荔枝不定胚發生之研究

Adventitious Embryogenesis of Litchi chinensis

以玉荷包荔枝（Litchi chinensis Sonn. cv. Yuherbau）花葯為培植體，可誘導體細胞胚性癒合組織的生成。胚性癒合組織在含NAA 0.1mg／l、2ip 1mg／l及ABA 0.2mg／l的SH培養基上可形成體胚。荔枝初生體胚發生後，在其發育的過程中，易產生次生體胚。在含0.5mg／l低濃度的NAA及2ip、0.2mg／l ABA與45g／l蔗糖組合的SH培養基上，最有利於次生體胚的發生。一個未成熟體胚經一個月的培養，可產生50-70個次生胚。次生體胚通常由初生體胚子葉、胚軸及胚根表面細胞直接發生，或經由初生體胚逆分化為癒合組織後再分化形成。未成熟的半透明體胚比成熟的綠色體胚有較高的能力發生次生胚。利用掃描式電子顯微鏡及組織切片可以觀察次生體胚之起源及發育。次生體胚發生能力至少可以維持兩年，經由次生體胚發生途徑能夠獲得大量再生植株，是一值得應用的再生體系。

A thorough investigation on somatic embryogenesis and plant regeneration in litchi (Litchi chinensis Sonn. cv. Yuherbau) is carried out in .this study. A large quantity of secondary embryos appear on the surface of immature primary somatic embryos when the culture medium contains the SH salts, 0.05mg/l NAA, 0.05mg/l 2ip, 0.2mg/l ABA, and 45g/l sucrose. Secondary embryos produce either from cotyledons, hypocotyls, and roots of somatic embryos directly or from embryo-derived callus. The immature somatic embryos produce more secondary embryos than the mature one. On the average, one immature somatic embryo can produce 50-70 secondary embryos after one month culture. The secondary embryos are initiated from the epidermal and subepidermal cells of somatic embryo. The secondary embryos can germinate and develop into plantlets. The in vitro grown plantlets are successfully transplanted to pots, and later in the orchard.