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Auteur Petra Nowak |
Documents disponibles écrits par cet auteur (4)
trié(s) par (Pertinence décroissant(e), Titre croissant(e)) Affiner la rechercheCharophytes in warm springs on Svalbard (Spitsbergen) : DNA barcoding identifies Chara aspera and Chara canescens with unusual morphological traits / Anders Langangen in Botany letters, vol. 167, n°2 (Année 2020)
Titre : Charophytes in warm springs on Svalbard (Spitsbergen) : DNA barcoding identifies Chara aspera and Chara canescens with unusual morphological traits Type de document : texte imprimé Auteurs : Anders Langangen, Auteur ; Andreas Ballot, Auteur ; Petra Nowak, Auteur ; Suzanne Schneider, Auteur Année de publication : 2020 Article en page(s) : pp. 179-186 Langues : Anglais (eng) Catégories : [ZG] Norvège
[Thèmes] Charophytes / CharacéesMots-clés : MATK (Megakaryocyte-Associated Tyrosine Kinase) Chara aspera Chara canescens morphologie génétique Résumé : "The Troll springs are warm springs on Svalbard (Spitsbergen). Charophytes were collected in the years 1910, 1912, 1958, 1992/1993, and 2018. However, since the Chara samples showed unusual morphological traits, there were doubts with respect to species identity. We here use DNA barcoding to show that there occur two Chara species in the Troll springs: Chara aspera and C. canescens." (source : auteurs) Type de publication : périodique Référence biblio : Langangen A., Ballot A., Nowak P., Schneider S., 2020 - Charophytes in warm springs on Svalbard (Spitsbergen) : DNA barcoding identifies Chara aspera and Chara canescens with unusual morphological traits. Botany letters, 167 (2) : 179-186. ID PMB : 69484 DOI : 10.1080/23818107.2019.1672104 Permalink : http://www.cbnbrest.fr/catalogue_en_ligne/index.php?lvl=notice_display&id=69484
in Botany letters > vol. 167, n°2 (Année 2020) . - pp. 179-186[article]Exemplaires(1)
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Titre : Diaspore bank analysis of Baltic coastal waters Type de document : texte imprimé Auteurs : Petra Nowak, Auteur ; Tim Steinhardt, Auteur ; Ulla Von Ammon, Auteur ; Henning Rohde, Auteur ; Arne Schoor, Auteur ; Anja Holzhausen, Auteur ; Ralf Schaible, Auteur ; Hendrik Schubert, Auteur Année de publication : 2018 Article en page(s) : pp. 159-173 Langues : Anglais (eng) Catégories : [habitats/milieux] 1 - Habitats littoraux et halophile
[Thèmes] Charophytes / CharacéesMots-clés : eutrophisation restauration germination diaspore oospore Résumé : "The coastal waters are important transition zones for terrestrial nutrient and pollutant runoff and the open Sea. During the last decades, eutrophication has negatively influenced macrophyte communities of the coastal ecosystems, making restoration activities inevitable. This study analysed recent macrophyte vegetation and the reproductive potential through the sediment diaspore reservoir along the German Baltic Sea coastline. Salinity was identified to be the responsible factor for shifts in the macrophyte community with most commonly found species like Stuckenia pectinata or Myriophyllum spicatum. In contrast, the oospores of small charophytes (e.g. Tolypella nidifica) clearly dominated the sediment diaspore bank. The germination rates differed in the recent vegetation composition and the diaspore bank composition with Zannichellia palustris as the dominant species. However, several species not visually detected at the respective sites were represented in the diaspore bank and germinated at a low rate (e.g. Chara contraria and Lamprothamnium papulosum). The maximal germination frequency corresponded to the sediment layer in which diaspore density was the highest (5–15 cm). In conclusion, the germinable diaspores were observed at all sites. Considering the differences between the diaspore composition, recent vegetation and germination success, we have illustrated the potential of the diaspore banks for the restoration of the macrophyte communities after at least mid-term periods of disturbance." (source : auteurs) Type de publication : périodique Référence biblio : Nowak P., Steinhardt T., Von Ammon U., Rohde H., Schoor A., Holzhausen A., Schaible R., Schubert H., 2018 - Diaspore bank analysis of Baltic coastal waters. Botany letters, 165 (1) : 159-173. Permalink : http://www.cbnbrest.fr/catalogue_en_ligne/index.php?lvl=notice_display&id=67244
in Botany letters > vol. 165, n°1 (Année 2018) . - pp. 159-173[article]Exemplaires(1)
