柃木苗期光合特性研究

Photosynthetic characteristics of Eurya muricata at seedling stage

运用美国Li COR公司制造的Li 6400便携式光合作用测定系统,研究柃木Euryamuricata苗期的光合特性。结果表明,柃木叶片净光合速率(Pn)的日变化曲线呈双峰型,有"光合午休"现象,第1个峰值出现在9:00左右,净光合速率(CO2)达到7 35μmol·m-2·s-1;第2个峰值出现在16:00,净光合速率为2 64μmol·m-2·s-1。柃木叶片CO2补偿点为53 8μmol·mol-1,饱和点为1621 4μmol·mol-1。柃木叶片光补偿点为42μmol·m-2·s-1,饱和点为1000μmol·m-2·s-1左右。

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).