PROBLEM TO BE SOLVED: To provide a medium for alga, vegetatively growing (vegetatively propagating) the alga without maturing the alga even without strictly regulating a temperature, a light wavelength, a quantity of light, or the like, and facilitating the preparation. SOLUTION: The medium used for propagating and producing seeds and seedlings of the alga by tissue culture is provided. Steviosides and steviols are added thereto as a mature inhibitor of the tissue culture. When a seaweed of Laminariaceae or the like is produced by the tissue culture, a haploid generation such as a gametophyte and a spore is used as the tissue, and a seawater medium is used as the medium. COPYRIGHT: (C)2009,JPO&INPIT
