<論文・報告>コケの微細構造と機能

Abstract

京都大学フィールド科学教育研究センター北白川試験地で採取したコケを光学顕微鏡や電子顕微鏡で観察し，そのコケを構成する細胞の微細構造を明らかにし，その機能について考察した．採取したコケは，葉，茎，仮根からなり，葉は緑色で中央部に中肋が存在した．葉の横断面を観察すると，中肋の両側に葉身細胞が1列に並んでいて，先端部は舷と呼ばれる厚い細胞壁を持った細胞が存在した．中肋部分にはラメラと呼ばれる細胞一層から成る板状の組織が数層見られた．これらの形態的特徴から，採取した試料はタチゴケ（Atrichum undulatum (Hedw.)P. Beauv.）と判断した．透過電子顕微鏡で観察した葉身細胞は，葉緑体を含み，核やミトコンドリアなどの細胞小器官が存在した．細胞壁は厚く，葉身細胞間は多数の原形質連絡が存在した．これは，光合成産物の輸送に関連しているものと推察された． A moss species was collected at Kitashirakawa experimental station, Field Science Education and Research Center, Kyoto University, and observed under a light microscope, a scanning electron microscope and a transmission electron microscope for observing the ultrastructure of cells. The moss was composed of leaves, stem and rhizoid. Green colored leaves had the mid-rib at its center. Mesophyll cells lined up on both sides of the mid-rib to form the leaf blade. The border of a leaf is composed of the cells with thick cell wall. Several lamellae of mesophyll cells forming a single row were located at mid-rib. These morphological characters suggest that this moss is Atrichum undulatum (Hedw.) P. Beauv. Transmission electron microscopic observation reveals that mesophyll cell has a thick cell wall, and contains nuclei, mitochondria and several chloroplasts. The cells were connected each other with many plasmodesmata which might be involved in transportation of photosynthetic products.