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PubMed1982

Enhancement of Phloem Exudation from Fraxinus uhdei Wenz. (Evergreen Ash) using Ethylenediaminetetraacetic Acid.

Ethylenediaminetetraacetic acid (EDTA) enhanced the exudation of (14)C-labeled assimilates from excised leaflets and whole plant specimens of Fraxinus uhdei Wenz. A 2 millimolar EDTA concentration was found to be most effective in promoting exudation from excised leaflets, while 10 millimolar EDTA was most effective in whole plants experiments. Exudation rate reached a maximum after 24 hours in both experiments. The continuous presence of EDTA throughout the treatment period was required for maximum exudation from excised leaflets. Stachyose, raffinose, verbascose, and sucrose were the principal compounds found to occur in exudate samples. These compounds are typically transported in sieve elements of various Fraxinus species suggesting the exudate was of phloem origin. Electron microscope studies of petiolule sieve plate pores from excised leaflets showed substantially less callose appearing after treatment with EDTA than after H(2)O treatment. It is suggested that EDTA enhances phloem exudation by inhibiting or reducing callose formation in sieve plate pores. The exudation enhancement technique described for whole plant specimens is suggested as a useful means of collecting phloem sap and studying translocation in woody plants.

Journal Article↗

PubMed1988

City spore concentrations in the European Economic Community (EEC). VII. Oleaceae (Fraxinus, Ligustrum, Olea).

In this paper we present the results of volumetric sampling of the airborne pollen grains of the Oleaceae family (Fraxinus, Ligustrum and Olea) in some European towns, in the period from 1982 to 1986. The sampling and appraisal of pollen content in the air is of particular interest to clinicians and allergic patients in order to assess exposure to the various pollen types in relation to allergy. In the Oleaceae family, the most allergenic pollen is produced by Olea europaea, the olive tree, which in the Mediterranean area has a pollination period lasting from May to the end of June and sometimes causes severe symptoms of pollinosis. In Northern and Central Europe, where there are no olive trees, there are two other commonly occurring genera of the Oleaceae family, namely Fraxinus and Ligustrum, but these have a low frequency of allergic sensitization.

Air Pollution↗

PubMed2001

[Variation of soil microsite moisture-physical properties and its effect on Fraxinus mandshurica juvenile stand growth].

Soil microsite plays an important role in the regeneration, seedling survival, and individual growth of trees. This paper studied the relationship between soil microsite moisture-physical properties and Fraxinus mandshurica growth. Variation was found not only among different sites in traditional scale, but also among different microsites. Some variations of soil properties among different microsite were greater than those among different sites. The growth of Fraxinus mandshurica varied greatly among different microsites. Microsites affected most soil moisture-physical properties and tree growth. The study demonstrated the importance of matching trees to the proper microsite on the growth of plantation stand.

Oleaceae↗

PubMed2006

Effect of meteorological factors on Betula, Fraxinus and Quercus pollen concentrations in the atmosphere of Lublin and Szczecin, Poland.

The aim of the study was to compare the concentration of 3 allergenic taxa pollen (ash, birch and oak) in the cities of Lublin (eastern Poland) and Szczecin (western Poland) during the years 2004 and 2005 and examine correlations between weather factors and pollen concentration. The meteorological parameters analysed were maximum and mean air temperature, relative humidity, amount of precipitation and wind speed. Measurements were performed by the volumetric method (Lanzoni 2000 pollen sampler). Pollen seasons were defined as the period in which 95 % of the total catch occurred. The pollen seasons of the studied taxa started earlier in Szczecin than in Lublin. In both cities much higher Betula pollen concentration and slightly higher Fraxinus pollen concentration were recorded in 2004 compared to 2005. But for Quercus, higher concentrations were recorded in Lublin and in Szczecin in 2005. Annual totals and maximum daily pollen grain concentrations of the tree taxa in question were higher in Lublin than in Szczecin. In 2005, maximum Betula and Fraxinus pollen concentrations occurred in each of the cities at the same time: in Lublin on 18 April, in Szczecin on 16 April. Among the meteorological parameters analysed, maximum temperature and relative humidity belong to the most important factors which affect ash, birch and oak pollen concentrations in the air.

