Sie können Bookmarks mittels Listen verwalten, loggen Sie sich dafür bitte in Ihr SLUB Benutzerkonto ein.
Medientyp:
E-Artikel
Titel:
Population Development, Demographic Structure, and Life Cycle Aspects of Two Hornworts in Switzerland
Beteiligte:
Bisang, Irene
Erschienen:
Nordic Bryological Society and Dutch Bryological and Lichenological Society, 2003
Erschienen in:
Lindbergia, 28 (2003) 3, Seite 105-112
Sprache:
Englisch
ISSN:
0105-0761;
2001-5909
Entstehung:
Anmerkungen:
Beschreibung:
Population development and structure of the regionally annual hornworts Anthoceros agrestis and Phaeoceros carolinianus were studied in cultivated fields in the lowland of NW Switzerland. Ontogenetic stages of gametophytes and sporophytes were repeatedly surveyed at short time intervals in plots excluded from routine management during one growing season, and recruitment of A. agrestis was recorded in the subsequent season. A. agrestis was more abundant than P. carolinianus at the site scale, and its population development appeared to be more dynamic. The results suggest that in A. agrestis, gametophyte mortality is density-dependent in the early phase of its population development, and a minimum size for sexual reproduction occurs. Gametophyte recruitment probability from spores for A. agrestis was estimated at 4.8×10⁻⁵. Mean gametophyte growth rate was 0.1 mm/d for both species. P. carolinianus gametophytes lived longer and grew larger than those of A. agrestis. Gametangial initiation, fertilisation, sporophyte development, and spore maturation occurred within a few weeks after germination in both taxa. Spore maturation peaked in August but sporophytes developed during the entire growing season in many plants.