Abstract
In higher plants, actin microfilaments (MFs) have essential roles in cell morphogenesis. We have reported regulatory mechanisms of intracellular architecture by MFs via modification of vacuolar structures (Higaki et al. 2006). On the other hand, some reports suggested involvements of MFs in stomatal movements, which regulated by changes in the volume of guard cells. However, little is known about the dynamics of MFs in maintaining stomatal aperture at the optimum with diurnal cycle. In the present study, we examined the involvement of cytoskeletal events in stomatal movement. To observe MFs, we have established transgenic Arabidopsis plants expressing GFP-AtFim1 ABD2. Cortical MFs began to be organized in radial array following the increase in the stomatal aperture size. Thereafter, MFs became to be random array following the decrease in the aperture. These results suggest that organization of MF array of guard cells may control diurnal stomatal movement.