Air Pollutants↗

PubMedDate not supplied

Study of sensitivity to the pollen of Fraxinus spp. (Oleaceae) in Cordoba, Spain.

The level of ash pollen grains (Fraxinus spp.) detected in the air in the city of Cordoba rarely surpasses the daily average of 8 g/m3 and is always detectable during the winter and the beginning of the spring. This fact, together with the knowledge of the presence of perennial symptoms in patients monosensitive to Olea in this area, allows us to suspect the possibility of cross-reactivity between both taxa. The skin tests carried out on a total of 1500 pollinotic patients with an extract of Fraxinus pollen offer us a global sensitization frequency of 59%. Furthermore, the Fx+ patients generally have a higher frequency of rural origin or they live in the most southerly district of the province. As for the age and sex of the patient, significant differences were found for the age groups between 5-10 years and over 25 but the frequency for both sexes was equal. As for the clinical features, differences in the family and personal antecedents of atopy were not observed, although rhinoconjunctival clinical antecedents seemed to prevail slightly over asthma antecedents. In relation to the duration of the symptoms, the patients presented a long evolution in their symptomatology. The great majority of the patients were polysensitive; only 8% were found to be monosensitive, with unimportant differences in their evolution after immunotherapeutic treatment. On the other hand, 92% of the Fx+ patients presented reactions to Olea pollen (but only 41% of the Fx- patients did), whereas 62% showed sensitivity to Cupressus, marking a strong contrast with the Fx-patients, who all tested negative for Cupressus pollen.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed2004

Photoinhibition in seedlings of Fraxinus and Fagus under natural light conditions: implications for forest regeneration?

Ash (Fraxinus excelsior L.) and beech (Fagus sylvatica L.) seedlings were grown in the field under three levels of natural light: (1) open, (2) gap and (3) shade. Light acclimation of photosynthesis was characterized by means of modulated chlorophyll a fluorescence of intact leaves and growth parameters were measured at the end of the growing season. Measurements of maximum photochemical efficiency (Fv/Fm) of dark-adapted leaves at intervals through the day showed that ash had a higher Fv/Fm than beech in open and gap plots but not in shade plots. This indicated a larger build-up of photoinhibition in beech under gap and open conditions. Steady-state light response curves of the operating efficiency of PSII (F'q/F'm), the electron transport rate (ETR) and the photochemical efficiency factor (F'q/F'v) showed greater variability across light treatments in ash than in beech. Both species exhibited similar responses of non-photochemical quenching (NPQ) to light. When the data were normalized to the mean maximum irradiance in the growth environment, all photochemical parameters showed a reduction in variation across treatments, indicating that light acclimation in the two species occurred primarily through adjustments in rates of photochemistry. Adjustments in thermal heat dissipation were small in both species. This pattern was stronger in ash, suggesting a greater degree of phenotypic plasticity in photosynthetic capacity in this earlier successional species. Contrary to our expectations, the build-up of photoinhibition in beech did not appear to have a negative effect on total biomass accumulation relative to ash.

Chlorophyll↗

PubMed2005

Physiological and foliar symptom response in the crowns of Prunus serotina, Fraxinus americana and Acer rubrum canopy trees to ambient ozone under forest conditions.

The crowns of five canopy dominant black cherry (Prunus serotina Ehrh.), five white ash (Fraxinus americana L.), and six red maple (Acer rubrum L.) trees on naturally differing environmental conditions were accessed with scaffold towers within a mixed hardwood forest stand in central Pennsylvania. Ambient ozone concentrations, meteorological parameters, leaf gas exchange and leaf water potential were measured at the sites during the growing seasons of 1998 and 1999. Visible ozone-induced foliar injury was assessed on leaves within the upper and lower crown branches of each tree. Ambient ozone exposures were sufficient to induce typical symptoms on cherry (0-5% total affected leaf area, LAA), whereas foliar injury was not observed on ash or maple. There was a positive correlation between increasing cumulative ozone uptake (U) and increasing percent of LAA for cherry grown under drier site conditions. The lower crown leaves of cherry showed more severe foliar injury than the upper crown leaves. No significant differences in predawn leaf water potential (psi(L)) were detected for all three species indicating no differing soil moisture conditions across the sites. Significant variation in stomatal conductance for water vapor (g(wv)) was found among species, soil moisture, time of day and sample date. When comparing cumulative ozone uptake and decreased photosynthetic activity (P(n)), red maple was the only species to show higher gas exchange under mesic vs. drier soil conditions (P < 0.05). The inconsistent differences in gas exchange response within the same crowns of ash and the uncoupling relationship between g(wv) and P(n) demonstrate the strong influence of heterogeneous environmental conditions within forest canopies.

