瓶內培養時間對粗肋草‘白馬’組織培養苗出瓶後生長之影響

Effect of In Vitro Cultural Duration on the Ex Vitro Growth of Micropropagated Aglaonema 'White Tip' Plantlets

適當的瓶內培養週數及出瓶瓶苗大小為組織培養苗出瓶馴化成功之重要因子。本試驗目的在評估不同培養週數之粗肋草組培苗出瓶後之生理變化，以找出最利於出瓶後生長之組培苗苗齡。經過16、20、24、28及32週等不同瓶內培養期之粗肋草‘白馬’組培苗出瓶後，以培養28週、帶3.7片葉者鮮重累積最快，16週者則最為緩慢，而32週者瓶內最後一片葉出瓶時淨光合作用最低，為-0.87CO2μmol•m^(-2)•s^(-1)。各培養週數處理之葉綠素螢光值在出瓶後第一天急遽下降，到第10天後開始回升，氣孔導度和蒸散速率在出瓶初期則有急速上升之情形，之後下降且逐漸趨於平穩。這些現象顯示瓶苗出瓶後具有調適環境之能力。葉片解剖方面，瓶內形成之葉片厚度及上下表皮厚度皆較瓶外生成之葉片薄，但出瓶馴化後其厚度逐漸增厚，柵狀組織細胞層數增加且排列較緊密，葉片解剖類似瓶外形成之葉片。 Adequate duration of in vitro culture and optimal plantlet size are important factors for successful ex vitro acclimatization of the plantlets in micropropagation. We evaluated the exvitro acclimatization growth of Aglonema 'White Tip' micropropagated plantlets with different in vitro cultural durations, namely: 16, 20, 24, 28 and 32 weeks. Among all treatments, the plantlets of 28 weeks, which had 3.7 leaves, had the highest fresh weight accumulation rate, while plantlets of 16 weeks had the lowest rate. The last formed in vitro leaf in the plantlet of 32 weeks had the lowest net photosynthesis rate, which was -0.87 CO2μmol•m^(-2)•s^(-1). The chlorophyll florescence value in all plantlets decreased abruptly on day 1 and began to recover on day 10 after transplanting. Stomatal conductance and transpiration rate of plantlet after transplanting increased at first and then decreased. These phenomena implicated that plantlets gradually adapted to the environmental changes during ex vitro acclimatization. The upper and lower epidermises of leaves formed in vitro were thinner than those of leaves formed during acclimatization or formed ex vitro. Leaves formed during acclimatization had more palisade cell layers, which were also more compactly arranged, approaching the normal anatomy of leaves formed ex vitro.