Effect of Polyethylene Glycol on Adventitious Bud Formation on Hypocotyl Segments of Tomato Seedling

Abstract

The effect of polyethylene glycol (PEG) on adventitious bud formation on excised hypocotyl segments of tomato seedling cv. KNVF-R, an interspecific hybrid rootstock between Lycopersicon esculentum x L. hirsutum, was investigated.
1. Segments excised from hypocotyls shorter than 8 cm, and incubated under light intensity exceeding 3 klx formed buds; the optimum segment length was 4 mm. About 95% of the segments formed adventitious buds in 1/2 strength Murashige-Skoog basal medium supplemented with 50 g•liter^-1 PEG-6000 and 30 g•liter^-1 sucrose. However, when the number of segments per flask (containing 40 ml of medium) exceeded 50, the percentage of segments which initiated buds decreased.
2. Mannitol and PEG-1500 were not effective at all. Abscisic acid (ABA) at 10 mg• liter^-1 stimulated bud formation.
3. Segments with buds of 2 mm length rooted within 2 weeks on a basal medium (1/2 MS supplemented with 30 g•liter^-1 sucrose and 8 g•liter^-1 agar)
All regenerated plants were established by transplanting to a vermiculite potting mixture.