1984 Volume 53 Issue 1 Pages 59-65
To promote the development of bulblets formed from leaf segments of Lilium rubellum Baker, the bulblets were excised and subcultured in a modified Murashige and Skoog medium (12) (a basal medium) supplemented with different concentrations of α-naphthaleneacetic acid (NAA) and 6-benzylaminopurine (BA), alone or in combination, both in diffused light at 150-300lx and in continuous darkness. In addition, the leaf emergence from the bulbs obtained by subculture was examined in the field.
1.NAA was the major factor in increasing fresh weight and root numbers of excised-bulbs. The optimum concentration was 0.1mg/l when NAA alone was added to the basal medium.
2. Effects of BA on the development of excised-bulbs varied with the concentrations of NAA added to the basal medium. BA at concentrations of 0.001mg/l synergistically increased the fresh weight of the excised-bulbs. In addition, excised-bulbs formed new adventitious bulblets when they were cultured in the basal medium supplemented with more than 0.01mg/l NAA and less than 0.1mg/l BA. However, the addition of 0.1mg/l BA in combination with NAA at any concentration added to the basal medium repressed the development of excised-bulbs and the formation of bublets.
3. When the excised-bulbs were cultured in diffused light in the medium containing 1mg/l NAA and 0.1mg/l BA, the highest increase in fresh weight of the bulbs occurred, but these concentrations of the growth regulators caused the aberrant growth of the bulbs. Thus, the bulbscales scarcely grew and the basal part of the bulbs (disc) enlarged abnormally.
4. Rooting of excised-bulbs was enhanced by the addition of only NAA at concentrations of 0.1 or 1mg/l to the basal medium. However, BA at any concentration lessened the rooting of excised-bulbs and at 0.1mg/l, almost completely inhibited rooting when combined with NAA at any concentration.
5. Increases in fresh weight, rooting and adventitious bulblets were generally superior in the excised-bulbs which had been cultured in diffused light when compared to those cultured in darkness.
6. The leaf emergence in the field was more excellent in the bulbs subcultured in diffused light than in the bulbs subcultured in darkness. NAA and BA supplemented in the subculture had scarcely any effect on the leaf emergence from the bulbs in the field. In some cases the addition of NAA and BA suppressed the leaf emergence, and the supression was quite noticeable in the bulbs subcultured in darkness in medium including 0.1mg/l BA and NAA at any concentration.
It can be concluded from these results that the extreme development of bulbs excised from leaf segments of L. rubellum Baker was performed by subculturing the excised-bulbs in diffused light in a modified Murashige and Skoog medium supplemented with 0.1mg/l NAA and 0.001mg/l BA.