Abstract:

Photosynthesis of differently directional leaves in Ping-ou 110 and Ping-ou 349 and its influencing factors were studied and analyzed. The results indicated that diurnal variation of net photosynthesis rate (P_n) of southern and northern leaf were two-peak curve. That of western leaf was single peak curve, and the peak appeared at 7:00—8:00 in the morning, but diurnal variation in net photosynthesis rate of eastern leaf was relatively steady, did not appear apparent peak. Pn changes of differently directional leaves at noon primarily were contributed to limitation of non stomatal factor; There were some difference in average net photosynthesis rate and assimilating CO₂ capacity of differently directional leaves, the highest was southern leaf, next was western and northern leaf, the lowest was eastern leaf; light saturation points of Ping-ou 110 and Ping-ou 349 were 691～724 μmol m^-2 s^-1 and 464～505 μmol m^-2 s^-1, light compensation points were 10～26 μmol m^-2 s^-1 and 8～21 μmol m^-2 s^-1, respectively, they were lower than those of common deciduous fruit trees; vapor pressure deficiency (VPD) and photo fluid density (PFD) were dominantly influencing factors of net photosynthesis rate as shown multiple stepwise regression analyses.

Key words: Corylus heterophylla ×, Corylus avellana, net photosynthesis rate, stomatal conductance, intercellular CO₂ concentration, environment factors