報告書番号

U98050

タイトル（和文）

レーザー誘起蛍光測定装置の開発とイネ葉内のクロロフィル含量の推定

タイトル（英文）

Development of the spectrometric imaging apparatus of laser induced fluorescence from plants and estimation of chlorophyll contents of rice leaves

概要 （図表や脚注は「報告書全文」に掲載しております）

紫外パルスレーザー（Nd:YAG）によって生葉からの蛍光を誘起し，その2次元画像およびスペクトルを計測する装置を開発した．パルス発光する誘起光源とイメージインテンシファイヤ付きCCDカメラ（ICCD）を用いると，青緑色域と赤色域のクロロフィル蛍光を照明下で測定可能なことを確認した．得られた蛍光を生葉の光合成能力の推定に用いるため，暗中で育成したクロロフィルを含まない黄化イネを光照射によって緑葉化させ，クロロフィル含量と光照射下での蛍光スペクトルを比較した．その結果，蛍光ピークの強度比（F460/F740および F510/F740）は，光照射時間の経過に従ってクロロフィル含量に比例して減少した．この指標は，従来クロロフィル含量の推定に用いられてきた方法（クロロフィル蛍光のピーク強度比F690/F740）に比べてクロロフィルが高い場合も少ない誤差で推定できることが明らかになった．

概要 （英文）

Photosynthetic activity of plants is an important factor to assess the micrometeorological effect of plant canopy or to estimate the influence of circumstances such as water stress. Light illumination induces fluorescence from a leaf or suspension of chloroplasts. The red chlorophyll fluorescence had been used to determine the process of the electron transportation in photosynthetic reaction. The fluorescence source other than chlorophyll is not announced sufficiently, but is supposed to be useful to determine the contents of the substance corresponding to physiological response of plants. We developed a fluorescence imaging apparatus to observe spectrum and distribution of laser induced fluorescence from a leaf. Pulsed UV-laser (Nd:YAG) induced blue-green fluorescence and red chlorophyll fluorescence from a green leaf. The pulse modulated measuring light and CCD with image-intensifier (ICCD) enable to detect the fluorescence from plants under illumination. The laser induced fluorescence (LIF) spectra were investigated to estimate the chlorophyll contents in leaves of rice. During the greening course of dark grown etiolated rice leaves, chlorophyll contents were determined using the extraction of leaves and steady state LIF spectra were measured. As a result, the ratio of fluorescent intensity between blue-green and red peaks (F460/F740 and F510/F740) decreased in proportion to alteration of chlorophyll contents respectively. These fluorescence intensity ratios perform more precise estimation of higher chlorophyll contents of leaves than reported red chlorophyll fluorescence intensity ratio (F690/F740).

報告者

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