The treatment did not significantly reduce ˘100 values in ‘LE’.
The osmotic potential of the treated plants showed greater fluctuations as a function of AWSD% changes. The ˘100 values of treated
leaves varied between −0.60 and −1.40MPa, and the range among
control plants was between −1.00 and −1.40MPa. In the case
of treated vines, AWSD% values did not drop below 40%, and the
˘100–AWSD% correlation was not significant (r = 0.53) (Fig. 2). In
contrast, we found a significant correlation (r = 0.88) in control
vines of ‘LE’, and the AWSD% values fell below 40% parallel with
decreasing ˘100 values below −1.00MPa. Significant decrease of
AWSD% values indicates that water volume increases in apoplastic spaces when osmotic potential becomes increasingly negative. This
change may be closely related to the change in cell wall elasticity
caused by different regulatory mechanisms of the cell wall.