Tissue culture conditions for seedling production method of Ulva prolifera using extract from the thalli

Abstract

In the seedling production method using Solution Extracted from Homogenized Thalli (SEHT), tissue culture conditions for increasing branch formation from Ulva prolifera subfragments have not been completely optimized yet for land-based cultivation. Thus, we examined the tissue culture conditions of temperature, nutrients and salinity for increasing branch formation from U. prolifera subfragments in the seedling production method using SEHT. For temperature, the average rate of branch formation was 0 ％ at 5 ℃, 2.8％ at 10 °C, increasing to 28.4 ％ at 15 °C and reached a maximum of 64.0 ％ at 20 °C. Subsequently, it decreased to 40.0 ％ at 25 °C. For nutrients, the average of branch formation was 67.2 ％ when PES as nutrients was not added. When PES was added, the average rate was 72 ％, 65.6 ％, 65.6 ％, 70.4 ％, 70.4 ％, and 70.8 ％ at a PES concentration of 0.0125 ％, 0.025 ％, 0.05％, 0.1％ and 0.2 ％, respectively. The average rate of branch formation was almost constant regardless of the different PES concentrations. For salinity, the average rate of branch formation was 29.2 to 31.6 ％ in salinities of 4.8 to 10.6 psu being almost constant, but 38.0 ％ in salinity of 16.0 psu and 54.0 ％ in salinity of 27.9 psu indicating increased branch formation in more saline conditions. In the seedling production method using SEHT, we recommend culture conditions for increased branch formation of U. prolifera subfragments as culturing temperature of 20 ℃, salinity of 27.9 psu and without adding nutrients.