燈果秋海棠（Begonia lanternaria Irmsch.）葉片誘導植株再生之研究

Induction of plant regeneration from lamina explants of Begonia lanternaria Irmsch

燈果秋海棠（Begonia lanternaria Irmsch.）是分布在中國西南潮濕石灰岩地區的特稀有物種，擬以組織培養方法建立大量繁殖系統，提供學術研究、園藝利用、境外保育的需求並降低盜採的壓力，因此本研究的目的在試驗不同的植物生長調節劑組合對燈果秋海棠葉片培植體不定芽再生和發根的效應。實驗取其葉片作為培植體，接種於1／2 MS基礎培養基，培養基中添加不同濃度之BA、zeatin或mT並與不同濃度NAA組合而成，在處理8周後，生長在添加8.0 μM BA與0.8 μM NAA組合的培植體可得到45%之不定芽再生率，為所有植物生長調節劑組合表現最高，以此處理所生之不定芽以不同濃度之NAA進行發根試驗，在培養4周後發現培養基添加0.54 μM NAA最佳，可得接近92％的不定根發根率。由組織學上的觀察可發現，其不定芽是由原始培植體直接分化而來，可避免間接再生產生的遺傳變異，在種原保存的應用上更為可靠。

Begonia lanternaria Irmsch. is a rare species endemic to limestone karsts of southwest China. The development of tissue cultural method to establish its mass breeding system could meet the demand of academic research, horticultural utility, ex situ conservation and reduce the threaten of illegal collection. Hence the aim of the study is to examine the effect of different combination of plant growth regulators on the regeneration of adventitious bud and rooting of the lamina explants of B. lanternaria. The lamina explants were cultured on 1/2 MS medium containing various concentration of BA, zeatin or mT in combinations with or without NAA. After 8 weeks of incubation, the explants cultivated on the medium containing 8.0 μM BA and 0.8 μM NAA had the highest adventitious bud regeneration rate at 45.3%, and the most amount of the adventitious buds. Subsequently, the induced adventitious buds were transferred onto rooting medium consisting of 1/2 MS and various NAA concentrations. After 4 weeks, the adventitious root regeneration rate of the explants cultured in the medium containing 0.54 μM NAA were 92%, highest of all treatments. Histological observation showed that the adventitious buds were directly differentiated from the original cultured explants. This could avoid the genetic variation caused by indirect regeneration, and is more reliable in the application of species conservation.