Abstract:

The leaves of Cotinus coggygria in Fragrant Hills Park at different altitudes were taken as the materials. The correlation between the leaf color and pigments composition of C. coggygria was analyzed. The results showed that the value of leaf color chroma a^* was negatively with the contents of chlorophylls and positively with anthocyanins, respectively. The descending chlorophylls and ascending anthocyanins contents were the main factors responsible for the leaf color reddening. The content of flavonols was in an upward trend, affecting the values of lightness L^* and chroma b^*, while the content of carotenoids kept stable, and was no significant correlated with the values of leaf color parameters. Based on the investigation in fall of 2007, temporal and spatial variation of the leaf color at different altitudes from Fragrant Hills Park was obtained. In time domain, the variation of the leaf color chroma a^* at high altitude area (564 m) and middle altitudes areas (466 m and 315 m) showed the same trend, take high altitude area (564 m) as an example, the values of leaf color chroma a^* ascended steeply from October 12 and reached the peak on October 24, and then descended slowly. The values of leaf color chroma a^* at low altitude area (195 m) ascended continuously from October 4 to November 9. In space domain, the values of leaf color chroma a^* at high altitude area (564 m) increased quickly, and decreased fast, it can be seen that the leaves of C. coggygria in this area changed color earlier, but defoliated quickly, so this area was suitable for appreciating in the early time (from October 20 to October 28). While the leaves of C. coggygria at middle altitudes areas (466 m and 315 m) changed leaf color together with those at high altitude area, but had longer duration of coloring to appreciating (from October 24 to November 5). The leaves of C. coggygria at low altitude area (195 m) changed color at latest, and defoliated slowly, so this area was suitable for appreciating in the late time (after November 1).

Key words: Cotinus coggygria, leaf color, anthocyanin, chlorophyll, temporal and spatial variation