Cotyledon and hypocotyl segment cultures were initiated from in vitro grown 19-day old seedlings of Siningia speciosa cv. Red and White Edge on Murashige-Skoog medium supplemented with kinetin, IAA, NaH₂PO₄·H₂O, adenine SO₄ and activated charcoal. Effect of regenerated shoot length and levels of IBA on in vivo rooting were also determined. For in vitro mutation breeding colchicine and EMS were employed on shoot tips taken from regenerants and then cultured on shoot proliferation medium, and characteristics of flowered plants were investigated in comparison.
Regeneration ability of cotyledon and hypocotyl explants depended on the kinds and concentrations of additives to the MS basal medium. However, in general shoot forming capacity was slightly higher with cotyledon explants. The same tendency was observed in reculturing shoot tips and also in stem segments taken from regenerated microplants through cotyledon cultures.
For rapid shoot multiplication, addenda to the MS basal medium were as follows (in ㎎/ℓ) 10.0 kinetin, 0.1 IAA, 50∼100 NaH₂PO₄·H₂O and 40 adenine SO₄. Activated charcoal added to the shoot proliferation medium had sharply decreased the number of shoot formation but increased plant height, leaf number and leaf area, thus making favorable for reestablishment into soil.
In vivo rooting was greatly enhanced by soaking regenerated shoots in 1.0 to 3.0㎎/ℓ IBA solution for 24 hr and root weight of a shoot after 3 weeks of cuttings was markedly increased in relation to shoot length when treated with IBA solution.
A variant in plant size and flower color appeared from 0.001 EMS treated shoot tips but plants derived from recultured leaf and petiole explant of a variant were morphologically normal and exhibited normal flowering after establishment into soil. Plants from shoot tips which were treated with various concentrations of colchicine were found to be phenotypically normal.
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