Aerenchyma formation has been described in depth in a number of species at a histological level. But large gaps remain in our understanding of its regulation as a developmental process. It is attempted to analyse essential mineral elements like K, Mg, Cu, Zn, Ca and P in the cell wall of aerenchyma cells in petioles of S. trifolia at five different developmental stages by CSEM-EDX technique. At early stage, K and Cl concentrations in cell wall were high up to 36% and 4.3% of dry weight, respectively. It supported the hypotheses that aerenchyma spaces are filled with liquid at early developmental stages of aerenchyma in S. trifolia petiole. Mg concentration was high at stage 2, up to 0.86% of dry weight. Zinc and Cu were detected only at rapid expansion stages, during which the concentrations were up to 1.5% and 2.5%, respectively. Calcium was detected in the cell wall only at mature stages, the concentration was high up to 1.3% of dry weight at stages 4 and 5. These results confirmed that the element concentration of aerenchyma cell wall undergoes dynamic changes during different developmental stages, and a low Ca with high Zn and Cu concentration are needed for cell expansion. Copper and Zn deposition in the cell wall showed a significant positive linear correlation, suggesting that these two elements share same or similar uptake and transport mechanism in plants.