Table II.
Effect of Cd2+ exposure on Em values and on in vitro plasma membrane H+-ATPase activity of maize root cells
| Time |
Em
|
H+-ATPase Activity
|
||
|---|---|---|---|---|
| Control | Cd | Control | Cd | |
| h | mV | μmol ADP released h−1 mg−1 protein | ||
| 0 | −96 ± 2 | – | – | – |
| 24 | −96 ± 3 | −105 ± 1 | 16.2 ± 0.5 | 18.4 ± 1.1 |
| 48 | −94 ± 2 | −104 ± 3 | 15.4 ± 0.7 | 17.0 ± 0.3 |
Plants were grown for 24 or 48 h in a complete nutrient solution supplemented or not with 10 μm CdCl2. Em values were measured in roots of intact plants perfused with the complete nutrient solution supplemented or not with 10 μm CdCl2. The values are the means ± se of three experiments (n > 20). ATPase activity was measured as ADP release in plasma membrane vesicles from control or Cd-exposed plants. The values are the means ± se of three experiments in run triplicate (n = 9).