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Auteur Irena Perglova
Documents disponibles écrits par cet auteur (3)
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Differences in germination and seedling establishment of alien and native Impatiens species / Irena Perglova in Preslia, 81 (2009)
Titre : Differences in germination and seedling establishment of alien and native Impatiens species Type de document : Électronique Auteurs : Irena Perglova ; Jan Pergl (1977-) ; Hana Skalova ; Lenka Moravcová ; Vojtěch Jarošík (1958-2013) ; Petr Pyšek Année de publication : 2009 Article en page(s) : 357-375 Langues : Anglais (eng) Catégories : [Thématique] Ecologie de la germination
[Thématique] Physiologie de la germination
[Thématique] Plantes subspontanées, naturalisées, envahissantes
[Thématique] Banque de semences
Mots-clés : Impatiens Résumé : Comparative studies of closely related species may provide useful insights into the effect of species traits on invasion success since some of the biases associated with multispecies studies, such as phylogenetic effects, are considerably reduced by virtue of the experimental design. In this study seed and seedling traits of three congeneric alien species in Europe, differing in their region of origin, invasion status and history (Impatiens glandulifera, I. parviflora, I. capensis), were compared with the native I. noli-tangere in laboratory and common garden experiments. Seeds of I. glandulifera required the shortest period of stratification, germinated well both under laboratory and experimental garden conditions and the seedlings produced more biomass than those of the other species. Seeds of I. parviflora required a longer period of stratification, had the highest percentage germination but seedling emergence in the experimental garden was poorer than in I. glandulifera. Neither of these two species invasive in the Czech Republic formed soil seed banks. The native I. noli-tangere had the lowest percentage germination and formed a short-term persistent seed bank. Impatiens capensis germinated well in the laboratory, had the highest seedling emergence in the garden and its seed remained viable in the soil for three years. This indicates that in terms of germination and emergence, this species is comparable with the two invasive alien congeners and there appear to be no constraints to its invasion in the Czech Republic where it does not occur yet. Its absence may be due to a low propagule pressure; in the national flora I. capensis is listed as a potential future invader without mentioning it being cultivated in this country. Our results indicate that differences in the invasiveness of three alien species of balsams in the temperate zone of Central Europe can be attributed, at least in part, to their differing performances in the early stages of their life cycle. The short period of time required for seed stratification and the high seedling biomass of I. glandulifera might have increased its invasion potential compared to other Impatiens species occurring in the Czech Republic.
in Preslia > 81 (2009) . - 357-375Perglova, I., Pergl, J., Skalova, H., Moravcová, L., Jarošík, V., Pyšek, P., 2009 - Differences in germination and seedling establishment of alien and native Impatiens species ; Preslia, 81 : 357-375.
Flowering phenology and reproductive effort of the invasive alien plant Heracleum mantegazzianum / Irena Perglova in Preslia, 78 (2006)
Titre : Flowering phenology and reproductive effort of the invasive alien plant Heracleum mantegazzianum Type de document : Électronique Auteurs : Irena Perglova ; Jan Pergl (1977-) ; Petr Pyšek Année de publication : 2006 Article en page(s) : 265-285 Langues : Anglais (eng) Catégories : [Thématique] Biologie de la reproduction
[Thématique] Plantes subspontanées, naturalisées, envahissantes
Mots-clés : Heracleum mantegazzianum Sommier & Levier Résumé : Heracleum mantegazzianum is one of the most invasive species in the Czech flora. The present study describes its flowering phenology and assess the effectiveness of protandry in preventing selfing in this self-compatible species, describes the timing of flowering in a heavily invaded area of Slavkovský les (Czech Republic) and estimates fruit set in a large sample of plants, which provides reliable data on the often exaggerated fecundity of this species. The study of flowering phenology revealed that protandry is always effective only within individual flowers, where male and female flowering phases are completely separated. In contrast, anther dehiscence in some flowers can occasionally overlap with stigma receptivity in other flowers in the same umbel, providing an opportunity for geitonogamous (i.e. between-flower) selfing. Nevertheless, the potential for selfing in H. mantegazzianum is determined mainly by an overlap in the male and female flowering phases