Study on photosynthetic characteristics of Macropanax rosthornii

The leaf photosynthetic parameters of the introduced Macropanax rosthornii were measured by LI-6400 portable photosynthesis system and its photosynthetic and physiological characteristics were investigated so that the results can provide a scientific guidance for its introduction and landscape application. The results showed that the diurnal course curves of the net photosynthetic rate, photosynthetically active radiation, air temperature, transpiration rate and stomatal conductance had peaks without midday depression; The relativity analysis indicated that the key ecological factors of photosynthetically active radiation, air temperature, the physiological factors of stomatal conductance and transpiration rate played key roles in the net photosynthetic rate, the yearly course curve of the net photosynthetic rate had a single peak, in which the net photosynthetic rate was in the peak in June and July of summer season, and in the middle in either spring or autumn and at the bottom in winter; No strong light suppression was found on the photosynthetic light response curve of M. rosthornii; The maximum net photosynthetic rate, light saturation point, light compensation point, and dark respiration rate simulated by modified rectangular hyperbola were 6.902 μmol·m-2s-1,1013.163 μmol·m-2s-1,4.794 μmol·m-2s-1 and 0.290 μmol·m-2s-1 respectively, and thereby the findings suggested that M. rosthornii had a good shade-tolerance and adaptation to weak light, so it was advisable for growing under shading conditions.