臺灣原生440種木本植物的光合作用性狀及耐陰性

耐陰性是森林生態學及育林學的基礎概念，但卻少有樹種耐陰性的量化資訊。本研究藉光合潛力此生理功能性狀，判斷臺灣原生木本植物的耐陰等級。共測定了440種木本植物，包含434種雙子葉、1種單子葉、5種裸子植物的光合作用性狀。結果發現供試物種的光合潛力在7.8～37.2 μmol CO_2 m^(-2) s^(-1)範圍，光合潛力≥ 30.0 μmol CO_2 m^(-2) s^(-1)有10種，最高者為蘭嶼鐵莧（Acalypha caturus）；光飽和點範圍為740～1800 μmol photon m^(-2) s^(-1)；光補償點分布於7.9～34.6 μmol photon m^(-2) s^(-1)；暗呼吸率則在0.85～3.09μmol CO_2 m^(-2) s^(-1)。供試434種雙子葉類判斷為耐陰等級Ⅰ（極不耐陰）、Ⅱ、Ⅲ、Ⅳ、Ⅴ（極耐陰）者，分別有28、81、138、107、80種，顯示臺灣原生木本植物以中等耐陰之物種較多。所有物種4項光合性狀間都呈極顯著正相關，且光合潛力與光補償點兩者為接近1:1的關係。在屬的分類群，很少有同屬的不同物種全都歸類在同一個耐陰等級。在科的分類群，經計算全科物種耐陰性指標值，發現親緣關係較接近的幾個科，耐陰等級會相同或近似。此外，所有440物種只有17%為落葉性，耐陰等級Ⅰ、Ⅱ兩級分別有46及42%為落葉物種，而耐陰等級Ⅴ者均為常綠性。本研究已完成台灣原生種喬木類63%及灌木類15%，共計43%原生木本植物的耐陰等級歸類，可供園藝景觀設計、林業種苗培育、造林樹種選擇、生態復育等實務工作參考，也可供量化林分演替階段之用。

關鍵字

葉習性；光合潛力；親緣關係；生理功能性狀；耐陰等級

並列摘要

Shade tolerance is a fundamental concept of forest ecology and silviculture, yet little quantitative information concerning the shade tolerance of many species has been documented. This study classified the shade-tolerance levels of native woody species in Taiwan by their physiological functional traits, i.e., photosynthetic capacity (A_(max)). In total, the photosynthetic characteristics of 440 woody species, including 434 dicotyledons, 1 monocotyledon, and 5 gymnosperms, were measured. Results showed that A_(max) values of all tested species were in the range of 7.8~37.2 μmol CO_2 m^(-2) s^(-1), while 10 species showed A_(max) values of ≥ 30.0 μmol CO_2 m^(-2) s^(-1), with the highest being Acalypha caturus. Light saturation points of all species ranged 740~1800 μmol photon m^(-2) s^(-1); light compensation points (LCPs) ranged 7.9~34.6 μmol photon m^(-2) s^(-1); dark respiration rates ranged 0.85~3.09 μmol CO_2 m^(-2) s^(-1). Among the tested 434 woody dicotyledons, 28, 81, 138, 107, and 80 species were respectively classified as shade-tolerance level Ⅰ (very intolerant), Ⅱ, Ⅲ, Ⅳ, and Ⅴ (very tolerant). This indicated that most native woody species are moderate shade-tolerant species. The 4 photosynthetic characteristics of all species showed significantly positive relationships. In particular, A_(max) and LCP were nearly 1:1 linearly related. Results showed that only a few genera had congeners classified into the same shade-tolerance level. This study also calculated the shade-tolerance index of families, and found that phylogenetically related families had the same or similar shade-tolerance levels. In addition, only 17% of the 440 tested woody species were deciduous; 46 and 42% of the species in the shade-tolerance levels Ⅰ and Ⅱ were deciduous; but all species in shade-tolerance level Ⅴ were evergreens. This study classified shade-tolerance levels for 63% of native tree species and 15% of native shrub species, which added up to 43% of all native woody species of Taiwan. Data of this study provide practical references for horticultural landscape design, forestry nursery tending, species-site matching, and ecological restoration, as well as for quantifying successional stages of stands.

並列關鍵字

leaf habit ； photosynthetic capacity ； phylogeny ； physiological functional traits ； shade-tolerance level

國際替代計量

臺灣原生440種木本植物的光合作用性狀及耐陰性

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