Study on photosynthetic characteristics of different pear cultivars.

The photosynthetic parameters(including photosynthetic rate) of 5 pear varieties were tested by portable photosynthesis determination system TPS-2.The results showed that the net photosynthetic rate of Laiyangchili(Pyrus bretschneideri Rehder) was the highest,but there was no significant difference in net photosynthetic rate among different pear cultivars.For the tested 5 pear cultivars,the daily variation curve of net photosynthetic rate showed two types: single-peak type and asymmetrical double-peak type,that of transpiration rate all presented single-peak type,that of intercellular CO2 concentration revealed single-valley type and double-valley type,and that of stomata conductance had many types.There were differences in light compensation point,light saturation point,CO2 compensation point and CO2 saturation point among different pear cultivars.