The Positioning of Chloroplasts Determines Their Positioning in the Protonemata of Physcomitrella patens

Abstract

The number of chloroplasts per cell is maintained virtually constant by chloroplast division and chloroplast partition at the time of cell division. But how chloroplasts are partitioned into daughter cells are not known in full detail yet. Protonema of Physcomitrella patens grows by tip growth or branching. We followed the positioning of chloroplasts with respect to the nucleus by continuous observation, and found only small changes in the positions.