Seed germination is a key step in the life cycle of all seed plants,and it is of immense significance in agriculture.Germination is controlled by multiple environmental cues such as light and moisture,and endogenous factors,especially phytohormones.Gibberellic acid (GA) has long been identified as a critical hormone in the regulation of seed germination by countering the inhibition imposed by abscisic acid (ABA) (Holdsworth et al.,2008;Lee et al.,2010).The underlying molecular mechanism involves multiple facets,including DELLA proteins such as RGA-LIKE2 (RGL2;Lee et al.,2002;Ravindran et al.,2017) along with other key signaling intermediates and specific biophysical forces as has recently been demonstrated (Sánchez-Montesino et al.,2018).The increase in GA levels upon imbibition is essential for the rupture of testa and the endosperm,and subsequent emergence of the radicle.The complexity of GA signaling and the associated molecular genetic networks working in a coordinated manner to influence biophysical parameters that ultimately result in seed germination is beginning to emerge.
展开▼
