不同耐陰性樹種葉片達最大光合潛力葉序之比較

Comparisons of Leaf Position in Reaching Maximum Photosynthetic Capacity for Tree Species with Various Tolerance Statuses

顏君靜(Chun-Ching Yan)

指導教授 ： 郭耀綸

國立屏東科技大學/農學院/森林系所/碩士(2013年)

https://doi.org/10.6346/NPUST.2013.00217

摘要

光合作用為植物重要之生理參數，研究人員選取葉片進行光合作用測定時，通常選擇形態成熟之葉片。然而，不同樹種葉片的形態及生理成熟時間不盡相同，因此本研究探討不同耐陰性樹種在何葉序有最大的光合潛力(Amax)。供試樹種包括山芙蓉、山黃麻、野桐、欖仁、水柳、茄苳及稜果榕等7種陽性樹種，香楠、紫黃、烏心石及銀葉樹4種中等耐陰樹種，以及種白樹仔、毛柿、黃心柿、柿葉茶茱萸、蘭嶼肉豆蔻、瓊楠、蘭嶼胡桐及鐵色8種耐陰樹。本研究藉兩種方法探討光合潛力在何葉序達到最大值，其一為連續監測稜果榕、紫黃及銀葉樹三樹種同一葉片從初展葉到該葉片達Amax後，下降至80% Amax的動態變化(連續測定法)。第二種方法是在短期內測定19種樹種，同一枝條不同葉序的光合潛力狀態(非連續測定法)。
連續測定法試驗結果發現，種稜果榕、紫黃及銀葉樹的葉片分別在葉齡第28、21及91天達最大光合潛力。稜果榕達最大光合潛力的葉序為第5葉序、紫黃為第5葉序，銀葉樹則為第9葉序。此3樹種達生理旺盛期的葉序範圍，分別是稜果榕第4 ~ 7葉序，紫黃第4 ~ 9葉序及銀葉樹第6 ~ 12葉序。
非連續測定法試驗結果發現，7種陽性樹種達最大光合潛力的葉序可分成3類樣式，第一類為分布在第3葉序，包括稜果榕、欖仁及山黃麻等3種；第二類為分布在第7葉序，為山芙蓉及野桐；第三類則是分布在第13 ~ 17葉序，為茄苳及水柳。中等耐陰樹種香楠、紫黃、烏心石及銀葉樹達最大光合潛力的葉序皆分布在第7葉序。耐陰樹種8種達最大光合潛力的葉序亦可分為3類樣式，第一類為分布在第3葉序，瓊楠及白樹仔即為如此；第二類為第5 ~ 7葉序，共有蘭嶼肉豆蔻、黃心柿、鐵色、柿葉茶茱萸及蘭嶼胡桐等5樹種；而第三類則是分布在第10~12葉序，只有毛柿一種。
藉連續及非連續兩測定法比較，發現稜果榕及銀葉樹達Amax之葉序沒有顯著不同，而紫黃在兩測定方法比較結果有顯著不同。本研究也發現長葉間隔天數較短的樹種，達最大光合潛力的葉片會出現在較後面的葉序。而比葉重較大的葉片，長葉間隔的時間會較長。綜上所述，本研究發現不同樹種葉片達最大光合潛力的葉序會因樹種而異，中等耐陰的樹種該葉序出現在第7葉序，而陽性樹種及耐陰性樹種該葉序並無一致性。

關鍵字

連續測定法 ； 非連續測定法 ； 葉序 ； 最大光合潛力 ； 耐陰性

並列摘要

Photosynthesis is an important physiological activity for a plant. Researchers usually choose morphologically mature leaves when measuring the plant’s photosynthesis. However, different species varies at the times of morphological maturity and physiological maturity. The objective of this study was to compare the leaf positions in reaching maximum photosynthetic capacity (Amax) for tree species with various shade-tolerant statuses, including pioneer, moderate shade-tolerant and shade-tolerant species. This study investigated 7 pioneer species, (i.e. Hibiscus taiwanensis, Trema orientalis, Mallotus japonicus, Terminalia catappa, Salix warburgii, Bischofia javanica, and Ficus septica), 4 moderate shade-tolerant species, (i.e. Machilus zuihoensis, Margaritaria indica, Michelia compressa, and Heritiera littoralis), and 8 shade-tolerant species (i.e. Gelonium aequoreum, Diospyros philippensis, D. maritima, Gonocaryum calleryanum, Myristica ceylanica var. cagayanensis, Beilschmiedia erythrophloia, Calophyllum blancoi, and Drypetes littoralis). The experiment was conducted with two methods. First, a continuous monitoring method was employed to monitor the dynamics of photosynthesis from a leaf’s initial expanding to maturity as Amax is reached and then reduced to 80% in Fic. septica, Mar. indica, and Her. littoralis. The second method (non-continuous monitoring method) measured the photosynthetic capacity of leaves at different positions along a same branch in 19 species. The results from these two methods were compared, and suitable species for each method were recommended.
Results of the continuous monitoring method showed that, for Fic. septica, Mar. indica, and Her. Littoralis, Amax was reached at 28 d, 21 d, and 91 d, respectively, and the leaf position at which Amax was reached was at the 5th, 5th, and 9th, respectively. Optimum physiological activites were detected in leaf positions of 4th~7th, 4th~9th, and 6th~12th for Fic. septica, Mar. indica, and Her. Littoralis, respectively.
Results of the non-continuous monitoring method showed that the leaf position at which Amax was reached in the 7 pioneer species could be classified into three types. The first type was at the 3rd position, including Fic. septica, Ter. catappa, and Tre. orientalis; the second type was at the 7th position, including Hib. taiwanensis and Mal. japonicus; the third type was between the 13th and the 17th position, including Bis. javanica and Sal. warburgii. All four moderate shade-tolerant species (i.e. Mac. zuihhoensis, Mar. indica, Mic. compressa, and Her. littoralis) reached Amax at the 7th leaf position. The leaf position at which Amax was reached in the 8 shade-tolerant species could also be classified into three types. The first type was at the 3rd position, including Bei. erythrophloia and Gel. aequoreum; the second type was between the 5thand the 7th position, including Myr. ceylanica var. cagayanensis, Dio. maritima, Dry. littoralis, Gon. calleryanum, and Cal. blancoi; the third type was between the 10th and the 12th position, and only Dio. philippensis belonged to this type.

Comparing the leaf positions for reaching Amax by the two methods, no significant differences were found in Fic. septica and Her. Littoralis; however, significant difference was found in Mar. indica. In addition, the species with shorter intervals for generating new leaves, Amax would be reached at the leaf of latter position. Moreover, species with larger leaf mass per area had longer intervals for generating new leaves.
In conclusion, leaf positions at which Amax was reached varied with different species. This position was at the 7th leaf position for moderate shade-tolerant species, while it was not consistent for pioneer and shade-tolerant species.

並列關鍵字

continuous monitoring method ； non-continuous monitoring method ； leaf position ； maximum photosynthetic capacity ； shade-tolerance

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