The aim of this work was to evaluate the effect of acclimatization on the cold tolerance of Eucalyptus dunnii Maiden (clone K-1007) and the relationship of the cold tolerance to the total soluble carbohydrates and proline contents in the leaves. The experimental design utilized was randomized blocks with four repetitions. The treatments were made up of different acclimatization periods (0, 7, 21 and 42 days of plant exposure to the temperatures of 5°C daily and 1°C at night.). After each acclimatization period, the seedlings were submitted to four sub-zero temperatures (-2°C, -4°C, - 6°C and -8°C ) for three hours each temperature. After each acclimatization period the concentrations of total soluble carbohydrates and proline in the leaves was evaluated. After each sub-zero temperature, leaf samples were collected for evaluation of the lethal temperature 50% (LT50). The data were submitted to linear regression analysis and Person's correlation test. The E.dunnii seedlings showed an increase in the content of total soluble carbohydrates up to 28 days of acclimatization, with stabilization occurring after this period. It was observed that there was a negative correlation between the temperature of lethal temperature 50% (LT50) and the concentration of total soluble carbohydrates in the leaf tissues, showing a relation of cold tolerance increase to the increase of contents of total soluble carbohydrates.
Lethal temperature of 50% (LT50); Acclimatization and Subzero temperature
