Anion transporters in stomatal movement

Anions also have a role in stomatal closure. Two different types of anion channels have been described in guard cells [21-23]. The first type has been named the S-type because it activates and deactivates very slowly in response to the appropriate voltages, and does not inactivate. The kinetics and voltage-dependence of S-type chaimels allow them to pass significant current at the more negative V s which appear to prevail in vivo [24,25]. Thus, 

Very fast activation, larger at positive potentials [42,45] Time-dependent activation, relatively voltage-independent [47] 

Significant time-dependent activation, opened at cytosolic positive potentials [45,47] 

Time-independent, open at cytosolic negative potentials [49] Instantaneous and time-dependent components, open at negative potentials [49] 

Not directly regulated by [Ca ]cy, (see other gating factors ) [49] Not directly regulated by Ca cy, (see other gating factors ) [49] 

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