南仁山亞熱帶雨林樹冠層葉片結構之研究

Abstract

本文旨在調查墾丁國家公園南仁山亞熱帶雨林永久樣區的樹冠層植物的葉片結構。共取樣五十二種樹種，分屬於22科37屬，包括32種迎風區樹種、5種背風區樹種、3種溪穀區樹種和12種廣泛分佈樹種，其總重要值（Important Value）達87.9，佔所有樹冠層植物的95％。測量項目包含葉片長寬比、被毛狀態、尖端與葉緣形態、葉片厚度、葉片面積、葉片比重、角質層與表皮細胞外周壁厚度、柵狀組織厚度與細胞層數、海綿組織厚度、柵狀與海綿組織的比例、下皮細胞層數、結晶數量、氣孔密度、氣孔長度、及氮、磷、鉀、鈉、鈣和鎂的含量等特徵，並用電腦進行分析。 經由判別分析（Canonical Discriminant Analysis）的結果顯示，生長在不同的生育地的植物其葉片特徵確實有所不同。與生育地有極為顯著之相關的特徵包含：葉片厚度，葉片面積，葉片比重，角質層與表皮細胞外周壁的厚度，柵狀組織厚度，海綿組織厚度，氮與磷元素的含量。大致說來，迎風區植群的葉片厚度、角質層與表皮細胞外周壁的厚度、柵狀和海綿組織厚度等特徵比較厚，葉片比重比較大，面積比較小，氮和磷含量較低。背風區植群則反之。主成分分析（Principal Component Analysis）的結果亦支持上述看法。此外，生長在不同生育地的廣泛分佈種的葉片特徵，也有上述的差異。而同屬分化種的葉片特徵，也因生育地的不同而有分化的現象。 從葉片結構的角度來看，可以將南仁山亞熱帶雨林歸類為介於暖溫帶和亞熱帶之間的雨林型硬葉森林。與世界其他類型的雨林比較後發現，本區森林與熱帶美洲的山地雨林較為類似。

The aim of this study is to investigate the leaf structure of canopy of Nanjenshan Subtropical Rain Forest. Fifty-two species belonging to 22 families and 37 genera are selected. Among them, thirty-two species are classified as the windward species, five as the leeward species, three as the creek species and the other twelve as widely distributed species. The total important value of sampling species is up to 87.9, occupying 95% of canopy species. The measured and recorded characters are: the ratio of blade length to width, status of hairiness, morphology of leaf tips and margins, thickness of lamina, area of blade, specific leaf weight, thickness of cuticle and outer epidermal cell wall, thickness and cell-layers of palisade tissue, thickness of spongy tissue, ratio of palisade to spongy tissue, cell-layers of hypodermis, content of crystals, density and length of stomata, and contents of N, P, K, Na, Ca and Mg. The results of the Canonical Discriminant Analysis showed that the leaf characters in different habitats were markedly different. The characters related to the environmental factors were thickness of lamina, area of blade, specific leaf weight, thickness of cuticle and outer epidermis cell wall, thickness of palisade, thickness of spongy tissue, and contents of N and P. Generally speaking, the leaves in the windward region had thick lamina, cuticle and outer epidermis cell wall, palisade and spongy tissue. They also had large specific leaf weight but smaller area and lower contents of N and P. The leaves in the leeward region are vise versa. The results of the Principal Component Analysis showed a similar trend. From the view of leaf structure, one may classify the Nanjenshan Subtropical Rain Forest as the Sclerophylly Rain Forest in between the Warm Temperate and Subtropical Zone. When compared to other rain forests in the world, this site is similar to the Tropical Montane Rain Forest in the Central America.