Abstract: The seed coat of Acacia mangium was investigated by light and scanning electron microscopy. The testa comprises a palisade epidermis, an osteosclerid layer and a thick-walled parenchyma with lignified walls, a thin cuticle covering a pectinaceous subcuticular layer which together form the outer covering of the layer of palisade cells. It is indicated that the impermeability barrier lies in the palisade layer, and suggested that light line zone situated on the outer ends of the palisade is surrounded by a compact layer of cellulous, which is probably responsible for the optical phenomenon known as the light line.

Key words: Acacia mangium, Seed coat anatomy, Light line

摘要： 马占相思种子的休眠由种皮的不透性引起，其种皮结构可分为4层：角质与角质下层、栅栏细胞层、骨状石细胞层、薄壁细胞层。引起种皮不透性的部位主要位于栅栏细胞层。明线的产生可能是由于该区域两侧纤维素的密集压缩引起的一种光学现象。

关键词: 马占相思, 种皮结构, 明线