Role of polyphenolic compounds in different biological functions like biotic and abiotic stress resistance make them important for plants. In the present investigation different cadmium (Cd) concentrations representing 0, 0.02, 0.04 and 0.06 mM were used in three pigeonpea cultivars (LRG30, LRG41 and ICPL85063) on various enzymatic activities. Polyphenol oxidase and acid phosphatase activity of the different parts of the three pigeonpea cultivars increased with increasing seedling growth and with increasing concentration of Cd supplied. However, the acid phosphatase activity of the cotyledons increased only up to 4 days of seedling growth. The greater activities of these enzymes were observed in cv. LRG30 in response to Cd treatment. The δ-amino levulinic acid dehydratase, phosphoenolpyruvate carboxylase, ribulose bisphosphate carboxylase, CO2 fixation, carbonic anhydrase and hill reaction activities of the three pigeonpea cultivars decreased with increasing concentrations of externally supplied Cd ions. These activities were conspicuously affected in cv. LRG41 and ICPL85063 and appeared more sensitive to Cd treatment.
