EFFECT OF OXIDATIVE STRESS ON COLD TOLERANCE IN RICE SEEDLINGS

Abstract:

Effects of different extents of oxidative stress caused by 10 μmol/L H₂O₂ or μmol/L methyl viologen (MV) on cold tolerance of rice seedlings were studied. Theresults showed that mild oxidative stress (10 μmol/L H₂O₂ or 10 μmol/L MV for 4 h)could induce cold tolerance, while severe oxidative stress might aggravated chilling injuryon rice seedlings. The antioxidatase (POX, SOD, CAT andf APX) activities in leaves fromvarious pretreated seedlings were all increased. After chilling stress, the changes in antioxidatase activities．electrolyte leakage and MDA content among different pretreated seedlings were difierent Mlid oxidative stress could sustain high IeveI of antioxidatase activities，reduce the increase of membrane lipid peroxidation and cellular electrolyte leakage induced by chilling stress； but contrary effect was observed by severe oxidative pretreatment. It is suggested that the mechanism of rice seedlings responsing to oxidative stress (cellular oxidative stress response) might be the important regulatory mechanism for rice seedlings during chilling stress or cold tolerance.