遮陰對大葉楠與香楠苗木光合作用及生理之影響

Photosynthesis and Physiological Characteristics of Largeleaved Nanmu(Machilus kusanoi Hay.) and Incense Nanmu(Machilus zuihoensis Hay. Var. zuihoensis) Seedlings Grown Under Shading

本研究探討光度對大葉楠及香楠苗木光合作用及葉部生理的影響，試驗中不同的光度處理採人工遮陰，以不同密度的遮陰網調節試驗樣區內的相對光度，分別設置相對光度10 %、20 %、40 % 及60 % 四種處理及全光為對照。測定各處理苗木的葉部可溶性蛋白質含量、葉綠素含量、光合作用曲線並分析光合參數。二種供試樹種在葉綠素的含量及葉綠素的比值都表現出對光度變化之調適，且有極大的變幅，不同光度處理間皆成顯著的差異，隨著遮陰程度的增加，葉綠素的含量亦增加。葉部可溶性蛋白質的含量受到遮陰的影響有顯著差異，在相對光度40 % 及60 % 處理者有較高的含量。光合參數分析之結果顯示二樹種在不同光度的處理間，光量子效能無明顯差異；光補償點在大葉楠則隨光度之減少，明顯下降，香楠各處理間則無差異。依本試驗的結果顯示供試二個樹種皆屬陰性樹種，大葉楠適應光域的範圍較大，而香楠較窄且較偏陰性。在應用上大葉楠可能較適於孔隙栽植，而香楠則適合在林冠下層更新。 The purpose of this study was to investigate the response of different light intensities on the photosynthesis and physiological characteristics of Large-leaved Nanmu and Incense Nanmu seedlings. Different light treatments were provided with 10 %、20 %、40 % and 60 % relative sun-light intensities by artificial shaded, and full sun-light as control. Leaf soluble protein, chlorophyll contents, photosynthetical response curve and the parameters of photosynthesis were also investigated. The chlorophyll contents were significantly different according to light treatments, and increased with increasing shaded. Leaf soluble protein contents of two species show great amount on 40 % and 60 % light treatments. Quantum efficiency was not affected by different light treatments on two species. It showed lower light compensation point on shading of Large-leaved Nanmu. In contrast of all parameters, we could conclude that Large-leaved Nanmu has greater adaptation to different light intensities, and Incense Nanmu belongs to shade species.

The purpose of this study was to investigate the response of different light intensities on the photosynthesis and physiological characteristics of Large-leaved Nanmu and Incense Nanmu seedlings. Different light treatments were provided with 10 %、20 %、40 % and 60 % relative sun-light intensities by artificial shaded, and full sun-light as control. Leaf soluble protein, chlorophyll contents, photosynthetical response curve and the parameters of photosynthesis were also investigated. The chlorophyll contents were significantly different according to light treatments, and increased with increasing shaded. Leaf soluble protein contents of two species show great amount on 40 % and 60 % light treatments. Quantum efficiency was not affected by different light treatments on two species. It showed lower light compensation point on shading of Large-leaved Nanmu. In contrast of all parameters, we could conclude that Large-leaved Nanmu has greater adaptation to different light intensities, and Incense Nanmu belongs to shade species.