The researchers studied how sugar levels change in peach fruits and leaves during growth, focusing on the difference between peach varieties with equal amounts of glucose and fructose (G/F≈1) and those with higher G/F ratios. They found that sucrose levels in fruits increased as they ripened, while sorbitol levels peaked early and then decreased. Glucose and fructose levels were high initially but decreased over time. The G/F ratio was consistently higher in fruits of varieties with high G/F. In leaves, sorbitol was the dominant sugar, and G/F ratios varied between the two types of peach cultivars. The transportation of sugars from leaves to fruits did not significantly affect the G/F ratio in fruits. The differences in G/F ratios between peach varieties were due to variations in sugar metabolism in the fruits.