Elements present in mineral nutrient reserves in dry Arabidopsis thaliana seeds of wild type and pho1, pho2, and man1 mutants

Abstract

Comparison of wild type and mutants of Arabidopsis thaliana offers an opportunity to study the genetic control of nutrient storage in seeds. We used energy dispersive X-ray analysis to determine the elements present and their relative amounts in globoids of dry wild-type seeds, as well as seeds of a reduced total P uptake mutant (pho1), a phosphate accumulator (pho2), and a metal accumulator (man1). Globoids are spherical inclusions, rich in phytate that function as a store for inositol, P, K, Mg, Ca, Fe, and Zn. Key findings of this study were the following: (i) globoids in protein bodies from nine different tissues and (or) organs in dry Arabidopsis thaliana seeds contained P, K, Mg, and Ca, and sometimes traces of Fe and Zn; (ii) globoids contained higher Ca and lower Mg amounts than occur in globoids in seeds of most other plant species; (iii) globoids in comparable tissue and (or) organ regions of seeds were very similar in elemental composition for wild type and all mutant plants.Key words: Arabidopsis, dry seeds, phytate, mineral nutrient mutants, phosphorus, globoids.