文心蘭Gower Ramsey小花發育及老化之生理變化

Physiological Changes of Development and Senescence in Oncidium Gower Ramsey Floret

本研究以文心蘭切花組織培養繁殖之Gower Ramsey開花株為材料，探討小花發育與老化階段釋放乙烯及二氧化碳變化、乾鮮重變化、電解質滲漏，並以石蠟切片觀察及掃描式電子顯微鏡觀察小花老化過程之變化。小花在盛開後進入萎凋期時，乙烯及二氧化碳大量生成達到高峰，老化謝花期電解質滲漏率可上升高達70%。全可溶性醣在花蕾微開期為高峰，達13.5%DW.，之後逐漸下降，萎凋期開始又達高峰。光學鏡檢發現花瓣表皮皮層維管束細胞在萎凋期花瓣細胞皺縮，花藥蓋連接點細胞在小花發育至半開期時細胞間出現空隙，全開期時連接點內面之外層細胞已出現部分剝離，花藥蓋易脫落，掃描式電子顯微鏡觀察小花在全開期表皮細胞呈圓錐形並擴大，萎凋期皺縮凹陷，去除花藥蓋3天後造成連接點細胞皺縮塌陷。

The development and senescence of floret on cut oncidium Gower Ramsey were investigated. The ethylene and carbon dioxide production, changes in fresh weight and dry matter were studied. Moreover, optical anatomical observation and morphological changes during senescence by SEM were also conducted. Ethylene and carbon dioxide reached peak production at the wilting stage. In the meantime, electrolyte leakage increased to 70% at the drop stage. Total soluble sugars increased at slight opening stage accounting for13.5% DW. , then decreased at the wilting stage. The peak of total soluble sugar occurred at the wilting stage. Epidermis, cortex, and vascular bundle cells of floret petal started to shrink at this stage. The pollinia cap lodgment connecting cells presented partial isolation, resulted in pollinia cap to dislodge easily. The round pillar cells showed enlargement with turgibity at full opening stage, then shrunk and collapsed. The pollinia cap lodgment connecting cells were found to have shrunk and collapsed 3 days affter pollinia cap dislodgment.