臺灣產土肉桂、山肉桂、及胡氏肉桂(樟科)之遺傳變異與分類地位

Abstract

山肉桂(Cinnamomum insulari-montanum Hayata)、胡氏肉桂(C. macrostemon Hayata)與土肉桂(C. osmophloeum Kanehira)等為臺灣樟科特有種植物，此三種肉桂類植物在植物分類上一直存有爭議及困難，本研究應用簡單序列重複（Inter-Simple Sequence Repeat，簡稱ISSR）分子指紋技術探討其遺傳變異與分類地位關係。研究分析了在臺灣自然分佈之22地區144個樣本，試驗共使用12個ISSR引子進行PCR擴增，產生了52個多型性條帶，遺傳變異分析結果，分子變方分析(AMOVA)顯示種間之變方成分是27.24％％(p＜0.01)，而種內之變方成分是72.67％(p＜0.001)，顯示變異來自各種內。根據POPGENE分析各種內之遺傳分化程度，山肉桂與胡氏肉桂可能受到地理隔離影響具有明顯的地理分化，Nm值分別為0.5024及0.6533；而土肉桂基因流值為1.2626，顯示較低的遺傳分化現象。探討分類地位關係所進行之歸群分析樹狀圖顯示土肉桂、山肉桂與胡氏肉桂族群各自形成三群團，這樣的結果亦受到主座標分析(Principal Coordinate Analysis, PCOA)之支持。

Cinnamomum insulari-montanum Hayata, C. macrostemon Hayata and C. osmophloeum Kaneh. are endemic species of the Lauraceae in Taiwan. Taxonomy of these closely related species remains unclear. In this study, ISSR fingerprinting using 12 microsatellite primers was employed to investigate the taxonomic status of the tree species and intraspecific diversity and differentiation. Analysis of molecular variance (AMOVA) revealed 27.24% variance residing among species(P<0.001), while 72.67% variance distributed within species (P<0.001). Significant structuring exists in C. Insulari-montanum and C.macrostemon; while gene flow, as indicated by Nm=1.26, was detected in C.osmophloeum. Both clustering and principal coordinates analyses Identified three major clusters that correspond to each species and revealed a close Phonetic relations between C. Insulari-montanum and C. macrostemon.