Effect of different iron forms on iron plaque on root surface and iron uptake in rice seedlings

Iron forms have great impacts on iron nutrition of rice seedlings, however, it remains unclear on how different iron forms influence iron uptake in rice seedlings. In this study, a hydroponic experiment was conducted to investigate the effects of FeCl2 and FeCl3 on iron uptake and iron plaque in rice seedlings. Results showed that the concentration of iron plaque on root surface under FeCl2 treatment was 197%233% of that under FeCl3 treatment. Fe(III) and Fe(Ⅱ) consisted of 85%92% and 8%15% of the total iron plaque respectively. The concentration of iron plaque on the root surface of Tianyou 998 (Oryza sativa L. cv. TY998) was significantly higher than that in Peizataifeng (Oryza sativa L. cv. PZTF). Iron uptake in TY998 was 115% and 138% of that in PZTF. Treatment with FeCl2 increased the activity of rice roots by 24%69%, while FeCl3 treatment by 16%54%. The activities of SOD、POD and CAT in rice roots were increased by 11%32%、15%30% and 30%31% respectively under FeCl2 treatment, while they did not change obviously under FeCl3 treatment. The above results suggested that the addition of a certain concentration of iron enhanced the formation of iron plaque on root surface and iron uptake in rice seedlings. In comparison to FeCl3 treatment, FeCl2 treatment was conductive to the increase of activities of antioxidant enzymes, thus improved iron uptake in rice seedlings.