香蕉胚性細胞懸浮培養的維持、增生、體胚發生與小植株建立

Somatic Embryogenesis, Proliferation, Plantlet Establishment and Maintenance of Suspension Culture in Triploid Bananas (Musa AAA and AAB)

‘北蕉’、'Robusta'、‘三尺蕉’、'Cavendish BF'（於1993年命名為台蕉二號）、‘粉蕉’等由雄花序衍生之胚性細胞之懸浮培養細胞團，以60目以下之細胞團稀釋30倍，取1 c.c散播於含4.5 mL SH修正培養基（SH鹽類加上0.2 mg•L^(-1)NAA、0.2 mg•L^(-1)2ip、0.1 mg•L^(-1)kinetin、0.05 mg•L^(-1)zeatin）及棉花濾紙墊之9 cm培養皿中培養，其體胚正常度均依接種細胞團之主要表現型態而定。未成結構體的單或雙聚細胞團於撒種後，只能長成癒合組織，聚合或游離之多胞結構體，於撒種後可以形成叢聚或單獨體胚，數量多但不易轉白成熟；而游離或聚集的團胞、球狀體、橢圓體、平頭體（初期）均可於撒播後形成正常之體胚，而且植株轉換率高；平頭體（中晚期）於撒播後會形成具有明顯生長點突起的體胚，植株轉換易生成矮胖植株；平頭伸長體、初期暗化伸長體、暗化伸長體於撒播後依次分別形成具有漏斗狀的畸形體胚、具有各種小胚聚生的根狀體、梨形畸形胚；梨形暗化體Ⅰ、Ⅱ、Ⅲ於撒播後形成褐色細胞團或癒合組織化的細胞團；重組體則於撒播後形成部分小胚叢生的癒合組織。另懸浮細胞長期繼代培養基用硝酸態氮與銨態氮比為1:1或1:2時，可以使懸浮細胞長期維持在非極化生長之胚性細胞群或小細胞群的狀況，而2:1時則可誘使細胞群極化生長朝向具球狀體細胞結構的分化，而有利平板培養產生正常体胚及小植株的建立。 The young male flower derived embryogenic suspension cell population of 'Pei Chiao', 'Robusta', 'Dwarf Cavendish', 'Cavendish BF' (registered as Taichiao No.2 in 1993), 'Fen Chiao' were used for plating with the culture condition as following: using the filter paper and cotton as the culture bridge and the size of inoculated cell clusters was smaller than 60 mesh, and diluted 30x; one milliliter of the diluted cell suspensions was dispersed on the plates. The 4.5 mL culture medium consisted of SH salt and a mixture of 0.2 mg•L^(-1) NAA, 0.2 mg•L^(-1) 2ip, 0.1 mg•L^(-1) kinetin and 0.05 mg•L^(-1) zeatin. The frequency of normal somatic embryos mainly depended on the types of inoculated cell clusters. After plating, unorganized single or double cell clusters only grew into callus. Aggregated or free tri-cellular or tetra-cellular cell clusters may become gathered or single somatic embryo, massive but they seldom turned white and matured. Free or gathered pro-embryos, globular bodies, oval bodies, early stage flat bodies all may become normal somatic embryos and the plantlet regeneration rate was high. During middle and late stage the flat bodies may become somatic embryos with clear pop-up growth point and are readily transform into short and fat plantlets. After plating, prolonged flat bodies, early prolonged dark bodies and prolonged dark bodies, became funnel-shaped somatic embryos, root-shaped bodies with all kinds of small embryos gathering together, and abnormal pear-shaped embryos, respectively. Dark pear-shaped bodies Ⅰ, Ⅱ, Ⅲ turned into brown cell cluster or cell cluster like callus. Re-organized bodies became callus with a few gathered small embryos. When the suspension culture maintenance medium contained a nitrate/ammonium ratio of 1:1 or 1:2, it could keep the suspension cell population remaining apolar growth in the type of embryogenic cell cluster or pro-embryo structure for a very long time. While nitrate /ammonium ratio was 2:1, suspension cells could be induced to polar growth and formed globular bodies which was advantageous for plating culture to produce normal somatic embryos and plantlet establishment.