Abstract: Leaf removal will change the microclimate around fruits during the stage of color-changing, also the fruit quality accumulation will be affected. To study the effect of leaf removal in different directions on the quality of mature fruits, taking the Cabernet Sauvignon planted in the north-south direction as the experimental materials, the leaf removal experiments in the east side, in the west side and in both sides were carried out at the Helan mountain east foothill wine region. The results showed that: (1) compared with the control, in the eastern leaf removal treatments, the content of soluble solids, glucose, fructose, total acid, ratio of sugar to acid, malic acid, citric acid, tartaric acid and Tannin in the mature fruit of Cabernet Sauvignon grape increased, especially the level of fructose, citric acid and tartaric acid increased significantly; There was no significant decrease in content of reducing sugar, total phenol, anthocyanidin. (2) In the west leaf removal treatments, the content of soluble solids, reducing sugar, total phenols and anthocyanins in fruits also decreased slightly, fructose, malic acid, citric acid and tannin increased significantly, and the glucose content, the ratio of sugar to acid and tartaric acid content increased slightly. (3) The tannin level of grape fruit in both side leaf-removal treatments increased significantly, the content of glucose, fructose, citric acid and tartaric acid increased slightly, and the content of soluble solids, reducing sugar, total acid, the ratio of sugar to acid, malic acid, total phenol and anthocyanin were lower than that in CK treatment. Through comparative analysis, the sugar content of the fruit with leaf removal all increased slightly, while in the eastern leaf removal treatment, the acid content increased, and the tannin content increased, falling of total phenols and anthocyanins was relatively small compared to the other two treatments. Considering the present level situation of high sugar and low acidity in the wine production areas of the Helan Mountain East Foothill Wine Region, the leaf removal in the east is recommended as the main pattern to manage the leaf curtain and to control the quality of fruit in the vineyard with the north-south row direction, which plays a role in balancing the overall flavor substances of grape fruits.

Key words: Helan mountain east foothill wine region, Cabernet Sauvignon, Leaf removal, Quality of fruit