| Summary: | 碩士 === 國立臺灣大學 === 森林環境暨資源學研究所 === 101 === 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.
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