Search results for "Pollen"
showing 10 items of 302 documents
MACC regional multi-model ensemble simulations of birch pollen dispersion in Europe
2015
Abstract. This paper presents the first ensemble modelling experiment in relation to birch pollen in Europe. The seven-model European ensemble of MACC-ENS, tested in trial simulations over the flowering season of 2010, was run through the flowering season of 2013. The simulations have been compared with observations in 11 countries, all members of the European Aeroallergen Network, for both individual models and the ensemble mean and median. It is shown that the models successfully reproduced the timing of the very late season of 2013, generally within a couple of days from the observed start of the season. The end of the season was generally predicted later than observed, by 5 days or more…
Authentication of phacelia honeys (Phacelia tanacetifolia) based on a combination of HPLC and HPTLC analyses as well as spectrophotometric measuremen…
2019
Abstract The growing interest in the quality of honey affects customer preferences and consumption trends. Generally, monofloral honeys are more expensive than multifloral honeys, and the price strictly depends on its botanical origin. The increasing popularity of a variety of monofloral brands has led to the increasing number of adulterations and therefore for the need to develop new analytical methods for assessing honey authenticity. The purpose of the present study was to develop a method for the authentication of phacelia honeys on the basis of HPLC and HPTLC analyses and spectrophotometry. The results obtained by spectrophotometric analysis indicated significant differences only betwe…
PREVISION JOURNALIERE DES POLLENS SUR LE TERRITOIRE NATIONAL FRANÇAIS, AVEC UN OBJECTIF D'INFORMATION SANITAIRE DES POPULATIONS ALLERGIQUES
2008
At present, 16% of French people suffer from allergies to one or several pollens. The corresponding symptoms can be presented as under benign form (rhinitis, conjunctivitis, cough) as under much more serious form : asthma. Forecast of the starting date of an allergic exposure risk to pollens is necessary from a sanitary and preventive standpoint. Forecast has to be more precisely as possible in order to begin anti-allergic treatments at appropriate moment, with a view of effectiveness and reduction of the costs due to this disease. The present study, taking place in all the French territory, concerns four pollen taxa among the most allergenic : ash, birch, grasses and ragweed. This work com…
<i>Limonium carvalhoi (Plumbaginaceae)</i>, a new endemic species from the Balearic Islands
1998
ROSSELLO, J.A., L. SAEZ & A.C. CARVALHO (1998). Limonium carvalhoi (Plumbaginaceae), a new endemic species from the Balearic Islands. Anales Jard. Bot. Madrid 56(1): 23-31. Limonium carvalhoi Rossello & L. Saez is described from a single salt marsh locality in southwest Majorca. Morphologically, L. carvalhoi is ciose to L. inexpectans, L. migjornense and L. magallufianum , all Balearic endemics. The new species has an apomictic breeding system and shows a single pollen/stigma combination (B/papillate type). Chromosome number ranges from 2n = 24 to 2n = 26. Based on the occurrence of a long metacentric chromosome in all cells examined, it is suggested that the original chromosome complement …
A statistical model for predicting the inter-annual variability of birch pollen abundance in Northern and North-Eastern Europe
2018
The paper suggests a methodology for predicting next-year seasonal pollen index (SPI, a sum of daily-mean pollen concentrations) over large regions and demonstrates its performance for birch in Northern and North-Eastern Europe. A statistical model is constructed using meteorological, geophysical and biological characteristics of the previous year). A cluster analysis of multi-annual data of European Aeroallergen Network (EAN) revealed several large regions in Europe, where the observed SPI exhibits similar patterns of the multi-annual variability. We built the model for the northern cluster of stations, which covers Finland, Sweden, Baltic States, part of Belarus, and, probably, Russia and…
Pollen-pollen interactions in Betula pendula in vitro
1998
Direct pollen interactions, as well as interactions mediated by a recipient, can have a remarkable influence on pollen fertilization ability. Under conditions of pollen competition it could be advantageous if pollen grains interfered with the germination of other pollen. The aim of this study was to find out if there are direct negative or positive pollen–pollen interactions between pollen grains from genetically slightly different donors. The in vitro germinability of the pollen from several Betula pendula Roth clones was investigated. The pollen interactions between the clones were examined pairwise by using equal pollen mixtures. In three of the eight cases the germination percentage of …
Effects of temperature and pollination site on pollen performance in Betula pendula Roth – evidence for genotype-environment interactions
2000
We studied whether the differences between genetically different pollen donors (Betula pendula Roth clones) with respect to pollen-tube growth rate were consistent under different thermal conditions during pollen germination in vivo and in vitro. We conducted a single-donor hand-pollination experiment with same pollen donors and recipients in a plastic house seed orchard and at an outdoor clone collection. The prevailing daily mean temperature during pollen germination was 13°C higher in the plastic house than outdoors. The pollen-tube growth rate of each pollen donor was additionally determined in vitro on agar medium at five temperatures (10°, 15°, 22°, 30° and 35°C). A significant intera…
Do pollen donors with fastest-growing pollen tubes sire the best offspring in an anemophilous tree,Betula pendula(Betulaceae)?
2001
The relationship between pollen and progeny performance has been a subject of many studies but the evidence for pollen-tube growth rate as an indicator of progeny fitness is equivocal. We used an anemophilous tree, Betula pendula, to examine the relationship between pollen-tube growth rate and seed and seedling performance. We crossed nine maternal plants with pollen from six pollen donors in a clonal B. pendula seed orchard, measured the pollen-tube growth rates for every cross, and analyzed the performance of the resulting seeds and seedlings. The only significant positive correlation was found between pollen-tube growth rate and seed mass when we controlled for seed number per infloresce…
Pollen‐tube growth rate and seed‐siring success among Betula pendula clones
1999
The aim of this study was to investigate whether genetically different pollen donors (Betula pendula clones) differed in pollen-tube growth rate across 11 maternal plants and in vitro, and whether the differences between the donors were consistent across the recipients. To compare the seed-siring success of competing pollen donors, a two-donor hand-pollination experiment with six donors and six recipients was conducted. The experiments were performed at a plastic-house seed orchard. The donors showed significant variation in pollen-tube growth rate on all the 11 recipients. The rankings of the pollen donors were statistically consistent across different maternal plants. A significant positi…
Eosinophil Cationic Protein in Nasal Secretions and Blood Serum in Grass-Pollen Allergic Rhinitis
1996
Concentration of the Eosinophil Cationic Protein (ECP) measured in different body fluids has been demonstrated to be a good marker of eosinophilic inflammation. In allergic asthma, ECP levels in both broncho-alveolar-lavage (BAL) fluid and serum can be used to monitor disease activity. In allergic rhinitis, the value of ECP determinations in serum and nasal secretions was not directly compared, so far. In the present study, ECP levels in blood serum (Se) and nasal secretions (NS) of grass pollen allergic and healthy individuals under pollen exposure were analyzed. Forty-three grass-pollen allergic subjects and 19 healthy volunteers were included. Grass-pollen counts were measured using Bur…