Phosphorylase activity during grain filling period of two rice cultivars differing in yield potential

The concentrations of soluble sugars and starch increased up to 14 days after flowering in the top two leaves and in the panicle followed by a decline in rice cultivars IR 50 and Ratna. There was a parallel increase in the activity of phosphorylase with the rise in the carbohydrate level. The high yielding IR 50 recorded higher levels of carbohydrate fraction and the enzyme activity at all stages of ripening.