Revista Chilena de Historia Natural 77 (4): 639-647, 2004
RESEARCH ARTICLE
Variability in per capita oogonia and sporophyte production from giant kelp gametophytes
(Macrocystis pyrifera, Phaeophyceae)
Vegetative growth and fertility of kelp gametophytes are thought to be antagonistic, such
that most successful kelp recruitment is assumed to result from fertilization of single oogonia released from unicellular female
gametophytes. We used laboratory culture experiments to study the effect of temperature and nutrient addition on the per capita
production of oogonia and sporophytes from Macrocystis pyrifera female gametophytes. Our results indicate that individual
multicellular female gametophytes can give rise to more than one oogonium and that per capita oogonia production significantly
increases with the enhancement of culture conditions (i.e., decreased temperature and increased nutrient concentration). Furthermore,
the production of multiple oogonia per female often led to the production of multiple sporophytes per female. We discuss the
importance of these results relative to variability in M. pyrifera life histories (e.g., annual vs. perennial) and their likely
ecological and evolutionary consequences.
Key words:
gametophytes,
Macrocystis pyrifera, nutrients, oogonia production, sporophyte production, temperatura
