Roles of actin filaments in cytoplasmic streaming and organization of transvacuolar strands in root hair cells of Hydrocharis

Effects of cytochalasin B and mycalolide-B on cytoplasmic streaming, organizations of actin filaments and the transvacuolar strand were studied in root hair cells of Hydrocharis, which shows reverse fountain streaming. Both toxins inhibited cytoplasmic streaming and destroyed the organizations of actin filaments and transvacuolar strands. However, we found a great difference between these toxins with respect to reversibility. The effects of cytochalasin B were reversible but not those of mycalolide B. The present results suggest that actin filaments work as a track of cytoplasmic streaming and as a cytoskeleton to maintain the transvacuolar strand. The usefulness of root hair cells of Hydrocharis in studying the dynamic organization of actin filaments of plant is discussed.