Influence of Lanthanum on Phosphorus Uptake and Its Chemical Fractions in Rice Crop (Oryza Sativa)

The effects of lanthanum on rice growth, phosphorus uptake and phosphorus chemical fractions in rice were studied with split-root solution culture. Results show that low concentration of La (0.05～1.5 mg*L-1) significantly increases rice yield while high La concentration (9～30 mg*L-1) markedly decreases rice yield. When La concentration is 0.05～0.75 mg*L-1, La increases stem and root dry weight, but the difference is not statistically significant. La significantly increases EDTA-P and inorganic-P content in the stem and root. More than 80% of the increase of phosphors content in roots attributing to increase of EDTA-P and inorganic-P. Low La concentration (0.05～0.75 mg*L-1) increases nucleic-P content in root, but high La concentration (30 mg*L-1) decreases nucleic-P and ester-P content in root. The residue-P content increases in the root and stem. Also the relationship between the chemical fractions of phosphorus and its uptake by rice was discussed.