ISSN:
1432-1793
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract Branching heads of symbiotic corals were pulse labeled with either 14C-acetate or 14C-bicarbonate for 1.33 h and the distribution and loss of label was then followed for 16d. The patterns of incorporation and washout were similar for both tracers. Non-solvent-extractable radioactivity (1/3 of the total) was divided into a CaCO3 and an organic fraction, both of which exhibited small if any decrease in radioactivity over 16d. In contrast, total solvent extractable (lipid) radioactivity (2/3 of the total) decreased during the washout period with the first half-life for bicarbonate at 2 d, the second at 4 d and the third could not be measured because of the persistence of a constant amount of radioactivity (18% of Day 1 value) from Day 8 to 16. Of the total retained activity, the zooxanthellae fraction contained between 8–18% from Day 1 to 5. The percentage of total animal (host) radioactivity in lipids rose from 35–40% at 0 time after tracer exposure to 70–90% at 60 min. The majority of 14C fixed into lipids was recovered in the fatty acyl moieties and not in the glycerol moiety as had been previously reported a number of times. These studies suggest that photosynthetically fixed carbon is immediately synthesized into lipid, which is translocated to the host. Analyses of the fatty acid compositions of triacylglycerols (TG) and wax esters (WE) of 40 species of coral from a small patch reef were made. In aposymbiotic species the absence of zooxanthellae appeared to be correlated with higher levels of total lipid, lower percentages of saturated fatty acids and lower TG/WE ratios than in species with symbionts.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00405994
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