Fig. 1

Morphology of calli on regeneration medium. Photographs a to e correspond to typical morphologies of calli Types-A to E, respectively. Photographs f and g are sections of green objects found on Type-C callus and adventitious shoots on Type-A callus, respectively. Objects were embedded in 5 % agar and sectioned into 50-μm slices using a Microslicer DTK-1000 (Dosaka EM, Kyoto, Japan). Before making microscopic observations (Olympus BX50 equipped with Olympus DP70, Olympus, Tokyo, Japan), the sections were stained with safranin