| Titre : |
The ecological significance of sexual reproduction in peat mosses (Sphagnum) |
| Type de document : |
texte imprimé |
| Auteurs : |
Sebastian Sundberg, Auteur |
| Editeur : |
Acta Universitatis Upsaliensis |
| Année de publication : |
2000 |
| Collection : |
Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology num. 581 |
| Importance : |
37 p. |
| ISBN/ISSN/EAN : |
91-554-4847-X |
| Langues : |
Anglais (eng) |
| Mots-clés : |
colonisation perturbation expérience longévité spore bryophyte |
| Résumé : |
"Peat mosses (Sphagnum) are widely distributed and are a major component of mire vegetationand peat throughout the boreal and temperate regions. Most boreal Sphagnum species regu-larly produce sporophytes, but the ecological role of the spore has been questioned. This studyshows that the spores can form a spore bank and have the ability to germinate and contributeto moss establishment whenever suitable conditions occur. The results suggest that spore pro-duction is important for explaining the wide distribution and omnipresence of Sphagnum innutrient-poor wetlands. The results further imply that initial recruitment from spores predomi-nates in Sphagnum after disturbance or formation of suitable habitats.A series of experiments showed that addition of phosphorus-containing substrates, suchas fresh plant litter or moose dung, resulted in spore establishment on bare, moist peat. A fieldexperiment indicated establishment rates of about 1% of sown, germinable spores on peatwith added substrates. Plant litter on moist soil, without a closed cover of bryophytes, is animportant safe site for the establishment of Sphagnum spores. The results fit the observed pat-tern of colonisation by Sphagnum beneath Eriophorum vaginatum tussocks in mires severelydisturbed by peat extraction. Successful long-distance dispersal was indicated by the occur-rence of several regionally new or rare Sphagnum species in disturbed mires.Spore number per sporophyte ranged among Sphagnum species from 18 500 to 240 000,with a trade-off between spore number and spore size. Annual spore production was estimatedat 15 million spores per square metre on two investigated mires. Sporophyte productionshowed a large interannual variation. Sporophyte production was positively related to theamount of precipitation the preceding summer. This was probably because a high water levelpromoted gametangium formation. Spore dispersal occurred in July and August. The earliertiming of spore dispersal in the more drought-sensitive, hollow-inhabiting sphagna should re-duce the risk of sporophytes drying out prematurely during summer droughts.Spores kept refrigerated up to 13 years retained high germinability. A field experimentshowed that Sphagnum can form a persistent spore bank, with a potential longevity of severaldecades." (source : auteur) |
| Type de publication : |
livre |
| Référence biblio : |
Sundberg S., [s. d.] - The ecological significance of sexual reproduction in peat mosses (Sphagnum). Acta Universitatis Upsaliensis, 37 p. (Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology ; 581). |
| En ligne : |
http://www.diva-portal.org/smash/get/diva2:166017/FULLTEXT01.pdf |
| Format de la ressource électronique : |
document |
| Permalink : |
http://www.cbnbrest.fr/catalogue_en_ligne/index.php?lvl=notice_display&id=66027 |
The ecological significance of sexual reproduction in peat mosses (Sphagnum) (2000)
