Figure 6.

The era1-2 Mutation Partly Restores ABA-Induced [Ca²⁺]_cyt Increases and Stomatal Closure in the era1-2 abi2-1 Double Mutant.

(A) Repetitive [Ca²⁺]_cyt transients induced by 10 μM ABA in wild-type (Landsberg erecta) Arabidopsis guard cells expressing YC2.1.

(B) [Ca²⁺]_cyt transients are not induced by 10 μM ABA in abi2-1 guard cells expressing YC2.1, although application of extracellular calcium elicits [Ca²⁺]_cyt transients.

(C) ABA at 0.1 μM fails to elicit [Ca²⁺]_cyt transients in the majority (69%; n = 29 from 42 cells) of era1-2 abi2-1 guard cells, although application of extracellular calcium elicits [Ca²⁺]_cyt transients.

(D) ABA at 0.1 μM elicits single [Ca²⁺]_cyt transients in a fraction (31%; n = 13 from 42 cells) of era1-2 abi2-1 guard cells.

(E) ABA-induced stomatal closure is impaired in the abi2-1 mutant but is partly restored in the era1-2 abi2-1 double mutant at 0.1 μM ABA using the same bathing solutions that were used for calcium imaging studies. Data are means ± sem relative to three replicates comprising 120 stomates per point.

Ler, Landsberg erecta.