Cytoskeletal pattern changes during branch formation in a centrifugedAdiantum protonema

Branch formation induced by microbeam irradiation ofAdiantum protonemata

“…In the former case of branch formation, as detected by cell swelling, branch development starts before the nucleus reaches the area where the branch develops (Wada 1995, Wada et al 1998. In the latter case, a branch develops only after the nucleus moves into the area (see Fig.…”

“…In branch formation near a septum under whole cell irradiation, a transient, ring like set of microtubules appears at the presumptive site of branching and disappears before branch formation (Wada et al 1998). This microtubule ring may play a role in the positioning of the branching site, similar to the preprophase band of microtubules (Wick 1991), or as an anchor for nuclear migration towards the branching site (Wada et al 1998).…”

“…~n these cells, division occurs after centrifugation because of the previous white light irradiation, and the daughter nuclei move away from the septum. A ring of microtubules appears near the septum transiently before branch initiation (Wada et al 1998), similar to the preprophase band which predicts the alignment of the new cell wall after division (Wick 1991). Since a branch develops near the septum where the microtubule ring existed in the apical and/ or basal cells, and the nuclei come back near the septum (Wada 1995), the ring of microtubules at the septum appears to predict the position of the new branch (Wada et al 1998).…”

“…Plant materials, methods for culturing, microtubule staining and observation were the same as described in previous papers (Wada 1995, Wada et al 1998. Briefly, spores of Adiantum capillus-veneris were harvested in a greenhouse of Tokyo Metropolitan University and stored in a refrigerator until use.…”

“…In the dark, branching never occurs and microtubules run parallel to the cell axis (see Fig. 2a of Wada et al 1998). Three to four hours after the onset of the red microbeam irradiation, microtubules surrounding the beam-irradiated area changed their pattern from parallel to oblique (Fig.…”