Résultat de la recherche
4 recherche sur le mot-clé 'Saxifraga sp.'
Affiner la recherche Générer le flux rss de la recherche
Partager le résultat de cette recherche
Breeding system and effects of plant size and flowering time on reproductive success in the alpine herb Saxifraga stellaris L. / S.M. Sandvik in Arctic and alpine research, 31 (2) (05/1999)
[article]
Titre : Breeding system and effects of plant size and flowering time on reproductive success in the alpine herb Saxifraga stellaris L. Type de document : Imprimé Auteurs : S.M. Sandvik ; Ørjan Totland (1968-) ; J. Nylehn Année de publication : 1999 Article en page(s) : 96-201 Langues : Anglais (eng) Catégories : [LOTERRE-Biodiversité] Pollinisateur Mots-clés : Saxifraga sp. Saxifraga stellaris L. Résumé : The pollination and reproductive ecology of Saxifraga stellaris was investigated in alpine southwest Norway. A breeding system analysis, with performance of controlled crosses, revealed that S. stellaris is self-compatible and that reproductive success after cross- and self-pollination is equal. Relative autodeposition efficiency (i.e. mean seed:ovule ratio in caged, nonmanipulated plants relative to mean seed:ovule ratio of control plants) was, however, low (0.29), suggesting that S. stellaris depends on insect visitation for maximum seed set. Seed set is not restricted by pollen availability, as indicated by a supplemental hand-pollination experiment. Plant size had a strong positive impact on ovule number, which in turn was positively correlated with seed number. Plant size also had a positive influence on seed weight. Seed weight was lowest for late-flowering plants, suggesting that shorter time for seed maturation and lower temperatures late in the season restrict seed weight. No correlations between flowering date and seed number were found, perhaps because the pollinators are relatively insensitive to temperature conditions and thus their activity does not change through the flowering season of S. stellaris. Lien pérenne : DOI : 10.1080/15230430.1999.12003298 Permalink : https://biblio.cbnpmp.fr/index.php?lvl=notice_display&id=137898
in Arctic and alpine research > 31 (2) (05/1999) . - 96-201Sandvik, SM., Totland, Ø., Nylehn, J. 1999. Breeding system and effects of plant size and flowering time on reproductive success in the alpine herb Saxifraga stellaris L. Arctic and alpine research, 31(2): 96-201.Documents numériques
Consultable
article (1999)URL Reproduction of the rare monocarpic species Saxifraga mutata L. / Rolf Holderegger in Botanical journal of the Linnean Society, 122 (4) (1996)
[article]
Titre : Reproduction of the rare monocarpic species Saxifraga mutata L. Type de document : Imprimé Auteurs : Rolf Holderegger (1965-) Année de publication : 1996 Article en page(s) : 301-313 Langues : Français (fre) Mots-clés : Saxifraga sp. Résumé : The aim of the study is to investigate the impact of reproduction and genetic variation on the persistence of populations of the prealpine, monocarpic Saxifraga mutata L. The species grows on erosion slopes or rocks, and its local populations are often small and isolated. Crossing experiments resulted in better seed-set than selfing, but both yielded viable seeds. Agamospermy did not occur. In an early-successional species like S. mutata, successful selfing is important in the colonization of new habitats. Flowers of S. mutata were visited by Syrphidae and unspecialized Hymenoptera. A germination rate of 40% was reached in cultivation after 20 weeks but germination continued until the end of the experiment after 92 weeks. Seeds stored dry for 30 months at room temperature mostly lost their germinability. In natural habitats, seedlings were found almost throughout the year with a peak in spring. Suitable safe sites were small patches of open soil, bare marl on erosion slopes, and rock crevices. AU individuals investigated were diploid with 2n = 26. Allozyme electrophoresis showed a lack of segregation within the populations. Intra- and interpopulation genetic variation was low. These results were in partial disagreement with theoretical expectations in a mixed mating species. It is concluded that demographic rather than genetic processes are the main cause of extinction of populations of S. mutata, at least in the short-term. Lien pérenne : DOI : 10.1111/j.1095-8339.1996.tb02078.x Permalink : https://biblio.cbnpmp.fr/index.php?lvl=notice_display&id=137895
in Botanical journal of the Linnean Society > 122 (4) (1996) . - 301-313Holderegger, R. 1996. Reproduction of the rare monocarpic species Saxifraga mutata L. Botanical journal of the Linnean Society, 122(4): 301-313.Documents numériques
Consultable
Article (1996)URL Reproductive ecology of Saxifraga oppositifolia : phenology, mating system, and reproductive success / M. Stenstrom in Arctic and alpine research, 24 (4) (1992)
[article]
Titre : Reproductive ecology of Saxifraga oppositifolia : phenology, mating system, and reproductive success Type de document : Imprimé Auteurs : M. Stenstrom ; Ulf Molau (1951-) Année de publication : 1992 Article en page(s) : 337-343 Langues : Anglais (eng) Catégories : [CBNPMP-Thèmes] Phénologie Mots-clés : Saxifraga sp. Saxifraga oppositifolia L. Résumé : We studied the reproductive biology in Saxifraga oppositifolia L. (Saxifragaceae) at a subarctic-alpine tundra site at Latnjajaure Field Station, North Swedish Lapland. Saxifraga oppositifolia is a perennial herb with circumpolar distribution, and it is one of the earliest flowering species in its habitats. Late-flowering genets were found to have accelerated phenology; this was correlated with heat acumulation per day. Individual flowers were found to last for 11.7 d. Strongly protogynous flowers (female phase lasted 4.2 d), declining stigma receptivity at the time of anther dehiscence, and more or less simultaneous flowering within genets reduce the probability for self-pollination. High seed abortion in naturally pollinated flowers (seed:ovule ratio = 0.25) supports this prediction. Crossing experiments showed that seed set is very low from autodeposition of pollen, and almost as low from selling. Reproductive success was found to be pollen limited. Lien pérenne : DOI : 10.1080/00040851.1992.12002966 Permalink : https://biblio.cbnpmp.fr/index.php?lvl=notice_display&id=137889
in Arctic and alpine research > 24 (4) (1992) . - 337-343Stenstrom, M., Molau, U. 1992. Reproductive ecology of Saxifraga oppositifolia : phenology, mating system, and reproductive success. Arctic and alpine research, 24(4): 337-343.Documents numériques
Consultable
article (1992)URL Genetic structure of fragmented plant populations : a comparison of two arctic-alpine species with contrasting breeding systems (a new project) / R. Bauert-Martin in Bulletin of the Geobotanical Institute ETH, 62 (0) (1996)
[article]
Titre : Genetic structure of fragmented plant populations : a comparison of two arctic-alpine species with contrasting breeding systems (a new project) Type de document : Imprimé Auteurs : R. Bauert-Martin ; Matthias Baltisberger (1951-) ; Peter John Edwards (1948-) Année de publication : 1996 Article en page(s) : 83-88 Langues : Anglais (eng) Mots-clés : Ranunculus sp. Saxifraga sp. Permalink : https://biblio.cbnpmp.fr/index.php?lvl=notice_display&id=137843
in Bulletin of the Geobotanical Institute ETH > 62 (0) (1996) . - 83-88Bauert-Martin, R., Baltisberger, M., Edwards, P.J. 1996. Genetic structure of fragmented plant populations : a comparison of two arctic-alpine species with contrasting breeding systems (a new project). Bulletin of the Geobotanical Institute ETH, 62(0): 83-88.Exemplaires (1)
Code-barres Cote Support Localisation Section Disponibilité R858 P-756 Revue Réserve Revues Consultable