Abstract
Size of leaves is determined by cell number and cell size. These two parameters are dually affected in several mutants that exhibit "compensation" which consists of increase in cell size in response to reduction of cell number. In this study, to understand leaf size control, we analyzed several compensation-exhibiting mutants, namely fugu1 through fugu5, angustifolia3 and erecta mutants, and KIP-RELATED PROTEIN2 overexpressor. Comparative kinematic analyses revealed that compensation is induced after the exit from mitotic cycle. Ploidy-level analyses in the above-mentioned mutants revealed that endoreduplication is not essential but might partially contribute to increase cell size. Importantly, enhanced cell expansion in compensation-exhibiting mutants is mediated by either increase in expansion duration or expansion rate depending on mutation. These results suggest that compensation is not mediated by a single pathway, but at least two different pathways are involved in it. Positional cloning of fugu2 and fugu5 genes is now in progress.
