproductive traits of manna ash (Fraxinus ornus) with regards to its expansive properties

Manna ash (Fraxinus ornus L.) is a Mediterranean shrub or a small tree with the northern limit of its natural range in central Europe. At the same time, it is also a tree species which, due to its considerable tolerance to high temperatures and lack of moisture, as well as some expansive properties, could be expected to increase its range in the coming decades as a result of the changing climate and the associated spontaneous spread. The paper summarizes the results of several years of our research, during which we evaluated the following growth and reproductive characteristics: (1) phenological traits and the length of the growing season, (2) the intensity and evenness of fruiting, and (3) the numbers of individuals and stems according to the height categories. In addition, the species composition of vegetation cover was analysed on the sites with the occurrence of manna ash. Observations were made in two autochthonous populations of manna ash in Southern Slovakia and one allochthonous population in its central region. The onset of spring vegetative and generative phenophases showed a noticeable latitudinal trend during our observations (2015‒2019). In Central Slovakia, flowering and leafing of manna ash occurred on average more than two weeks later than in its southernmost region. The “Central Slovakian” population of manna ash was also characterised by the earliest onset of autumn vegetative phenophases and the lowest total length of the growing season. Despite these trends, flowering and fruiting in this population were relatively regular ‒ in contrast to the other two sites, it was observed every year. In this locality, we also observed the highest total numbers of individuals and stems in all the height categories and the markedly decreased occurrence of competing species. The achieved results point out to the considerable vigour and high reproductive ability of the allochthonous population of manna ash outside its natural range and the natural range of its most important competitors.

Combining micro- and portable-XRF as a tool for fast identification of virus infections in plants: The case study of ASa-Virus in Fraxinus ornus L.

Plant viruses can affect micro- and macro-nutrients homeostasis in woody plants, with fluctuation in the concentration of some elements at the leaf level due to the pathogen activity and/or the plant physiological response to the infection.Leaves of Fraxinus ornus L. (flowering ash) were sampled for three consecutive years in the city of Hamburg (Germany), from both trees showing the typical symptoms of the ash shoestring associated virus infection (ASaV+) and healthy trees (ASaV-). Such leaves were analyzed by μ-XRF, using both laboratory and synchrotron X-ray sources, and large differences between symptomatic and not symptomatic leaves were observed: ASaV+ samples showed uneven element distribution and regions of the lamina with severe depletions of P, S, and Ca. Differently, K appeared more concentrated. Thus, 139 leaflets sampled from various healthy and infected ash trees over the three-year period were analyzed for K and Ca concentration with a portable XRF instrument. We found that the K:Ca concentration ratio was always significantly higher in ASaV+ samples, and this trend was verified for all the samplings over the tree years. We conclude that the K:Ca ratio parameter has potential in the frame of trendsetting diagnostics and could be used, together with visual symptoms, for a rapid, non-destructive, on-site and cheap indirect ASaV detection.