ibclogo XVI International Botanical Congess


Abstract Number: 5295
Session = 20.16.1


SIGNAL TRANSDUCTION IN OPENING RESPONSES OF STOMATAL GUARD CELLSINDUCED BY BLUE LIGHT


Ken-ichiro Shimazaki & Toshinori Kinoshita, Dept. Biol., Fac. Sci., Kyushu Univ., Ropponmatsu, Fukuoka 810-8560, Japan


Stomata open through the activation of proton pump in guard cells by blue light (BL). In this study, we will present progresses in the signal transduction pathway leading to the pump activation. The pump is identified as the plasma membrane H+-ATPase. The ATP hydrolysis was stimulated by BL. Stimulation of ATP hydrolysis and proton pumping in guard cell protoplasts (GCPs) had a similar fluence requirement for BL. Both the pump activation in GCPs and light-induced stomatal opening in the epidermis were inhibited by protein kinase inhibitors, Ca2+-ATPase inhibitors in ER and by caffeine, which releases Ca2+ from the intracellular stores. We will discuss the activation mechanism of the H+-ATPase in relation to the phosphorylation status of the enzyme.


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