培養基添加蘋果酸對蝴蝶蘭瓶苗生長及光合作用之影響

Effect of Malic Acid Supplement in Medium on Plantlet Growth and Photosynthesis of Phalaenopsis in vitro

本研究為探討培養基中添加蘋果酸對大白花蝴蝶蘭I-Hsin Cream 'KHM246'分生瓶苗生育以及對瓶苗葉片Rubiso活性之作用與瓶內二氧化碳濃度之影響。瓶內二氧化碳濃度會隨培養基中蘋果酸濃度由0增加至120 mg•L^(-1)而提高。瓶內二氧化碳濃度具有日變化現象，明期開始後4小時內，二氧化碳濃度急遽上升，之後趨於平緩，待至明期末又快速下降，進入暗期後，瓶內二氧化碳濃度又逐漸向上攀升至暗期結束。瓶苗在暗期具有蘋果酸的累積。適量蘋果酸的添加可促進瓶苗根部生長，以90 mg•L^(-1)蘋果酸處理表現較佳，根長及根寬分別比對照組增加15.6%及8.4%，平均根數達4.1條。繼代培養28天時，測得培養基添加蘋果酸處理組葉片Rubiso活性較高，並以60 mg•L^(-1)蘋果酸處理表現最佳，Rubisco活性在每mg蛋白質高達0.97 nmol•min^(-1)RuBP carboxylase。又隨著培養天數增加，各處理之酵素活性逐漸下降。 Effects of malic acid supplement in medium on Phalaenopsis I-Hsin Cream 'KHM246' plantlet growth, components of the gaseous environment in vitro, and Rubisco activity were studied. In vitro carbon dioxide concentration increased as malic acid concentration increased from 0 to 120 mg•L^(-1). There was a diurnal change of carbon dioxide concentration during culture in vitro. The carbon dioxide concentration increased rapidly during the first four hours of light period, decreased rapidly at the end of light period, and then increased gradually during dark period. Malic acid concentration accumulated at the end of dark period. The 90 mg•L^(-1) malic acid treatment increased root length by 15.6% and root diameter by 8.4%, and resulted in 4.1 roots. The treatment of 60 mg•L^(-1) malic acid promoted Rubisco carboxylase activity to 0.97 n mol•min^(-1) per mg protein, measured 28 days after subculture. However, the Rubisco activity decreased gradually thereafter in all treatments.