山楜椒、光葉柃木及錐果櫟樹苗的生長與生理對不同光環境的反應

Growth and Physiological Responses to Light Environment in Seedlings of Litsea cubeba, Eurya nitida var. nitida, and Cyclobalanopsis longinux

林文智(Wen-Chin Lin) ； 郭耀綸(Yau-Lun Kuo)

《作物、環境與生物資訊》 4卷4期 (2007/12) Pp. 297-306

https://doi.org/10.30061/CEB.200712.0003

摘要

山胡椒、光葉柃木及錐果櫟是南臺灣多納地區針闊葉林常見的樹種，此三樹種天然更新苗出現的光環境並不相同，前二種能在強光下更新而後者不能。本研究將此三樹種的盆栽苗分別培育在全光空地、樹冠孔隙（相對光量15%）、以及森林下方（相對光量3%），比較其生長與生理對不同光環境的反應。經過8個月的試驗，發現隨生長環境可用光量的增加，山胡椒與光葉柃木的全株生物量會顯著提高。山胡椒在全光環境下，會將82%的生物量分配在根部，犧牲莖葉的生長，在形態方面對高光有很明顯的馴化。然而，山胡椒在林下環境植株則呈匍伏狀，對低光馴化不良。錐果櫟在全光環境的生物量顯著低於孔隙環境，在形態上不能馴化於高光環境。在光合作用性狀方面，此三樹種苗木的光補償點、暗呼吸率及光飽和光合作用率(A(下標 sat))均以全光環境最高，林下環境最低。在全光與孔隙兩環境下，山胡椒的A(下標 sat)顯著高於光葉柃木及錐果櫟，但在林下環境卻以光葉柃木最高。光葉柃木的生長與生理對高光與低光都有良好的馴化。錐果櫟生長在全光環境的植株於2000 μmol m^(-2) s^(-1)高光時，光合作用率會遭光抑制而明顯降低。本研究三種樹苗的光合作用性狀隨光量改變的樣式都很類似，但各樹種在形態方面則對光量的反應樣式很不同，較能顯現各樹種馴化強光或低光能力的差異。

關鍵字

馴化 ； 生物量分配 ； 孔隙 ； 光環境 ； 光合作用

並列摘要

Litsea cubeba, Eurya nitida var. nitida, and Cyclobalanopsis longinux are three common tree species of a broadleaf-coniferous forest at Dona in the southern Taiwan. Light environments where natural recruits of these species occurred are different. The first two species can, while the third species can not, regenerate on open fields. In this study, seedlings of these species were grown in an open field, at a canopy gap (15% full light), and in forest understory (3% full light) to reveal their morphological and physiological responses to light environments. After eight months of treatment, biomass of L. cubeba and E. nitida increased significantly as the light availability increased. Litsea cubeba allocated 82% of its biomass to root in expense of stem and leaf biomass when grown in the open field, indicating well acclimated to high light. However, it became crawling on the ground when grown in the understory, which showed its poor acclimation to low light. Biomass of C. longinux in the open field was significantly less than those at the canopy gap, and morphologically it did not acclimate to high light. In the aspect of photosynthetic traits, all three species showed the highest light compensation point, dark respiration rate, and light-saturated photosynthetic rate (A(superscript sat)) in the open field, and the lowest in the understory. In both open and gap environments, L. cubeba had significantly higher A(superscript sat) than E. nitida and C. longinux. However, in the understory, E. nitida showed the highest A(superscript sat). Both morphological and physiological traits of E. nitida acclimated well to either high or low light environments. Photoinhibition occurred in photosynthesis of C. longinux grown in the open field when illuminated with high light of 2000 μmol m^(-2) s^(-1). We found that the patterns in the photosynthetic traits response to light environments were very similar for these three species. However, the patterns of their morphological traits response to light environments were very different. Thus, morphological responses could reveal the differences in acclimation ability to light environments for these species.

並列關鍵字

Acclimation ； Biomass allocation ； Gap ； Light environment ； Photosynthesis