Diurnal variations of photosynthetic characteristics of middle age Ziziphus jujuba cv. Huizao trees under different irrigation conditions (T1, T2 and CK) were measured and compared by using the Li-6400 portable photosynthesis meter in order to explore the optimal irrigation method. The results show that(1)The diurnal variations curves of net photosynthesis rate (Pn), stomatal conductance (CCond) and transpiration rate (Tr) all presented as a bimodal pattern curve and all showed a signiifcant photosynthetic“lunch break”phenomenon;(2)The water use efifciency(WUE) of Z. jujuba cv. Huizao under different irrigation conditions gradually decreased after 8:00 a.m.;(3) The utility rate of luminous energy (LUE) of Z. jujuba cv. Huizao under different irrigation conditions gradually decreased after 8:00 a.m. and gradually increased after 6:00 p.m.;(4) There were signiifcantly differences in net photosynthesis rate (Pn) and water use efifciency (WUE) of Z. jujuba cv. Huizao between T1 and T2, and there was a highly signiifcant difference in Pn and WUE between CK and T1;there were highly signiifcant differences in LUE of Z. jujuba cv. Huizao among T1, T2 and CK. And no signiifcant differences existed among the other photosynthetic characteristics parameters;The well-type irrigation method promoted the higher photosynthesis characteristics (in Pn, WUE, LUE, Ci and Cond) than the other irrigations, and had lower values in Tr, Ls.%通过测定井式灌溉（T1）、地表滴灌（T2）和对照漫灌（CK）条件下中龄灰枣光合生理指标的日变化，探索不同灌溉方式下枣树的光合特性。使用Li-6400便携式光合测定仪测定3种灌溉方式下中龄灰枣的光合特性日变化并进行分析比较。结果表明：（1）3种灌溉方式下中龄灰枣的净光合速率（Pn）、气孔导度（Cond）和蒸腾速率（Tr）的日变化均呈“双峰型”曲线，有明显的光合“午休”现象；（2）3种灌溉条件下中龄灰枣的水分利用效率（WUE）在上午8：00之后逐渐下降；（3）3种灌溉条件下中龄灰枣光能利用率（LUE）8：00后逐渐下降，18：00后又逐渐升高；（4）T1条件下中龄灰枣的Pn、WUE较T2条件下有显著性差异，与CK条件下有极显著差异。LUE表现为在T1较T2和CK条件下均存在极显著差异。而各灌溉条件下其他光合参数则无显著性差异。与其他灌溉方式相比，井式灌溉有较高的Pn、WUE、LUE、Ci、胞间CO2浓度（Cond）和较低的Tr、气孔限制值（Ls）。
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