Abstract:Three cultivars of Cucumis melo L.,differing in suitable cultivation models,were employed to study the effects of light intensity on leaf characteristics,such as photosynthetic pigment content,net photosynthetic rate (Pn) and specific leaf weight (SLW) etc.The results indicated that shading treatment induced melon leaf chlorophyll and carotenoids (Car) contents increased and Chl a/b deceased significantly in comparison with normal light intensity.Under full light,the diurnal change of net photosynthetic rate (Pn) of three melon cultivars showed clear midday depression,but only a single delayed peak under shading conditions.The diurnal change of stomatal conductance (Gs) of melon leaves was similar to Pn.Under full light,the differences of SLW among melon cultivars were not significant,but SLW of melon leaf was remarkably reduced under shading conditions,and SLW under 26% of natural light treatment dropped significantly,the SLW decrease of ‘Huanghemi 3’ (31.83%) was significantly higher than those of ‘Yindi’ (27.22%) and ‘Yujinxiang’ (26.01%).It could be seen that shading treatment reduced net photosynthetic rate of melon leaves and specific leaf weight of functional leaves.The photosynthetic pigment content of plant would be increased in order to alleviate the influence of shade and enhance the adaptability to the environment.Yindi showed the stronger low light intensity tolerance.