Langdale J A, Lane B, Freeling M, Nelson T
Department of Biology, Yale University, New Haven, Connecticut 06511.
Dev Biol. 1989 May;133(1):128-39. doi: 10.1016/0012-1606(89)90304-7.
Maize leaves are divided into repeated longitudinal units consisting of vascular tissue, bundle sheath (BS), and mesophyll (M) cells. We have carried out a cell lineage analysis of these cell types using six spontaneous striping mutants of maize. We show that certain cell division patterns are preferentially utilized, but not required, to form the characteristic arrangement of cell types. Our data suggest that early in development a central cell layer is formed, most frequently by periclinal divisions in the adaxial subepidermal layer of the leaf primordium. Lateral and intermediate veins are initiated in this central layer, most often by divisions which contribute daughter cells to both the procambium and the ground meristem. These divisions generate "half vein" units which comprise half of the bundle sheath cells around a vein and a single adjacent M cell. We show that intermediate veins are multiclonal both in this transverse direction and along their lengths. BS cells are more closely related to M cells in the middle layer of the leaf than to those in the upper and lower subepidermal layers. An examination of sector boundaries has shown that photosynthetic differentiation in M cells is affected by the phenotype of neighboring BS cells.
玉米叶片被划分为由维管组织、维管束鞘（BS）和叶肉（M）细胞组成的重复纵向单元。我们利用玉米的六个自发条纹突变体对这些细胞类型进行了细胞谱系分析。我们发现某些细胞分裂模式被优先利用，但并非形成细胞类型特征排列所必需。我们的数据表明，在发育早期形成了一个中央细胞层，最常见的是通过叶原基近轴表皮下层的平周分裂形成。侧脉和中间脉在这个中央层起始，最常见的是通过向原形成层和基本分生组织都贡献子细胞的分裂。这些分裂产生“半脉”单元，其围绕一条脉包含一半的维管束鞘细胞和一个相邻的M细胞。我们表明，中间脉在这个横向方向及其长度上都是多克隆的。与叶片上下表皮层的M细胞相比，维管束鞘细胞与叶片中层的M细胞关系更密切。对扇形边界的检查表明，叶肉细胞中的光合分化受相邻维管束鞘细胞表型的影响。
