The effects of coalescence on survival and development of <Emphasis Type="Italic">Mazzaella laminarioides</Emphasis> (Rhodophyta,Gigartinales)

The potential benefits associated with coalescence in red algae have been best documented with early stages of development. In this study, we report on the effects of the original number of spores on branching and fertility during later stages of development. Measurements for 20 months of survival rates, field growth, and fertility of a set of 96 sporelings produced in the laboratory with different number of spores, and outplanted at mid levels of the Mazzaella laminarioides belt at a locality in central Chile, indicate significant differences between multisporic holdfasts (50 and 100 coalescing spores) and uni- or oligosporic (ten spore) holdfasts in the number of branches and erect axes produced 10 and 15 months after germination. The difference is related to the persistence of clusters of axes and branch initials in deep portions of holdfasts of multisporic plantlets and their absence from equivalent portions of uni- or oligosporic holdfasts. This is an example in macroalgae of an event occurring during germination and expressing its effects in the next growing season (some 10 months after).