Study on Photosynthetic Eco-physiological Characteristics of Alnus cremastogyne

[Objective]The aim was to reveal photosynthetic eco-physiological characteristics of Alnus cremastogyne.[Method] LI-6400 portable photosynthesis system was used to determine net photosynthetic rate.[Result] Diurnal variation curves of net photosynthetic rate of Alnus cremastogyne showed one peak in April and November and two peaks in June,July,September,August and October.Maximum net photosynthetic rate was in June,which was 18.56 μmol CO2/m2·s.Diurnal variation curves of stomatal conductance showed two peaks in April,July,August,September,November,and one peak in June,October showed a certain degree of volatility.Changes in water use efficiency was divided into three phases,each phase showed the different trends.Daily variation of transpiration rate was similar to the diurnal variation of net photosynthetic rate.[Conclusion] Major factors that decided the net photosynthetic rate of Alnus cremastogyne varied with periods,but the major impacting factors were stomatal conductance(Cond),transpiration rate(Trmmol),intercellular CO2 concentration(Ci),effective light radiation(PARi),etc.