Effects of temperature and light level on the growth and development of conchocelis in Pyropia suborbiculata (Bangiales, Rhodophyta)

Several strains with long-type blade have been isolated from Pyropia suborbiculata , showing application potential for commercial Pyropia cultivation. In this study, using strain PS-M4 of P. suborbiculata , the effects of temperatures and light levels on conchocelis growth, conchosporangia formation, and conchospores release, were examined. The optimal conditions for conchocelis growth were 24 °C and 30–40 μmol photons/(m 2 ·s), whereas the conchosporangia formation ratio peaked at 30 °C and 10–20 μmol photons/(m 2 ·s), yielding the highest conchospore release under these conditions. Compared with strain PH-WT10 of P. haitanensis , the conchocelis of PS-M4 displayed higher thermotolerance and superior conchospore yield. These attributes underscore the suitability of PS-M4 for convenient and climate-resilient conchocelis cultivation.