Plant cell-size control: growing by ploidy?

The size of plant cells is determined by genetic, structural and physical f actors as well as by internal and external signals. Our knowledge of the mo lecular mechanisms of these controls is still rudimentary. Recent studies i ndicate that ploidy level exerts an important control on cell size. By incr easing ploidy, endoreduplication may allow cells to reach extraordinary siz es. This process is widespread in plants and may provide a means to manipul ate the cell volume.