Involvement of Microtubules on Nuclear Positioning during Apical Growth in Adiantum protonemata

Abstract

The position of the nucleus during apical growth of a single-celled protonema in Adiantum capillus-veneris under continuous red light was observed to find whether any cytoskeletons were involved in determining its location. The nucleus migrated through the filamentous cell keeping a constant distance of ca. 55 μm from the tip, but was not able to maintain this position in the presence of colchicine. The nuclei in most cells could be displaced by centrifugation at 110×g for 15 min in the presence of anti-micro-tubule drugs such as colchicine, ethyl N-phenylcarbamate and griseofulvin, but not when these drugs were absent. Similar treatment with cytochalasin B did not cause the displacing effect. These results suggest that microtubules have a role determining the position of the nucleus when it migrates during apical growth.