Differences in light response characteristics of oil peonies from eight provenances in China

Two tree peony species, Paeonia ostii and Paeonia rockii, from eight different provenances in China (four provenances for each species) were collected for their photosynthetic characteristics. Their diurnal variations of photosynthesis, the light- and CO2-response curves and chlorophyll content were determined. Among all eight provenances, Ziwuling P. rockii had a significantly higher average daily net photosynthetic rate, showing a superior photosynthetic capacity, followed by Fengxiang P. ostii and Xunyang P. ostii. In addition, Ziwuling P. rockii had the highest maximum net photosynthetic rates, thus, presented a strong photosynthetic potential. Furthermore, Xunyang P. ostii, Fengxiang P. ostii, and Heze P. ostii also exhibited a great photosynthetic capacity and light adaptability, which was consistent with their high chlorophyll a/b values. Taken together, Ziwuling P. rockii had the strongest photosynthetic capacity among all tested sources, followed by Fengxiang P. ostii, and Xunyang P. ostii, which are recommended to be used as seed sources for oil peony cultivation and cross-breeding.