3.3.3. SS-I

The changes in SS-I activity are shown in Figure 2c. The dynamic changes in enzyme activity in the high-Ca treatment group and CK group were different. The values in the high-Ca treatment group were significantly lower than those in the CK group at 71 d after anthesis. There was no significant difference at the other time points. Therefore, combined with the results of the sugar content determination, the results here indicate that high-Ca treatment may inhibit the conversion of sucrose to reducing sugars by reducing SS-I activity and subsequently inhibiting the accumulation of reducing sugars in the fruit pulp.

## 3.3.4. SS-II

The changes in SS-II activity are shown in Figure 2d. The SS-II activity in the high-Ca treatment group was significantly lower than that in the CK group before 64 d after anthesis and vice versa after 64 d after anthesis, but there was no significant difference at 43 and 77 d after anthesis. These results indicated that high-Ca treatment inhibited SS-II activity before 64 d after anthesis, resulting in the inhibition of sucrose accumulation.
