Quantitative Analysis of Leaf Color of 10 Species of Rosaceae in Xinjiang

The leaf color, as a persistent and stable visual element in the landscape design of garden plants, has increasingly demonstrated its esthetic and ecological value. The plants of the genus Rosa L. in the Rosaceae family exhibit rich species diversity and ornamental potential, yet the systematic research on their leaf color characteristics and the physiological mechanisms underlying coloration remains relatively scarce. By using 10 wild rose species as the materials, the L^*a^*b^* color model was employed to quantify the leaf color parameters (L^* brightness, a^* red-green axis, b^* yellow-blue axis), and the correlation analysis was performed combined with chlorophyll content, in order to analyze the physiological basis of leaf color variations in Rosa plants. The results showed that there were significant differences among different rose species in L^*, a^*, and b^* values. Among them, Rosa beggeriana Schrenk and Rosa laxa Retz. exhibited the highest brightness, while Rosa xanthina Lindl. showed the lowest brightness. The a^* value indicated a greenish bias across all species, though the greenness exhibited significant differentiation. The b^* value revealed the distinct yellowish tendencies in some species. Through the quantitative phenotyping of rose varieties, a ranking and grading system was established based on the comprehensive score（S）, with all varieties ranked from highest to lowest and categorized into three grades according to their rankings. The correlation analysis demonstrated a significant negative correlation between a^* and chlorophyll content, confirming the physiological role of chlorophyll in red light absorption. L^* values generally showed no significant correlation with chlorophyll, indicating that brightness was primarily influenced by the physical properties such as leaf surface structure. The relationship between b^* and chlorophyll varied among species, reflecting the regulatory role of non-chlorophyll pigments. In this study, the leaf color of the rosa plants was objectively quantified, which provided the basis and reference for the evaluation and classification of rose germplasm resources and the color design of garden landscape.