臺灣博碩士論文加值系統

木荷是台灣重要原生及造林樹種之一，港口木荷則是木荷之變種，由於二者之間並沒有很可靠的形態特徵可加以判別之，因此本試驗採用逢機擴大多型性核酸分析法(即RAPD)，以探討木荷與港口木荷之分類地位，即藉由20種長度較短(10 nucleotides)之人工合成引子進行RAPD-PCR反應後，得到147條核酸條帶，其中90(的條帶呈現多型性，且由引子U2、T1、V5及X11擴增之電泳圖譜中，得到分屬木荷或港口木荷特有之DNA標識，顯示二者雖在外表形態特徵上，沒有可靠的區別特徵，但在DNA層次上，仍具有相當程度的遺傳變異。由Nei氏相似值矩陣中，得知木荷之族群內變異(1－F＝0.150∼0.314)較港口木荷者(1－F＝0.110∼0.289)略大，乃因前者遍布台灣各地，多樣的生長環境造成木荷有較大的遺傳變異；而後者僅分布於恆春半島一地，具有較明顯的基因交流現象之故。另在樹狀關係圖中，發現木荷與港口木荷族群各自歸為一群(d＝0.400)；當d＝0.213時，木荷族群又分成三亞群，此乃因木荷在惠蓀林場之各採集地均相隔一段地理距離，而產生隔離現象，導致其間歧異度較大；此外，港口木荷族群同樣也因採集地之不同可再分成三亞群。

Schima superba var. superba is an important native and plantation species in Taiwan and S. superba var. kankaoensis is a variety of S. superba var. superba. Since there is no reli-able morphological characteristic to distinguish the two of them, we tried to use a new technique, random amplified polymorphic DNA(RAPD), to study the taxonomic identity of the two species. Twenty arbitrary sequenced primers(10 nucleotides in length) were selected to proceed RAPD-PCR. One hundred and forty seven bands were recorded and 90(%) of them were polymorphic bands. DNA markers generated by primers U2, T1, V5 and X11 have specific bands that can differentiate S. superba var. superba from S. superba var. kankaoensis. These results indicate that the two species do have some levels of genetic variation.In Nei''s similarity matrix, S. superba var. superba has higher variation within population(1－F＝0.150∼0.314) than that in S. superba var. kankaoensis(1－F＝0.110∼0.289). The cause of this variation may due to the former species spreading widely in Taiwan that may generate higher genetic variation than the latter species that is restricted in Heng-Chun peninsula. Based on the dendrogram generated by the RAPDistance program, when the genetic distance is equal to 0.400, the two species can be separated intotwo groups. However when the genetic distance reduced to 0.213, the S. superba var. superba population can be further divided into three subgroups. This may due to the samples originally collected from plots in Hue-Sun Experimental Forest Station were geographically separated long enough to diverge. On the other hand, samples collected from the S. superba var. kankaoensis population in Heng-Chun peninsula also geo-graphically separate enough to diverge into three subgroups.