Effects of phosphorus on absorption and transport of selenium in rice seedlings

The effects of different concentrations of phosphorus (P) on absorption and transfer of selenium (Se) in rice seedlings were studied by hydroponics experiment. The interaction between iron plaque and phosphorus on absorption and transport of selenium were studied by adding a large amount of iron-induced iron plaque, to provide a theoretical basis for rational application of phosphate fertilizer in the selenium bio-strengthening process of rice. The results showed that phosphorus deficiency may result in the formation of reddish brown iron oxide coating on the root surface of rice. The formation of root iron plaque of rice is related to concentration of phosphorus, and low concentration of phosphorus (0-1.5 mmol L^-1) can increase the amount of root iron plaque. Compared P deficiency culture and 2 mmol L^-1 P culture, Se content in the shoots and roots decreased by 76 and 47%, respectively. Addition of Fe²⁺ significantly reduced biomass of shoot and had no significant effect on the roots; when the P concentration increased from 0.1 to 0.3 mmol L^-1, transfer coefficient of Se decreased. Therefore, both root iron plaques induced by phosphorus deficiency and iron addition have a strong adsorption effect on selenium, which reduces the transport of selenium from the rice roots to the shoots. In the lower range of phosphorus concentration, low phosphorus can promote selenium content of rice shoot, while higher on the contrary. In the practice of rice production, proper management of phosphorus nutrient is of great significance to control selenium content in rice grain.