Olena Zamora, 
Sebastian Schulze, 
Tamar Azoulay-Shemer, 
Helen Parik, 
Jaanika Unt, 
Mikael Brosché,
 Julian I. Schroeder, 
Dmitry Yarmolinsky, 
Hannes Kollist

Jasmonic acid (JA) and salicylic acid (SA) regulate stomatal closure, preventing pathogen invasion into plants. However, to which extent abscisic acid (ABA), SA, and JA interact and what the roles of SA and JA are in stomatal responses to environmental cues remains unclear. Here, by using intact plant gas-exchange measurements in JA and SA single and double mutants, we show that stomatal responsiveness to CO₂, light intensity, ABA, high vapor pressure deficit, and ozone either did not or for some stimuli only very slightly depended on JA and SA biosynthesis and signaling mutants, including dde2, sid2, coi1, jai1, myc2, and npr1 alleles. While stomata in the studied mutants clearly responded to ABA, CO₂, light, and ozone, ABA-triggered stomatal closure in npr1-1 was slightly accelerated comparing with the wild type. Stomatal re-opening after ozone pulses was quicker in the coi1-16 mutant than in the wild type. In intact Arabidopsis plants, spraying with methyl-JA led to only a modest reduction in stomatal conductance 80 min after the treatments, whereas ABA and CO₂ induced pronounced stomatal closure within minutes. We could not document a reduction of stomatal conductance after spraying with SA. Coronatine-induced stomatal opening was initiated slowly after 1.5-2 h and reached a maximum in 3 h after spraying intact plants. Our results suggest that ABA, CO₂ and light are major regulators of rapid guard cell signaling, whereas JA and SA could play only minor roles in whole-plant stomatal response to environmental cues in Arabidopsis and tomato.