青蘋果竹芋瓶內芽體增殖及其出瓶馴化生理

Abstract

短暫淹灌系統(Temporary immersion system, TIS)結合了液態培養之優點和通氣性的特性，本研究利用短暫淹灌系統培養青蘋果竹芋；並與半固態培養相比，期能增加繁殖倍率和植株生長速率。此外，也探討培養系統、培養基糖以及光強度對組培苗出瓶光合作用能力與生長之影響，期望找出適合青蘋果竹芋的培養基蔗糖濃度、培養系統和馴化光度，以利組培苗的後續生長。 短暫淹灌系統中，以每培植體80 mL液態培養基對於芽體形成表現較佳。青蘋果竹芋於全量MS培養基，添加4%蔗糖、2.2 μM NAA及26.7 μM BA誘導芽體數較多。隨著培養基TDZ濃度由0 µM增加至3.64 µM，可誘導較多芽體，但高TDZ濃度(2.73、3.64 µM)會導致芽體叢生捲曲且無法正常伸長。 青蘋果竹芋組培苗培植在含2%、4%或6%蔗糖之半固態培養基，調查出瓶馴化期間之光合作用及生長狀況。結果顯示以4%蔗糖處理者生長、葉片厚度表現較佳。組培苗瓶內形成之葉片，在出瓶初期Fv/Fm值皆下降。以2%蔗糖處理者之Fv/Fm值降至0.55，之後回復較慢。組培苗之蒸散速率和氣孔導度測值，在剛出瓶時皆很高，出瓶一天之測值即急速下降。在瓶內形成葉片的二氧化碳交換速率在剛出瓶時約為1.3-1.8 µmol CO2 m-2•s-1，於出瓶7天時較低，之後呈上升趨勢。 不同培養系統之青蘋果竹芋組織培養苗，出瓶後置於生長箱中馴化35天，再經溫室栽培65天，調查其葉片形態解剖、光合作用及生長狀況，結果顯示短暫淹灌系統培養之組織培養苗葉片較厚、氣孔密度較低及較多表面蠟質堆積，與瓶外生長之葉片形態較相近。因此在出瓶馴化時期，葉片Fv/Fm值回升較快、葉綠素計讀值隨馴化時間上升，顯示短暫淹灌系統培養之組織培養苗具較佳之環境適應性。 青蘋果竹芋組織培養苗置於生長箱中，分別以40、120或200 µmol•m-2•s-1光度馴化35天。再經溫室栽培65天調查後其生長狀況，結果顯示出瓶後以40 µmol•m-2•s-1處理者生長、葉片厚度表現較佳。組培苗瓶內形成之葉片，在出瓶初期Fv/Fm值皆下降，處理光度越高測值越低。以120和200 µmol•m-2•s-1處理下之Fv/Fm值降至0.27和0.19，之後回復較慢。組培苗之蒸散速率和氣孔導度測值，在剛出瓶時皆很高，出瓶一天之測值即急速下降。在瓶內形成葉片的二氧化碳交換速率在剛出瓶時約為0.85 µmol CO2 m-2•s-1，於出瓶7天時較低，之後呈上升趨勢。

Temporary immersion system (TIS) has both advantages of maximum gas exchanges in solid culture media and increased nutrient up take in liquid culture. To increase the rate of multiplication and plant growth, effects of sucrose concentration, cultural system and photosynthetic photon flux (PPF) during ex vitro acclimatization on photosynthetic behaviors and growth were studied in micropropagated Calathea orbifolia. The objectives of this research were to determine the proper sucrose concentration, cultural system and ex vitro PPF during acclimatization that could promote the subsequent growth of plantlets after transfer. An addition of 80 mL culture medium per explant in TIS resulted in maximum shoot formation. Full MS medium supplemented with 4% sucrose, 2.2 μM NAA and 26.7 μM BA produced maximum shoot number. Shoot number increased with increasing TDZ concentration, while high TDZ concentrations of 2.73 and 3.64 µM resulted in shorter and rosetted shoots. Micropropagated Calathea orbifolia plantlets, cultured with 2%, 4% or 6% sucrose concentrations, were transplanted to a soilless mix and placed in a growth chamber to measure their photosynthetic capacity and growth. Plants cultured with 4% sucrose in vitro had greater growth. All the Fv/Fm values in the in vitro-formed leaves decreased in the early period after transfer. The Fv/Fm value reduced to 0.55 and recovered slower afterwards in plants at 2%. For all the plantlets tested, the stomatal conductance and transpiration rate in the in vitro-formed leaf were high at transfer and decreased dramatically on day one after transfer. Photosynthetic rate of in vitro-formed leaf was measured as 1.3-1.8 µmol CO2 m-2•s-1 at transfer, decreased after transferring for seven day, and then increased gradually. After having been acclimatized for 35 days in the growth chamber, the micropropagated Calathea orbifolia plantlets, cultured in solid medium or in a TIS, were then transferred to a shaded greenhouse for 65 days and their leaf anatomy, growth and photosynthetic capacity was determined. In vitro-formed leaves in TIS were thicker, had lower stomatal frequency and more surface wax, similar to the ex vitro-formed leaf. In TIS treatment, leaf Fv/Fm value recovered earlier and SPAD-502 reading increased during acclimatization, suggesting that plantlets could adapt to the changing environments. Micropropagated Calathea orbifolia plantlets were transplanted to a soilless mix and placed in a growth chamber under fluorescent lamp providing PPF of 40、120 0r 200 µmol•m-2•s-1. After having been acclimatized for 35 days in the growth chamber, the plantlets were then transferred to a shaded greenhouse for 65 days and their growth was measured. Plantlets under 40 µmol•m-2•s-1 had greater growth. All the Fv/Fm values in the in vitro-formed leaf decreased in the early period after transfer, and then increased thereafter. High PPF at 120 or 200 µmol•m-2•s-1 reduced the Fv/Fm value to 0.27 or 0.19, clearly exhibiting photo inhibition and a slow increase in the Fv/Fm value afterwards. For all the plantlets tested, the stomatal conductance and transpiration rate values in the in vitro-formed leaf were high at transfer and decreased dramatically on day one after transfer. Photosynthetic rate of in vitro-formed leaf was measured as 0.85 µmol CO2 m-2•s-1 at transfer, decreased after transferring for seven day, and then increased gradually.