以‘牛心李’成龄树为试材测定了不同类型枝条和树体部位的净光合速率 (Pn)。结果表明 ,不同类型枝条叶片 Pn存在一定差异 ,短果枝叶片 Pn显著高于其他类型枝条叶片 Pn;在同一果枝上 ,果实上位叶具有最强的光合性能 ,果实的存在促进叶片 Pn提高 ,且显示出源 -库关系只在较近距离时作用显著 ;树体不同部位及不同层次叶片 Pn与光合有效辐射密切相关 The net photosynthetic rate (Pn) of different types of shoots and tree body parts was determined by using ’Niuxinli’ adult tree. The results showed that Pn of different types of branches had some differences, Pn of short fruit branches was significantly higher than that of other branches. On the same fruit branch, the upper leaves had the strongest photosynthetic property, and the presence of fruit promoted the increase of leaf Pn The relationship between source and sink is significant only at a relatively short distance; Pn is closely related to photosynthetically active radiation in different parts of tree body and in different layers