山鹽菁、山水柳在石灰石礦區及控制環境下之光合成氣體交換反應

Photosynthetic Gas Exchange Responses of Roxburgh Sumac and Dense-Flowered False-Nettle in Limestone Mining Spoil and in Controlled Environments

林信輝(Shin-Hwei Lin)

《中華水土保持學報》 26卷2期 (1995/06) Pp. 103-120

https://doi.org/10.29417/JCSWC.199506_26(2).0004

摘要

爲探討山鹽菁興山水柳葉片光合成作月、氣孔導度等氣體交換反應，分別以高雄縣大崗山石灰石礦區棄石地自然群落及控制環境下生長之植物，探討其對主要環境因子之反應性差異。有關試驗結果如下：（1）山鹽菁之光補償點爲70〜110 μmol m^(-2) S^(-1)，山水柳則低於50 μmol m^(-2) s^(-1)，低光下山水柳之用水放率高於山鹽菁。兩種植物對高溫之反應性不同，高溫（40°C）下山鹽菁之葉片淨光合成率甚低，此與其氣孔反應有關。（2）生長在CO_2濃度700 ppm之生長箱內5個月後，山鹽菁之光合成率具明顯受抑制現象。其A / C_i，曲線在C_i大於250 ppm後光合成率之增加值甚小，而山水柳則無此現象。（3）斷水處理過程中，山水柳之氣孔反應略較山鹽菁敏感，而山鹽菁能在高土壤水分應力下維持較高之光合成率。兩種植物之耐旱性均高。（4）在石灰石礦區於晴天強光下測得山鹽菁之淨光合成率，多季之測值爲2〜4 μmol m^(-2) s^(-1)，生長季節之測值爲8〜12 μmol m^(-2) s^(-1)。山水柳冬季爲3〜7 μmol m^(-2) s^(-1)，生長季節爲8〜13 μmol m^(-2) s^(-1)。此略高於一般闊葉林樹種，但仍低於試區其他優勢植物。估算所得山鹽菁之用水效率介於0.65〜1.99 μmol CO_2/mmol H_2O之間。山水柳介於0.69〜3.12 μmol CO_2/mmol H_2O之間。另外，本文亦綜合探討石灰石礦區棄土場之立地特性，礦區環境下山鹽菁與山水柳之光合成特性及其生態習性等，期建立基本資料，供礦區植生復育之參考。

關鍵字

石灰石礦區 ； 物理環境 ； 光合成率 ； 氣孔導度 ； 生理反應

並列摘要

Net photosynthetic rate (P_n), stomatal conductance (g_s) and related characters of Roxburgh Sumac (Rhus javanica var. roxburghiana) and Dense-flowered False-nettle (Boehmeria densiflora) were measured in limestone mining area and in controlled environments. The results obtained were as follows: (1) Within the assimilation chamber, light compensation point of Roxburgh Sumac is 70~100 μmol m^(-2) s^(-1) and Dense-flowered False-nettle was below 50 μmol m^(-2) s^(-1). Dense-flowered False-nettle has higher water use efficiency under low light intensity. P_n of Roxburgh Sumac was very low at high temperature (40°C). That could be related to stomatal response. (2) According to the A/C_i curve, Roxburgh Sumac had acclimated after growing under elevated CO_2 concentration (700 ppm) for 5 months, but Dense-flowered False-nettle had not. (3) Stomatal response of Roxburgh Sumac was more sensible than Dense-flowered False-nettle during water withholding process, Roxburgh Sumac can remain higher photosynthesis during high water stress. Drought resistance of two species was greater than general woody plants. (4) P_n of Roxburgh Sumac measured in the field at 9:00 AM to 2:30 PM of fine day were 2~4 μmol m^(-2) s^(-1) in winter and 8~12 μmol m^(-2) s^(-1) in growing season, while Dense-flowered False-nettle were 3~7 and 8~13 μmol m^(-2) s^(-1). Calculated water use efficiency of Roxburgh Sumac was 0.65~1.99 μmol CO_2/mmol H_2O, while Dense-flowered False-nettle was 0.69~3.12 μmol CO_2/mmol H_2O. In addition, the site characteristics of limestone mining area, photosynthetic rate affected by environmental factors and ecological habitats of Roxburgh Sumac and Dense-flowered False-nettle were also discussed in this paper.

並列關鍵字

Limestone Mining Area ； Physical Environment ； Photosynthetic Rate ； Stomatal Conductance ； Physiological Responses