Abstract: Gas exchan ge an d chlorophyll fluorescence were used to explore the photosynthesis of Areca triandra Roxb. in greenhouse before and after partial shading． It showed that light saturation photon flow density of Areca triandra Roxb． Was about 200—300~tmol·m一 ·s一 and optimal leaf temperature Was about 25℃ ．The average daily photos yn thetically active solar irradian ce decreased by about 55％ ， while for the air an d leaf temperaturea decrease of about 3—4℃ were observed after shading compared with before shading．Distinct photoinh ibition of Areca triandra R0xb． Was observed before shading， however， there Was no obvious photoinhibition occurred after shading． The average daily net photosyn thetic rate of Areca triandra R0xb． Was only reduced by about 12％ after shading． All these results indicated that partial shading Was be nefit for the growth of Areca triandra R0xb． in greenh ouse in summer.

Key words: Areca triandra R0xb．, Greenh ouse, Partial shading, Photosyn th esis, Chlorophyll fluorescence