Mature seeds of flowering plants contain globoids, mineral nutrient storage particles that are rich in phosphorus, potassium and magnesium. Globoids, which are located inside protein bodies, may also contain small amounts of calcium, iron, manganese and zinc. Previously published research from this laboratory demonstrated that seeds from different genera in the conifer Family Pinaceae contain two different mineral nutrient rich particles, namely globoids and iron-rich particles. The iron-rich particles generally are rich in iron, phosphorous, and potassium. These particles, which occur inside plastids, also contain some magnesium and perhaps chlorine. We used energy dispersive x-ray analysis and transmission electron microscopy to study embryo axis tissue from seeds of other gymnosperms. Both globoids and iron-rich particles were located in representatives of Phyla Cycadophyta, Ginkgophyta, Gnetophyta and Coniferophyta (Families Araucariaceae, Cephalotaxaceae, Cupressaceae, Podocarpaceae, Sciadopityaceae and Taxaceae). It thus appears that two types of mineral nutrient rich structures in seeds is an ancestral condition for seed producing plants and that the iron-rich particles appear to have been lost from seeds during evolution of the Anthophyta.

Key words: engergy dispersive x-ray analysis, globoids, gymnosperms, iron-rich particles, mineral nutrient stores, seed embryos