Accumulation of manganese and zinc in growing Hijiki (Sargassum fusiforme) plants.

Abstract

Hijiki (Sargassum fusiforme) plants were collected during their growth period from the end of November through April at 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. Manganese (Mn) and zinc (Zn) in 1N HCl were determined with an atomic absorption spectrophotometer.

Mn and Zn accumulated in the respective tissues at concentrations of 10 to 50 μg/g dry weight of tissues at the beginning of growth, and their concentrations remained at similar levels until the beginning of April. These may, as discussed, suggest that the levels of Mn and Zn are their biochemically required concentrations in the tissues of Hijiki.