南仁山森林四種台灣特稀有樹種之光合作用光反應及溫度反應

Photosynthetic Light and Temperature Responses of 4 Rare and Endemic Tree Species in the Nanjenshan Forest, Taiwan

郭耀綸(Yau-Lun Kuo) ； 陳瑄培(Hsuan-Pei Chen)

《台灣林業科學》 20卷3期 (2005/09) Pp. 215-226

https://doi.org/10.7075/TJFS.200509.0215

摘要

希蘭灰木、細葉茶梨、小葉樟及烏心石舅是台灣特有且稀有樹種。本研究探討此4樹種在南仁山森林冬夏兩季的光合作用溫度反應及光反應，藉以了解各樹種的生理耐性範圍。光合作用溫度反應測定結果，此4樹種樹冠上層陽葉的光合作用最適溫度在夏季比下層陰葉高，但在冬季相反，比下層陰葉低。此4樹種光合作用最適溫度有明顯季節馴化能力。在冬季此4樹種陽葉的光合作用最適溫在22~25℃之間，由冬季到夏季，陽葉可提高5~6℃而陰葉只提高2~4℃。希蘭灰木無論在冬季或夏季，其光合作用最適溫均比其它3種低2~3℃，且生理適溫範圍也較另3樹種廣，顯示本樹種可生育在溫度較低的環境。此4樹種光合作用最適溫雖有季節改變，但最適溫時的淨光合作用率在冬夏兩季並無顯著差異。夏季光反應測定結果，烏心石舅陽葉的光飽和光合作用率可達7.2 μmol m^(-2)s^(-1)，其它3種在5.7~6.7μmol m^(-2)s^(-1)間，由此生理性狀判斷這4樹種均為耐陰樹種。本研究也發現此4樹種陽葉的光飽和光合作用率在冬夏兩季均無顯著差異，光合作用潛力對溫度的馴化明顯。

關鍵字

光合作用最適溫度 ； 希蘭灰木 ； 細葉茶梨 ； 小葉樟 ； 烏心石舅

並列摘要

Anneslea lancolata Kaneh, Cinnamomum brevipedunculatum Chang, Magnolia kachirachirai Dandy, and Symplocos shilanensis Liu & Lu are all rare and endemic tree species in Taiwan. In order to reveal their ability to physiologically adjust to temperature and light, the photosynthetic temperature responses and light responses of these species in the Nanjenshan Forest were measured during the summer and winter Results from the summer measurements showed that sun-exposed leaves of the upper canopy had higher optimum temperatures for photosynthesis (T(subscript opt)) than did shaded leaves. In contrast, the opposite results were measured in winter The T(subscript opt) in sun-exposed leaves of the 4 species were between 22 and 25℃ in winter In comparison to results from summer measurements, T(subscript opt), increased 5~6 and 2~3 ℃ for sun-exposed and shaded leaves, respectively, indicating significant seasonal acclimation abilities of all 4 species. The T(subscript opt) of S. shilanensis was 2~3℃ lower than that of the other 3 species in both seasons. Furthermore, S. shilanensis with a wider temperature range for optimum photosynthesis might have the ability to grow in cooler environments than the other 3 species. In addition, sun-exposed leaves of all 4 species had higher net photosynthetic rates at the optimum temperature (A(subscript opt)) than did shaded leaves measured in the same season. However, no seasonal difference was found in A(subscript opt) either in sun-exposed or in shaded leaves of each species. The light-saturated photosynthetic rate (A(subscript sat)) of sun-exposed leaves of M. kachirachirai in the summer was 7.2 μmol m^(-2)s^(-1), and those of the other 3 species were only 5.7~6.7 μmol m^(-2)s^(-1). These low A(subscript sat) values revealed that all 4 species are shade-tolerant species. There were no seasonal differences in A(subscript sat) values for sun-exposed leaves of any of these species. All 4 species exhibited high degrees of temperature acclimation in terms of their photosynthetic capacity.

並列關鍵字

optimum temperature for photosynthesis ； Anneslea lancolata ； Cinnamomum brevipedunculatum ； Magnolia kachirachirai ； and Symplocos shilanensis