THE EFFECT OF POST-HYPOXIA ON ROOTS IN SENECIO AND MYOSOTIS SPECIES-RELATED TO THE GLUTATHIONE SYSTEM

This paper shows the effect of re-aeration following hypoxic pretreatm ent on the glutathione system in plants with different flooding tolera nce. Re-aeration of hypoxically pretreated roots led to an increase of TBA-rm content indicating an accelerated lipid peroxidation (post-ano xic injury). Re-admission of oxygen resulted in a clear increase in th e content of total glutathione in both flooding-intolerant species Myo sotis arvensis and Senecio jacobaea. Simultaneously, the high ratio be tween reduced (GSH) and oxidized (GSSG) glutathione decreased in these species upon the onset of re-aeration, while the tolerant Myosotis pa lustris and Senecio aquaticus showed only little changes in contents o f GSH and GSSG. An imbalance in GSH/GSSG ratio reflects oxidative stre ss. The glutathione reductase (GR) reacted very differently in the inv estigated genera. The metabolic response to varying oxygen pressure is much stronger in the flooding-intolerant species compared to species naturally growing in wetlands. The present results suggest that glutat hione system is an important component in overcoming oxidative stress.