Bulletin of the Society of Sea Water Science, Japan

We have been making a study on the physicochemical properties of the amidoxime type chelating resins to enhance the rate of uranium adsorption per volume. Amidoxime resins crosslinked with both TEGDM and DVB were synthesized. Their adsorptive properties of uranium from sea water were examined. The resin, which was crosslinked with 13 wt% TEGDM and 27wt% DVB, showed the highest uranium adsorption rate per volume from sea water.

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A mangrove plant is one of the typical halophytes, and is distributed at the mouth of rivers and canals and along the muddy shores of well-protected estuaries at tropical and sub-tropical areas in the world. The main distribution of mangrove plants in Japan is the Nansei Islands of Okinawa. he inorganic ions (anions and cations) and organic acids of the three stages of leaves (young, adult and old leaves) about mangrove of 4 species of Okinawa were analyzed. Also, abscisic acid of deciduous hormone was analyzed. Accumulation of Na, Mg, Ca, and Cl ions in the leaves of 4 species increased with leaf growth (leaf aging). And also, organic acids in the leaves of 4 species increased with leaf aging. K concentration of young leaves in Rhizophora stylosa(Yaeyamahirugi),Kandelia candel(Mehirugi) and Sonneratia alba(Mayapushiki) was the highest, and K concentration slowly decreased with leaf aging of each species. On the other hand, Na concentration increased with leaf aging of 4 species. From such high accumulation of Na ion, mangrove is supposed to be able to grow under high salinity environmental conditions. And these mangroves can adjust pH and osmosis in their cell for normal growth by neutralization with organic acids and increase cell water (succulence).
When the concentration of inorganic ions in the leaves by accumulation was higher than the normal growth level, abscisic acid synthesis was started for a fallen leaf. Abscisic acid was only existed in the old leaves stage of 4 species, and the amount of abscisic acid differed according toeach species.
These mangrove species were used to regulate their ion concentration by a combination ofthree methods: salt excusion at root, succulence in the leaf and discarding salt-laden leaves (organs).

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