1980 Volume 48 Issue 4 Pages 495-502
Bulb tissue segments excised from 12 species in the Amaryllidaceae and the Liliaceae were cultured aseptically on a nutrient agar without growth substances at 25°C in the dark.
Basal plate segments of all the species induced neither bulblet nor callus, and segments of scale base attached to basal plate tissue produced bulblets at a high rate without intervening callus regardless of species. No clear dependences on the time of isolation and on the age of individual scales were shown.
In the species belonging to the Liliaceae, not only the scale base segments but also the segments from the middle and the apical portions of the scale induced bulblets. In contrast to that, bulblet regeneration in the Amaryllidaceae was confined to the segments from the portion near scale base.
Though the bulblets were always formed in the proximal end of the segments, the manifestation of dorsiventral polarity of regeneration differed with the families. Namely, the regenerative capacity of the segments from the species in the Liliaceae and the Amaryllidaceae was high on the adaxial and the abaxial side, respectively. Orientation of the segments in relation to culture medium had some effect on the polarity of the regeneration.
In a circular scale, the leaf-blade extended side is thicker than the opposite side. When single scale segments were cultured, no difference in the regenerative capacity was shown between the thick segments and the thin ones. In double scale segments, containing two scale pieces attached to basal plate tissue, bulblets developed at a higher rate and more rapidly from the position between the two scale pieces than from either of the scale-surface exposed sides. When the double scale segments were composed of thick portion of a scale and thin portion of its neighbour scale, the surface exposed sides of the thicker scale pieces showed higher regenerative capacity than those of the thinner ones in the case of the Liliaceae and the opposite situation existed in the Amaryllidaceae. This indicates that there is some gradient in regenerative power around a circle of scale base and the position showing the highest regenerative potential varies with the family.