ABA metabolism genes like NCED and CYP707A have
been extensively studied in the Brassicales model plant
Arabidopsis (Nambara & Marion-Poll 2005). Similar to
other species, Arabidopsis NCED genes have been found
to be involved in seed dormancy (Nambara et al. 2010;
Frey et al. 2011). Recently, also in Arabidopsis, it could
be confirmed that transgenic manipulation of ABA synthesis
by up-regulating endogenous NCED6 during
seed imbibition leads to increased dormancy (MartinezAndujar
et al. 2011). Changes in ABA metabolism during
dormancy loss resulting in a low ABA content in imbibed
seeds have also been described for the Fagales species
Fagus sylvatica (beech) (Le Page-Degivry, Garello &
Barthe 1997).