A. Hegedus et al., Comparative studies of H2O2 detoxifying enzymes in green and greening barley seedlings under cadmium stress, PLANT SCI, 160(6), 2001, pp. 1085-1093
Cadmium(Cd) stress induced alterations in the activities of several represe
ntatives of the enzymatic antioxidant defense system such as guiacol peroxi
dase (POD), catalase (CAT) and ascorbate peroxidase (APX) were comparativel
y studied in green and greening barley seedlings that represent two differe
nt stages of plant development. Although roots were the main site of Cd acc
umulation, 1.5-3% of Cd was translocated into leaves and it induced oxidati
ve damage which was indicated by the reduced chlorophyll and increased malo
ndialdehyde content of the leaves. In roots of both types of seedlings expo
sed to various Cd concentrations, the APX activity was enhanced without any
increase in the activity of POD. In leaves, however, elevated activities o
f both POD and APX could be observed. In roots of green seedlings at high c
oncentration of Cd, the APX activity was reduced on the fourth day of cultu
re but no inhibition was found in the POD activity. Leaf CAT which mainly r
epresented the peroxisomal enzyme activity did not display any changes unde
r Cd stress. Our results show that at both developmental stages barley seed
lings exhibit a well-defined activity of the enzymatic antioxidant system,
which operates differentially in roots and shoots subjected to Cd stress. (
C) 2001 Elsevier Science Ireland Ltd. All rights reserved.