Isoenzyme variation patterns and species concept in Astragalus gossypinus and Astragalus persicus complexes (Fabaceae) in Iran

Isoenzyme electrophoresis was employed to examine the relationships of 21 individuals representing four populations of Astragalus gossypinus complex as well as 20 individuals representing five populations of Astragalus persicus complex. A total of 27 bands from three enzyme systems (superoxide dismutase, esterase, and peroxidase) were obtained. UPGMA clustering method resulted in two distinct clusters for different populations corresponding to the two species complexes analysed. In both species, populations distributed on Alborz mountain range in northern Iran form separated clusters from those distributed on Zagros mountain range in the West. The results also show that both species complexes exhibit a high diversity based on Shannon–Weaver diversity index (H′) compared with other species of Astragalus reported previously. The mean number of bands per each presumed isoenzyme ranges from 2.14 to 3.57. The value of Euclidean distance ranges from 1.251 to 3.152. Our data suggest that both species should be circumscribed wider than that treated by most taxonomists, and several taxonomic names should be reduced under synonymy of the corresponding species.