劍葉蘭和石斛蘭亞族之系統分類研究

A Phylogenetic study on the Genus Oxystophyllum and the Subtribe Dendrobiinae (Orchidaceae)

張國強(Cheong, Kok Keong)

指導教授 ： 李家維

國立清華大學/生命科學院/分子與細胞生物研究所/碩士(2011年)

摘要

中文摘要

蘭科植物為開花植物中物種數最多的一科，目前已知有5亞科22族70亞族880屬27, 000種。樹蘭亞族為蘭科最大之亞科，有19族39亞族576屬和15,000種。在樹蘭亞科中最大族為石斛蘭族，同為在蘭科和石斛蘭族第二大屬的石斛屬已歸類出48節1, 400種。石斛屬中的鱗葉節(Aporum) 和劍葉蘭 (Oxystophyllum) 都具有細長莖節、扁平互生的肉質尖葉及槽糠狀的花柄基部，產地分布也同樣自緬甸到新幾內亞。一些鱗葉節石斛莖節前端的無葉總狀花序而在劍葉蘭物種中僅有在莖軸和莖節頂端長出一到兩朵花的形態差異，過去鱗葉節和劍葉蘭被認為同為石斛屬的近緣節。
不過在先前分子分類研究顯示當時為石斛一節的以兩種劍葉蘭 (O. govidjoae and O. sinuatum) 和兩種絨蘭亞族的物種，認為劍葉蘭應該從過去的石斛蘭族移到柄唇蘭族(Podochileae)絨蘭亞族(Eriinae)的規範內。本研究便將所採集的蘭科植物的葉片進行DNA萃取後，利用兩個常在植物界中常用以做為分類依據的兩種基因，matK (maturase coding gene) 以劍葉蘭4種 (O. minutigibbum, O. changjiangense, O. sp. Hainan* and O. sp. Sabah*) 和其他蘭科植物83種與rbcL (ribulose 1,5-biphosphatase large subunit)以劍葉蘭3種 (O. minutigibbum, O. changjiangense and O. sp. Hainan*) 和其他蘭科植物57種進行序列比對分析。結果顯示，劍葉節蘭屬於在柄唇蘭族的族群內。另外，本研究在花粉塊數目比對發現尖葉蘭具有左右各兩對的4個花粉塊，這點與絨蘭亞族中8個花粉塊的特徵不相符。綜合以上的結果，認為劍葉蘭屬不該歸類在絨蘭亞族之一屬。

關鍵字

劍葉蘭 ； 石斛蘭亞族 ； 柄唇蘭族 ； 絨蘭亞族 ； 分類 ； 石斛蘭族

並列摘要

Abstract

Orchidaceae, with 5 subfamilies, 22 tribes, 70 subtribes, 880 genera and 27, 000 species, is the largest family in flowering plants. Epidendroideae with 19 tribes, 39 subtribe, 576 genera and 15, 000 species, is the largest subfamily. Dendroibeae is the largest tribe in this subfamily and the second largest genus Dendrobium of Orchidaceae is located in this tribe. Dendrobium has 48 sections and 1, 400 species being classified. Among these sections, the sections Oxystophyllum (39 species) and Aporum (45 species) share the two following features: 1) wiry stem, fleshy and triangular sharp-pointed leaves are arranged in two ranks; 2) flowers are borne laterally from the apical region and usually form a cluster of chaffy bracts around the base of infloresence. Moreover, their distributions are overlapped from Myanmar to New Guinea. Thus, they were traditionally treated as closely related sections, with a slight difference in morphology: elongated terminal extension of the stem that lacks leaves and bears flowers in Aporum, but never appear in Oxystophyllum that bear one or two flower at a time and are formed in the leaf axils along the stem or apically.
However, a previous study using molecular phylogeny with only two species of Oxystophyllum (O. govidjoae and O. sinuatum) and two species of subtribe Eriinae showed that Oxystophyllum should be moved from tribe Dendrobieae to the subtribe Eriinae in the tribe Podochileae. In this study, we analyzed this result by aligning two frequently employed phylogenetic marker genes, maturase coding gene (matK) in 4 Oxystophyllum species (O. minutigibbum, O. changjiangense, O. sp. Hainan* and O. sp. Sabah*) and other orchid 83 species and ribulose 1,5-biphosphatase large subunit (rbcL) in 3 Oxystophyllum species (O. minutigibbum, O. changjiangense and O. sp. Hainan*) and other orchid 57 species. The result shows that Oxystophyllum should be an independent genus and should be in tribe Podochileae. However, pollinia number comparison reveals that Oxystophyllum has four pollinia, which is different from the eight-pollinium character in subtribe Eriinae, and thus, we suggest that Oxystophyllum should not be in subtribe Eriinae.

並列關鍵字

Oxystophyllum ； Dendrobiinae ； Podochileae ； Eriinae ； Phylogenetics ； Dendrobieae

參考文獻

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