Abstract
Stomatal movement that originates from changes in shape and volume of the guard cells is discussed in combination with the vacuolar structure. By using transgenic Arabidopsis thaliana line expressing GFP-AtVam3p, we reported last year that during stomatal closure, many intra-vacuolar membrane structures appeared and the surface area of stomatal vacuole increased. In this study, we investigated the origin of the increased vacuolar membrane (VM). Inhibition of the activity of phosphatidylinositol- 3-kinase that is involved in vesicle transport inhibited both the stomatal closure and the internalization of the VM. Measurement of fluorescence intensities of a vital staining-dye, FM4-64 that firstly incorporated into plasma membrane (PM) of Vicia faba guard cells, showed that its movement from PM to VM was accelerated in proportion to ABA-induced stomatal closure. These results suggest a possibility that excess PM produced during stomatal closure was stored as VM.
