石斛离体培养中ABA对诱导花芽形成的影响

由兰科植物铁皮石斛（Ｄｅｎｄｒｏｂｉｕｍ ｃａｎｄｉｄｕｍ Ｗａｌｌ．ｅｘ Ｌｉｎｄｌ．）种子诱导形成的愈伤组织，在光照下置于ＭＳ附加０．３ ｍ ｇ／ＬＮＡＡ 的培养基上繁殖，可以形成原球茎。将原球茎转入ＭＳ含２ ｍ ｇ／Ｌ ６－ＢＡ 和０．５ ｍ ｇ／ＬＮＡＡ 的培养基上，花芽形成频率为２７．０％ 。原球茎先在０．５ ｍ ｇ／ＬＡＢＡ的培养基上预培养１５ ｄ，再转入含２ ｍ ｇ／Ｌ６－ＢＡ 的ＭＳ培养基上培养，花芽形成频率明显提高，可达８４．４％ ，而且每株植株花的数目增加；但是在仅有ＡＢＡ 的ＭＳ培养基上培养的原球茎再生的植株未见花芽形成

EFFECT OF ABA ON THE IN VITRO INDUCTION OF FLORAL BUDS OF DENDROBIUM CANDIDUM WALL. EXLINDL.

An in vitro flowering system of Dendrobium candidum Wall. ex Lindl., a wild species of orchid, was established. Callus was induced from seeds and protocorms formed on MS agar medium supplemented with 0.3 mg/L NAA under diffused light. Floral buds were induced when protocorms were cultured on MS agar medium supplemented with 2 mg/L 6 BA and 0.5 mg/L NAA, the frequency of floral bud induction being 27.0%. When protocorms were precultured on MS medium supplemented with 0.5 mg/L ABA for 15 days and then transfered onto MS medium supplemented with 2 mg/L 6 BA, the frequency of floral bud induction increased greatly reach 84.0% during a period of 5 months. Meanwhile the number of branches and floral buds also increased and in some instances inflorescence appeared. Never the less, no floral bud was formed if protocorms continued to be cultured on the ABA containing MS medium.