Inorganic carbon uptake by photosynthetically active protoplasts of the red macroalgaChondrus crispus

✍ Scribed by R. G. Smith; R. G. S. Bidwell

• Book ID: 104752496
• Publisher: Springer-Verlag
• Year: 1989
• Tongue: English
• Weight: 555 KB
• Volume: 102
• Category: Article
• ISSN: 0025-3162
• DOI: 10.1007/bf00391317

✦ Synopsis

Photosynthetically active protoplasts were isolated from Chondrus crispus Stackh. by treating thalli with z-carrageenase produced from batch culture of Pseudomonas carrageenovora. Using the silicone oil centrifugation technique, it was found that the protoplasts: (1) did not generally accumulate inorganic carbon (C0 above the concentration in their incubation medium; (2) were saturated at C~ concentrations of 3 to 4 raM; (3) had an intracellular pH of 7.50 when incubated at pH 7.5; and (4) their initial carbon fixation rate was reduced by carbonic anhydrase inhibitors. Although the carbon fixation rate of the protoplasts was about 30% that of thallus fragments, presumably due to the relatively harsh protoplast isolation treatment, the behavior of the protoplasts was similar to that of fragments. This similarity indicates that the protoplasts are photosynthetically active and behave as thallus fragments. Further, the data are consistent with the hypothesis that C. crispus acquires C i for photosynthesis by the diffusion of CO2 across the plasma membrane.