Diospyros Endosperm Tissue
The white holes are where the protoplasts are located. The purple-stained matrix is all primary cell wall. In these seeds, the food for the embryo is actually stored in these walls. The size of the primary walls makes both the middle lamella and the plasmodesmata visible with the light microscope. All primary walls have these features but we simply can't see them in most plant tissues..
White Arrows = Plasmodesmata
Yellow Arrows = Middle Lamella