Characters of plants regenerated from callus and protoplasts of taro (Colocasia esculenta Schott cv. Yatsugashira) were studied. Many green compact cell masses (calloid) and small number of yellow friable calli were formed by culturing segments of etiolated stem on Murashige and Skoog's (MS) medium supplemented with 30 g･liter-1 sucrose, 1 mg･liter-1 2,4-D and 2ip. Friable calli were proliferated by subculturing on the same fresh medium, and then they were suspension-cultured in a liquid medium. Protoplasts were isolated from these suspension cells. Shoots were regenerated from calloids, friable calli and protoplast derived-calli by transferring them to MS medium supplemented with 30 g･liter-1 sucrose, 0~2 mg ･liter-1 NAA and 2 mg･liter-1 BA or 2 ip. These shoots formed roots after being transferred to basal MS media. Plantlets were acclimatized and grown in the field. Original 'Yatsugashira' formed many shoots from the main corm, whereas 2 of 4 plants regenerated from calloid formed a single shoot from the main corm. Plants regenerated from friable calli were dwarf type and grew slowly. plants regenerated from both friable calli and protoplasts formed larger number of shoots than original 'Yatsugashira'.サトイモの品種'八頭'供試、カルスおよびプロトプラストから再生した植物の形成を調査した。無菌植物を暗黒下で培養した伸長させた黄化茎の切片を、30g･liter-1ショ糖、1mg･liter-1 2,4-D+ 1mg･liter-1 2ipおよび2g･liter-1ジェランガムを添加したMS培地で培養し、カルスを誘導した。黄化茎切片から形成した組織は、ほとんどが緑色の塊状であったが、一部黄白色の柔らかいカルスも形成された。この黄白色の柔らかいカルスを同組成の培地で継代培養して増殖させた。このカルスを振とう培養として懸濁細胞を形成し、それから、プロトプラストを単離した。緑色塊状組織、カルスおよびプロトプラストを、種々の濃度のNAAとBAを添加した培地で培養し、植物体の再生させた。'八頭'は、親芋から多くの菌条が伸長する性質を持っているが、緑色塊状組織から再生した植物4個体のうち2個体は、親芋から1本しか苗条が伸長しなかった。カルス由来の再生植物や、カルスから単離したプロトプラスト由来の再生植物は、元の'八頭'植物に比べて草丈が著しく低く、苗条数、葉数が多かった
