Abstract
The phragmoplast develops through repeating polymerization/depolymerization of phragmoplast microtubules, which are harmonized with the development of the cell plate. To know mechanisms that harmonize these phenomena, we examined the deposition of callose into the cell plate during the development of the phragmoplast in aniline-blue stained living BY-2 cells expressing YFP-tubulin. Until the leading edge of the expanding cell plate reached the parental cell wall, the central, microtubule-free portion of the cell plate was brightly stained with aniline blue. When the cell plate reached the wall, the marginal region of the cell plate where microtubules still remained became to be stained brighter, indicating that the callose deposition itself does not trigger the depolymerization of phragmoplast microtubules. These results together with the previous result that caffeine inhibits both the depolymerization of phragmoplast microtubules and the callose deposition suggest that both phenomena are triggered by a same signal.
