Abstract
Transdifferentiation of matured cells to a totipotent stem cell is a well-known feat of plants, but the molecular mechanisms are mostly unexplored. We established a moss Physcomitrella patens as a model for the transdifferentiation, in which differentiated leaf cells of a dissected leaf turn into an apical stem cell within a couple of days. We developed a multiple-point timelapse imaging system to capture the entire process. Leaf cells that faced to the dissected dead cells were easy to change to a stem cell. The transdifferentiation did not require any exogenous phytohormones under the appropriate light conditions. The effective wavelengths of the light were in the blue and red regions, suggesting the involvement of cryptochrome and phytochrome mediated signaling. We also found a nuclear swelling during the transdifferentiation process and the changes of DNA contents during the process will be presented.