應用DAPI螢光染劑及流式細胞術評估蝴蝶蘭原生種基因組之差異

Variation of the Genome Size among Phalaenospsis Species Using DAPI Fluorochrome and Flow Cytometry

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.