Effects of triadimefon and osmotic stress on plasma membrane composition and ATPase activity in white spruce (Picea glauca) needles |
| |
Authors: | Eva Sailerova Janusz J. Zwiazek |
| |
Affiliation: | Dept of Forest Science, Univ. of Alberta, Edmonton, Alberta, Canada T6G 2H1. |
| |
Abstract: | White spruce [ Picea glauca (Moench) Voss.] seedlings were grown in solution culture and treated with 20 mg I-1 triadimefon [1-(chlorophenoxy)-3,3-dimethyl-1-(1,2,4-triazol-1-yl)-2-butanol] for 4 weeks and then subjected to osmotic stress with polyethylene glycol 3350. Water potentials and electrolyte leakage were measured in control and triadimefon-treated seedlings before and after the plants were subjected to osmotic stress. The plasma membranes were isolated from needles to study their lipid composition and the activity of plasma-membrane bound ATPase. Triadimefon treatment reduced water potentials and increased leakage of electrolytes from seedlings. However, when the seedlings were exposed to osmotic stress, triadimefon-treated plants maintained higher water potentials and leaked less electrolytes compared with the control plants. Both triadimefon and osmotic stress treatments inhibited the activity of plasma membrane-bound ATPase and altered the composition of free sterols in the plasma membranes. Triadimefon-treated plants contained traces of campesterol, which was not present in control. Osmotic stress drastically reduced phospholipid:protein and sterol:protein ratios and increased sterol:phospholipid ratios in the plasma membranes |
| |
Keywords: | ATPase osmotic stress Picea glauca plasma membranes sterols triadimefon white spruce |
|
|