| Summary: | 碩士 === 國立臺灣大學 === 森林學研究所 === 89 === ABSTRACT
The object of this study was aimed to ascertain the effects of light intensity and fertilization on the seed germination, seedlings growth, morphology, physiology and ecophysiological characteristics of four native tree species of Taiwan.
The germination percentage of four species , Trema orientalis, Zelkova serrata, Acer serrulatum and Michelia compressa showed significant differences under the different light intensities. Seeds of T.orientalis had the highest germination rate in full sunlight，and significantly increased as light intensity increased. M.compressa had the similar germination performance. However, the highest germination rates of Z.serrata and A.serrulatum, were appeared in 25% relative light intensity.
The seedling performances of T.orientalis and Z.serrata, such as height growth, diameter growth, branch numbers, branch lengths, branch diameters, root lengths, dry weight(leaf, branch, stem and root weight), relative height and Dickson quality index were increased as light intensity or fertilization increased. Those performances of A.serrulatum and M.compressa were also significantly affected by light intensity but not by fertilization. The leaf morphology of Z.serrata, A.serrulatum and M.compressa, such as the ratio of leaf area and specific leaf area (SLA) were significantly affected by light intensity. Both leaf area ratio (LAR) and leaf weight ratio (LWR) of all four treated species were lowest 100% sunlight. The light intensity also significantly affected the LAR , LWR and R/T. Under the lower light intensities most of the biomass were accumulated in the leaves of T.orientalis, but were not in those of other tree species.
The results of this study showed that shading is not necessary in germination and seedling growth of T.orientalis. The growth and accumulation of biomass of A.serrulatum seedlings were the highest in 100% sunlight. Although the seed germination rates of Z.serrata and A.serrulatum, were the highest in low light intensity(25%), the growth and accumulation of biomass of seedlings were highest in 100% sunlight. The insignificant effect of fertilization on germination rates of four species was discovered, but significant to the growth of seedlings and accumulation of biomass. Besides, according to several parameters of investigations, such as the sizes, the germination rates, light intensities and fertilization of the seedlings showed that T. orientalis was the pioneer tree during the forest succession. Z. serrata and A. serrulatum and M.compressa were the following trees.
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