チリメンドロの放射柔細胞一次壁の構造

Abstract

表面生長期にあるチリメンドロの放射柔細胞一次壁のミクロフィブリル配列をレプリカ法および超薄切片法を用いて電子顕微鏡で調べた。放射柔細胞は始原細胞から分化して行く間に伸長し, 最終的には約10倍程度の長さとなった。しかし, その間細胞壁の厚さはほとんど変化しなかった。また, 細胞壁中のミクロフィブリル配列は細胞の分化中を通じてほぼ一定しており, 細胞壁の内の方で細胞長軸に対して横方向のネット状, そして細胞壁の外側に向ってランダムネット状, さらに細胞壁の外の方で細胞長軸にほぼ平行であった。

The texture of microfibrils in the primary wall of ray parenchyma cell in poplar (Populus koreana REHD.) during surface growth was electron-microscopically investigated with the replication and ultrathinsectioning techniques. A ray parenchyma cell elongated remarkably in the radial direction during the differentiation from the ray initial, and the fully elongated cell was about ten times longer than the ray initial (Fig. 1). During elongation, however, there was little change in the thickness of the wall. Moreover the microfibrillar orientation remained constant in spite of considerable expansion of the wall; that is, throughout the differentiation of the cell the microfibrils of the inner part formed a transversely oriented mesh, and on passing outwards they became more randomly disposed, and then in the outer part of the wall they lay nearly parallel to the cell axis (Figs. 2 and 3). This result is consisted with the multi-net growth hypothesis proposed by ROELOFSEN and HOUWINK1), and explained by PRESTON6) with some modifications.