Table 2. Relationship between cold injury, ice nucleation and freezing temperature in four Eucalyptus globulus genotypes subjected to different drought hardening regimes. Values are means of 5 replicates for the thermal analysis and 8 replicates for the LT50 ± 1 SE. Means with different letters are significantly different (P ≤ 0.05). Lower case letters compare nucleation and freezing temperatures (Columns and rows). Upper case letter compare only within the LT50 column. LT50 = lethal temperature for 50% of leaf cellular damage evaluated by relative conductivity; FS = freezing sensitive, FT = freezing tolerant.


Genotype

Hardening
regime
(MPa)

Nucleation
temperature
(ºC)

Freezing
temperature
(ºC)

LT50
(ºC)

Freezing
resistance
category

EG-13

-0.2

-7.3 ± 0.2 cd

-4.6 ± 0.2 efgh

-7.7 ± 0.2 E

FS

-1.8

-7.6 ± 0.3 d

-4.9 ± 0.1 fgh

-6.3 ± 0.2 BC

FS

-2.6

-5.8 ± 0.2 abc

-3.0 ± 0.2 e

-7.0 ± 0.3 CDE

FT

EG-23

-0.2

-7.3 ± 0.3 cd

-5.3 ± 0.4 gh

-7.6 ± 0.2 E

FS

-1.8

-7.0 ± 0.3 bcd

-5.6 ± 0.4 h

-6.0 ± 0.3 AB

FS

-2.6

-4.8 ± 0.3 a

-3.1 ± 0.2 e

-7.0 ± 0.2 CDE

FT

EG-22

-0.2

-6.5 ± 0.3 abcd

-4.6 ± 0.3 efgh

-6.8 ± 0.0 BCD

FS

-1.8

-6.8 ± 0.7 bcd

-5.1 ± 0.5 bgh

-6.7 ± 0.1 BCD

FS

-2.6

-5.4 ± 0.3 ab

-3.2 ± 0.6 ef

-6.7 ± 0.1 BCD

FT

EG-14

-0.2

-5.6 ± 0.3 abc

-3.3 ± 0.3 ef

-5.2 ± 0.0 A

FS

-1.8

-5.8 ± 0.3 abc

-3.9 ± 0.2 efgh

-7.4 ± 0.1 DE

FT

-2.6

-5.9 ± 0.5 abcd

-3.6 ± 0.4 efg

-6.6 ± 0.1 BCD

FS

 

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