The Photosynthetic Characteristics of Michelia alba in Autumn

The photosynthetic characteristics study of leaves in perennial evergreen arbor Michelia alba were determined with the Li-6400 Photosynthetic system.The results showed that the curve of daily of M.alba net photosynthetic rate was a double-peak curve and there was a clear depression at noon.Its first peak occurred at 14:00 p.m.,the second one at 9:00 a.m..The maximum of photosynthetic rate was 5.22 μmol·m-2·s-1.Correlation analysis showed that there were positive relationship between photosynthetic rate and transpiration rate and stomatal conductance,there is a negative relationship between photosynthetic rate and internal CO2 concentration.The light compensation point of M.alba is 10.38 μmol·m-2·s-1,its light saturation point is 1 100 μmol·m-2·s-1.The light compensation and saturation point indicates that M.alba is a little shade-resistant plant and it cann't bear the glare.