Ploidy Effects in Isogenic Populations of Alfalfa (Medicago sativa L.)

Abstract

Ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBPCase) was isolated from isogenic diploid-tetraploid and tetraploid-octoploid sets of alfalfa (Medicago sativa L.) leaves. Molecular weights of RuBPCase subunits were similar across ploidy levels of both isogenic sets with subunits of 52,000 and 14,000. Apparent K_m(CO₂) values and substrate specificity factors (V_cK_o/V_oK_c) of RuBPCase were similar across ploidy levels of both isogenic sets. These results indicate that ploidy had no effect on the kinetic properties of RuBPCase in alfalfa.