Plant Regeneration via Shoot Organogenesis from Cotyledons in Two Wild Cucumis Species, C. Figarei and C. metuliferus
Efficient plant regeneration system of Cucumis figarei and C. metuliferus from cotyledon was developed. Excised cotyledon explants from young seedlings after 3 days of germination were cultured on MS medium containing 30 g/L sucrose, 2.5 g/L gelrite and several combinations of phytohormones. In C. figarei, the effect of the combination of BA and IAA on shoot organogenesis was investigated. Adventitious shoots were induced from cotyledonary explants and the highest regeneration frequency was 40% on MS basal medium supplemented with 1 mg/L BA. It was demonstrated that the use of IAA decreased the regeneration frequency, and the application of 2 mg/L IAA suppressed shoot organogenesis completely. Subsequently, other combinations of phytohormones were investigated to improve the regeneration frequency. Combination of 1 mg/L BA and ABA (1 or 2 mg/L) increased the regeneration frequency (ca. 60%), while the combination of 1 mg/L BA and Zeatin (0.5, 1 and 2 mg/L) did not enhance shoot organogenesis and the addition of TDZ (0.2, 0.5, 1 and 2 mg/L) inhibited shoot organogenesis. In C. metuliferus, the highest regeneration frequency was 92.5% when cotyledonary explants were cultured on MS medium with 1 mg/L BA and 0.2 mg/L IAA. Lower concentration of IAA (0.2 mg/L) stimulated shoot organogenesis, while a higher concentration of IAA (2, 4 and 8 mg/L) exhibited an adverse effect, and especially, shoot organogenesis was suppressed completely by the addition of 8 mg/L IAA to induce adventitious roots in the greenhouse.
|作成者||Yutaka TABEI Tomohiro YAMADA Toshikazu MORISHITA Takeshi OSAKI|