發光二極管人工光源影響蝴蝶蘭組織培養苗生長及基因表達

Light-emitting Diodes Affect Growth and Gene Expression of ＂Phalaenopsis＂ Tissue-Cultured Plantlets

發光二極管（Light-emitting Diode, LED）具有省電及固定特定光波長等特性，近年已逐漸被使用於栽培植物的人工光源。蝴蝶蘭（Phalaenopsis spp.）是世界性重要的花卉，而組織培養是蝴蝶蘭量產的主要技術。本試驗以白螢光燈（White Fluorescent Lamp, WFL），LED紅光（LR），以及LED紅藍光（LRB,5:2比例）作為培養蝴蝶蘭組織培養苗之光源，光強度為50μmol•m^(-2)•s^(-1)PPF（photosynthetic photon flux）。培養6週後，LR光源培養大白花Phal. Sogo Yukidian 'V3'的培養苗葉片呈現黃化，葉綠素含量降低，但葉組織累積較高總糖含量，並且促進根組織生長。不同光源培養下蝴蝶蘭組培苗累積不同量抗氧化酵素蛋白，LRB光源誘導最低的ascorbic acid peroxidase（APX）及最高的superoxide dismutase（SOD）抗氧化酵素蛋白累積。LRB光源活化參與碳水化合物合成及代謝的酵素活性，因為LRB光源誘導最高量rubisco large subunit（RbcL）及cytosolic fructose-1，6-bisphosphatase（cFBPase）蛋白的累積，並誘導最高量蔗糖分解酵素sucrose synthase（SUS）基因之表達。LRB以及WFL光源增加glutamine胺基酸合成酵素glutamine synthetase 1（GS1）蛋白的累積量，而LR光源增加細胞分裂蛋白cell-division-cycle kinase 2（CDC2）及光系統蛋白photosystem II PsbA之累積量。LED光源處理另一紅花品種Doritaenopsis Queen Beer‘滿天紅’，LRB 50及100μmol•m^(-2)•s^(-1)PPF光源顯著促進組培苗生長及增加其鮮物重。本試驗結果顯示，以紅光作為蝴蝶蘭組織培養單獨光源可活化細胞分裂並促進根組織生長，但葉綠素合成受明顯抑制。而紅藍雙光混合光源可活化蝴蝶蘭組培苗代謝活性，加速組培苗生長。 Light-emitting diodes (LED), with energy-efficient and fixed emission wavelength, have been used as light source for plant growth recently. Tissue culture is a main tool for mass-propagation for Phalaenopsis. In this study, in vitro plantlets of large white-flowered cultivar, Phal. Sogo Yukidian 'V3', were grown under various light sources including white fluorescent lamp (WFL), LED light of monochromatic red light (LR), and LED bichromatic red and blue light with a ratio of 5 to 2 (LRB) as artificial light sources for tissue culture with light intensity of 50 μmol•m^(-2)•s^(-1) photosynthetic photon flux (PPF). The results showed that, after 6-week-culture, the plantlets with LR produced yellowish leaves with the lowest chlorophyll contents but had the highest total sugar content and the longest root length. Plantlets with LRB had the lowest level of ascorbic acid peroxidase (APX) and the highest level of superoxide dismutase (SOD). Plantlets with LRB exhibited higher activity for carbohydrate synthesis, including increased accumulation of photosynthetic protein such as rubisco large subunit (RbcL) and hexose synthesis protein like cytosolic fructose-1,6-phoshpatase (cFBPase), and the highest expression of sucrose hydrolysis protein like sucrose synthase (SUS) gene. LRB and WFL resulted in higher levels of protein involved in amino acid synthesis such as glutamine synthetase 1 (GS1), while LR increased protein accumulation of photosystem II protein PsbA and cell division protein such as cell-division-cycle kinase 2 (CDC2). LRB with 50 and 100 μmol•m^(-2)•s^(-1) PPF significantly improved plantlet growth and increased fresh weight in the red flower cultivar, Doritaenopsis Queen Beer 'Red Sky'. The results show that, for in vitro Phalaenopsis plantlets, LED monochromatic red light promoted cell division activity and root growth, but reduced chlorophyll synthesis. LED red and blue bichromatic light could activate carbohydrate metabolism and promote plantlet growth.