Isodon rubescens leaves

The characteristics of photosynthesis and chlorophyll fluorescence in Epimedium brevicornu Maxim need to be defined to study the cultivation of E. brevicornu. The diurnal variation of photosynthesis, light response curve and CO₂ response curve in E. brevicornu leaves were determined with Li-6400 Photosynthesis system. Fluorescence characteristics of chlorophyll in the leaves were determined with PAM-2500 portable chlorophyll fluorescence apparatus. The results showed that there was obvious midday depression in the photosynthesis of E. brevicornu leaves. The light compensation point of the leaves was about 15µmol·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 summers. The CO₂ saturation point of E. brevicornu leaves was much higher than the content of CO₂ in general air. E. brevicornu, which could survive in very low sunlight, is typically a shade plant. 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 it was below CO₂ saturation point. E. brevicornu possessed great potential of photosynthesis.