The large amount of PAO could be found in the cytoplasm of parenchyma in cotyledon and in the cell membranes and intercellular spaces of cortical parenchyma in phyllogen.

• 顶芽皮层薄壁组织细胞的细胞膜、细胞间隙和子叶薄壁组织细胞的细胞质也有PAO的大量分布。