本研究以蝴蝶蘭花的子房組織為材料，應用4,6-diamidino-2-phenylindole (DAPI)螢光染劑及流式細胞儀測定蝴蝶蘭各原生種之細胞核DNA 的螢光比並予以 分析，螢光比為樣本螢光強度與對照P. aphrodite 的螢光強度的比值。分屬於10 個 分類群(taxon)的52 個蝴蝶蘭原生種之DAPI 螢光比值的顯示，不同原生種的基因組 大小有顯著的變化。蝴蝶蘭亞屬及節間亦呈顯著的差異。而在各亞屬及節內的原生 種間之螢光比值，大部分呈高度異質性，但有一些亞屬及節內原生種的螢光比值具 同質性，無顯著差異。比較DAPI 及propidium iodide(PI)的螢光比值，兩組的比值 呈高度的正相關，但在核DNA 含量較高的原生種中，其DAPI 比值的增加幅度亦有 較大的趨勢。

Evaluation of the genome size of 52 Phalaenopsis species was carried out using DAPI fluorochrome and flow cytometry in this study. These species belong to 10 taxa of the genus Phalaenopsis. High variations of DAPI fluorescence ratios were observed among these species and 10 taxa, with different degree of variation among species within each taxon. DAPI fluorescence ratios of the species within some taxa were heterogeneous while in others were homogeneous. The fluorescence ratios of DAPI and PI of the same species showed high positive correlation. Furthermore, there was a tendency that the increase of DAPI fluorescence ratios was higher when the nuclear DNA content of a species increased.