A COMPARISON BETWEEN 2 POPULATIONS OF LESSONIA-TRABECULATA (PHAEOPHYTA, LAMINARIALES) MICROSCOPIC STAGES

Lessonia trabeculata is the most important brown seaweed in northern C hilean subtidal environments. It usually grows in areas with high to m oderately high water movement, and only occasionally in sheltered habi tats. These different hydrodynamic environments produce morphologicall y and physiologically distinct plants. The purpose of this study was t o determine probable differences in reproductive features between two L. trabeculata populations exposed to different water movement intensi ties. The zoospore production, settlement, germination, gametophyte fe rtility and survival were studied. Zoospore release and spore attachme nt capacity were higher from blades from El Frances Beach, the localit y with higher water movement energy. Germination at 24 hours was highe r in the germlings from El Frances Beach than those from La Herradura Bay. However, after 4 days of culture germination rates were similar. Average survival rates of gametophytes were similar for both populatio ns. After 20 days culturing gametophytes from El Frances Beach fertili zation was observed, while in samples from La Herradura Bay the sporop hytes were seen at 27d. The results suggest a higher reproductive vita lity in plants of Lessonia trabeculata living in an environment with a n active water movement, than plants growing in a sheltered environmen t.