Abstract: Triticum aestivum cv. “Yang Mai # 1” was used to study the celI wall formation in free-nuclear endosperm with electronmicroscopy and fluorescence microscopy. During the initiation of cellularization the peg-like wall ingrowths developed, and the freely growing walls gradually cleaved the cytoplasm into small compartments in both regions (ventral and dorsal) of the 'endosperm sac, but in ventral region the anastomose of freely growing wall often occured. The striking resemblance and close connection betwteen nucellar debris and freely growing walls showed the possibility that the disintegrated nucellus played an important role in supporting the wall formation of endosperm during the early stages of cellularization.

Key words: Triticum aestivum, Cellularization: Endosperm, Freely growing wall, Nucellus