Effect of exogenous polyamines on glycolate oxidase activity and active oxygen species accumulation in wheat seedlings under osmotic stress

Exogenous polyamines applied to wheat roots increased both polyamine conten t and glycolate oxidase activity in leaves. -0.85 MPa osmotic stress not on ly increased the content of O-2(-) and H2O2, but also decreased glycolate o xidase activity in leaves, and 5 mM putrescine, 2 mM spermidine, and 1 mM s permine partly inhibited these effects. Exogenous oxalic acid decreased gly colate oxidase activity, increased O-2(-) content, and had no effect on H2O 2 content. The correlation coefficient between glycolate oxidase activity a nd O-2(-) content was -0.89. These results suggest that exogenous polyamine s inhibit O-2(-) accumulation under osmotic stress by enhancing glycolate o xidase activity. Exogenous polyamines also inhibit H2O2 accumulation in whe at seedlings under osmotic stress, but this does not correlate With the gly colate oxidase activity.