单 位：
Key Laboratory of Agricultural Ecology and Environment,College of Forestry,Shandong Agricultural University,Taian 271018;Key Laboratory of Agricultural Ecology and Environment,College of Forestry,Shandong Agricultural University,Taian 27101
摘 要：
[Objective] The paper presents the diurnal changes of photosynthesis and transpiration of different alfalfa varieties and their relationship with the associated physiological and ecological factors during branching stage,so as to provide a basis for the development,utilization,and breeding of alfalfa.[Method] Under natural conditions,the diurnal changes of net photosynthetic rate (Pn),transpiration rate (Tr),the relevant physiological factors including leaf temperature (Tl),stomatal conductance (Gs) and internal CO2 concentration (Ci),as well as the relevant physiological factors including photosynthetic available radiation (PAR),CO2 concentration in field (Ca) and air temperature (Ta) were measured in four alfalfa varieties (Algonguin,WL323 HQ,WL414,and Millionaire).The water use efficiency (WUE) and light use efficiency (LUE) were calculated,and the correlation among them was also analyzed.[Result] The Pn,Tr,PAR and Ta of the four varieties appeared to vary in a single-peak curve;the sequence of WUE was WL323 HQAlgonguinWL414Millionaire;there was no significant difference in LUE of the four alfalfa varieties;coefficient analysis showed that Pn was mainly affected by PAR,Gs,and Ci,while Tr by PAR and Ta.[Conclusion] WL323 HQ is the variety with high Pn,high WUE and low Tr,and it has strong adaptability to drought.In four alfalfa varieties,PAR,Ta,Gs,and Tl are the primary determining factors while Ca and Ci the limiting factors of Tr;Gs is the primary determining factor while Ci the limiting factor of Pn.
