樹蘭根尖及葉基培植體類原球體形成與植株再生

Formation of Protocorm-like Bodies and Plant Regeneration from Root Tip and Basal Leaf Explants of Epidendrum radicans Pav. ex Lindl

本研究旨在探討影響樹蘭（Epidendrum radicans Pav. ex Lindl.）根尖及葉基培植體類原球體誘導及增殖的因子及其植株再生。樹蘭根尖及葉基培植體培養在含不同植物生長調節劑的二分之一MS基本培養基中，結果顯示根尖在0.1 mg．L^(-1)phenyl-N'-（1,2,3-thiadiazol-5-yl）urea（Thidiazuron, TDZ）條件下，形成類原球體，而葉基在對照組及含1 mg．L^(-1)6-benzylaminopurine（BAP）、1或10 mg．L^(-1)zeatin及10 mg．L^(-1)1-naphthaleneacetic acid（NAA）的二分之一MS基本培養基的條件下，誘導類原球體形成，經繼代後抽芽並發育為完整植株，全程約13週。由石蠟切片及掃瞄式電子顯微鏡觀察到，培植體表皮及次表皮細胞層形成透明球狀結構後，接續膨大轉綠，形成類原球體。根尖及葉基來源的類原球體，在40 g．L^(-1)蔗糖組合0.1 mg．L^(-1)BAP的條件下，類原球體增殖倍數達17倍。 In vitro plant regeneration of Epidendrum radicans Pav. ex Lindl. through formation of protocorm-like body (PLB) derived from root tip and leaf base explants was established and the influence factors on formation and proliferation of PLB were studied in this research. The root tip and leaf base explants were cultured on half-strength MS basal medium containing different concentrations of plant growth regulators. The results showed that root tip explants formed PLBs in the condition of 0.1 mg．L^(-1) phenyl-N'-(1,2,3-thiadiazol-5-yl) urea (Thidiazuron, TDZ) under light culture. For leaf base explants, in the conditions of half-strength MS basal medium or containing 1 mg．L^(-1) 6-benzylaminopurine (BAP), 1 or 10 mg．L^(-1)zeatin and 10 mg．L^(-1) 1-naphthaleneacetic acid (NAA), PLBs can be induced. After the subculture of PLB, shoot formed and developed into whole plantlets. The process from PLB initiation to plant regeneration takes only 13 weeks. We observed that the transparent nodular masses protruded from epidermal and sub-epidermal cell layers and then enlarged into green PLBs with paraffin section and scanning electron microscopy. Proliferation folds of PLBs derived from root tip and leaf base explants were the highest (~17-folds) on half-strength MS basal medium containing 40 g．L^(-1) and 0.1 mg．L^(-1) BAP.