Energy-dispersive X-ray microanalysis (EDX) of a tangle (Laminaria japonica Areschoug) was performed using an analytical electron microscope (JEM 1200EX-Tracor Northern TN2000).
1. Fresh tangle was dried in the sun and fractured by a razor blade. A small piece of fractured tissue was placed on a holder, coated with carbon in vacuum, and examined at scanning electron microscopic (SEM) range. Some dried samples were soaked in distilled water for 60 minutes. The soaked and not-soaked samples were fixed with glutaraldehyde and osmium tetroxide before being dehydrated and embedded in Epon. Semithin sections were obtained, and examined at scanning-transmission electron microscope (STEM) range. Results are as follows:
Fractured specimens of dried tangle were adequate for EDX-SEM analysis to show exact contents of all contained elements.
2. X-ray peaks of C1, K, Na, Mg, P and S were detected in the cortical cells and their cell walls of untreated samples.
3. X-ray peaks of C1 K, Na, Mg, P and S were disappeared in the soaked tangle.
4. Ca element localized in the cell walls, but was not extracted, probably because of its tight bound to some polysaccharides in the cell wall structure.