臺灣原生蝴蝶蘭碳代謝及光合特性之研究

Indentification of Native Phalaenopsis Photosynthetic Characteristics

羅聖賢(Sheng-Chien Lo)

《臺東區農業改良場研究彙報》 18輯 (2008/11) Pp. 15-44

https://doi.org/10.6959/RBTDAIS.200811.0015

摘要

臺灣原生蝴蝶蘭大、中、小苗時為絕對性行景天酸代謝（Crassulacean acid metabolism，CAM）植物，瓶苗時為C3-CAM植物，上下表皮氣孔密度有明顯差異，上表皮氣孔密度為2.8±0.9個/mm^2，下表皮氣孔密度為26.2±3.6個/mm^2，上下表皮氣孔數相差約10倍。氣孔開關與一般C3及C4植物不同，是屬於夜間開孔型，上午10時起氣孔完全閉合到下午6時氣孔才張開，持續開孔至次日上午10時。於上午2：00時上表皮氣孔打開的百分比達100%，孔度大小約3.87μm。下表皮氣孔開度百分之百有2個時段，為晚上20：00及清晨4：00，其孔度前者為4.06 μm，後者為4.59μm。夜間氣孔打開固定CO2為蘋果酸，白天氣孔關閉進行C3路徑的碳代謝。臺灣原生蝴蝶蘭成苗植株光合作用之光飽和點的光度約為400μmolphotonsm^(-2)s^(-1)，此時其光合作用CO2固定率約為0.16μmolm^(-2)s^(-1)，蝴蝶蘭光合作用具有典型的日夜韻律變化，暗期自下午6時至次日清晨6時，是葉片主要的CO2固定時段，午夜2時可高達3.2μmolm^(-2)s^(-1)，氣孔導度則維持在0.54～0.56μmmolm^(-2)s^(-1)左右，當清晨6時Co2固定率降至-0.03μmolm^(-2)s(-1)，其氣孔導度達到最高峰約0.88μmolm^(-2)s^(-1)。蝴蝶蘭瓶苗其δ13C為千分之-19.5～千分之-21.4，介於C3-CAM植物間，其Phosphoenol-pyruvate carboxylase活性白天為0.118μmolhr^(-1)mg^(-1) protein，夜間為0.018μmolhr^(-1)mg^(-1) protein，而Rubisco之活性夜間為0.033μmolhr^(-1)mg^(-1) protein，較白天0.014μmolhr^(-1)mg^(-1) protein高；而小苗、中苗及大苗其δ13C分別為千分之-13.2、千分之-12.3、千分之-12.4，具CAM型特性，夜間時其PEPC酵素活性高，花瓣之δ13C為千分之-13.5，亦呈現CAM代謝型式。

關鍵字

臺灣原生蝴蝶蘭 ； 碳代謝 ； 景天酸代謝 ； 氣孔

並列摘要

With regards to phalaenopsis Aphrodite subsp. Formosana., its seeding, medium, and adult are obligate CAM plants. Its bottle seedlings are C3-CAM plants. The stomatal distribution of the adaxial epidermis and of the abaxial epidermis are obviously different. The stomatal density of the former is 2.8 ± 0.9/mm^2, and the stomatal density of the latter is 26.2 ± 3.6 mm^(-2), The stomatal frequency on both side differ about one to ten. The stoma opening of Aphrodite subsp. Formosana. is different from general C3 and C4 plants, it is open in night. The stomata are closed from 10 am to 6 pm and keep opened to 10 o'clock in the next morning. The stomata of the adaxial epidermis are 100% opened at 2 am, and the pore size is about 3.87 μm. The stomata of the abaxial epidermis are 100% opened at 8 pm and 4 am. The pore size of the lower epidermis opening at 8 pm. is 4.06 μm, and pore size of the ones opening at 2 am is 4.59 μm The stomata open to stabilize CO2 at night and close to photosynthesize in the morning.The photosynthetic light saturation point of the five-years old of Aphrodite subsp. Formosana. is 400 μmolm^(-2)s^(-1). The CO2 fixation diel rate is 0.16 μmolm^(-2)s^(-1). The photosynthesis of Aphrodite subsp. Formosana, has typical alteration of diurnal rhythm. The dark period begins from 6 pm to 6 am the next day, and it is the main period for CO2 fixation. At 2 am, the CO2 assimilation reaches 3.2 μmolm^(-2)s^(-1) , and stomatal conductance keep at 0.54~0.56 mmolm^(-2)s^(-1). At 6 am, the CO2 assimilation decrease to -0.03 μmol^(-2)s^(-1), and the stomatal conductance reaches its highest, 0.88 μmolm^(-2)s^(-1), About the bottle seedlings of phalaenopsis, their δ13C is -19.5 per mille~21.4 per mille and is belong to C3-CAM plants. PEPC is enzyme activity 0.118 μmolhr^(-1)mg^(-1) protein in daytime and 0.018 μmolhr^(-1)mg^(-1) protein at nighttime. However, the activity of Rubisco is 0.033 μmolhr^(-1)mg^(-1) protein in nighttime and is higher than daytime 0.014 μmolhr^(-1)mg^(-1). The δ13C of the small, medium, and large seedlings is -13.2 per mille, and -12.4 per mille, respectively. They belong to CAM type, whose PEPC enzyme activity is high at night. The δ13C of petals of Aphrodite subsp. Formosana is -13.5 per mille, belongs to CAM type, too.

並列關鍵字

Native phalaenopsis ； Carbon metabolism ； stomatal movement PEP carboxylase ； Rubisco ； Tatal acid content ； Crassulaecean Acid Matabolism