乳源木莲光合特性研究

Research on photosynthetic characteristics of Manglietia yuyuanensis

运用Li—6400便携式光合作用测定系统对自然条件下乳源木莲的光响应特性、CO2响应特性及光合作用日变化进行了研究。结果表明:乳源木莲的光补偿点为98μmol.m-2.s-1,光饱和点为1123μmol.m-2.s-1,表观量子效率为0.021μmol.m-2.s-1;乳源木莲的CO2补偿点为108μmol.mol-1,CO2饱和点为2132μmol.mol-1,羧化速率为0.022μmol.mol-1;乳源木莲的光合作用的日变化为双峰曲线,有明显的光合"午休"现象,其峰值出现在10∶00和14∶00。主要的生理生态影响因子为气孔导度、大气温度和光合有效辐射等。

The light response characteristic, carbon dioxide response characteristic and photosynthesis diurnal variation of M. yuyuanensis were studied under the natural conditions by using Li-6400 portable photosynthesis measurement system. The results showed, light compensation point ofM. yuyuanensis was 98μmol·m^-1·s^-1, light saturation point was 1 123 μmol·m^-1·s^-1, apparent quantum efficiency was 0. 021 μmol·m^-1·s^-1. Carbon dioxide compensation point of M. yuyuanens/s was 108μmol·mol^-1 , carbon dioxide saturation point was 2 132 μmol·mol^-1 , carboxylation rate was 0. 022μmol·mol^-1. The curve of diurnal variation of photosynthesis demonstrated two peaks in clear day, which appeared at 10：00 and 14：00 respectively, there was a clear depression at noon. The stomatal conductance, atmospheric temperature and photosynthetic active radiation were the key physiological and ecological factors that influenced the photosynthetic characteristics of M. yuyuanensis.