Daminozide對「旭」蘋果果實成熱期間及氣調貯藏期間乙烯生成之影響

Effect of Daminozide on the Ethylene Formation of 'Mclntosh' Apples during Maturation and in Controlled Atmosphere Storage

採前2個月噴施Daminozide有延遲'旭（McIntosh）'蘋果在樹上完熟及乙烯劇升之效果。Daminozide處理同時抑制影響果實生成乙烯速率之1-aminocydopropane-1-carboxylic acid（ACC）含量及Ethylene forming enzyme（EFE）活性。對照蘋果在乙烯氣調貯藏環境（2.5～3.0% O2，3.0% CO2, ＜1 ppm C2H4, 3.0°C）下，前4個月果實內部乙烯含量之上升極為緩慢。其後乙烯、ACC含量及EFE活性均加速增加。ACC含量與EFF活性之上升與乙烯生成之上升有很顯著的正相關。噴施Daminozide之蘋果在低乙烯氣調貯藏中，前6個月幾無乙烯上升之現象，這期間ACC含量及EFE活性均甚低，顯示Daminozide之抑制乙烯生成係因同時抑制ACC合成及EFE活性之緣故。氣調貯藏中存在高濃度之乙烯能促進果實內乙烯之生成。Daminozide處理可以減輕外加乙烯促進果實乙烯生成之效果。減輕之原因似由於Daminozide能部分壓抑高乙烯促進之ACC合成，但不能壓抑高乙烯促進之EFE活性之增加。

Tree-spray with daminozide in mid-summer significantly delayed the time of onset and the speed of progress of the climacteric rise of internal ethylene of 'Mcintosh' apples on the tree. Daminozide suppressed the ACC content and the EFE activity of the apples simultaneously. The internal ethylene concentration of the control apples increased slowly in the first four months of low ethylene CA storage (2.5 to 3% O2, 3% CO2, <1ppm C2H4, 3°C), but increased rapidly afterward. Increases of ACC content and EFE activity always occurred concurrently with the increase of internal ethylene. Daminozide-treated apples almost had no increase in the internal ethylene in the first six months of low ethylene CA storage, and had only a slight increase in the subsequent two months of storage. When the internal ethylene was low, the ACC content and EFE activity were also low. Apples after being stored in high ethylene (500ppm) CA produced more ethylene than comparable apples after being stored in low ethylene CA. High ethylene almost completely overcame the inhibitory effect of daminozide on EFE activity, but only partially overacame the effect on ACC content. Therefore, the rate of ethylene production of daminozide-treated apples was lower than that of the control apples after high ethylene CA storage.