Table V.
The effect of calcium or EGTA on stomatal closure, of alkalization, and ROS production in response to ABA or MJ, in guard cells of P. sativum
| Phenomenon and Calcium Modulator
|
Hormone (20 μm)
|
||
|---|---|---|---|
| None | ABA | MJ | |
| Stomatal opening (μm) | |||
| None | 4.0 ± 0.5 | 1.9 ± 1.0 | 1.8 ± 0.7 |
| 10 μm Ca(NO3)2 | 2.8 ± 0.5 | 2.5 ± 1.1 | 2.0 ± 0.9 |
| 2 mm EGTA | 4.8 ± 0.8 | 3.4 ± 1.2 | 4.4 ± 0.8 |
| Change in pH (% Control) | |||
| None | 100 ± 2.7 | 120 ± 2.1 | 125 ± 3.1 |
| 10 μm Ca(NO3)2 | 99 ± 3.2 | 121 ± 2.8 | 124 ± 2.9 |
| 2 mm EGTA | 100 ± 2.9 | 120 ± 3.2 | 124 ± 3.7 |
| Change in ROS (% Control) | |||
| None | 100 ± 3.3 | 122 ± 2.8 | 130 ± 3.2 |
| 10 μm Ca(NO3)2 | 105 ± 2.8 | 126 ± 3.1 | 135 ± 3.0 |
| 2 mm EGTA | 96 ± 3.4 | 118 ± 3.4 | 123 ± 3.7 |
Change in pH or ROS levels were analyzed by measuring BCECF-AM or H2DCF-DA fluorescence in guard cells in response to ABA or MJ or solvent control. Stomata were allowed to open in light for 2 h, then ABA or MJ was applied. The cellular pH and ROS production were examined after 15 and 30 min, respectively. The fluorescence intensity of the dye in the control sets (without ABA or MJ or calcium or EGTA) is taken as 100 and other values were expressed in relation to control. Results are the averages ±se of 3 to 4 independent experiments.