Evaluate the photosynthesis and chlorophyll fluorescence of Epimedium brevicornu Maxim

The diurnal variation of photosynthesis, light response curve and CO₂ response curve in Epimedium brevicornu Maxim leaves were determined with Li-6400 photosynthesis system to evaluate the photosynthesis of E. brevicornu. Fluorescence of chlorophyll in the leaves were determined with PAM-2500 portable chlorophyll fluorescence apparatus in the study. The results showed that the midday depression of photosynthesis was very obvious in the E. brevicornu leaves. The light compensation point of E. brevicornu leaves was about 15 µmol m^-2 s^-1. The light saturation point of E. brevicornu leaves was below 800 µmol m^-2 s^-1, which was lower than the general sunlight intensity at noon in summer. The CO₂ saturation point of E. brevicornu leaves was much higher than the content of CO₂ in general air. E. brevicornu was a typical shade plant and could survive in very low sunlight. E. brevicornu could not endure strong sunlight and high air temperature. The net photosynthetic rate of E. brevicornu leaves linearly correlated with the content of CO₂ in the leaf chamber when the content was below CO₂ saturation point. E. brevicornu possessed great potential of photosynthesis.