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The stomatal response to CO 2 is linked to changes in guard cell zeaxanthin*
Author(s) -
Zhu J.,
Talbott L. D.,
Jin X.,
Zeiger E.
Publication year - 1998
Publication title -
plant, cell and environment
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.646
H-Index - 200
eISSN - 1365-3040
pISSN - 0140-7791
DOI - 10.1046/j.1365-3040.1998.00323.x
Subject(s) - guard cell , zeaxanthin , vicia faba , chemistry , biophysics , botany , biology , biochemistry , carotenoid , lutein
The mechanisms mediating CO 2 sensing and light–CO 2 interactions in guard cells are unknown. In growth chamber‐grown Vicia faba leaves kept under constant light (500 μ mol m –2 s –1 ) and temperature, guard cell zeaxanthin content tracked ambient [CO 2 ] and stomatal apertures. Increases in [CO 2 ] from 400 to 1200 cm 3 m –3 decreased zeaxanthin content from 180 to 80 mmol mol –1 Chl and decreased stomatal apertures by 7·0 μ m. Changes in zeaxanthin and aperture were reversed when [CO 2 ] was lowered. Guard cell zeaxanthin content was linearly correlated with stomatal apertures. In the dark, the CO 2 ‐induced changes in stomatal aperture were much smaller, and guard cell zeaxanthin content did not change with chamber [CO 2 ]. Guard cell zeaxanthin also tracked [CO 2 ] and stomatal aperture in illuminated stomata from epidermal peels. Dithiothreitol (DTT), an inhibitor of zeaxanthin formation, eliminated CO 2 ‐induced zeaxanthin changes in guard cells from illuminated epidermal peels and reduced the stomatal CO 2 response to the level observed in the dark. These data suggest that CO 2 ‐dependent changes in the zeaxanthin content of guard cells could modulate CO 2 ‐dependent changes of stomatal apertures in the light while a zeaxanthin‐independent CO 2 sensing mechanism would modulate the CO 2 response in the dark.