© 1990 Heron Publishing—Victoria, Canada
Influence of cold hardening on water relations of three Eucalyptus species
R. Valentini, G. Scarascia Mugnozza, E. Giordano and E. Kuzminsky
Istituto Biologico Selvicolturale, Università della Tuscia, Via De Lellis 4-01100, Viterbo, Italy / Received June 2, 1989
Summary
Water relations of three Eucalyptus species (E. × trabutii Wilm., E. viminalis Labill., E. dalrympleana Maid.), widely planted in the Mediterranean basin, were analyzed throughout an entire year in relation to natural cold hardening.
Osmotic potential, both at saturation and at the turgor loss point, showed a greater reduction during hardening in the more
frost-resistant E. viminalis and E. dalrympleana than in the more frost-sensitive E. × trabutii. The hardening capabilities of all species were analyzed in relation to the freezing dehydration index, FDI, a parameter
derived from pressure–volume analysis which represents the water lost when cells, initially at the turgor loss point, attain
thermodynamic equilibrium with extraplasmatic ice. The FDI at the killing temperature showed little variation either between
frost-sensitive and frost-resistant species, or between hardened and non-hardened plants. The index may, therefore, be useful
for evaluating a plant’s potential for injury by freeze-induced desiccation.
