Formation of iron plaque on mangrove Kandalar. Obovata (S.L.) root surfaces and its role in cadmium uptake and translocation.

In this study, a pot experiment was conducted to investigate the formation of iron plaque under Cd stress and its role in Cd uptake and translocation by mangrove Kandalar. Obovata (S.L.). Results showed: 1. the Fe in dithionite–citrate–bicarbonate (DCB) extracts increased with an increasing rate of Cd treatments. 2. the Cd in DCB extracts and in roots and above-ground tissues significantly increased with an increasing Cd application; 3. significant positive correlation between concentration of Cd and Fe in DCB extracts existed (p < 0.05); and that 4. the proportion of Cd in DCB extracts was significantly lower than that in roots or above-ground tissues (p < 0.001). In conclusion, formation of Fe plaque can precipitate Cd on root surfaces and impede its uptake and translocation in Kandalar. Obovata (S.L.). However, in comparison with root tissues, Fe plaque is of little significance. It is the mangrove root tissue that acts as the main buffer to Cd uptake and translocation.