中文摘要 百金( Centaurium japonicum (Maxim.)Druce) 屬龍膽科
(Gentianaceae)植物,為一年生草本,主要分布於日本九州屋九島,琉球及
臺灣;在臺灣則散生於臺灣北部,東部,綠島及蘭嶼之海濱,呈不連續之分
布.本實驗使用同功異構酵素電泳法,檢視臺灣地區11個百金族群的遺傳變
異與遺傳結構.在使用的20個同功酵素中,可辨識出37個基因座,其中4個基
因座屬多型性基因座.分析結果顯示,族群遺傳變異度之理論值He=
0.013,多型性基因座百分比(P) 為3.54, 平均每個基因座有1.06個對偶基
因,顯示百金族群遺傳變異度偏低.利用F-統計分析百金族群的遺傳結構,
發現有16.8%的變異是存在於族群之間,83.4%的變異累積於族群之內.由於
基因交流不順暢(Nm= 1.02),族群易受基因漂變的影響,導致遺傳變異度偏
低;而離島上的族群,由於海洋隔離,基因無法與其他族群交流.遺傳變異度
更遠低於本島的族群(He=0.006 VS 0.017). 參考百金的受粉模式,基因交
流程度與其他島嶼植物的分析,近親交配與受侷限之基因交流,是造成族群
變異度偏低的主要原因.

Abstract Centaurium japonicum (Maxim.) Druce (Gentianaceae) is
an annual herb distributed in Yakushima of Japan, Rukyu
archipelago and Taiwan. In Taiwan, many small and isolated
populations are found on seashores og Lue Tao, Lan Yu and along
the northern and eastern coastlines of the main island. Allozyme
analysis of 11 C. japonicum populations revealed relatively low
level of genetic diversity: 4 of 37 loci were polymorphic (P=
3.45 in population level ), mean number of alleles per locus was
1.06 and the mean expected heterozygosity was 0.013. According
to the result of F-statistics, there was 16.8% of variation
between populations and 83.4% of variations within populations
(Fst= 0.168). Lack of gene flow among populations, estimated to
be almostly 1 migrating individual per generation for C.
japonicum is a likely cause of low genetic variation in
populations. Gene flow can hardly occure between islands and the
populations in Lue Tao and Lan Yu reveal lower level of genetic
diversity than that in Main island (He= 0.006 VS 0.017). The
decrease in genetic variation is attributed to inbreeding and
restricted gene flow.
Abstract Centaurium japonicum (Maxim.) Druce (Gentianaceae) is