Abstract: To explore the leaf partitioning of essential mineral elements in Newhall navel orange plants grafted on trifoliate orange and citrange，ten elements（N，P，K，Ca，Mg，Fe，Mn，Cu，Zn and B）in leaf tip，leaf margin，leaf middle，leaf base，and winged petiole of the new leaves and old leaves were determined by ICP-MS and Kjeldahl apparatus，and analyzed using multivariate analysis and principal component analysis（PCA）. The PCA results showed that the first two principal components could explain 43.4% and 21.1% of the total variables，respectively. The first component separated new leaves from old leaves，the second component generally discriminated the different leaf parts，especially the winged petiole of new leaves from other leaf parts. For the new leaves，in both rootstock，showed a steep gradient in the K concentrations（winged petiole > leaf base > leaf middle > leaf margin ≈ leaf tip）and Mg concentrations（leaf tip ≈ leaf margin > leaf middle > leaf base > winged petiole）；and the old leaves showed a steep gradient in the Mn concentrations（leaf tip ≈ leaf margin > leaf middle > leaf base > winged petiole）and B concentrations（leaf tip > leaf margin > leaf middle > leaf base > winged petiole）. There was no significant difference in the contents of N，P and B among the different leaf parts of the new leaf blade and the contents of P and Ca among the different leaf parts of the old leaf blade. The contents of Mn，Cu and Zn in the new leaf petiole wing of Newhall navel orange plants grafted on trifoliate orange were not significantly different from those of the other new leaf parts，while the contents of Mn，Cu and Zn in the new leaf petiole wing of Newhall navel orange plants grafted on citrange were significantly lower than those of the other new leaf parts. These results suggest that there are obvious differences in the element distribution characteristics of leaf partitioning，and the element concentrations and ion composition in the leaf petiole wing are very different from other leaf parts.

Key words: citrus, leaf petiole wing, macro-element, micro-element, leaf partitioning