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  • 學位論文

原位圍封採樣技術應用於4種臺灣針葉樹BVOCs動態變化之分析

Application of in situ Enclosure Sampling Technique on the Dynamic Change Analyses of BVOCs from Four Conifers in Taiwan

指導教授 : 張上鎮

摘要


森林釋出於空氣中的生物性有機揮發化合物(Biogenic volatile organic compounds,BVOCs)濃度很低,不易收集與分析,故有關臺灣森林立木BVOCs組成及含量的研究十分缺少。本研究主要目的係利用原位圍封採樣技術(in situ Sampling with enclosure technique)從事臺灣針葉樹立木葉子所釋出BVOCs之分析,試驗樹種包括紅檜(Chamaecyparis formosensis)、臺灣扁柏(C. obtusa var. formosana)、臺灣肖楠(Calocedrus macrolepis var. formosana)及柳杉(Cryptomeria japonica)。同時,也利用2種常見的方法—水蒸餾法(Hydrodistillation)及固相微萃取(Solid-phase microextraction, SPME)技術,分別萃取葉子精油與離體葉子(Detached leaves)所釋出之揮發成分,再以氣相層析質譜儀(Gas chromatography-mass spectrometry, GC-MS)及氣相層析火焰離子偵測器(Gas chromatography-flame ionization detector, GC-FID)分析它們的組成分並比較3種方法所得之結果。 原位圍封採樣所得BVOCs之分析結果顯示,紅檜與臺灣肖楠立木葉子所釋出BVOCs的主要成分為α-Pinene,它們於試驗期間的最大釋出速率分別為175及12,352 ng h-1 g-1,而柳杉及臺灣扁柏立木葉子所釋出BVOCs的主要成分則為Sabinene,它們的最大釋出速率分別為419及2,975 ng h-1 g-1,顯示原位圍封採樣技術能成功分析立木葉子釋出的BVOCs並能測得其釋出速率。 由GC-MS與GC-FID的分析結果得知,紅檜、臺灣扁柏、臺灣肖楠及柳杉葉子精油的主要揮發化合物分別為α-Pinene、cis-Thujopsenal、α-Pinene及ent-Kaurene;而臺灣扁柏離體葉子所釋出的主要揮發化合物為Thujopsene,其餘3種針葉樹皆為α-Pinene,顯示葉子精油或離體葉子所釋出的揮發化合物確實不同於立木葉子所釋出的BVOCs。 本研究以原位圍封採樣技術監測葉子BVOCs釋出速率的動態變化,並探討它與溫度及光度的關係。試驗結果顯示,4種針葉樹立木葉子BVOCs釋出速率皆會受溫度或光度的影響而改變。進一步分析得知,4樹種立木葉子BVOCs釋出速率與溫度均呈指數關係;柳杉及紅檜立木葉子釋出速率與光度為曲線關係,而臺灣扁柏與臺灣肖楠則為線性關係。根據柳杉立木葉子所有單萜類化合物釋出速率與溫度的指數關係,進一步標準化後可得標準釋出速率(Basal emission rate)3.775 µg h-1 g-1及β係數0.226oC-1,依此可估算單株柳杉及柳杉林單萜類化合物的釋出量分別為129.72 mg h-1 tree-1及1.06 mg h-1 m-2。 此外,臺灣肖楠枝條剪下後,無論向陽面或背陽面的葉子,它們BVOCs的組成與枝條未剪下前一樣,且釋出速率對溫度及光度的反應亦與枝條未剪下前相似,顯示剪下枝條的方式可應用於葉子不易圍封的林木,降低採樣的困難度,並有助於未來監測森林林木不同冠層葉子所釋出的BVOCs。

並列摘要


The concentration of biogenic volatile organic compounds (BVOCs) emitted from forest in the air is considerably low. Studies on their composition and content were very limited due to difficulties in BVOCs’ collection and analysis. The aim of present study is to analyze the BVOCs emitted from living leaves using the in situ sampling with enclosure tenchniques. Four coniferous species, Chamaecyparis formosensis, C. obtusa var. formosana, Calocedrus macrolepis var. formosana and Cryptomeria japonica grown in Taiwan were studied. Concurrently, two common methods, hydrodistillation and solid-phase microextraction (SPME), were used to collect the volatile components in the essential oils and detached leaves. The compositions of these volatile components were then analyzed using a gas chromatography-mass spectrometry (GC-MS) and a gas chromatography-flame ionization detector (GC-FID), and the results from these 3 methods were compared. Results from in situ sampling with enclosure tenchniques showed that α-pinene was the major BVOC emitted from living leaves of C. formosensis and C. macrolepis var. formosana. Their maximum emission rates were 175 and 12,352 ng h-1 g-1, respectively, during the experiment period. Sabinene was the major BVOC emitted from C. japonica and C. obtusa var. formosana and their maximum emission rates were 419 and 2,975 ng h-1 g-1, respectively. These results demonstrated that in situ sampling with enclosure technique can successfully analyze compositions and emission rates of the BVOCs emitted from living leaves of 4 coniferous species. Results from GC-MS and GC-FID showed that α-pinene, cis-thujopsenal, α-pinene and ent-kaurene were the major volatile components in the leaf essential oils of C. formosensis, C. obtusa var. formosana, C. macrolepis var. formosana and C. japonica, respectively. Results from SPME technique showed that thujopsene was the major volatile component emitted from the detached leaves of C. obtusa var. formosana, and α-pinene was the major compound emitted from the other 3 conifers. These results revealed that the compositions of volatile components in essential oils or detached leaves differed from that of BVOCs emitted from living leaves. Dynamic changes in emission rates of BVOCs emitted from living leaves were monitored via in situ sampling with enclosure technique. The relationships between emission rates and both temperature and light intensity were discussed in this study. Results obtained showed that the changes in temperature or light intensity affected the emission rates of BVOCs. The emission rates of major component from 4 conifers correlated with temperature in an exponential manner. Among 4 conifers, the emission rates of major component emitted from C. japonica and C. formosensis correlated with light intensity in a curve-like shape, while those from C. obtusa var. formosana and C. macrolepis var. formosana were a linear relationship. Two parameters, basal emission rate (3.775 µg h-1 g-1) and β coefficient (0.226oC-1), were obtained accroding to the exponential relationship between emission rate and temperature. Emission flux of the C. japonica studied and its stand were estimated to be 129.72 mg h-1 tree-1 and 1.06 mg h-1 m-2, respectively, by using the basal emission rate and β coefficient. Besides, the compositions of BVOCs emitted from leaves, whether sunlit or shaded leaves, in the intact and detached twigs of C. macrolepis var. formosana were consistent. Also, the emission rates of these BVOCs in response to temperature and light intensity were similar, indicating that detachment of twig did not affect the emission rates of BVOCs. Since this treatment reduces difficulties in collecting the BVOCs in situ, it could apply to the leaves hard to be enclosed. This easy practice can be used to monitoring the BVOCs emitted from leaves in different crowns of trees in the forest.

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被引用紀錄


林怡文(2017)。芬多精成分之生心理效益初探-以α-蒎烯及芳樟醇為例〔碩士論文,國立臺灣大學〕。華藝線上圖書館。https://doi.org/10.6342%2fNTU201700454

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