甘藍組織培養不定芽發生及再生模式

Caulogenesis and Model of Regeneration in Cabbage (Brassica oleracea L. var. capitata) Tissue Culture

生長素picloram、2,4-D及PAA在不同濃度下具有誘導甘藍下胚軸段節不同形態發生效果。MS基本培養基單獨添加picloram 0.05 mg/l誘導不定芽發生，0.01 mg/l時則朝向直接不定根發生，提高為O.lmg/1則易逆分化產生癒合組織。2,4-D濃度低至O.Ol mg/l亦可誘導不定芽發生。而PAA誘導不定芽發生濃度為0.5〜2.0 mg/1。當picloram 0.05 mg/1組合BA 0.5 mg/1，則對不定芽誘導呈相加效果。「初秋」、「春陽」及「高峰」三品種顯示均有85%不定芽發生率、平均芽數可達28～31個，「中甘十一號」發生率可高達100%。 picloram濃度至0.1 mg/l，「初秋」及「春陽」不定芽發生率分別降低為16.5%及36.2%。添加乙烯作用抑制劑AgN0₃或STS，前者不定芽再生率兩品種提舁為81.2%及45.3%；而後者提昇為76.2%及47.6%，顯示高濃度picloram可能會誘導「初秋」品種之乙烯的生成，進而抑制不定芽之再生，然而對「春陽」品種較無影響。花托培植體，單獨添加任一生長素則無法誘導產生不定芽，參試picloram 0.05 mg/l與BA 0.5 mg/1組合則可有效誘導不定芽發生，兩品種再生率皆達95%以上。培植體以組織切片觀察，picloram 0.05 mg/1誘導下胚軸段節，從生理頂端形或擬分生中心，然後再分化多數的不定芽芽原體。另一再生形態為生理頂端組織逆分化為癒合組織，形成初生不定芽後，再由兩葉原體間增生多數次生之不定芽始體。picloram 0.05mg/l與BA 0.5mg/l組合，為由維管束周圍細胞逆分化並散生形成擬分生中心，十天後分立之擬分生中心形成初生不定芽，並可從表層持續增生不定芽原體。花托組織培植體，五天後由未分化的雄蕊 原體內部形成芽原體，每個芽原體自成擬分生組織增生不定芽。

The hypocotyl sections, receptacle and filament of cabbage were used as explants cultured on MS medium supplemented with various plant growth regulators. It was demonstrated that the auxin had multiple effect on morphogenesis, varied with explant source, auxin type and concentrdtion. For the hypocotyl sections, the picloram initially induced rhizogenesis, caulogenesis and callogenesis at the level of 0.01, 0.05 and 0.1 mg/1 respectively. In contrast, 2,4-D stimulated caulogenesis, rhizogenesis and callogenesis at 0.01, 0.05 and 0.1 mg/1. PAA ranging from 0.5 to 2.0 mg/1 induced caulogenesis. The combination of 0.05 mg/l picloram and 0.5 mg/1 BA showed additive effect on proliferation of adventitious buds through indirect caulogenesis. Hie frequency of adventitious buds of K-Y Cross'., Spring Light' and Summer Summit' cultivars were about 80 %, and obtained 28 to 31 shoots per explant within a month. The regeneration frequency of Chung-Kan No. 11 was highest up to 100%. It was shown that higher picloram (0.1 mg/l)decreased the frequency of bud formation. Addition of AgN0₃ and STS respectively enhanced regeneration to 81.2% and 76.2% in 'K-Y Cross'. The ethylene inhibitor were less effective in 'Spring Light' for bud regeneration. Interpreting that the inhibition of higher auxin concentration on adventitious bud formation might be mediated through ethylene evocation. In the cultured of receptacle tissues, no morphogenetic event as observed with auxin alone. When a combination, of 0.05 mg/1 picloram and 0,5 mg/1 BA were used, more than 95% of explants from , K-Y Cross' and Spring Light' indued bud proliferation. The anatomical feature in sole picloram induction of caulogenesis was initiated from the distal end of hypocotyl sections. The neighbor tissue of vascular bundle dedifferentiated into meristemoids. then regenerated adventitious buds 14 days after culture. In combination of picloram and BA, emitting cells from the neighbor tissue of vascular bundle differentiated into discreted meristematic center and primary buds. Multiple shoot proliferated from the periphery of meristematic belts or primary buds. In culturing receptacle tissue, the caulogenesis mainly derived from the pre-existing undeveloped stamen primodium, that perform as meristematic structure body. The internal bud primordium initiated as early as 5 days after culture. Thereafter, the based of raising primary bud and callus-mediated meristemoids proliferated numerously adventitious buds.