
TY  - JOUR
A1  - Harwood, CE 
T1  - Frost Resistance of Subalpine <I>Eucalyptus</I> Species. II. Experiments Using the Resistance Index Method of Damage Assessment
JF  - Australian Journal of Botany
JO  - Aust. J. Bot.
Y1  - 1981
VL  - 29
IS  - 2
SP  - 209
EP  - 218
KW  - 
UR  - https://doi.org/10.1071/BT9810209 
N2  - Frost damage to leaves of Eucalyptus pauciflora seedlings was measured by an electrical resistance ratio method. Leaves were exposed to below-freezing temperatures by a liquid bath apparatus that allowed accurate temperature control. Unhardened seedlings exposed to an 18/9&#176;C temperature regime with 12 h-photo- and thermoperiod did not harden significantly, the minimum temperature producing 50% leaf death (T50) remaining higher than - 5&#176; An 18/4&#176;C regime lowered the T50 to - 14&#176; in 50 d, but exposure of hardened seedlings to 18/9&#176;C produced rapid dehardening back to a T50 higher than - 5&#176;. Rapid (1-2&#176;C min-I) cooling to the frost minimum was much more damaging than was the standard (2-4&#176;C h-I) rate used in the experiments. 
ER  -

