Plant Regeneration from Ipomoea triloba L. Protoplasts

Abstract

Plants were regenerated from protoplasts of Ipomoea triloba L., one of the related species of sweet potato (I. batatas (L.) LAM.) at a high frequency. Protoplasts were isolated from in vitro-grown plants of I. triloba L. and then cultured in a modified liquid MURASHIGE and SKOOG (MS) medium containing 0.5mg/l 2, 4-dichlorophenoxyacetic acid (2, 4-D) and 1.0mg/l kinetin. First cell division occurred within 3-4 days. After 2 weeks protoplast plating efficiency was up to about 60%. After 12 weeks protoplast-derlved calli up to 2 mm in diameter were transferred onto solid MS medium supplemented with 0.2mg/l 2, 4-D for the proliferation. Three weeks after transference, they were further transferred onto MS medium supplemented with 0- 0.1mg/l 3-indoleacetic acid (IAA) and 1.0-5.0mg/l 6-benzylaminopurine (BAP) (regeneration medium) and after 2 weeks started to form adventitious roots. Subsequently, the calli were further cultured on MS medium without plant growth regulators and started to regenerate shoots 5 days after transference. When 2.0mg/l BAP was added to the regeneration medium, the regeneration frequency of protoplast-derived calli up to 36.7% was achieved. It was found that (0.2mg/l) 2, 4-D included in the proliferation medium played an important role in promoting shoot regeneration. After the regenerated shoots were transferred onto fresh MS medium without plant growth regulators, they developed into whole plants which were grown to maturity in pots with vermiculite.