Study on the photosynthetic characteristics of different cultivars of pear

The photosynthetic characteristics of Huangguan pear,Huangjin pear and Red Fragrant pear were measured in the field conditions.The results showed that three pear cultivars had a double-peak curve of diurnal variation of photosynthesis and a phenomenon of photosynthetic noon breaking in sunny days.There were some different changes between the photosynthetic rate of different varieties.The photosynthetic noon breaking of Huangguan pear was the most obvious.However,the photosynthetic noon breaking of Red Fragrant pear was relatively light.The light saturation points(1 200 μmol/m2.s) and light compensation points(30 μmol/m2.s) of Huangguan pear were obviously lower than the other two pear cultivars.The light saturation points(1 400 μmol/m2?s) and light compensation points(70 μmol/m2.s) of Huangjin pear were relatively higher.The saturated CO2 concentration of each cultivar were higher,the differences of CO2 compensatory point of different cultivars were little.