ADAPTABILITY TO DROUGHT IN SUGAR-BEET CULTIVARS

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.