Thursday, December 15, 2016
Guard cell anion channels control stomatal movements
Molecular Plant Physiology and Biophysics laboratory, Julius-von-Sachs Institute for Biosciences, Würzburg University
Stomata play a key role in plant growth, as these pores in the leaf surface open to enable C02 – uptake, whereas they close to reduce the transpiration of water during drought. The movements of the stomata thus need to the tightly regulated, to balance the photosynthetic demand for C02, with the availability of water. We used combinations of intracellular microelectrode – and fluorescence microscopy techniques to study the signaling mechanisms that control stomatal movements. Light was shown to provoke stomatal opening by switching guard cells from a depolarized state in which they extrude K+ – ions, to a hyperpolarized state in which K+ is taken up. As a result, guard cells accumulate K+ salts in the light, which causes an increase in osmolites and provokes stomatal opening. This guard cell response is induced by photosynthetic active light, as well as the blue light specifically. Both light stimuli inhibit the activity plasma membrane anion channels. In contrast, signals that evoke stomatal closure, such as the drought hormone ABA, atmospheric C02 and Microbe Associated Molecular Patterns, cause activation anion channels. The signaling pathways that control the activity of guard cell anion channels and the interconnections between such pathways are currently studied and will be discussed during the presentation.
Contact : Anne-Aliénor Véry