Quantitative and Qualitative Changes in Peroxidase during Germination of Mung Bean under Salt Stress

Seeds of mung bean (Phaseolus aureus Roxb.) cv. Pusa Baisakhi were surface sterilized with sodium hypochlorite solution and sown both in Petri dishes and in sand culture containing aqueous solutions of four different salts, viz. NaCI, KCI, Na₂SO₄ and K₂SO₄, each at 5 and 10 S/cm. Peroxidase activity and its isoenzymes were studied in different plant parts at suitable time intervals during germination. Activity of peroxidase increased in embryo axis and leaves but decreased in cotyledons and roots with different salt treatments to varying degrees. A highly significant inverse correlation (r= -0.931 was found between the peroxidase level and the growth of embryo axis under saline conditions. The number of isoenzymes of peroxidase increased with increase in the time of germination. Salinity treatments resulted in the appearance of new isoenzymes in all the plant organs except roots where the isoenzymic pattern remained unchanged. Different types of salinity resulted in the appearance or/and disappearance of different isoenzymes.