武威山烏皮茶之保育生物學：分類地位、生態、種子發芽與育苗試驗

Abstract

武威山烏皮茶 (Pyrenaria buisanensis) 為嚴重瀕臨滅絕之稀有植物，目前僅知台灣屏東縣瑪家鄉與來義鄉兩處生育地。根據本研究利用ITS序列分析所得到的親緣關係，確認武威山烏皮茶為台灣特有種，而近緣種為中國的多萼核果茶 (P. jonquieriana subsp. multisepala) 、大果核果茶 (P. spectabilis var. spectabilis) 與長萼核果茶 (P. wuana) 。武威山烏皮茶生育環境為海拔300-1100公尺之原始林或次生林山坡或稜線，土壤具有較好之通氣與排水性，結果量與天然更新情形良好，但生育地受人為干擾程度大且頻繁。武威山烏皮茶果實為多汁的蒴果，不同於茶科植物典型的乾燥蒴果，並且藉由重力滾落進行散佈，成熟後不開裂或略微開裂。種子較烏皮茶大且無休眠性，新鮮種子之發芽率可達90%，發芽率在30/20℃、25/15℃、20/10℃與25℃之下沒有差異，其平均發芽日數僅在20/10℃明顯增加。種子施用激勃素GA3、GA4與低溫層積4週處理皆可加速發芽，尤以低溫層積效果最為顯著，但對於最終之種子發芽率無明顯影響，兩種GA的促進效應也沒有差異。幼苗為子葉出土型，土壤pH 3-pH 7之間對其苗高與葉數生長沒有顯著趨勢，但土壤pH 6之環境在幼苗生長增量的表現較佳。幼苗容易因為缺鐵而呈現新葉黃化或葉脈間黃化導致生長停滯，施以鐵肥可恢復其正常生長。以GA處理之種子，發芽後下胚軸有明顯增長，但對後續生長之影響則不顯著。本研究之前武威山烏皮茶尚未被詳細調查或研究，因此這是第一篇對於其親緣關係、果實和種子型態、種子發芽及幼苗培育進行深入探討的研究報告。

Pyrenaria buisanensis is a critically endangered species distributed in only two habitats, Majia and Laiyi, Pingtung County, Taiwan. According to the ITS data, it was confirmed to be endemic to Taiwan. The sister clade includes P. jonquieriana subsp. multisepala, P. spectabilis var. spectabilis and P. wuana, all distributed in China. P. buisanensis grows in the natural forest or secondary forest of the altitude about 300-1100 meters, and on the mountain slope or ridge with well-aerated and -drained soil. The fruiting and natural regeneration are stable in the field, but the habitats have been constantly disturbed by human activities. Fruits are non-dehiscent or slightly dehiscent succulent capsules, different from the typically dry capsules in the Theaceae. Fruits spread by rolling downslope. Seeds are not dormant, and the germination percentage reached as high as 90%. The germination percentages had no difference under 30/20℃, 25/15℃, 20/10℃ and 25℃ treatments. Seeds treated with 10/20℃took longer to germinate. Applying GA3, GA4 and cold stratification to seeds for 4 weeks sped up germination. While cold stratification was the most effective treatment, it made no differences on final germination percentages. Seedlings are epigaeous, and seedling heights and leaf numbers were insensitive to soil pH ranging from 3 to 7. Nevertheless, soil pH 6 was the most favorable for seedling growth. Seedlings were susceptible to iron deficiency with the symptoms including chlorosis and intervenal chlorosis on young leaves. The iron deficiency also caused stunting or death, but could be corrected by iron fertilization. Seeds of P. buisanenesis treated with GA significantly extended hypocotyl after germinating, but the growth above cotyledons was not significantly different. Since P. buisanensis had never been thoroughly investigated previously, this is the first report focusing on the phylogeny, fruits and seeds morphology, seed germination and seedling cultivation of P. buisanensis.