Abstract:

In order to understand the tolerance to shade of Vihurnum opulus L, the diurnal variation of photosynthetic characteristics and its relationship to the environmental factors of Vihurnum opulus L. under different shading treatment were studied with the Licor-6400 portable photosynthetic system. The results showed as following: (1) The diurnal variation of net photosynthetic rate (Pn) of Vihurnum opulus L. showed double-peak curve under the 100% light and 60% light, and showed obviously midday depression, however, under 20% light, the diurnal variation of Pn showed single-peak curve. (2) The Vihurnum opulus L’s controlling factor of photosynthetic rate was non-stomatal limitation. (3) Under 100% light and 60% light, the first factor affecting Pn was stomatal conductance(Gs); Under 20% light, the first factor affecting Pn was Transpiration rate(Tr).(4) The proper shade had not strong effect on the photosynthesis of Vihurnum opulus L. To strengthen the shade, the photosynthesis rate decreased significantly. The photosynthetic characteristics’ ability of about three treatments were 100% light＞60% light＞20% light. Vihurnum opulus L could be planted in the shadow.