Abstract: The experimental materials were EMS mutagenesis progeny M₁ and M₂ and CK without mutagenesis. The M₁,M₂ and CK populations were divided into A,B and C 3 groups. The diurnal dynamics of photosynthetic characteristics of different species in each group were measured to Screen sainfoin materials with high photosynthetic potential. The result showed:Pn and Gs were decreased but Ci increased in M₁,M₂ and CK populations after 15:00,which illustrated the decrease of photosynthesis of Mengnong Sainfoin was non-stomatal factor. Pn in type B in the M₂ population was the maximum in all categories,A and C in M₂ and B in CK were the next. Gs in types A,B and C in the M₂ population and classification of A in the M₁ were the maximum in all categories. The lowest Ci was in class A of the CK. The highest WUE was in class A of the CK. Therefore,the B group in the M₂ generation in Mengnong Sainfoin can be used as a parent material for high-yield breeding.

Key words: Mengnong sainfoin, Mutation population, SPAD, Pn

摘要： 本研究以蒙农红豆草（Onobrychis viciifolia Scop ‘Mengnong’） 甲基磺酸乙酯（EMS，Ethyl Methane Sulfonate）诱变后代（M₁和M₂）和未经诱变（CK）为试验材料，采用逐步聚类法基于株高和SPAD值将M₁，M₂和CK群体分为A，B，C 3类，测定每个群体中不同类别材料光合日动态，筛选出具有高光合潜力的红豆草材料。结果表明：M₁，M₂和CK在15：00以后，净光合速率和气孔导度降低，胞间CO₂浓度上升，说明导致其光合作用降低的原因是非气孔因素。B类的M₂代净光合速率日均值最大；A，B，C 3类的M₂以及A类的M₁的气孔导度日均值最高；A类的CK和B类的CK和M₂的水分利用效率较大。总体而言，B类M₂代净光合速率（5.76 μmol·CO₂·m^-2·s^-1）最高，水分利用效率（2.33 μmol·mmol^-1）相对较高。因此，EMS诱变蒙农红豆草M₂代的B类群体可作为高产育种的亲本材料。

关键词: 蒙农红豆草, 突变群体, SPAD, 净光合速率