Abstract:

Transgenic plants appear to be a new way to citrus improvement and a powerful tool for studying gene functions. The establishment of an efficient in vitro plant regeneration system suitable for genetic transformation is the first step in this approach. Using epicotyl and hypocotyl pieces and cotyledons of Citrus grandis Osbeck cv. Shatianyou seedlings grown in vitro as explants，a efficient regeneration system was established. The results were obtained as follow. When the epicotyl pieces were explants were cultured on the adventitious shoot regeneration medium (MS salts +100 mg/L inositol +0.2 mg/LV-B1+1 mg/LV-B6+1 mg/L niacin + 3% sucrose + 5 mg/L6- BA + 0.8% agar，pH5.8) and incubated in darkness for 7 days，then in the condition of 16/8 h light/darkness cycle，adventitious shoot regenerated from 91.1% of the epicotyl explants. When the adventitious shoots were cultured on the medium (1/2MS＋1.5 mg/L IBA ＋3％sucrose ＋0.7％agar，pH5.8) , adventitious root regenerated from 80% of the adventitious shoot after grown in vitro for 40d. A s a selectable agent, concentration of Kanamycin is 50 mg/L for epicotyl pieces.