Cell-wall regeneration in pollen-tube subprotoplasts

Pollen-tube subprotoplasts of Nicotiana tabacum L. regenerate a new cell-wall with a random texture and a relatively high content of P 1-3 glucan (callose). The subprotoplasts become vacuolized during culture, and both the cytoplasm and wall deposition are limited to a single site of the subprotoplast. After 8 h of culturing, wall formation becomes restricted to a very small area and a fibre-like structure evolves. Fibre formation seems to result from a spontaneous clustering of multiple wall-synthesizing sites. These sites probably give rise to the different strands seen in the fibre. Wall deposition and fibre formation take place independent of the presence of a nucleus or microtubules and actin filaments.