POD was occurred apparently at the middle lamella, and then their signals extended rapidly from the middle lamella at the cell wall corner to S1 layer with S1 layer deposition.

• 形成层细胞阶段和伸展生长阶段，POD主要分布在径壁上，尤其是细胞壁角隅处和初生纹孔场附近的细胞壁。在次生壁S1层的沉积开始后，胞间层的POD反应强烈。