Cytoplasmic calcium elevations, transients, and oscillations are thought to encode information that triggers a variety of physiological responses in plant cells. Yet Ca2+ signals induced by a single stimulus vary, depending on the physiological state of the cell and experimental conditions. We compared Ca2+ homeostasis and stimulus-induced Ca2+ signals in guard cells of intact plants, epidermal strips, and isolated protoplasts. Single-cell ratiometric imaging with the Ca2+-sensitive dye Fura 2 was applied in combination with electrophysiological recordings. Guard cell protoplasts were loaded with Fura 2 via a patch pipette, revealing a cytoplasmic free Ca2+ concentration of around 80 nM at -47 mV. Upon hyperpolarization of the plasma membrane to -107 mV, the Ca2+ concentration increased to levels exceeding 400 nM. Intact guard cells were able to maintain much lower cytoplasmic free Ca2+ concentrations at hyperpolarized potentials, the average concentration at -100 mV was 183 and 90 nM in epidermal strips and intact plants, respectively. Further hyperpolarization of the plasma membrane to -160 mV induced a sustained rise of the guard cell cytoplasmic Ca2+ concentration, which slowly returned to the prestimulus level in intact plants but not in epidermal strips. Our results show that cytoplasmic Ca2+ concentrations are stringently controlled in guard cells of intact plants but become increasingly more sensitive to changes in the plasma membrane potential in epidermal strips and isolated protoplasts.
%0 Journal Article
%1 RN1139
%A Levchenko, V.
%A Guinot, D. R.
%A Klein, M.
%A Roelfsema, M. R. G.
%A Hedrich, R.
%A Dietrich, P.
%D 2008
%J Protoplasma
%K calcium myOwn
%N 1-2
%P 61-72
%R 10.1007/s00709-008-0307-x
%T Stringent control of cytoplasmic Ca
in guard cells of intact plants compared to their counterparts in epidermal strips or guard cell protoplasts
%U /brokenurl#<Go to ISI>://WOS:000259188100007
%V 233
%X Cytoplasmic calcium elevations, transients, and oscillations are thought to encode information that triggers a variety of physiological responses in plant cells. Yet Ca2+ signals induced by a single stimulus vary, depending on the physiological state of the cell and experimental conditions. We compared Ca2+ homeostasis and stimulus-induced Ca2+ signals in guard cells of intact plants, epidermal strips, and isolated protoplasts. Single-cell ratiometric imaging with the Ca2+-sensitive dye Fura 2 was applied in combination with electrophysiological recordings. Guard cell protoplasts were loaded with Fura 2 via a patch pipette, revealing a cytoplasmic free Ca2+ concentration of around 80 nM at -47 mV. Upon hyperpolarization of the plasma membrane to -107 mV, the Ca2+ concentration increased to levels exceeding 400 nM. Intact guard cells were able to maintain much lower cytoplasmic free Ca2+ concentrations at hyperpolarized potentials, the average concentration at -100 mV was 183 and 90 nM in epidermal strips and intact plants, respectively. Further hyperpolarization of the plasma membrane to -160 mV induced a sustained rise of the guard cell cytoplasmic Ca2+ concentration, which slowly returned to the prestimulus level in intact plants but not in epidermal strips. Our results show that cytoplasmic Ca2+ concentrations are stringently controlled in guard cells of intact plants but become increasingly more sensitive to changes in the plasma membrane potential in epidermal strips and isolated protoplasts.
@article{RN1139,
abstract = {Cytoplasmic calcium elevations, transients, and oscillations are thought to encode information that triggers a variety of physiological responses in plant cells. Yet Ca2+ signals induced by a single stimulus vary, depending on the physiological state of the cell and experimental conditions. We compared Ca2+ homeostasis and stimulus-induced Ca2+ signals in guard cells of intact plants, epidermal strips, and isolated protoplasts. Single-cell ratiometric imaging with the Ca2+-sensitive dye Fura 2 was applied in combination with electrophysiological recordings. Guard cell protoplasts were loaded with Fura 2 via a patch pipette, revealing a cytoplasmic free Ca2+ concentration of around 80 nM at -47 mV. Upon hyperpolarization of the plasma membrane to -107 mV, the Ca2+ concentration increased to levels exceeding 400 nM. Intact guard cells were able to maintain much lower cytoplasmic free Ca2+ concentrations at hyperpolarized potentials, the average concentration at -100 mV was 183 and 90 nM in epidermal strips and intact plants, respectively. Further hyperpolarization of the plasma membrane to -160 mV induced a sustained rise of the guard cell cytoplasmic Ca2+ concentration, which slowly returned to the prestimulus level in intact plants but not in epidermal strips. Our results show that cytoplasmic Ca2+ concentrations are stringently controlled in guard cells of intact plants but become increasingly more sensitive to changes in the plasma membrane potential in epidermal strips and isolated protoplasts.},
added-at = {2024-02-14T14:38:32.000+0100},
author = {Levchenko, V. and Guinot, D. R. and Klein, M. and Roelfsema, M. R. G. and Hedrich, R. and Dietrich, P.},
biburl = {https://www.bibsonomy.org/bibtex/29e4f2f14308333f836a92890fd7d657d/rainerhedrich_2},
doi = {10.1007/s00709-008-0307-x},
interhash = {8b9e32465fb4c4846c0fd21633ab6639},
intrahash = {9e4f2f14308333f836a92890fd7d657d},
issn = {0033-183x},
journal = {Protoplasma},
keywords = {calcium myOwn},
note = {348ch
Times Cited:11
Cited References Count:53},
number = {1-2},
pages = {61-72},
timestamp = {2024-02-14T14:38:32.000+0100},
title = {Stringent control of cytoplasmic Ca
in guard cells of intact plants compared to their counterparts in epidermal strips or guard cell protoplasts},
type = {Journal Article},
url = {/brokenurl#<Go to ISI>://WOS:000259188100007},
volume = 233,
year = 2008
}