Efficient and simple plant regeneration via organogenesis from leaf segment cultures of persimmon (Diospyros kaki Thunb.)

An efficient and simple plant regeneration system via organogenesis from le af segments of persimmon (Diospyros kaki Thunb.) cultivars 'Fuyu' and 'Nish imurawase' has been developed. The regeneration capacity was influenced by the culture vessels, gelling agents, plant growth regulators, and light con ditions. Leaf explants taken from in vitro shoots were cultured on a modifi ed Murashige and Skoog medium (MS 1/2 N) for 16 wk without transfer to fres h medium. Adventitious shoots appeared after 4 and 8 wk in culture of 'Nish imurawase' and 'Fuyu' tissues, respectively. The culture of leaf explants i n Erlenmeyer flasks with medium containing 4 g l(-1) agar enhanced shoot fo rmation in comparison to media with increased agar concentrations. Optimal shoot regeneration was obtained with 5 mg l(-1) (22.8 muM) zeatin and 0.1 m g l(-1) (0.05 muM) indole-3-butyric acid (IBA) for 'Nishimurawase', and 10 mg l(-1) (45.6 muM) zeatin and 0.1 mg l(-1) (0.05 muM) IBA for Tuyu'. Shoot regeneration frequencies in both cultivars were 100%, and shoot numbers pe r explant reached up to 9.2 for 'Nishimurawase' and 2.2 for 'Fuyu'. Dark in cubation during the first 4-5 wk was the most effective condition to succes sfully influence shoot regeneration in both cultivars. While dark incubatio n was essential for adventitious shoot formation by 'Fuyu', it was only sli ghtly beneficial to 'Nishimurawase'. More than 80% of the regenerated shoot s rooted within 4 wk on hormone-free MS 1/2 N medium after having been dipp ed for 30 s in 250 mg l(-1) (1.1 mM) IBA solution.