Objective] To investigate the diurnal patterns and photosynthetic characteristics of the leaves of litchi (Litchi chinensis) at full-bloom stage, and provide references for cultivation and management of litchi at flowering stage .[Method]Under natural conditions , the photosynthetic parameters of three litchi cultivars including ‘Feizixiao ’ , ‘Guiwei ’ and ‘Nuomici ’ at full-bloom stage were measured using a LI-6400 portable photosynthesis system .[Result]The curves of diurnal changes in net photosynthetic rate ( Pn) had two peaks and clear midday depression for all three cultivars , the first peak was measured at 10:30, and the second peak was at 13:30.The average daily Pn of ‘Nuomici’ (3.76μmol· m-2 · s-1 ) was significantly higher than those of ‘Feizixiao ’ ( 2.38 μmol · m-2 · s-1 ) and ‘Guiwei ’ ( 2.41μmol· m-2 · s-1 ).Pn of three cultivars were significantly positively correlated with photosynthetic available radiation (PAR).In addition, Pn of ‘Guiwei’ was significantly positively correlated with air temperature (θa), and Pn of‘Nuomici’ was significantly positively correlated with stomatal conductance ( Gs) .[Conclusion]PAR is the primary ecological factor influencing Pn of the three litchi cultivars , and the effects of other factors on photosynthesis of litchi leaves vary among different cultivars .%【目的】阐明不同荔枝Litchi chinensis品种盛花期叶片光合作用的日变化规律及光合特性，为荔枝开花期的栽培管理提供指导。【方法】在自然条件下，利用LI-6400便携式光合测定系统对‘妃子笑’、‘桂味’和‘糯米糍’3个主栽荔枝品种盛花期的光合作用参数进行测定。【结果】3个品种的净光合速率（ Pn）日变化均呈双峰曲线，首峰出现在10：30，次峰出现在13：30，午休现象明显。‘糯米糍’的Pn日均值（3.76μmol· m－2· s－1）显著高于‘妃子笑’（2.38μmol· m－2· s－1）和‘桂味’（2.41μmol· m－2· s－1）。3个荔枝品种的Pn都与光合有效辐射（PAR）呈显著正相关，‘桂味’的Pn与气温（θa ）呈显著正相关，‘糯米糍’的Pn与气孔导度（ Gs）呈显著正相关。【结论】PAR是影响3个荔枝品种Pn的主要生态因子，其他因子对荔枝叶片光合作用的影响因品种不同存在差异。
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