Acer↗

PubMed2006

Gravitational infusion of ethylenediurea (EDU) into trunks protected adult European ash trees (Fraxinus excelsior L.) from foliar ozone injury.

Adult ash trees (Fraxinus excelsior L.), known to be sensitive or insensitive to ozone, determined by presence or absence of foliar symptoms in previous years, were treated with ethylenediurea (EDU) at 450 ppm by gravitational trunk infusion on six occasions at 21-day intervals in summer 2005 at Turin, Italy. At the end of the season, foliar ozone injury on EDU-treated trees was not complete, but was greatly and significantly reduced when compared to results from trees infused with water. Significant symptom reduction occurred at any crown level in the treated trees suggesting that EDU protected whole crowns. Gravitational infusion of EDU resulted in protection from ozone injury for ozone-sensitive ash trees. The amount of EDU needed to provide protection is assumed to be in the range 13-26 mg m(-2) leaf.

Environmental Exposure↗

PubMed2004

Study of the hypoglycaemic activity of Fraxinus excelsior and Silybum marianum in an animal model of type 1 diabetes mellitus.

The hypoglycaemic effect of the aqueous extracts of Fraxinus excelsior (FE) seed and Silybum marianum (SM) aerial part was investigated in normal and streptozotocin (STZ) diabetic rats. After a single dose or 15 daily doses, oral administration of the aqueous extracts (20 mg/kg) produced a significant decrease of blood glucose levels in both normal and STZ diabetic rats (P < 0.001). From the first week, the body weight was increased in normal rats (P < 0.05) and decreased in STZ rats (P < 0.01) after FE administration. In addition, no changes were observed in basal plasma insulin concentrations after both FE and SM treatments in either normal and STZ diabetic rats indicating that these plants exert their pharmacological activity without affecting insulin secretion. We conclude that the aqueous extracts of FE and SM exhibit potent hypoglycaemic and anti-hyperglycaemic activities in normal and STZ rats, respectively, without affecting basal plasma insulin concentrations.

Administration, Oral↗

PubMed2004

Phlorizin-like effect of Fraxinus excelsior in normal and diabetic rats.

The purpose of this study was to determine the underlying mechanism of the hypoglycaemic activity of the aqueous extract perfusion of Fraxinus excelsior L. (FE) in normal and streptozotocin-induced diabetic rats. The aqueous extract was administered intravenously and the blood glucose changes were determined within four hours after starting the treatment. Plasma insulin concentrations and glycosuria were determined. The aqueous extract at a dose of 10 mg/kg/h produced a significant decrease in blood glucose levels in normal rats (P < 0.001) and even more in diabetic rats (P < 0.001). This hypoglycaemic effect might be due to an extra-pancreatic action of the aqueous extract of FE, since the basal plasma insulin concentrations were unchanged after FE treatment. A potent increase of glycosuria was observed both in normal and diabetic rats (P < 0.001). We conclude that aqueous extract perfusion of FE caused a potent inhibition of renal glucose reabsorption. This renal effect might be at least one mechanism explaining the observed hypoglycaemic activity of this plant in normal and diabetic rats.

Animals↗

PubMed2003

Physiological and foliar injury responses of Prunus serotina, Fraxinus americana, and Acer rubrum seedlings to varying soil moisture and ozone.

