Boodlea Cell Wall Microfibril Orientation Unrelated to Cortical Microtubule Arrangement

Abstract

Microfibril arrangement patterns and the relationship between microfibril and cortical microtubule arrangement were investigated in growing thallus cells in the coenocytic green alga. Boodlea coacta. The thallus exhibited tip growth with a slight spiral. Microfibril layers in the walls showed three characteristic fibril orientations: longitudinal, oblique, and transverse to the cell axis. The fibrils in each layer formed from the cell apex to the base. Cortical microtubules in the peripheral cytoplasm were always longitudinal. Newly formed, longitudinally oriented microfibrils were parallel to the cortical microtubules, but oblique and transversely oriented microfibrils never were. This is an indication that microfibril orientation in Boodlea cell walls is not necessarily related to cortical microtubule arrangement.