Abstract: Some photosynthetic characteristics of two pear varieties(Pyrus bretschneideri Rehd and Xinli No.7) were studied,Analysis their photosynthesis general character and the characteristic,The results showed: Diurnal change of sunny day in net photosynthetic rate(Pn) in Pyrus bretschneideri Rehd and Xinli No.7 were typical ″none-drop″ bimodal curve,and the phenomenon of″the midday rest″ were obvious.Pn daily variation of cloudless day were the split-blip curve.″The midday rest″ phenomenon in Xinli No.7 was more obvious than Pyrus bretschneideri Rehd,also the photosynthesizes ability under the cloudy day weak light condition was stronger than Pyrus bretschneideri Rehd.The light compensation points and light saturation points approximately was 1 392 and 42 μmol/(m²·s),the apparent quantum yield was 0.048 2 mol/mol.When photoinhibition occurred in Xinli No.7,AQY and Pn decreased obviously.

Key words: Pyrus bretschneideri Rehd, Xinli No. 7, Net photosynthetic rate, Annual changes, Photoinhibition

CLC Number: 

• S661.2