台灣原生闊葉樹種75種的光合作用性狀及其耐陰性

Photosynthetic Characteristics and Shade-tolerance of 75 Native Broadleaf Tree Species in Taiwan

林倉億(Lin TSang-Yi)

指導教授 ： 郭耀綸

國立屏東科技大學/農學院/森林系所/碩士(2020年)

https://doi.org/10.6346/NPUST202100039

摘要

瞭解樹種的耐陰性對苗木培育或造林樹種選擇都很重要。本研究目的為測定臺灣75種原生闊葉樹種的光合潛力、光飽和點、光補償點及暗呼吸率等4項生理參數，並藉各樹種光合潛力判斷其耐陰性等級，增加臺灣原生樹種的耐陰性資料庫。本研究於屏東科技大學森林系苗圃、達仁林場、林試所蓮華池及恆春研究中心測定75種臺灣原生闊葉樹種的光合作用性狀。供測樹種中包括台灣特有種19種，受脅類別分屬於極危、瀕危、易危者分別有5、6及9種。於雨季期間上午7:00至11:00以攜帶式光合作用測定系統(LI-6400)進行測定，測定時將CO2 濃度控制在400 μl L-1。研究結果發現，此75 樹種的光合潛力範圍在8.7~37.1 μmol CO2 m-2 s-1 之間；光飽和點在960~1860 μmol photon m-2s-1；光補償點分布在9.2~36.8 μmol photon m-2s-1 之間；暗呼吸率範圍在0.95~3.09 μmol CO2 m-2s-1。其中光合潛力最高者為蘭嶼鐵莧，最低者為早田氏柃木。此75樹種依據其光合潛力，參考Kuo and Yeh (2015)的分級標準，得知先驅樹種有6種，陽性樹種有12種，中等耐陰樹種21種，耐陰樹種21種，極耐陰樹種15種。供試樹種的光合潛力分別與光飽和點、光補償點或暗呼吸率間皆呈極顯著正相關，今後可藉較易測得的光補償點或暗呼吸率初步判斷其耐陰性等級。本研究也發現樹種的光補償點或暗呼吸率在乾、雨兩季間具有顯著差異。本研究新增臺灣原生闊葉樹種75 種的耐陰性名錄，可供育林、園林植栽、樹種空間配置、林下經濟應用樹種選擇之參考。

關鍵字

暗呼吸率 ； 光補償點 ； 光合潛力 ； 耐陰性等級 ； 台灣原生樹種

並列摘要

Understanding the shade-tolerance of a tree species is critical for nursery practices and species selection in forestations. The objective of this study was to measure the photosynthetic capacity, light saturation point, light compensation point, and dark respiration of 75 native broadleaf tree species of Taiwan. Furthermore, the photosynthetic capacity would be used to determine the shade-tolerance level of each tree species and added valuable information to shade-tolerance database of Taiwan native tree species. The experiments were conducted in the nursery of Department of Forestry, National Pingtung University of Science and Technology, as well as in Tajen Experimental Forest Station, Lianhuachi and Hengchun Research Center of Taiwan Forestry Research Institute. In total, the photosynthetic characteristics of 75 tree species were measured. Among them, 19 species were endemic species of Taiwan, while 5, 6, and 9 species were Critically Endangered, Endangered, and Vulnerable species, respectively. From 7 to 11 am of each experimental day during the raining season, a LI-6400 portable photosynthesis system was employed to take the photosynthetic measurements of tested species with CO2 concentration maintained at 400 μl L-1. Results showed that, the photosynthetic capacity of the 75 species was in the range of 8.7 ~ 37.1 μmol CO2 m-2 s-1, light saturation point in the range of 960 ~ 1860 μmol photon m-2s-1, light compensation point in the range of 9.2 ~ 36.8 μmol photon m-2s-1, and dark respiration in the range of 0.95~3.09 μmol CO2 m-2s-1. Among them, Acalypha caturus had the highest while Eurya hayatae had the lowest photosynthetic capacity. According to the shade-tolerance classifying criteria by Kuo and Yeh (2015), there were 6 pioneer species, 12 shade intolerant species, 21 mid-tolerant species, 21 shade tolerant species, and 15 very shade tolerant species among the 75 tested species. The photosynthetic capacity of each tested species was positively correlated to light saturation point, light compensation point, and dark respiration, respectively. Thus, the more accessible measurements of light compensation point and dark respiration could be used to determine the shade-tolerance level of a species. This research also found that light compensation point or dark respiration of a species showed significant difference between dry and rainy season. The newly added data of shade-tolerance of these 75 native broadleaf tree species could serve as a reference for silvicultural practices, urban arboriculture, spatial allocation of tree species, and under-canopy economic use.

並列關鍵字

dark respiration ； light compensation point ； photosynthetic capacity ； shade-tolerance level ； Taiwan native tree species

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