Changes in Enzyme Activity during Accelerated Ageing in Soybean ( Glycine max (L.) Merrill)

The object of this work was to study the effect of accelerated ageing on enzyme activity for soybean ( Glycine max (L.) Merrill). Under accelerated ageing conditions at 42°C temperature and 100% relative humidity on eight varieties of soybean, namely: PK-416, PK-472, PK-327, PS-1241, PK-262, PUSA-16, PUSA-37 and SL-525, were studied. Their seeds were examined under differential ageing conditions namely: 1st day, 3rd day, 5th day and 6th day of aging at different moisture levels of 3, 4, 6 and 7%. The best germination result was shown at 6 and 7% moisture content which can hence be considered suitable for the long term storage. The effect of aging was least on PK-262 and SL-525 that means these varieties can easily be stored for long time without getting deteriorated in their quality. Varieties PK-327 and PK-416 were maximally affected by ageing and as the ageing proceeded their viability was almost negligible. This test reflects the ability of the seed sample to withstand the stresses of high temperature and humidity and estimates the relative storability (longetivity) and vigour of seeds. For this, initial moisture of eight varieties was measured and after that moisture was brought to the level of 3, 4, 6 and 7% by keeping them in beads, sodium hydroxide solution and silica gel, respectively. The germination percentage vigour index and conductivity values were taken for one day, three days, five days and six days aged seeds of all samples respectively and enzyme activity was taken on 0, 3 and 5 days aged seeds in four varieties, PK-262, SL-525, PK-327 and PK-416. Seed deterioration leads to impairing go enzyme activity. The extent of seed deterioration can be best assessed in terms of damage to the membrane bound enzyme. A steady decrease in activities of catalase, paroxidase, superoxide dismutase, ascorbate peroxidase enzymes were observed except in lipoxygenase activity which increases consistently with ageing.