Gibberellin(GA) plays an essential role during germination of Arabidopsis seeds. We have revealed that two GA 3-oxidases that catalyze the final step of GA biosynthesis to produce active GAs are expressed in the cortex and endodermis of the hypocotyl in germinating seeds. This result suggests that biologically active GA is produced in these cell types. In order to compare the sites of GA biosynthesis and GA response in germinating seeds, we have analyzed expression sites of GA responsive genes using in situ hybridization. We have previously identified more than 400 GA responsive genes during seed gemination using the oligonucleotide-based DNA microarray (GeneChip, Affymetrix). About 30 GA-regulated genes with relatively high expression levels were selected for in situ hybridization analysis. To verify that hybridization signals from each probe are GA dependent, GA-treated and non-treated gal-3 seeds (severe GA-deficient mutant) were prepared for samples. Moreover, in order to investigate whether these genes are expressed in response to an increase in the endogenous GA synthesis during wild-type seed germination, germinating wild type seeds were also prepared. Hybridization signals from 20 genes out of 34 probes that we tested were detectable. Our data indicated that GA-regulated genes are expressed not only in the site of GA biosynthesis, but also in other cell types. Thus, our results suggest that GA signals originated from limited cell-types are transmitted to a variety of cell-types during seed germination.