蝴蝶蘭花朵之呼吸作用

Respiration of Phalaenopsis Flowers

白花蝴蝶蘭花序上愈幼嫩花蕾呼吸作用愈旺盛，花朵綻開1～2天的呼吸率也高於已綻放1～3星期花齡者。綻開花朵採收後呼吸率迅速下降，於採後7～8小時趨於穩定，之後並有略降趨勢。採後18日進入老化時，呼吸率快速上升，乙烯也隨著大量釋出，到呼吸高峰後呼吸率略降，而乙烯在高峰後迅速下降。在呼吸與乙烯放出快速上升中，花朵切口流出溢汁，花朵失水萎凋而老化，呈現如果實之「更年性呼吸型式」。在呼吸平穩期，20°C與25°C的呼吸率相近，在15~25°C及20~30°C，白花和粉紅花之Q₁₀在1.7-2.1之間。授粉後呼吸率急劇上升，授粉後36小時達呼吸高峰。授粉後13小時花朵已流出溢汁而萎凋老化。除雄在初期雖呼吸率也略升高，但在4.7天後也老化。外施乙烯0.09ppm就可誘發花朵老化，濃度增高，加速老化，其呼吸高峰亦愈高。花朵在呼吸缸濕潤空氣中，不插水可維持18天的壽命，若空氣乾燥，立即促進呼吸率上升，使花朵在採後2.7天便老化萎凋。花朵受折壓或刺傷，也會引起呼吸率的上升並縮短壽命。

The respiration of Phalaenopsis flowers was studied in relation to bud development, age of flowers, pollination, emasculation, ethylene, low relative humidity and wounding. The tight buds had the highest rate of respiration, which decline after the buds opened. The highest respiration was also observed in flowers opened 1~2 days, then followed by a gradual decline to the age opened for 3 weeks. The respiration rate decreased rapidly during the first 6 hours after harvest, then maintained in low respiration rate for about 17 days, then increased again as the flowers undergo senescence. The phase of rising respiration accompanied the exudation and wilting of the flowers, and upsurge in ethylene production. This is a typical pattern of respiratory drift similar to that of ripening fruits with 'climacteric respiration'. The respiration rate at 20°C and 25°C were very similar. In Phalaenopsis white and pink flowers the Q₁₀ at temperatures 15~25°C and 20~30°C was about 1.7 and 1.9 respectively. A marked increase in respiration and ethylene production of Phalaenopsis after pollination. A peak was reached 36 hours after pollination, followed by a slight drop of respiration and sharply drop of ethylene. However, the exudation and wilting of flowers appeared 13 hours after pollination.The rising respiration and senescence of flowers were observed 4.7 days after emasculation. Ethylene concentration as low as 0.09 ppm was sufficient to induce rising respiration and senescence, the treatment with increasing concentration of ethylene increased the ultimate peak respiration value and shortened the floral life. Flowers under low relative humidity and wounding stress increased respiration and decreased longevity, especially under low relative humidity, flowers longevity 2.7 days compared with control flower 18 days.