分化中の木部細胞膜内表面の電子顕微鏡観察法

Abstract

分化中の樹木木部細胞に原形質分離処理および凍結乾燥法を適用して, 形成段階の細胞膜の内表面を電子顕微鏡で観察する方法を試みた。樹幹より分化帯を含む木材ブロックを切り出し, 0. 8Mのショ糖の高張液で原形質分離をおこさせた。ついでそれより凍結切片を得, 凍結乾燥してカーボン一段レプリカを作製した。この方法を分化中のアカマツ仮道管の観察に適用した結果, 細胞内容物の付着のない, また乾燥に伴うアーティファクトの少ない仮道管膜内表面のレプリカ像を得ることができた。したがってこの方法は細胞膜の形成過程を追跡することによって木材細胞の膜層構造を研究する上に有用である。

A preparation method for electron microscopic studies of the inner surface of the cell wall in the differentiating cell is described. Two treatments are performed in the preparation of the material for replication: 1. the removal of the cytoplasm by plasmolysis and 2. the application of a freeze-drying method to aid the preservation of the newly formed wall in native condition. The block containing the xylem differentiating zone is first taken from the tree and then immersed in the high pertonic agent of saccharose of a concentration of 0.8 Mol/1. The radial longitudinal sections for replication are sliced from that block in frozen condition and freeze-dried after rinsing in the distilled water. Through the application of this method to the differentiating xylem of Pinus densiflora S. et. Z., it is possible to detect the innermost surface of the tracheid wall which is detached from the cytoplasm and free of the artificial modifications induced by drying (Figs. 2, 4, 5 and 6). This method makes it useful to observe the organization of the wood cell wall in the process of its formation.