The light promoted germination of the seeds of Chenopodium album L.; II. Effects of (RS)-Abscisic acid

The visible germination phenomena of Chenopodium album seeds can be divided into two stages. The first stage, being light-dependent in these seeds, consists of the splitting of the outer testa layer only and the extending of the radicle from within the seed. This stage is not prevented by incubation in (RS)-abscisic acid (ABA). Only the protrusion of the radicle through the inner testa layer and the underlying endosperm layer (the second stage) is prevented by ABA. This effect is more pronounced in darkness than in light. After 2 weeks of incubation the inhibition can be released by transfer to water. After 4 weeks in most of the seeds only scarification of the inner layers enables the start of rootlet growth. It is assumed that ABA inhibits one or some components of the cell expansion of the embryo.