Effects of the disaggregation of high-polymerized particles in guard cell vacuoles on osmoregulation of stomatal aperture (stomata opening)

摘要

Observation under an electron microscope reveals that in closed and open stomata of V. faba, the aver-age volume of particles in guard cell vacuoles (GCV) reduces about 3 orders in magnitude, while the distribution density of the particles increases about 2 orders of magnitude. By using the method of the ratio of fluorescent emissions with laser scanning confocal microscopy, the monitoring to sto-mata opening shows that during 10 to 30 s before the first distinguishable aperture of stomata, there is a change of pH in GCV about -0.5 units. A quick stomatal opening immedi-ately follows the changes of pH in GCV to reach a steady aperture about 12 mm in 100200 s. This work proposes a model for the osmoregulation in GCV for stomatal opening. The proposed osmoregulation is related to the disaggregation of some polymerized particles inside GCV, which is probably induced by a -DpH in the vacuole. This model describes a process of osmoregulation that avoids the massive energy consuming transportation across cell membranes, which is a foundation of the current chemiosmotic hypothesis. This model is a supplement to the multiple controlling hypothesis for the stomatal movement, which widens research principle ideas for other quick movements in plants.