洋桔梗花瓣老化過程中微細構造之變化

Ultrastructural Changes in the Petals of Senescing Flowers of Eustoma russellianum

本研究主要探討單瓣洋桔梗花瓣老化過程中微細構造之變化。以掃描式電子顯微鏡觀察，花瓣近軸面之表皮細胞呈圓凸狀；遠軸面則呈長柱形，略為彎曲，表面有螺旋狀皺褶。小花盛開時，表皮細胞均呈最飽滿和膨潤的狀態，萎凋時細胞萎縮，導致塌陷。穿透式電子顯微鏡觀察，花瓣表皮細胞和基本組織細胞在初開時，可見液胞膜內凹形成小泡囊，細胞自體吞噬能力增加，此時小花的呼吸率和乙烯釋放量也開始增加盛開時，液胞膜開始破裂，並可見質壁分離現象，細胞已失去完整陸，呼吸率達最高峰，乙烯量亦大量增加。初萎期，液胞破裂嚴重，細胞質被稀釋。萎凋期，胞器瓦解，細胞中有胞器瓦解後的沉積物。以上結果顯示，洋桔梗小花初開時，花瓣細胞內部已開始出現老化之症狀。盛開時，細胞內部已失去隔室作用而此時表皮細胞外觀卻呈現最膨飽滿的狀態，當花瓣出現萎凋時，則內部細胞已受到嚴重之破壞。

The ultrastructures of the petals of Eustoma russelliamum were observed by scanning electron microscopy and transmitted electron microscopy in various flower senescence processes and the release of CO2 and ethylene from the senescent flowers were measured, which were able to explore the phenomena of flower senescence of Eustoma russelliamum. The results showed that at the slightly open stage of flowers the adaxial epidermal cells were turgid, then proceeded to shrinkage and even collapse at the stage of wilt. At the slightly open stage of flowers, the autophagic activity of the vacuoles of epidermal cells of petals increased, while the CO2 and ethylene released from the flowers also increased. At the fall open stage of flowers CO2 and ethylene released from flower reached a peak, and the cells occurred vacuole member plasmolysis and lost integrity. At the wilt stage that appeared the deposits of the decomposed organelles. It is concluded that the senescence of flowers of Eustoma rasselliamum appeared at the slightly open stage, at the full open stage, the turgid epidermal cells of petal showed the decomposition of vacuole membrane, finally proceeded to serious destruction at the initiation of petal wilt.