低遺傳多樣性的易危植物濱槐之保育

Low genetic diversity of the vulnerable Ormocarpum cochinchinense (Fabaceae: Papilionoideae) in Taiwan and implications for its conservation

濱槐(Ormocarpum cochinchinense (Lour.) Merr.)為豆科蝶形花亞科濱槐屬植物，在臺灣僅見於基隆和平島、綠島及蘭嶼，已被評為易危(VU)等級，為能確立其保育管理單位，本研究利用細胞核internal transcribed spacer及葉綠體trnH-psbA及trnL-trnF片段探討遺傳結構及分化，研究結果顯示分布在臺灣之濱槐遺傳多樣性極低，推測該物種曾受到基因漂變影響，喪失遺傳多樣性；族群間無分化推測可能與經由海流進行基因交流相關，而族群數量小及自花授粉亦為遺傳多樣性喪失原因之一。保育策略上建議應將3個族群視為1個管理單位，並以蘭嶼族群優先進行保育規劃，未來應收集種子與種苗進行域外保育，培育之個體可作為原生之景觀植物。

Ormocarpum cochinchinense (Lour.) Merr. (Fabaceae: Papilionoideae) has been categorized as a vulnerable species in Taiwan, as its distribution is restricted in Heping Island, Green Island (Lyudao), and Lanyu. To establish a management unit for species conservation, the nuclear internal transcribed spacer, as well as the chloroplast psbA- trnH and trnL-trnF regions were applied to assess the genetic structure and the level of population differentiation of O. cochinchinense. Low genetic diversity was detected in all three populations in Taiwan, suggesting that genetic drift has reduced their genetic variations. No differentiation among populations may be attributable to a high level of gene flow via ocean currents. The loss of genetic diversity may be also related to their small population size and self-fertilization. Three populations of O. cochinchinense should be integrated as one management unit. The population of Lanyu should be protected in priority. Seeds and seedlings should be collected for ex situ conservation, and those cultivated individuals could be used as native landscape plants.