Diurnal changes of photosynthetic characters of four Juglans regia cultivars

Diurnal changes of photosynthetic characteristics in four Juglans regia cultivars were studied by LI6400 portable photosynthesis analyzer for a theoretical basis of higheryield，higherquality and standardized production .The results showed that the diurnal changes of Pn in the four cultivars, all exhibited double peak curve and significant lunch break phenomenon at 14:00; Photoinhibition of Qiangtele and Zhonglin5 occurred earlier than Luguang and Zha343.There was a significant positive correlation between Pn and PAR of four cultivars in Juglans regia , however, their correlation coefficient was different, correlation coefficient descending order: Zha343＞Qiangtele＞Luguang＞Zhonglin5