In this research, to observe the influence of lght intensity and temperaure on the callus development and differentiation from blade pieces (about 0.5 x0.5 mm) exciesed from young sporophytes (about 5 mm in blade length) ofseveral species of Laminariales.
Agarum cribrosum, Alaria crassiforia, costaria costata, eckolnia cava, E.kurome, E.stolonifera, Eckloniopsis radicosa, Eisenia bicyclis, Laminaria japonica, Streptophyllopsis kuroshioensis, Undaria pinnatifida and U.undarioides were used in the experiment. Callus development and differentiation was examined under various temperatures (10, 15, 20, 25ﾟC) and light intensities (10, 20, 40, 80 mu mol m^<-2>s^<-1>) with a photoperiod of 14L : 10D for 32 days.
Callus cells were produced on the cut edge of explants after four days. These primodial callus cells were hemispherical in eight species of A.cribrosum, C.costata, E.cava, E.kurome, E.stolonifera, Ec. radicosa, Ei. bicyclis, L.japonica, except for four species of A.crassiforia, S.kurosh
ioensis, U.pinnatifida, and U.undarioides in which they were club-shaped. The callus development occurred in nine species except for A.crassiforia, S.kuroshioensis, and U.undarioides. Plastids in developed callus cells were smaller than those in original blade cells. The callus development was favorable under lower light intensities and lower temperatures ; 10ﾟCat all light intensities examined in A.cribrosum, 15ﾟC at 10-20 mu mol m^<-2>s^<-1>, in C.costata, E.kurome and E.stolenifera, 20ﾟC at 10-20 mu mol m^<-2>s^<-1>, in E.cova, 15ﾟC at 20 mu mol m^<-2>s^<-1>, in Ec. radicosa, 20ﾟC at 10 mu mol m^<-2>s^<-1>, in Ei. bicyclis and 15ﾟC at 10 mu mol m^<-2>s^<-1>, in U.pinnatifida. The differentiation of callus cells into blade occurred in seven species except for A.cribrosum and E.kurome. The earliest differentiation of callus cells into blade ocurred at higher temperatures and higher light intensities ; 20ﾟC at 80 mu mol m^<-2>s^<-1>, inC.costata, L.japponica and U.pinnatifida, 25ﾟC at 80 mu mol m^<-2>s^<-1>, in E.cava, E.stolonifera, Ec. radicosa and Ei. bicyclis. Less