磷酸二氫鈉處理對香蕉胚性細胞極化生長與體胚發生之影響

The Effect of Sodium Dihydrophosphate on Polar Growth and Somatic Embryo Formation in Cell Suspension Culture of Triploid Bananas

香蕉AAA華蕉系北蕉、'Robusta'及AAB'Raja等栽培種之胚性細胞，懸浮培養於增生培養基中並補充磷酸氫鈉鹽，顯示1.6 mM NaH2P04·2H20比Na2HP04能有效的矯正增殖相及增生相細胞之胞外pH值，以繼代培養來更新含磷酸二氫鈉的養液，可使pH逐步調昇為4.8-5.3 ,同時引發前胚性細胞（preembryogenic cells）極化生長及促使其發育為球狀體。由外控制亦印證細胞自調pH高於4.5時，為胚性細胞導向極化及前胚期發育之必要條件。懸浮細胞經磷酸氫鈉鹽前處理後，再平板培養於體胚再生培養基，可有效提高北蕉與'Robusta'增殖相細胞族群之體胚發生率，估算每個培養皿接種1/30 mL細胞沉積體積（CPV）•由對照組產生56.2-82.8個體胚，可增加至736.5-1312個體胚。而增生相細胞族群之對照組可產生798.2-1259.2體胚，前處理後雖無顯著差異，但可同步化及提早體胚成熟。

Embryogenic cells of triploid bananas AAA cv. Pei-Ch國o, cv. Robusta and AAB cv. Raja were subculture by maintained medium supplying buffer agent hydrophosphate salts. It was demonstrated that the addition of 1.6 mM NaH2P04 ·2H20 was capable to rectify the extracellular pH in the cell population of multiplication and proliferation types upgrading to 4.8 - 5.3 by the second and the first subculture generation, and concomitantly transformed the embryogenic competent cells into polar growth and formed globules or clustered globules. It was also given support that the extracellular pH threshold over 4.5 is the pre-condition for establishment of polar axis and proembryogenesis. The advantage ofNaH2P04·2H20 pre-treatment were greatly enhanced the increase of somatic embryos from 56.2-82.6 to 736.5- I 312 in the multiplication types of Musa AAA cv. Pei-Chiao and Robusta, and imwoved the quality and mature of proliferation phase derived embryoids of AAA and AAB cultivars.