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 valuewas the highest , which occurred at about 9 :00 a.m ., the net photosynthetic rate was 7.35 molm-2 s-1 ;the second peak value occurred at 16 :00 p.m ., the net photosynthetic rate was 2.64 mol 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 CO2 caused photosynthetic midday depression .The CO2 compensation point was 53.8 molmol-1 and CO2 saturation point was 1 621.4 mol mol-1 .The light compensation point was 42 molm-2 s-1 and light saturation point was about 1 000 molm-2 s-1 .[ Ch , 5 fig .11 ref .]