貯運條件對蝴蝶蘭植株生理及貯後品質之影響

Abstract

本研究探討蝴蝶蘭長時間模擬黑暗貯運後生長勢恢復所需時間、葉片淨光合作用速率、葉綠素螢光值及植體碳水化合物之變化。並藉由測量上述變化，進一步比較裸根與帶盆貯運、貯運溫度（15、20、25 ℃）、貯運前的低溫馴化（日夜溫 25/20 ℃ 10天）、及貯後光度馴化（34、72、140、200、399 μmol•m-2•s-1）對蝴蝶蘭植株生理及品質之影響。另外亦探討溫度對蝴蝶蘭花朵受1-Methylcyclopropene（1-MCP）保護效期之影響。 大白花蝴蝶蘭（Phalaenopsis Sogo Yukidian ‘V3’）經20 ℃帶盆模擬黑暗貯運21天後，葉片淨光合作用速率、蘋果酸濃度、可滴定酸濃度較貯運前顯著下降，之後隨出庫時間增加逐漸恢復，恢復所需時間約3 - 9天。而Fv/Fm值不隨出庫時間改變而有明顯變化，故測量淨光合作用速率較Fv/Fm值適合作為判斷貯後恢復所需時間之指標。裸根貯運者之鮮重損失、葉片ABA濃度、黃葉數、及出庫後日間呼吸速率均較帶盆貯運者高，並隨貯運天數增加（7、14、21天）而上升，然貯後淨光合作用速率恢復時間不受裸根及帶盆貯運影響。葉片ABA濃度於出庫後隨時間增加有一先升後降之趨勢。不同溫度貯運下，25 ℃貯運者之黃葉數較高，Fv/Fm值較低。貯運前經低溫馴化能降低遭遇15 ℃低溫時之寒害程度。貯運後馴化光度推薦以梯度上昇（34 - 72 - 140 - 200 μmol•m-2•s-1）或維持在140 μmol•m-2•s-1能使蝴蝶蘭有較佳PSII效能及淨光合作用恢復能力。長期黑暗貯運後，蝴蝶蘭無法忍受399 μmol•m-2•s-1 之光度。 蝴蝶蘭貯運前所含碳水化合物，地上部澱粉較地下部高，但可溶性醣則以地下部為高。而隨貯運時間增加（0、10、20、30、40天）地上部及地下部之可溶性醣濃度下降，且地下部下降幅度較地上部大。地上部及地下部的澱粉濃度都於貯運10天後顯著下降，貯運10天後至40天則持平。15 ℃貯運者，貯後地上部蔗糖濃度、地下部葡萄糖、果糖及總可溶性醣濃度較其他溫度貯運組高，應與抗寒有關。不論貯運前是否經低溫馴化，以貯運於 20 ℃者之貯後品質較佳。 在蝴蝶蘭花朵品質方面，臺灣蝴蝶蘭（Phal. amabilis）燻蒸0.8 μL•L-1 1-MCP 8小時後，花朵不受乙烯危害之保護效期，在日夜溫25/20 ℃環境下為4 - 8天；在20/15 ℃環境下為10 - 13天；在15/13 ℃環境下為13 - 17天。保護效期隨施用後的環境溫度的增加而縮短。

In order to realize how long-distance shipping affects physiological status in Phalaenopsis, changes of net CO2 uptake, photosystem II efficiency, and carbohydrates after a long-term simulated dark shipping were determined. Effects of potted and bare-rooted treatment, storage temperature (15, 20, and 25 oC), low-temperature acclimatization (day/night 25/20 oC for 10 days) before simulated dark shipping, and light acclimatization ( 34, 72, 140, 200, and 399 μmol•m-2•s-1 ) after shipping on post-shipping performance with regards to the above photosynthetic parameters were then further investigated. Effect of temperature on 1-methylcyclopropene (1-MCP) residual protection on Phalaenopsis flowers was also studied. Net CO2 uptake, malate concentration, titratable acidity concentration in potted Phal. Sogo Yukidian ‘V3’ decreased after a 21-day simulated dark shipping at 20 oC, but recovered gradually with time after shipping. It took three to nine days to recover. Fv/Fm was little affected by shipping. Thereby, net CO2 uptake would be a better indicator for estimating recovery time after shipping. Fresh weight loss, leaf ABA concentration, yellowed leaf number, and CO2 production during daytime of bare-rooted plants were higher than that of potted plants, and increased with increasing shipping duration ( 7, 14, and 21 days). ABA concentration of leaf rose in first 3-day after simulated dark shipping and then decreased within next 3-8 days. Plants shipped at 25 oC resulted in more yellowed leaves, and lower Fv/Fm. Low-temperature acclimatization reduced chilling injury in Phal. after shipping at 15 ℃. Light intensity at 399 μmol•m-2•s-1 after shipping resulted in lower PS II efficiency and net CO2 uptake rate. It was recommended to have a gradient light increase ( 34 - 72 - 140 - 200 μmol•m-2•s-1 ) or maintain a 140 μmol•m-2•s-1 light level after shipping for Phalaenopsis to achieve a better photosynthetic rate. Starch was higher in shoot than that in roots before simulated dark shipping, and higher total soluble sugar was found in roots than that in shoot. Soluble sugars in both shoot and roots decreased with increasing duration of simulated dark shipping (0, 10, 20, 30, and 40 days), and decreased more significantly in roots than that in shoot. Starch decreased significantly in both shoot and roots 10 days after shipping and maintained steady from 10 to 40 days after shipping. After simulated dark shipping at 15 oC, the sucrose concentration in shoot, glucose, fructose and total soluble sugar concentrations in roots were higher comparing with other shipping temperature treatments. Better plant performance after shipping was obtained with shipping temperature at 20 oC, regardless of low-temperature acclimatization. 1-Methylcyclopropene was able to protect flowers of Phal. amabilis against ethylene injury, but the residual effect depended on post-treatment temperature. The duration of 1-MCP residual protection on flowers at day/night temperature of 25/20 oC, 20/15 oC, and 15/13 oC was 4-8, 10-13, and 13-17 days, respectively. Higher temperature after 1-MCP application resulted in a reduced residual protection in Phalaenopsis.