Abstract
We have reported the localization of active gibberellins (GAs) and GA-inducible α-amylase (PnAmy1) around the starch grains in the integuments of immature seeds of Pharbitis nil cv. Violet. We also proposed that the GAs play an important role for the seed development of P. nil through the induction of α-amylase and degradation of starch temporarily accumulated in integuments. To examine whether the similar process proceeds in the seed development of other dicotyledonous plants, we analyzed immature seeds of Arabidopsis thaliana, because further experiments by transformation can be applied for this plant. We harvested green siliques at different maturities from wild type plant (Col.), and prepared their paraffin-embedded sections. The KI/I_2 staining of the embedded sections showed the positive blue stains in seed coat where some granules were observed at the same time. In accordance with the maturation of siliques, both of the positive stains and the granules harmoniously disappeared. The expressions of GA 20-ox genes and a-amylase genes were analyzed by using RT-PCR technique. All specific primers required for the analysis were designed based on the sequence information from online database. In situ hybridization analyses are proceeding for some clones that are expressed at comparatively high levels.
