The influence of the zona radiata on the toxicity and uptake of cadmium in embryos of Atlantic salmon ( Salmo salar )
Eyed embryos of Atlantic salmon (Salmo salar) were significantly more resistant to cadmium if the zona radiata (capsule) was removed (10-day LC 50 , 4.80 mg Cd/L) than if the zona radiata was intact (10-day LC 50 , 3.20 mg Cd/L). Differences in resistance times were attributed to slower absorption o...
| Published in: | Canadian Journal of Zoology |
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| Main Authors: | , |
| Format: | Article in Journal/Newspaper |
| Language: | English |
| Published: |
Canadian Science Publishing
1983
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| Subjects: | |
| Online Access: | http://dx.doi.org/10.1139/z83-309 http://www.nrcresearchpress.com/doi/pdf/10.1139/z83-309 |
| Summary: | Eyed embryos of Atlantic salmon (Salmo salar) were significantly more resistant to cadmium if the zona radiata (capsule) was removed (10-day LC 50 , 4.80 mg Cd/L) than if the zona radiata was intact (10-day LC 50 , 3.20 mg Cd/L). Differences in resistance times were attributed to slower absorption of cadmium by decapsulated embryos than by encapsulated embryos. The metal content of naked embryos increased slowly and in direct proportion to the length of exposure. The metal content of encapsulated embryos was proportional to the logarithm of the exposure period and rapidly approached an asymptotic maximum. As a consequence, the cadmium content of naked embryos after a 24-h exposure to 8 mg Cd/L was less than 3% of that of encapsulated embryos. An opaque precipitate formed around the head and anterior portion of the body of encapsulated embryos but not of naked embryos exposed to acutely lethal cadmium concentrations. This material was probably cadmium carbonate and may have facilitated metal absorption by effectively exposing the encapsulated embryos to cadmium concentrations considerably greater than those in the ambient environment. |
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