Accumulation of iron and magnesium in growing Hijiki (Sargassum fusiforme) plants.

Abstract

Hijiki (Sargassum fusiforme) plants were collected during their growth period from the end of November through April on the sea coast of Kushimoto, Wakayama, Japan. The samples were brought back to the laboratory under ice-cold conditions and washed thoroughly with artificial sea-water and distilled water successively. The plants were cut into pieces of a 10 cm length along the stalk, and separated into leaves and stalks. The samples were lyophilized, and decomposed in a mixture of conc H₂SO₄ and conc HNO₃ (3 to 1, v/v) on an electric heater. Iron (Fe) and magnesium (Mg) in 1N HCl were determined with an atomic absorption spectrophotometer.

Fe accumulated in the respective tissues at concentrations of 70 to 110μg/g dry weight of tissues at the beginning of growth and Mg, at concentrations of 7 to 9 mg/g dry weight of tissues. Fe accumulated at 20 to 300μg/g dry weight through the growing period until the beginning of April. Mg accumulated at 5 to 30 mg/g dry weight of tissues through the growing period. Mg accumulation seemed to be more than enough for its biochemically required concentrations in the tissues of Hijiki.