New Zealand Journal of Marine and Freshwater Research abstracts
Aspects of the reproductive phenology of Lessonia trabeculata
(Laminariales: Phaeophyceae) from three populations in northern Chile
Fadia Tala
Mario Edding
Julio Vásquez
Departamento de Biología Marina
Facultad de Ciencias del Mar
Universidad Católica del Norte
P.O. Box 117
Coquimbo, Chile
email: ftala@ucn.cl
Abstract Lessonia trabeculata is a brown seaweed
inhabiting the rocky subtidal zone along the coast of central and northern
Chile, where it is the dominant kelp, and an important species in community
structure. Morphological and reproductive aspects of this alga are dependent
on environmental conditions and geographic distribution, and the present
study gives data on its reproductive periodicity. The reproductive phenology
for three populations from northern Chile (29-30°S) was evaluated by
means of seasonal examination of morphological and reproductive characteristics
of both macroscopic sporophytes and microscopic gametophytes. Comparative
laboratory cultures of spores were made to determine seasonal differences
in their capacity to produce viable plants. This species is perennial, and
demonstrates year-round presence of reproductive tissues, although showing
variation in reproductive phenology over time and among populations. The
size of blades increases in spring and summer, whereas its reproductive potential
(e.g., area and proportion of the reproductive tissue and the release of
spores) increases in autumn. Culture experiments showed that spring and summer
reproductive tissue released zoospores which had low germination rates compared
to those of autumn and winter, and which produced female gametophytes of
low fertility. The population differences depended on the character analysed
and the season of the year. The development of both phases of the life cycle
of L. trabeculata may be influenced by the local environmental conditions
and their seasonal changes, and were expressed as morphological and/or reproductive
changes in the plants. A better understanding of the seasonal adaptations
may be obtained if future comparisons are made between widely separated populations
or between individuals from the extremes of geographic distribution of the
species.
Keywords Phaeophyceae; Lessonia trabeculata;
kelp; reproductive phenology; spore culture; Chile
M03018; Received 30 April 2003; accepted 8 January 2004; Online publication
date 8 June 2004
New Zealand Journal of Marine and Freshwater Research, 2004, Vol. 38:
255-266
0028-8330/04/3802-0255 © The Royal Society of New Zealand 2004
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