Abstract: The influences of different light environments（open field，shadow by house，green-house with shade cloth）on photosynthetic characteristics of Clematis‘Vyryan Pennell’were compared. The results were showed that，when compared with the plant growing in the open field and shade cloth，the plant growing in half-shadow by house had higher light saturation point（LSP），maximum net photosynthetic rate（Pmax），maximum carboxylation rate（Vcmax）and photochemical efficiency. This difference was associated closely with the environmental factors under half-shadow by house conditions，i.e. appropriate light intensity and temperature. This species adapt to the changes of growing environment mainly through the changes in leaf mass area（LMA），light saturation point（LSP），light compensation point（LCP）and respiration rate（Rd）. The content of chlorophyll，leaf nitrogen content and leaf nitrogen distribution in the photosynthetic apparatus had little contritution to the adaptation of‘Vyryan Pennell’to changing environments. 　　

Key words: Clematis, light environment, photosynthetic characteristic