Role of thioproline on seed germination: Interaction ROS-ABA and effects on antioxidative metabolism

In this work we investigate the effect of the imbibition of pea seeds with different thioproline (TP) concentrations on the germination percentage and the early growth of the seedlings. The interaction between TP and hydrogen peroxide (H2O2) treatments is also analysed in order to test if any synergy in germination and growth occurs. gh the imbibition of pea seeds in the presence of TP did not significantly improve the germination percentage, TP and/or H2O2 pre-treatments increased seedlings growth. This increase in seedling growth was reduced by abscisic acid (ABA) addition. Imbibition of pea seeds in the presence of ABA also reduced the endogenous H2O2 contents of pea seedlings in control and TP-treated seeds. cubation of pea seeds with TP and/or H2O2 in presence or absence of ABA decreased the activity of H2O2-scavenging enzymes. The increase of the endogenous H2O2 contents observed in TP and/or H2O2 treatments in absence of ABA could be correlated with the decrease in these activities. Finally, the hormone profile of pea seedlings was investigated. The results show that the increase in seedling growth is correlated with a decrease in ABA in samples pre-treated with H2O2 and TP + H2O2. Nevertheless, no significant differences in endogenous ABA concentration were observed with the TP pre-treatment. aper suggests a relationship between endogenous H2O2 contents and plant growth, so reinforcing the intricate crosstalk between reactive oxygen species (ROS) and plant hormones in seed germination signalling and early seedling development.