1. A defined range of guard cell calcium oscillation parameters encodes stomatal movements.
- Author
-
Allen GJ, Chu SP, Harrington CL, Schumacher K, Hoffmann T, Tang YY, Grill E, and Schroeder JI
- Subjects
- Abscisic Acid metabolism, Arabidopsis cytology, Arabidopsis genetics, Electrophysiology, In Vitro Techniques, Mutation, Plant Leaves cytology, Plant Leaves metabolism, Arabidopsis metabolism, Calcium metabolism, Calcium Signaling genetics, Calcium Signaling physiology
- Abstract
Oscillations in cytosolic calcium concentration ([Ca2+]cyt) are central regulators of signal transduction cascades, although the roles of individual [Ca2+]cyt oscillation parameters in regulating downstream physiological responses remain largely unknown. In plants, guard cells integrate environmental and endogenous signals to regulate the aperture of stomatal pores and [Ca2+]cyt oscillations are a fundamental component of stomatal closure. Here we systematically vary [Ca2+]cyt oscillation parameters in Arabidopsis guard cells using a 'calcium clamp' and show that [Ca2+]cyt controls stomatal closure by two mechanisms. Short-term 'calcium-reactive' closure occurred rapidly when [Ca2+]cyt was elevated, whereas the degree of long-term steady-state closure was 'calcium programmed' by [Ca2+]cyt oscillations within a defined range of frequency, transient number, duration and amplitude. Furthermore, in guard cells of the gca2 mutant, [Ca2+]cyt oscillations induced by abscisic acid and extracellular calcium had increased frequencies and reduced transient duration, and steady-state stomatal closure was abolished. Experimentally imposing [Ca2+]cyt oscillations with parameters that elicited closure in the wild type restored long-term closure in gca2 stomata. These data show that a defined window of guard cell [Ca2+]cyt oscillation parameters programs changes in steady-state stomatal aperture.
- Published
- 2001
- Full Text
- View/download PDF