As often happens with hormones, GA stimulates gene activity so that mRNA is transcribed and an enzyme (amylase in this case) is produced. It is the enzyme that produces the phenotypic change - amylase breaks down starch (in the endosperm or cotyledons) to sugars and the embryo uses the sugars for growth.


Match the abbreviations ABA (abscisic acid) CK (cytokinin) GA (gibberellin) and IAA (indoleacetic acid) to the structures:


ABA CK GA IAA


ABA CK GA IAA


ABA CK GA IAA


ABA CK GA IAA