Abstract: This paper introduced two strategies of iron uptake in rice, the components of iron plaque on root surface and its significances for ecological environment and nutrient absorption. Two bases of iron plaque formation driven by increment of root oxidative capacity, i.e. formation of aerenchyma and the enzyme-mediated radical oxygen species (ROS) were analyzed emphatically. The formation of aerenchyma contributes to oxygen secretion enhancement as well as ameliorating phosphate deficiency and iron toxicity; besides, it also results in ROSmediated programmed cell death. By analyzing ROS scavenge by antioxidant enzymes, Fenton reaction was assumed to be the key reaction in the process of iron plaque formation, and the hypothesis that the class III peroxidase located at cell wall of epidermis and outer cortex tissue might be associated with the formation of iron plaque on rice root surface was put forward. Moreover, the functions of iron chelate reduction oxidase, iron transporter and peroxidase at molecular level were discussed, and strategy I like iron absorption pathway was regarded as a possible main source of iron for iron plaque formation. Finally, the hot spots needed to be solved on iron plaque were discussed after conclusively analyzing the process and condition of iron plaque formation.

Key words: runoff scouring, riparian zone, slope erosion, hydrodynamic characteristics, interaction