Effects of Lanthanum and Cerium on Seeds Fatty Acid Composition in Soybean

Soybean Dongnong 42 from northeast of China was used as an experimental material. The samples were tested by spraying different concentrations of LaCl3, CeCl3 and LaCl3+CeCl3 solutions on the leaves at the seedling stage and the early flowering stage of the soybeans. Gas chromatography was used to determine the fatty acid content and ratio of the soybean seeds at the maturity stage. The fatty acid ratio of soybean seeds were evaluated by calculating saturated fatty acid（SFA）, monounsaturated fatty acid（MUFA）, polyunsaturated fatty acid（PUFA）, unsaturated fatty acids（UFA）, UFA/SFA, index unsaturated fatty acid（IUFA） and double bond index（DBI）.（MUFA+PUFA）/SFA was used to study the effects of rare earths on the quality of soybean seeds. The results showed that spraying the rare earth solution could significantly optimize the fatty acid distribution ratio of soybean seeds. Compared with the control group（CK）, stearic acid was reduced by 5% and linolenic acid was reduced by 3.72%. Except for La10, the oleic acid content increased significantly by 2.22%. Under the treatment of 30 mg·L^-1 CeCl₃, UFA, UFA/SFA and DBI were 83.56, 5.08 and 9.47, respectively, which were the highest in each group. Under the treatment of 150 mg·L^-1 LaCl₃,（MUFA+PUFA）/SFA was 4.89, the closest meal to the recommended ratio. The above results showed that spraying appropriate concentrations of rare earth at the seedling stage and the early flowering stage could optimize the fatty acid ratio of soybean seeds and improve dietary fatty acid ratios.