The effects of NaCl and polyethylene glycol (PEG) on superoxide dismut
ase (SOD) and peroxidase (P) activities, lipid peroxidation (LP) and p
roline content in seeds and leaves of drought tolerant (FC-506 and MS-
100) and drought sensitive (MS-612 and MS-13) sugar beet cultivars wer
e examined. After PEG and NaCl treatment in tolerant cultivars both in
seeds and leaves SOD activity mainly increased, though P activity inc
reased only in leaves of tolerant cultivars. In drought sensitive cult
ivars the decrease of SOD and P activity was mostly observed. LP incre
ased in seeds and leaves of all examined cultivars. The proline conten
t increased in the leaves of examined cultivars and was significantly
higher in drought tolerant plants. On the other hand, in the seeds onl
y slight increase in proline content was found. The results obtained i
ndicated that drought tolerance could be correlated with high proline
content and enzymatic defense against lipid peroxidation.