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Titre : Genetic and morphological variation in Chara contraria and a taxon morphologically resembling Chara connivens Type de document : texte imprimé Auteurs : Ivana Trbojevic, Auteur ; Aleksandra Markovic, Auteur ; Jelena Blazencic, Auteur ; Gordana Subakov Simic, Auteur ; Petra Nowak, Auteur ; Andreas Ballot, Auteur ; Suzanne Schneider, Auteur Année de publication : 2020 Article en page(s) : pp. 187-200 Langues : Anglais (eng) Catégories : [Thèmes] Charophytes / Characées Mots-clés : génétaique morphologie MATK (Megakaryocyte-Associated Tyrosine Kinase) Chara contraria Chara connivens comparaison d'espèces Résumé : "Charophyte species delineation is regularly based on a set of thallus morphological characteristics, but considering pronounced phenotypic plasticity, difficulties and doubts commonly occur in Chara species determination. DNA barcoding may contribute to solving these challenges. Here we characterize Chara contraria with an unusual set of morphological characteristics, and specimens morphologically resembling Chara connivens collected in Serbia, by describing their morphological traits and analysing matK barcoding results. Our results indicated that dioecious Chara specimens, tentatively determined as Chara “connivens” based on morphological traits, were genetically more closely related to C. globularis. These Chara “connivens” specimens formed a sister group to a monophyletic C. globularis cluster, suggesting that it may be neither C. connivens nor C. globularis. We strongly encourage further barcoding of C. “connivens” samples from freshwater, in order to find out if there are consistent genetic differences between the dioecious freshwater C. “connivens” and monoecious C. globularis. Barcoding of matK placed the monoecious Chara specimens, which based on morphological characteristics initially were determined as C. virgata, into the C. contraria group. This indicates that the microscopic traits which commonly are used for Chara species determination sometimes are misleading. In general, our study challenges the commonly used phenetic species concept in Charophyte taxonomy and illustrates the importance of molecular approaches to evaluate the validity of morphological characteristics of the plant thallus in species delineation." (source : auteurs) Type de publication : périodique Référence biblio : Trbojevic I., Markovic A., Blazencic J., Subakov Simic G., Nowak P., Ballot A., Schneider S., 2020 - Genetic and morphological variation in Chara contraria and a taxon morphologically resembling Chara connivens. Botany letters, 167 (2) : 187-200. ID PMB : 69485 DOI : 10.1080/23818107.2019.1703808 Permalink : http://www.cbnbrest.fr/catalogue_en_ligne/index.php?lvl=notice_display&id=69485
in Botany letters > vol. 167, n°2 (Année 2020) . - pp. 187-200[article]Exemplaires(1)
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Titre : Morphological adaptations of Chara baltica and Chara liljebladii (Characeae) under different light conditions Type de document : texte imprimé Auteurs : Petra Nowak, Auteur ; Hendrik Schubert, Auteur ; Anja Holzhausen, Auteur ; Veronika Sommer, Auteur ; Ralf Schaible, Auteur Année de publication : 2018 Article en page(s) : pp. 67-75 Langues : Anglais (eng) Catégories : [Thèmes] Algues
[Thèmes] Charophytes / Characées
[Thèmes] EcologieMots-clés : Phenotypic plasticity light acclimation Résumé : "Individuals within wild populations differ substantially in their fitness as a result of either genetic differences or acclimation. Within the Charophyte algae, the two taxa Chara baltica and C. liljebladii predominate at different water depths of the same habitat. The two taxa are mainly distinguished by quantitative characteristics, pointing to light acclimation. In particular, they differ by a length of the internode and the bract cells, as well as the cortication type. Genetic analyses revealed that individuals of both morphotypes are genetically identical, and hence may belong to the same species. In the present paper, we tested a hypothesis that C. liljebladii is a low-light phenotype of C. baltica. Can a C. baltica phenotype be transferred into a C. liljebladii (and vice versa) by manipulation of the environmental conditions such as irradiance? We observed significant changes in the morphology of C. baltica: decreasing the irradiance significantly increased the growth of the branchlets and internodal cells. Consequently, the plants grew larger, changing their morphology in the direction of the C. liljebladii morphotype. In the reverse experiment, subjecting C. liljebladii to increasing irradiances, the individuals had slightly better growth, but none of the analysed morphological characteristics changed significantly. Both taxa have thus shown different adaptations to light limitation. Their morphologies cannot be transferred into each other by environmental factors. Thus, the presence of the different morphologies reflects the ecological characteristics of their habitats, such as light availability or turbidity." (source : auteurs) Type de publication : périodique Référence biblio : Nowak P., Schubert H., Holzhausen A., Sommer V., Schaible R., 2018 - Morphological adaptations of Chara baltica and Chara liljebladii (Characeae) under different light conditions. Botany letters, 165 (1) : 67-75. ID PMB : 67226 Permalink : http://www.cbnbrest.fr/catalogue_en_ligne/index.php?lvl=notice_display&id=67226
in Botany letters > vol. 165, n°1 (Année 2018) . - pp. 67-75[article]Exemplaires(1)
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