With the aid of the CI 301PS portable photosynthesis system,a field study on the photosynthetic characteristics in leaves of Liriodendron chinense seedlings was made.The midday photosynthetic depression was observed on sunny day in summer,which was possibly due to the stomatal limitation and photoinhibition of photosynthesis.The light compensation point was about 20μ mol photons/m 2s,the light saturation point was around 1200μmol photons/m 2s,and the light saturating photosynthetic...