Cell Wall Architecture Prerequisite for the Cell Division in the Protoplasts of White Poplar, Populus alba L.

White poplar (Populus alba L.) protoplasts were investigatedat 0, 3,10, 20 and 30 d after regeneration to visualize thecell wall architecture prerequisite for cell division. The 10day-old cells just before cell division developed a thin walllayer with uneven deposition of cell wall materials and weresaved from bursting by suspension in low osmotic medium. Thethree dimensional architecture of the cell wall, as revealedby rapid-freezing and deep-etching electron microscopy, in 10day-old cells, constituted thin innermost lamellae on the plasmamembrane along with highly extended micronbrillar networks.These results suggest that the deposition of thin lamellae isimportant not only for cells to withstand bursting but alsoto induce cell division. The present investigations give thefirst account of the visualization of the three-dimensionalarchitecture of regenerated cell wall right before cell division. (Received July 31, 1997; Accepted April 6, 1998)