Contrasting studies on photosynthetic characteristics of Zizyphus jujuba cv. Dongzao grafted seedlings from different producing places

In order to study the photosynthetic characteristics of Zizyphus jujuba cv. Dongzao, grafted seedlings from different places, which were planted in Huanghua and Cangxian, Hebei Province of northern China, were used as experimental materials for the measurement of photosynthesis using Lico-6400. The results showed that the light response curves of net photosynthetic rate of Z. jujuba cv. Dongzao from different places were similar to each other, and the net photosynthetic rate of Z. jujuba cv. Dongzao from Jidong,Hebei Province was higher than that of others with the same photosynthetic active radiation. The diurnal variation of net photosynthetic rate exhibited dual-peak curves, and the annual variation showed single-peak curves. The light compensate points of Z. jujuba cv. Dongzao from Qingyun, Shandong Province and Huanghua were lower than that of others, the light saturation points of Z. jujuba cv. Dongzao from Leling, Shandong Province and Cangxian were higher than that of others, suggesting different ability of adapting radiation intensity. The difference of net photosynthetic rates of Z. jujuba cv. Dongzao among different orchards and varied years was significant.