著者

前田 敏 小島 均

出版者

九州大学

雑誌

九州大學農學部學藝雜誌 (ISSN:03686264)

巻号頁・発行日

vol.17, no.1, pp.33-39, 1959-03

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It was said that, in general, foliar-absorbed P-32 moves through the phloem of the stem both upward and downward from the leaf, or ascendes the stem through the xylem and descendes through the phloem. However, it was also reported that, when the radiophosphorus was accompanied by a large amount of water, it was transported in the stem both upward and downward chiefly through the xylem. As the m o re definitive observations on these problems were desirable the authors made researches with the macro-as well as microautoradiography method. Submerging the leaf entirely in a P-32 aq., the radiophosphorus was ab s orbed with relatively rich amount of water through the leaf surface. Then the P-32 movcd upward and downward in the stem ; and the microautoradiograph on the section of stem above the leaf which absorbed the solution showed that the radioactive substance was found merely in the contents of the vessel or in the xylem. The macroautoradiograph of the total stem of the plant and the radioactivity (measured with the G. M. counter) in the ash of leaves of the plant also proved that the radioactive phosphorus moved through the vascular bundle system.葉面吸収後の物質の移行経路は, 一般に師管を通つて上下するか, 或いは道管を経て上り, 師管を経て下るものとされている. しかし, 葉面吸収に際し大量の吸水を伴う場合には蒸散流の影響のため上下向とも主として木部を通ると云う報告があり, 筆者らはこれを microautoradiography によつて検討した. その他 macroautoradiography 及び G. M. counter による組織のradioactivityの測定等の知見から次の様なことが云える. 葉をP-32水溶液につけてP-32と共に大量の水を吸わせると, 水は吸収させた葉から葉柄を経て上方下方に進むが, 此の様な場合には, P-32は根からの上方への移行と同様に大部分道管を通つて上方に移動するものと思われる.