ROS Signaling in Seed Dormancy Alleviation.

Reactive oxygen species have been suggested to play a signaling role in seed dormancy alleviation. When sunflower seeds become able to fully germinate during dry after-ripening, they accumulate high amount of hydrogen peroxide and exhibit a low detoxifying ability through catalase, resulting from the decrease in CATA1 transcript. ROS accumulation entails oxidative modification of soluble and storage proteins through carbonylation, which suggests that this process might play an important role in plant developmental processes. However other oxidative signaling pathways cannot be excluded. For example, a cDNA-AFLP study shows that seed after-ripening is also associated with changes in gene expression and that changes in ROS content during seed imbibition are also related to changes in expression pattern.