Technical Abstract: Our current knowledge is limited as to the form of iron imported by developing seeds, on the processing that may occur in the seed coat, and on the factors that regulate its subsequent transport to and storage in the ovule. It is believed that Fe enters the seeds in a chelated form via the phloem pathway; storage of Fe in seeds involves the protein ferritin. We are using the Fe-hyperaccumulating pea mutant, dgl, which transports exces Fe to its seeds, to identify Fe forms in seed coats and to assess the influence of excess Fe on the expression of ferritin. When Fe was supplied to both wildtype (WT) and mutant plants at 10 uM levels, the Fe content of dgl seeds increased 3- to 4-fold relative to WT seeds. Furthermore, dgl seed coats contained higher Fe concentrations than their ovules. Western- blot analysis with a pea ferritin antibody showed no change in total ferritin levels in response to Fe supply; ferritin was not detected in seed dcoats. Currently, research is in progress to identify an Fe-chelating compound in pea seed coats by immobilized metal affinity chromatography and SDS-PAGE analyses. The identification of this compound will further our understanding of how Fe is processed and stored in seeds. This research was funded in part by USDA-ARS Coop. Agr. No. 58-6250-1-003 and USDA-CSRS Grant No. 94-37100-0823 to MAG.