Abstract
Shell infiltration of free-living conchocelis of the three commercial Pyropia species ( P. yezoensis , P. seriata , and P. dentata ) were examined in various conditions of temperatures (20–25°C), light intensities (1, 10, 40, and 80 μmol photons m -2 s -1 ), conchocelis quantities (100, 150, 200, 250, and 300 mg) and sizes (108, 209, 324, 411, and 519 μm). The optimal shell infiltration conditions were 20°C and 40 μmol photons m -2 s -1 in all species. The infiltration densities were 44.81–146.15 conchocelis cm -2 for P. yezoensis , 51.40–190.49 conchocelis cm -2 for P. seriata , and 22.24–92.49 conchocelis cm -2 for P. dentata . Inefficient shell infiltration was observed with the different conchocelis quantities from 100 to 300 mg. A positive corelationship was observed between shell infiltration density and the amount of conchocelis. The optimal blending time for maximizing infiltration density was 40 s for P. yezoensis and P. seriata and 25 s for P. dentata . This blending time correlated with a cell count of 5–7 cells. Total conchocelis lengths of 5–7 cells were approximately 300 μm for P. yezoensis and P. seriata (with cell size of about 45 μm) and approximately 400 μm for P. dentata (with a cell size of about 65 μm). These results suggest that, to achieve optimal shell infiltration density for P. dentata , the blending time should be reduced by half, and the amount of conchocelis should be increased twofold, making it comparable to the other two Pyropia species.