IN VITRO DEVELOPMENT OF THE ISOLATED SHOOT APICAL MERISTEM OF ANGIOSPERMS

Development of complete plants was achieved from isolated shoot apical meristems of Nicotiana tabacum L., Daucus carota L., Nicotiana glauca Grah., Tropaeolum majus L., and Coleus blumei Benth. The explants consisted of only meristematic dome tissue with no visible leaf primordia. A simple nutrient medium composed of the Murashige and Skoog salt mixture, 100 mg/liter myo ‐inositol, 0.4 mg/liter thiamin‐HCl, 1‐2 mg/liter IAA, 30 g/liter sucrose, and 1% agar was adequate. Histologically there occurred principally tissue enlargement during the first 3‐6 days, followed by appearance of bipolar organization in 6‐9 days and formation of a well‐defined root apex and initiation of first leaf primordium by 12 days.