Sixteen black cherry (Prunus serotina, Ehrh.), 10 white ash (Fraxinus americana, L.) and 10 red maple (Acer rubrum, L.) 1-year old seedlings were planted per plot in 1997 on a former nursery bed within 12 open-top chambers and six open plots. Seedlings were exposed to three different ozone scenarios (ambient air: 100% O3; non-filtered air: 98% ambient O3; charcoal-filtered air: 50% ambient O3) within each of two different water regimes (nine plots irrigated, nine plots non-irrigated) during three growing seasons. During the 1998 and 1999 growing season, leaf gas exchange, plant water relations, and foliar injury were measured. Climatic data,ambient- and chamber-ozone-concentrations were monitored. We found that seedlings grown under irrigated conditions had similar (in 1998) but significantly higher gas exchange rates (in 1999) than seedlings grown within non-irrigated plots among similar ozone exposures. Cherry and ash had similar ozone uptake but cherry developed more ozone-induced injury (< 34% affected leaf area, LAA) than ash (<5% LAA), while maple rarely showed foliar injury, indicating the species differed in ozone sensitivity. Significantly more severe injury on seedlings grown under irrigated conditions than seedlings grown under non-irrigated conditions demonstrated that soil moisture altered seedling responses to ambient ozone exposures.

Acer↗

PubMed2002

HIV gp41 binding phenolic components from Fraxinus sieboldiana var. angustata.

By means of HIV gp41 binding affinity directed chromatographic fractionation, three phenylethanoid glycosides; calceolarioside A ( 1), calceolarioside B ( 2) and acteoside ( 3), along with four hydroxycoumarins; esculin ( 4), fraxin ( 5), fraxetin ( 6) and esculetin ( 7), and one lignan, (-)-olivil ( 8) were isolated from the n-butyl alcohol fraction of Fraxinus sieboldiana var. angustata. Among the isolated compounds, calceolarioside B ( 2) and esculetin ( 7) showed moderate binding affinity on HIV gp41 with IC 50 values of 0.1 mg/ml and 0.5 mg/ml, respectively. Calceolarioside A ( 1), calceolarioside B ( 2), acteoside ( 3), and (-)-olivil ( 8) were isolated for the first time from this plant.

Binding, Competitive↗

PubMed2004

Effect of NaCl and mannitol iso-osmotic stresses on proline and free polyamine levels in embryogenic Fraxinus angustifolia callus.

With the aim to differentiate the ionic and osmotic components of salt stress, short and long-term changes in free polyamines and proline induced by iso-osmotic concentrations of NaCl (0.1 mol/L and 0.2 mol/L) and mannitol (0.2 mol/L and 0.4 mol/L) were determined in Fraxinus angustifolia callus. The peculiarities of the short-term responses were: i) a very early (30 min) and temporary increase in Putrescine (Pu) and Spermine (Spm) as a consequence of salt treatment, and ii) a continuous accumulation of Spermidine (Spd) and Spm in response to mannitol. The changes of Proline (Pro) were quite limited both in the short and in the long term, and generally occurred later than Polyamine (PAs) changes took place, suggesting a regulatory mechanism of PAs metabolism on Pro biosynthesis. In the long-term, no drastic accumulations of Pro or PAs in response to NaCl and mannitol were observed, suggesting that their physiological role is unlikely to be that of osmo-compatible solutes in this plant system. The salt induced a higher callus growth inhibition effect than did mannitol and this inhibition was associated with the reduction of endogenous levels of PAs, especially Pu. However, while a diverging time course was observed under lethal salt concentration (0.2 mol/L NaCl), a high parallelism in the endogenous changes of Pro and Pu was observed under all non-lethal conditions (control--0.2 and 0.4 mol/L mannitol--0.1 mol/L NaCl). Therefore the synchronous changes of Pro and Pu can be considered as a physiological trait associated with cell survival. These results indicate a strong metabolic co-ordination between PAs and Pro pathways and suggest that the metabolic fluxes through these pathways start competing only when the stress level is high enough to be lethal for cells.

Climate↗

PubMed2006

Similar gender dimorphism in the costs of reproduction across the geographic range of Fraxinus ornus.

