Catalase Activity in Rice Shoot Apex during Panicle Initiation

Abstract

There was a gradual increase in the catalase activity in the shoot apices of the two rice varieties—Ratna and BAM 11, till panicle initiation. Peroxide content in the Ratna shoot apices decreased with time and was low during and after panicle initiation. In Ratna plants, exogenous application of cycloheximide and 3-amino-1,2,4-triazole resulted in a delay in panicle initiation with a corresponding decrease in catalase activity. Exogenous application of hydrogen peroxide caused a rise in catalase activity and delayed panicle initiation in both Ratna and BAM 11 varieties. In BAM 11 plants treated with 28 consecutive short photoinductive cycles there was an earliness in flowering accompanied by an early peak in catalase activity.