XVI International Botanical Congess

Ditylum brightwellii cells were plasmolysed in 0.5M NaCl, and the spherical protoplasts became free within the valve. Recovery was followed using time-lapse video microscopy. During recovery filopodia grew from the protoplast and attached to specific sites on the valve, it then expanded fully. Cells were treated with cytochalasin-D (CD), latrunculin B (LatB) and oryzalin at different stages of recovery. When CD and latB were used to treat cells before and during growth of filopodia, these continued to grow and attach to the valve at specific sites, but the protoplast did not expand. When cells were treated with oryzalin at the protoplast sphere" stage, the filopodia did not grow. Oryzalin added after filopodia began to grow caused those that were not attached to retract fully, implying that microtubules are essential for establishing structure within the cells.