Comparison of phytate in radicle, plumule, scutellum and endosperm of Zea mays and Zea diploperennis seeds

Abstract

Phytin element composition and phytate distribution and content were determined in endosperm, scutellum, radicle and plumule of mature Zea diploperennis and Zea mays grains. The embryo of Z. diploperennis and Z. mays contained 90% and 86% of total grain phytate, respectively, with most of the phytate localized in the scutellum and radicle. All examined parts of Z. diploperennis had a higher phytate concentration than Z. mays. A strong similarity in phytate distribution was found in both species despite variability in grain size and year of production. Phytate was stored as phytin in globoid crystals with variable diameters. The size of the globoid crystals reflected the phytate content in each tissue. The largest globoid crystals as well as the highest phytate content were found in the scutellum of Z. diploperennis. Energy-dispersive X-ray microanalysis showed that globoid crystals of both species were dominated by P, K, and Mg. Phytate content in different embryonic parts correlated with the amount of K and Mg, but not with the less abundant elements (Zn, Ca and Fe) found in the tissues. Even though some differences in the elemental composition of phytin and the phytate content were found, a similarity in phytate distribution patterns in grains of these species may reflect their close taxonomic relationship.