ISSN:
1573-5176
Keywords:
Gracilaria
;
epiphytes
;
allelopathy
;
interaction
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract In a previous study (Svirski et al., 1993), it was found that growth inhibition ofGracilaria spp., when cultured in the presence ofUlva cf.lactuca, was not due to shading or nutrient depletion, but seemed to be caused by competition for inorganic carbon or some type of allelopathy. In the present study, we attempted to differentiate between these two possible influences by (1) growing the two algae in biculture under various conditions, but keeping inorganic carbon levels constant and measuring net photosynthesis, respiration and growth rates, and by (2) measuring growth rates ofGracilaria spp. in the presence of extracts derived from media previously used to growUlva cf.lactuca. Both net photosynthesis and growth rates ofGracilaria spp. in biculture were inhibited, despite CO2 (and also HCO3 −) levels being kept constantly high in the culture media. It is likely that these responses were due to markedly enhanced rates of dark respiration inGracilaria spp. when grown together withUlva cf.lactuca. Growth ofGracilaria spp. was also inhibited by extracts derived from seawater in whichUlva cf.lactuca had previously been grown. The strong inhibition by ethyl acetate and chloroform extracts indicate an allelopathic effect onGracilaria spp.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF02186217
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