STUDY ON GAMETOPHYTE VEGETATIVE GROWTH OF UNDARIA PINNATIFIDA AND ITS APPLICATIONS

When cultured under certain environmental coriditions (25℃, light intensity 80 μmol/m·s, LD12/12, in enriched seawater medium with 7 × 10mol/L NO,-N, 1.56× 10mol/L, PO-P and supplementsof other elements like Mn, Fe, I, etc.), mate and female gametophytes of U pinnatifida keptgrowing vegetatively and propagated fast at average daily fresh weight increase rate of about 20%. Theempirical formula G=G. 3was established to estimate the output of vegeative gametophytes. Vigorousvegetative gametophyte cells began to form reproductive structures (oogonium and spermatangium, whenthe tmperature was lower than 25℃ and other environmental factors wrre kept optimal. The sufficientsupply of gametophyte cells provided enough seeds for raising Undaria sporelings on prodiction scale.Controlled cross-breeding experiments using selcted male and female gametophyte clones which increasetheir cell number by mitosis instead of meiosis were also carried out in vitro. Juvenile sporophytes fromthe cro