Agriculture Reference
In-Depth Information
system). NADP-dependent isocitrate dehydrogenase (NADP-
ICDH) (TCA cycle), and glucose-6-phosphate dehydrogenase
(G6P-DH) (Pentose phosphate cycle) activity. CAT activities
in both cultivars were drastically decreased, by the chilling. In
Dunghan Shali, these activities were recorded and stimulated
by rewarming. However, in K-Sen4, the rewarming decreased
the activities in the embryo and root at the leaf stage. For APX at
the germination stage, chilling resistance was found with both
cultivars, but the rewarming enhanced the activities effectively
in Dunghan Shali while not as effectively in K-Sen 4. APX
activities at the leaf stage in both cultivars were not affected
very much by the chilling. However, only 10% of the initial
activity was detected in K-Sen 4 root after rewarming. The other
enzymes, SOD, GR, ICDH, G6P-DH, displayed no signifi cant
differences in cold sensitivities between the two cultivars. It is
concluded that the tolerance of rice cultivars to chilling injury
is closely linked to the cold stability of CAT and APX.
It is also noted, that the analysis of the isozyme profi le
and activity of superoxide dismutase (SOD), catalase (CAT),
ascorbate peroxidase (APX) and glutathione reductase (GR)
suggests that signifi cant induction of expression and activity
of antioxidative enzymes CAT and APX in the leaves and SOD,
CAT, APX are most important for cold acclimatization and
chilling tolerance. Increased activity of antioxidants in roots
is more important for cold tolerance than increased activity in
shoots (Kuk et al. 2003).
Antioxidative
active enzymes
Superoxide
dismutase (SOD)
Catalase (CAT)
Ascorbate
Peroxidase (APX)
Cold
Stress
Rice
Plant
Plant
acclimation
to cold
