紅檜及台灣扁柏苗木於不同水勢及養分條件下之生長與生理性狀

The growth and physiological characteristics of Chamaecyparis formosensis and Chamaecyparis obtusa var. formosana seedlings grown under different water potential and nutrient regimes

王儷儒(Li-Ju Wang)

指導教授 ： 郭幸榮

國立臺灣大學/生物資源暨農學院/森林學研究所/碩士(2004年)

https://doi.org/10.6342/NTU.2004.01253

摘要

台灣原生檜木為珍貴的經濟樹種，為瞭解其生理生態習性及影響檜木林生長之環境因素，以利未來造林及林分經營之參考，本研究針對生長介質施以不同水勢及養分處理進行試驗，以模擬紅檜及台灣扁柏於自然狀態下可能遭遇的水分及養分逆境。本研究將生長介質水勢分為三級：田間容水量、-50kPa~-150kPa、-150kPa~-250kPa，養分分為四級： 50kgNha-1yr-1、100 kgNha-1yr-1、200 kgNha-1yr-1、300 kgNha-1yr-1。試驗日期為2002年3月至2004年2月。
試驗期間每日平均所需澆水量在兩樹種間有顯著差異，紅檜苗木之需水量及蒸發散量顯著大於台灣扁柏苗木。在充分供水狀況下，紅檜苗木之苗高生長量較台灣扁柏苗木大，但台灣扁柏於生長介質水勢較低時比紅檜有較高的生長潛勢；同一樹種之相對苗高在處理間無顯著差異，但在不同樹種間以紅檜苗木之相對苗高較大。另外，植物體內的養分積聚、乾重分配、脯胺酸濃度以及葉綠素濃度皆因處理組合及樹種不同而有顯著差異。
光合作用測定結果顯示，低光下台灣扁柏苗木之光量子效益較紅檜苗木高，但是補償點光量比紅檜低。以模式推估之最大光合作用速率在充分供水時兩樹種間無差異，但於缺水時台灣扁柏苗木之最大光合作用速率大於紅檜苗木。氣孔導度以紅檜較大，但台灣扁柏苗木之水分利用效率大於紅檜苗木。由上述結果推測，台灣扁柏苗木於較低的生長介質水勢時將較紅檜苗木有更高的適應能力。

關鍵字

水勢 ； 台灣扁柏 ； 苗木 ； 紅檜 ； 光合作用

並列摘要

Two indigenous cypresses are important economical tree species of Taiwan. In order to understand the physiological and ecological features as well as the possible environmental factors that influence the distribution of both cypresses for reference of future reforestation and forest management, this study simulates the natural stress that Taiwan false and yellow cypress would possibly experience via detailed analysis of different medium water potential treatments and nutrient classification. This experience classifies the medium water potential into three levels: field capacity, -50kPa ~ -150kPa and -150kPa ~ -250kPa, and the nutrients into four levels: 50kgN/ha/yr, 100 kgN/ha/yr, 200 kgN/ha/yr and 300 kgN/ha/yr. The experiment lasted from March 2002 to February 2004.
From the experiment, significant difference of average daily-required water supply was found between the two tree species. The water requirement and eva-transpiration of Taiwan false cypress seedling was significantly higher than that of Taiwan yellow cypress seedling. With adequate water supply, the seedling height growth of Taiwan false cypress was better than that of Taiwan yellow cypress. However, with comparatively low medium water potential, Taiwan yellow cypress has higher growth potential than Taiwan false cypress. The relative seedling height was of no significant difference in various treatments, but difference was found between the two species: the relative seedling height of Taiwan false cypress was larger. Furthermore, significant differences of nutrient accumulation and dry weight distribution in the plant bodies, proline concentration and chlorophyll content were found between various treatments and tree species.
The measurement results of photosynthesis rate show the light quantum yeild of Taiwan yellow cypress is higher than that of Taiwan false cypress under low light, but the light compensation point of Taiwan yellow cypress is lower than that of Taiwan false cypress. No significant difference of the assessment results of the maximum photosynthesis rate is found between the two species when adequate water supply is given. However, under inadequate water supply conditions, the maximum photosynthesis rate of Taiwan yellow cypress is higher than that of Taiwan false cypress. The water use efficiency of Taiwan yellow cypress is higher than that of Taiwan false cypress. Therefore, the results indicate Taiwan yellow cypress has higher ability to adapt to relatively low medium water potential than Taiwan red cypress.

並列關鍵字

photosynthesis ； seedlings ； Chamaecyparis obtusa var. formosana ； water potential ； Chamaecyparis formoensis

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