Evolution of apical meristem structures in vascular plants with respect to plasmodesmatal network

用透射电子显微镜对被子植物、裸子植物和蕨类植物14科19种植物根尖分生组织的胞间连丝网络进行了比较。种子植物的根尖具有多细胞初始细胞，单位面积上的PD密度较低。相比之下，蕨类植物和一些只有一个顶端细胞的石蕊植物的根尖显示出比种子植物高三倍以上的PD密度。与顶端分生组织一样，根尖上的PD网络与顶端组织密切相关。

Plasmodesmatal (PD) networks in the root apical meristem were compared for 14 families and 19 species of angiosperms, gymnosperms, and pteridophytes, using transmission electron microscopy. Root apices of the seed plants, which have multicellular initial cells, show low PD densities per unit area. In contrast, root apices of ferns and some lycophytes, which have single apical cell, show high PD densities that are more than three-times higher than those of seed plants. Like the shoot apical meristem, PD networks in the root apex are strongly correlated to apical organizations.