Figure 7.

Effect of redox and osmotic treatments on freezing tolerance. Electrolyte leakage was measured in leaf segments of Ch (A) and Tsp (B) after 3 weeks of cold hardening at -11°C and -13°C. Various compounds were applied to 12-day-old seedlings of Ch and Tsp at 20/17°C for 3 days and subsequently at 5°C during the first 4 days of the 3-week cold hardening period. High values of electrolyte leakage indicate severe damage to the cell membranes and high freezing sensitivity. Values indicated by asterisks are significantly different from the control, treated with no chemicals, at the P ≤ 0.05% level.