Leaf photosynthetic characteristics and fruit quality of Actinidia arguta as affected by slope aspect and gradient

To guide orchard site selection, this study examined how slope gradient and aspect affect the photosynthetic characteristics and fruit quality of Actinidia arguta . Seven plots with different slope gradients and aspects were established in the same orchard. After measuring the photosynthetic parameters and fruit quality traits, the data were evaluated using Duncan’s multiple range test and principal component analysis (PCA). Among the seven plots, Plot 5 on a west-facing 17° slope achieved the highest photosynthetic performance. Its net photosynthetic rate (Pn), transpiration rate (Tr), and intercellular CO 2 concentration (Ci) were more than 5% higher than those in the other plots. The best fruit appearance quality occurred in Plot 3 on an east-facing 30° slope. In contrast, Plot 1 on a southwest-facing 5° slope ranked highest for nutritional quality, including soluble solids, solid-acid ratio, soluble sugar, and vitamin C content. PCA identified Plot 6 on a northeast-facing 20° slope as having the best overall fruit quality. Collectively, the northeast-facing 20° slope and moderate canopy index recorded in Plot 6 represented ideal conditions for A . arguta fruit quality. Therefore, orchard site selection should include multidimensional comparisons based on local latitude and light intensity to benefit tree growth and flavor development.