Search results for "Alnus"
showing 10 items of 21 documents
Boron mobility in deciduous forest trees in relation to their polyols
2004
Summary • Boron (B) has been found to be phloem mobile in species that translocate polyols, whereas it is almost immobile in other species. The objectives of the present study were to survey B mobility in deciduous trees, and to relate it to the presence of polyols. • The stable isotope 10B was applied as a tracer to mature leaves of seedlings, and growing leaves were subsequently harvested for B isotope analysis. • Extensive B mobility was found in Sorbus aucuparia and Prunus padus, species with high sorbitol content, but also in Ulmus glabra, with only trace amounts of B-complexing polyols. Alnus incana, Fraxinus excelsior, Betula pubescens and Larix sibirica also translocated 10B into ne…
Annual pollen traps reveal the complexity of climatic control on pollen productivity in Europe and the Caucasus
2010
Annual PAR (pollen accumulation rates; grains cm−2 year−1) were studied with modified Tauber traps situated in ten regions, in Poland (Roztocze), the Czech Republic (two regions in Krkonoše, two in Šumava), Switzerland (4 regions in the Alps), and Georgia (Lagodekhi). The time-series are 10–16 years long, all ending in 2007. We calculated correlations between pollen data and climate. Pollen data are PAR summarized per region (4–7 traps selected per region) for each pollen type (9–14 per region) using log-transformed, detrended medians. Climate data are monthly temperature and precipitation measured at nearby stations, and their averages over all possible 2- to 6-month windows falling within…
Early screening of new accumulating versus non-accumulating tree species for the phytomanagement of marginal lands
2019
International audience; The use of fast-growing trees producing a high quantity of biomass can bring significant practical and economic benefits to the reclamation of marginal lands. The present study aims to identify new shrub/tree species to offer a wider range of shrubs/trees useful for phytomanagement practices. We implemented three experimental sites in France of 1 ha each (Thann, Carrières-sous-Poissy and Leforest) contaminated by different potentially toxic elements (PTE) with a total of 38 different tree species. After two years of growth, the element concentrations in stem and leaf biomasses, tree survival rate and growth of plants were assessed. Although the three sites had elevat…
Determination and separation of diarylheptanoids from alder growing in Latvia
2015
The composition of diarylhepatnoids fraction isolated from bark of two alder species (grey alder and black alder) was studied. The efficiency of three extraction methods used for isolation of diarylhepatnoids from alder bark was compared. Two diarylhepatnoids: 1,7-bis-(3,4-dihydroxyphenyl)-heptan- 3-one-5-O-β-D-xylopyronoside (oregonin) and 1,7-bis-(3,4-dihydroxyphenyl)-3-hydroxyheptane-5-O-β-D- xylopyranoside were isolated from the bark of grey alder. The phenolic components of the extracts were analyzed by high-performance liquid chromatography (HPLC). Quantitative determination of oregonin was performed using an internal standard method. The results obtained show that alder barks are ric…
Metabolite specific effects of solar UV-A and UV-B on alder and birch leaf phenolics
2008
We measured the concentrations of ultraviolet (UV)-absorbing phenolics varying in response to exclusion of either solar UV-B or both solar UV-A and UV-B radiations in leaves of grey alder (Ainus incana) and white birch (Betula pubescens) trees under field conditions. In alder leaves 20 and in birch leaves 13 different phenolic metabolites were identified. The response to UV exclusion varied between and within groups of phenolics in both tree species. The changes in concentration for some metabolites suggest effects of only UV-A or UV-B, which band being effective depending on the metabolite. For some other metabolites, the results indicate that UV-A and UV-B affect concentrations in the sam…
The ongoing naturalisation of Eucalyptus spp. in the Mediterranean Basin: new threats to native species and habitats
2019
The genus Eucalyptus has been widely introduced into many regions of the world outside its native range and has become invasive in some Mediterranean biomes (e.g. in southern Africa and California). In the Mediterranean Basin and Europe, eucalypts were introduced at the end of the 18th century. However, natural regeneration events in these regions are recent in time and limited in terms of affected areas, except for the Iberian Peninsula. An updated overview about the natural spread of Eucalyptus species in Italy is still lacking. This paper aims to fill this knowledge gap, using both published data and unpublished field data regarding naturalisation events, with a specific focus on Sicily.…
Elucidation of antioxidant properties of wood bark derived saturated diarylheptanoids: a comprehensive (DFT-supported) understanding.
2013
A series of diarylheptanoids, namely 1,7-bis-(3,4-dihydroxyphenyl)-heptan-3-one-5-O-D-xylopyranoside (oregonin), 1,7-bis-(3,4-dihydroxyphenyl)-3-hydroxyheptane-5-O-β-D-xylopyranoside and 1,7-bis-(4-hydroxyphenyl)-heptane-3-one-5-O-β-D-glucopyranoside (platyphylloside), were isolated from the bark of alder family trees, a species widely spread over in Europe. As antioxidants, these natural polyphenols have a promising potential in various fields of application, but their redox reactivity is insufficiently characterized. In this work, their antioxidant activity is described using assays based on DPPH and ABTS(+) radical scavenging, oxygen anion radicals (O2(-)) quenching. The standardized ORA…
Alder pollen in Finland ripens after a short exposure to warm days in early spring, showing biennial variation in the onset of pollen ripening
2017
Abstract We developed a temperature sum model to predict the daily pollen release of alder, based on pollen data collected with pollen traps at seven locations in Finland over the years 2000–2014. We estimated the model parameters by minimizing the sum of squared errors (SSE) of the model, with weights that put more weight on binary recognition of daily presence or absence of pollen. The model results suggest that alder pollen ripens after a couple of warm days in February, while the whole pollen release period typically takes up to 4 weeks. We tested the model residuals against air humidity, precipitation and wind speed, but adding these meteorological features did not improve the model pr…
Possible Fungistatic Implications of Betulin Presence in Betulaceae Plants and their Hymenochaetaceae Parasitic Fungi
2010
Betulin and its derivatives (especially betulinic acid) are known to possess very interesting prospects for their application in medicine, cosmetics and as bioactive agents in pharmaceutical industry. Usually betulin is obtained by extraction from the outer layer of a birch bark. In this work we describe a simple method of betulin isolation from bark of various species of Betulaceae trees and parasitic Hymenochaetaceae fungi associated with these trees. The composition of the extracts was studied by GC-MS, whereas the structures of the isolated compounds were confirmed by FTIR and 1H NMR. Additionally, the significant fungistatic activity of betulin towards some fi lamentous fungi was deter…
Particularities of Grey Alder (Alnus incana) Stands in Riparian Galleries Along Streams of the Southern Transylvanian Tableland (Romania)
2019
Abstract Grey Alder (Alnus incana (L.) Moench.) stands are distributed in the Carpathian area on alluvial deposits with sediments of different grain size as galleries along rivers and streams of the sub-montane to the middle montane level. The geological structure (Tertiary sedimentary deposits) in relation to the hydromorphological processes is the base for the structure of the stream valleys, which are in part very deep. Under the special microclimate of these deeper stream stretches with lower temperatures there are favourable conditions for the development of grey alder stands.