BACKGROUND AND AIMS: The reproductive costs for individuals with the female function have been hypothesized to be greater than for those with the male function because the allocation unit per female flower is very high due to the necessity to nurture the embryos until seed dispersal occurs, while the male reproductive allocation per flower is lower because it finishes once pollen is shed. Consequently, males may invest more resources in growth than females. This prediction was tested across a wide geographical range in a tree with a dimorphic breeding system (Fraxinus ornus) consisting of males and hermaphrodites functioning as females. The contrasting ecological conditions found across the geographical range allowed the evaluation of the hypothesis that the reproductive costs of sexual dimorphism varies with environmental stressors. METHODS: By using random-effects meta-analysis, the differences in the reproductive and vegetative investment of male and hermaphrodite trees of F. ornus were analysed in 10 populations from the northern (Slovakia), south-eastern (Greece) and south-western (Spain) limits of its European distribution. The variation in gender-dimorphism with environmental stress was analysed by running a meta-regression between these effect sizes and the two environmental stress indicators: one related to temperature (the frost-free period) and another related to water availability (moisture deficit). KEY RESULTS: Most of the effect sizes showed that males produced more flowers and grew more quickly than hermaphrodites. Gender differences in reproduction and growth were not minimized or maximized under adverse climatic conditions such as short frost-free periods or severe aridity. CONCLUSIONS: The lower costs of reproduction for F. ornus males allow them to grow more quickly than hermaphrodites, although such differences in sex-specific reproductive costs are not magnified under stressful conditions.

Climate↗

PubMed2004

Xylem sap flow and drought stress of Fraxinus excelsior saplings.

We report on diurnal and seasonal variations in sap flow rate and stem water potential of Fraxinus excelsior L. saplings growing at the edge of a Fraxino-Aceretum forest in western Germany. Because of shallow soil, the trees were subjected to drought in summer. When soil water availability was not limiting, sap flow rate was related to changes in solar radiation and vapor pressure deficit. Maximum transpiration rates per leaf area were 3.5-7.4 mmol m-2 s-1, and maximum daily totals were 1.7-3.3 kg m-2 day-1. Under drought conditions, stem water potential dropped to midday minima of -2.6 to -3.5 MPa and sap flow rate was strongly related to this parameter. After the drought period, reduced apparent (whole-plant) hydraulic conductance was observed, which was attributed to a continued reduction in stomatal conductance after the drought stress had ceased. A model was developed that linked sap flow rate directly to climatic variables and stem water potential. Good correlation between measured and simulated sap flow rates allowed the model to be used for data interpretation.

Circadian Rhythm↗

PubMed2004

Chloroplast DNA variation and postglacial recolonization of common ash (Fraxinus excelsior L.) in Europe.

We used chloroplast polymerase chain reaction-restriction-fragment length polymorphism (PCR-RFLP) and chloroplast microsatellites to assess the structure of genetic variation and postglacial history across the entire natural range of the common ash (Fraxinus excelsior L.), a broad-leaved wind-pollinated and wind-dispersed European forest tree. A low level of polymorphism was observed, with only 12 haplotypes at four polymorphic microsatellites in 201 populations, and two PCR-RFLP haplotypes in a subset of 62 populations. The clear geographical pattern displayed by the five most common haplotypes was in agreement with glacial refugia for ash being located in Iberia, Italy, the eastern Alps and the Balkan Peninsula, as had been suggested from fossil pollen data. A low chloroplast DNA mutation rate, a low effective population size in glacial refugia related to ash's life history traits, as well as features of postglacial expansion were put forward to explain the low level of polymorphism. Differentiation among populations was high (GST= 0.89), reflecting poor mixing among recolonizing lineages. Therefore, the responsible factor for the highly homogeneous genetic pattern previously identified at nuclear microsatellites throughout western and central Europe (Heuertz et al. 2004) must have been efficient postglacial pollen flow. Further comparison of variation patterns at both marker systems revealed that nuclear microsatellites identified complex differentiation patterns in south-eastern Europe which remained undetected with chloroplast microsatellites. The results suggest that data from different markers should be combined in order to capture the most important genetic patterns in a species.