between umbels on the same plant; at least a short overlap between some umbels was observed in 99% of the plants at the Slavkovský les. Although the degree of protandry in H. mantegazzianum favours outcrossing, the opportunity to self may be of crucial importance for an invasive plant, especially if a single plant colonizes a new location. At Slavkovský les, flowering started within one week (from 20 to 27 June 2002) at all 10 sites. The duration of flowering of an individual plantwas on average 36 days,with maximum of 60 days, and increased significantly with the number of umbels on a plant. In the second half of August, the majority of the fruits were ripe and had started to be shed. The beginning of flowering of a plant was significantly negatively correlated with the number of umbels it had – the earlier a plant started to flower the more umbels it had produced. A significant negative relationship was also found between basal diameter and beginning of flowering; plants with large basal diameters started to flower earlier. An average plant at Slavkovský les produced 20,671 fruits. Of these, 44.6% were produced by the terminal umbel, 29.3% by secondary umbels on satellites, 22.6% by secondary umbels on branches and only 3.5% by tertiary umbels. The estimated fruit number of the most fecund plant was 46,470 – compared to an average plant, the proportional contribution of tertiary umbels increased relative to the primary umbel. This study revealed a significant positive relationship between fecundity and plant basal diameter. Although the results of this study indicate that the fecundity of this species is often overestimated in the literature, the number of fruits produced by H. mantegazzianum provides this invasive species with an enormous reproductive capacity.
in Preslia > 78 (2006) . - 265-285Perglova, I., Pergl, J., Pyšek, P., 2006 - Flowering phenology and reproductive effort of the invasive alien plant Heracleum mantegazzianum ; Preslia, 78 : 265-285.
Article (2006)Adobe Acrobat PDF
Seasonal pattern of germination and seed longevity in the invasive species Heracleum mantegazzianum / Lenka Moracova in Preslia, 78 (2006)
Titre : Seasonal pattern of germination and seed longevity in the invasive species Heracleum mantegazzianum Type de document : Électronique Auteurs : Lenka Moracova ; Petr Pyšek ; Jan Pergl (1977-) ; Irena Perglova ; Vojtěch Jarošík (1958-2013) Année de publication : 2006 Article en page(s) : 287-301 Langues : Anglais (eng) Catégories : [Thématique] Plantes subspontanées, naturalisées, envahissantes
[Géographique] République Tchèque
Mots-clés : Heracleum mantegazzianum Sommier & Levier Résumé : We investigated the effects of different temperature regimes and dry storage on germination of H. mantegazzianum (Apiaceae, native to Caucasus) seeds in the laboratory and linked the results with studies of seasonal seed bank depletion in a common garden experiment and under field conditions. Seeds were collected at seven sites in the Slavkovský les region, Czech Republic, cold-stratified for 2 months and germinated at seven temperature regimes. Under all temperature regimes, fresh seeds germinated to significantly higher percentages than older (1, 2, 3 years) seeds. For all storage lengths, seeds germinated best at alternating day/night temperatures of 20/5 °C. The length of the germination period had a significant effect only at low constant temperatures of 2 and 6 °C, where germination percentage increased between 2 and 6 months. Seasonal germination exhibited a distinct pattern, with rapid depletion of seed bank by the first spring after seed burial. Non-dormant seeds were present in the soil early in spring and late in autumn. The higher summer temperatures prevented dormancy breaking and another cold period of at least two months below 10 °C was needed to bring non-germinated seeds out of dormancy. The results suggest that (1) seed dormancy of H. mantegazzianum was not completely broken until the first spring, but that some seeds re-enter or retain dormancy during high summer temperatures and that (2) the threshold needed for breaking the dormancy was achieved gradually during the cold autumn and winter months. However, in a small fraction of seeds the dormancy breaking process took several years. Of seeds buried in 10 different regions of the Czech Republic, on average 8.8% survived 1 year, 2.7% 2 years and 1.2% remained viable and dormant after 3 years of burial. The ability of even small fraction of H. mantegazzianum seeds to survive for at least 3 years can result in re-invasion of this species into controlled sites.
in Preslia > 78 (2006) . - 287-301Moracova, L., Pyšek, P., Pergl, J., Perglova, I., Jarošík, V., 2006 - Seasonal pattern of germination and seed longevity in the invasive species Heracleum mantegazzianum ; Preslia, 78 : 287-301.
Article (2006)Adobe Acrobat PDF