OXIDATION IN THE RHIZOSPHERE OF MANGROVE KANDELIA-CANDEL SEEDLINGS

A study of the mechanism of oxidation capacity in mangrove roots was undertaken in Kandelia candel. By applying leuco methylene blue in semi-agar medium, the oxidation power of Kandelia candel roots was found. Oxidation activity was shown by a color change in the rhizosphere. There was substantial activity in the apical section of the root, decreasing progressively through the central and basal sections. Excised root, and the roots of seedlings with the shoots greased with vaseline showed a near failure of oxidation power. Similar result was given in another experiment which the root of K. candel was submerged in FeS precipitate in semi-agar medium. Due to the oxidation of FeS, after a few days the color of the medium changed from black to colorless or yellowish in the rhizosphere. This indicates that oxygen was released from K. candel root to the media. The oxidative power was also evaluated by alpha-naphthylamine oxidation. Activity was found to be the highest in the apical section of the root, declining progressively toward the basal section, which agrees with the results of the first experiment. However, the oxidation activity in the mangrove roots was much lower than in rice roots. Oxygen released from the roots is thus ascertained to be the major cause of the oxidation power of K. candel.