Photosynthetic characteristics of Eurya muricata at seedling stage

The Li-6400 Portable Photosynthesis System made by American Li-COR Company was used to study the photosynthetic characteristics of Eurya muricata at seedling stage. The results showed that the daily variation of net photosynthetic rate in leaves presented a bimodal curve and an obvious 'midday depression' phenomenon. The first peak value was the highest, which occurred at about 9:00 a.m., the net photosynthetic rate was 7.35 μmol·m~(-2)·s~(-1);the second peak value occurred at 16:00 p.m., the net photosynthetic rate was 2.64 μmol·m~(-2)·s~(-1). The main reason for the midday depression was stomatal factors. At midday, the largest light intensity, the maximum vapor pressure deficit between leaves and air and the minimum air relative humidity, stomatal conductance and intercellular CO_2 caused photosynthetic midday depression. The CO_2 compensation point was 53.8 μmol·mol~(-1) and CO_2 saturation point was 1 621.4 μmol·mol~(-1). The light compensation point was 42 μmol·m~(-2)·s~(-1) and light saturation point was about 1 000 μmol·m~(-2)·s~(-1).