| Abstract: | We have determined the conditions which give optimal growth and conchospore release in laboratory cultures of free conchocelis of the red alga Porphyra torta Krishnamurthy. With cool white fluorescent light on a 16L.8D photoregime, the fastest sustained growth (5% volume increase d?1) was observed from 10–15°C and 25–100 μE-m ?2.s?1; slightly faster growth was observed at 15°C and 300 μE.m?2.s?1, but such conditions are close to lethal. Conchoporangin will form under a wide range of conditions in conchocelis of this species. However, conchospores will mature and release only when the cultures are exposed to a short day photoperiod. The critical pholoperiod is just shorter than 12 h, The minimum number of photoinductive cycles for complete conchospore release is four for a range of conditions but can be just one depending on pretreatment. |
