1995 Volume 63 Issue 4 Pages 843-852
Lilium japonicum growing in the experimental field were collected in early May and segments of their scales, leaves and stems of the plants were cultured in vitro on a basal medium consisting of Murashige and Skoog's inorganic salts (1962) supplemented with several organic nutrients. Young leaf-segments were a suitable source for propagation, because they were least contaminated and almost had the same capacity as scale seg- ments for bulblet regeneration. Bulblets were proliferated by culturing whole scales or segments on the basal medium supplemented with 0.1 mg•lliter-1 NAA and 0.01 mg•lliter-1 BA. A cold treatment at 4 °C for more than 12 weeks broke the dormancy of in vitro cultured bulblets. In vitro light conditoin affected both post-in vitro bulblet-rot infection and plant growth in soil. The bulblets incubated in the dark were more sus- ceptible to soil-born organisms than were those incubated in the light. Nearly all the bulblets of more than 400 mg in weight grew into plants with elongated axes (epigeous type plant; ETP). The ETP plantlets required at least 2 years' cultivation before they flowered.