为探索蝴蝶兰蜜露形成的生理机理,以蜜露分泌严重的蝴蝶兰‘大辣椒’和无蜜露分泌的蝴蝶兰‘双龙’两个品种为试验材料,研究不同叶龄的叶片(新叶、功能叶和老叶)光合生理指标的差异。结果表明:蝴蝶兰‘大辣椒’不同叶片类型之间的净CO_2吸收速率并没有显著差异,蝴蝶兰‘双龙’新叶的净CO_2吸收速率显著高于功能叶和老叶,而且比‘大辣椒’的新叶高64%;同时,蝴蝶兰‘双龙’所有类型叶片的可滴定酸含量都高于蝴蝶兰‘大辣椒’。两个蝴蝶兰品种不同叶片类型的叶绿素荧光参数有显著差异。在新叶中,蝴蝶兰‘双龙’的最大荧光(F_m)、可变荧光(F_v)、PSII的实际光合量子产量(Yield)和光化学淬灭系数(q_P)都显著大于蝴蝶兰‘大辣椒’,但非光化学淬灭系数(NPQ)小于蝴蝶兰‘大辣椒’;在功能叶和老叶中,蝴蝶兰‘双龙’的PSII潜在活性(F_v/F_o)大于蝴蝶兰‘大辣椒’,但q_P和表观光合电子传递速率(ETR)小于‘大辣椒’。与蝴蝶兰‘双龙’不同,蝴蝶兰‘大辣椒’的碳水化合物含量在3种叶片中呈现老叶>功能叶>新叶的趋势,其中,蝴蝶兰‘大辣椒’老叶的可溶性糖和淀粉含量分别比蝴蝶兰‘双龙’高40%和27%。虽然可溶性蛋白在两种蝴蝶兰的3种叶片中的含量呈相似趋势,都表现为新叶大于功能叶和老叶,但是蝴蝶兰‘双龙’的叶绿素含量显著高于蝴蝶兰‘大辣椒’。以上数据表明,叶片中碳水化合物的积累,可能是蝴蝶兰‘大辣椒’分泌蜜露的主要原因。 In order to explore the physiological mechanism of the formation of honeydew of Phalaenopsis, two varieties of Phalaenopsis ’Big Pepper’ secreted by honeydew and non-nectar secreted Phalaenopsis ’Ssangyong’ were used as experimental materials to study the effects of different leaf age , Functional leaves and old leaves) photosynthetic physiological differences. The results showed that there was no significant difference in the net CO 2 uptake rate between different leaf types of Phalaenopsis ’Big Pepper’. The net CO 2 uptake rate of Phalaenopsis ’Ssangyong’ new leaf was significantly higher than that of functional leaf and old leaf, ’Of the new leaves 64% higher; at the same time, all types of leaves of Phalaenopsis’ Ssangyong ’titratable acid content than’ Phalaenopsis ’big pepper’. There were significant differences in chlorophyll fluorescence parameters between two leaf types of Phalaenopsis. In fresh leaves, the maximum fluorescence (F_m), variable fluorescence (F_v), PSII yield and photochemical quenching coefficient (q_P) of Phalaenopsis were significantly higher than those of Phalaenopsis ’Big Pepper’ , But the non-photochemical quenching coefficient (NPQ) was less than that of Phalaenopsis’ Big Pepper ’. In the functional leaves and the old leaves, the PSII potential activity (F_v / F_o) of Phalaenopsis was higher than that of the Phalaenopsis’ And the photosynthetic electron transfer rate (ETR) is less than that of ’big pepper’. Different from Phalaenopsis, the carbohydrate content of Phalaenopsis ’Big Pepper’ showed the trend of old leaf> functional leaf> new leaf in three kinds of leaves, in which the soluble sugar and starch of old leaf of ’Phalaenopsis’ Content respectively than the Phalaenopsis ’Ssangyong’ 40% and 27% higher. Although the content of soluble protein in the three kinds of leaves of two Phalaenopsis showed a similar trend, the new leaves were larger than the functional leaves and the old leaves, but the chlorophyll content of the Phalaenopsis ’Ssangyong’ was significantly higher than that of the Phalaenopsis ’Big Pepper’. The above data show that the accumulation of carbohydrates in the leaves may be the main reason for the secretion of honey dew in ’Phalaenopsis’.