DNA, Chloroplast↗

PubMed2006

Fat-tailed gene flow in the dioecious canopy tree species Fraxinus mandshurica var. japonica revealed by microsatellites.

Pollen flow, seed dispersal and individual reproductive success can be simultaneously estimated from the genotypes of adults and offspring using stochastic models. Using four polymorphic microsatellite loci, gene flow of the wind-pollinated and wind-seed-dispersed dioecious tree species, Fraxinus mandshurica var. japonica, was quantified in a riparian forest, in northern Japan. In a 10.5-ha plot, 74 female adults, 76 male adults and 292 current-year seedlings were mapped and genotyped, together with 200 seeds. To estimate dispersal kernels of pollen and seeds, we applied normal, exponential power, Weibull, bivariate t-distribution kernels, and two-component models consisting of two normal distribution functions, one with a small and one with a large variance. A two-component pollen flow model with a small contribution (26.1%) from short-distance dispersal (sigma = 7.2 m), and the rest from long-distance flow (sigma = 209.9 m), was chosen for the best-fitting model. The average distance that integrated pollen flows inside and outside the study plot was estimated to be 196.8 m. Tree size and flowering intensity affected reproduction, and there appeared to be critical values that distinguished reproductively successful and unsuccessful adults. In contrast, the gene flow model that estimated both pollen and seed dispersal from established seedlings resulted in extensive seed dispersal, and the expected spatial genetic structures did not satisfactorily fit with the observations, even for the selected model. Our results advanced small-scale individual-based parentage analysis for quantifying fat-tailed gene flow in wind-mediated species, but also clarified its limitations and suggested future possibilities for gene flow studies.

Alleles↗

PubMed2006

Standardization of an ash (Fraxinus excelsior) pollen allergen extract.

BACKGROUND: Ash tree (Fraxinus excelsior) is the main representative of the Oleaceae family in temperate zones. Diagnosis of ash pollen allergy is made difficult due to (1) an overlapping pollinization period with Betulaceae, (2) non-inclusion in current diagnostic assays, and (3) some cross- reactivity with minor allergens from Betulaceae. The aim of this study was to calibrate an ash pollen in-house reference preparation (IHRP) in allergic patients in order to produce standardized products for diagnosis and immunotherapy purposes. METHODS: Ash pollen IHRP was extracted, ultrafiltered and freeze dried. Allergens in the extract were detected after 2-dimensional PAGE using specific sera and a monoclonal antibody. The Fra e 1 content of IHRP was evaluated by quantitative immunoprint. Forty-eight subjects from the North-East of France exhibiting clinical symptoms, a positive skin test and specific IgE levels > or =class 2 to ash pollen were recruited. IgE immunoprints were performed to select patients sensitized to the ash Fra e 1 allergen as opposed to cross-reacting allergens. Serial 10-fold dilutions of the IHRP were tested by skin prick tests in order to determine the concentration inducing a geometrical mean wheal diameter of 7 mm, said to correspond to an index of reactivity (IR) of 100 per millilitre. RESULTS: IgE-reactive molecules in IHRP comprise Fra e 1, Fra e 2, a 9-kDa molecule (presumably Fra e 3), as well as a doublet at 15 kDa and high molecular weight allergens. The 100 IR concentration of IHRP inducing a geometrical mean wheal diameter of 7 mm in 22 patients sensitized to Fra e 1 corresponds to the 1/126 (w/v) extraction ratio (i.e. 259 microg/ml of protein by Bradford) and contains 17 microg/ml of Fra e 1. The variability in total activity of 5 batches of standardized extracts was found to be significantly reduced when compared with 7 non-standardized extracts. CONCLUSION: An ash pollen IHRP was defined and molecularly characterized. Its successful standardization at 100 IR/ml in patients specifically sensitized to Fra e 1 allowed a skin reactivity-based calibration in properly diagnosed patients. Such a standardized ash pollen extract is a reliable tool to support immunotherapy of ash pollen allergy.

Adolescent↗