Abstract:

The photosynthetic characteristics and chlorophyll fluorescence characteristics of introduced three almond(Amygdalus communis)cultivars 3^#、4^# and 7^# were studied.The curves of diurnal variation of net photosynthetic rate(P_n)in leaves of almond showed two peaks,occurring at 10:00 and 16:00 respectively.Midday depression of P_n(10:00—15:00)was found in leaves of almond.P_n of leaves of 4^# and 7^# almond was significantly higher than that of 3^# during 10:00—15:00.Some physioecological parameters showed significant difference among different cultivars.The light compensation and saturation points of P_n in 4^# leaves were higher than those in 3^# and 7^#,25.82 μmol·m^-2s^-1 and 1 206 μmol·m^-2s^-1 respectively.The CO₂ compensation and saturation points of P_n in 4^# leaves were higher than those in 3^# and 7^#.P_n was increased linearly with the increase of CO₂ concentration below the CO₂ saturation point,thus increasing CO₂ concentration could improve productivity greatly.And the results of diurnal variations of chlorophyll fluorescence showed that F_v/F_m and q_P of 4^# and 7^# were higher than 3^#,and F_v/F_m restored very fast after noon.The leaves of 4^# and 7^# not only could absorb the light energy more effectively,but also had higher PSⅡa ctivity and light energy transform efficiency,which could turn light energy absorbed into chemical energy effectively,then the transmit speed of electrons was improved.So more ATP and NADPH were formed,which could offer abundant energy and reduction ability for CO₂ assimilation.

Key words: Almond(Amygdalus communis), net photosynthetic rate, chlorophyll fluorescence