LAUSR

Abstract Several studies have shown hydrogen peroxide (H2O2) as a metabolic messenger that increases plant tolerance to various stress conditions. However, little is known about its effect on the mobilization of seed reserves in the establishment of seedlings. Thus, this study aimed to evaluate the effect of pretreatment with H2O2 in salt-tolerance and mobilization of reserves during the germination of seeds and establishment of sunflower seedlings. Seeds were pre-imbibed for 24 hr in solutions containing: deionized water (control); H2O2 (1 mM); NaCl (100 mM). Subsequently, seeds were distributed on germitest paper, moistened with deionized water or saline solution (100 mM NaCl). In seedlings not pretreated with H2O2, the salinity increased Na+ and Cl− ions contents and reduced the growth of sunflower seedlings. However, pretreatment of seeds with H2O2 reduced the negative effect of salinity, promoted an increase in salt-tolerance by the reduction of Na+ and Cl− uptake, lower energy cost for osmoprotection by compatible solutes accumulation, and by the higher equilibrium in the mobilization of the cotyledon reserves for the development of the embryonic axis.