Changes in Activities of Key Enzymes for Starch Synthesis and Glutamine Synthetase During Grain Filling of Rice Hybrid Progeny

The hybrid progenies differed in amylose and protein contents in grains derived from Dongnong 423×Toukei 180 were used to study the changes in the activities of ADP-glucose pyrophosphorylase(AGPP),soluble starch synthase(SSS),starch branching enzyme(SBE),glutamine synthetase(GS) during grain filling.The activities of AGPP,SSS,SBE in the hybrid progenies with high and low amylose contents gradually increased and declined as a single-peak curve during grain filling.The progeny with high amylose content peaked earlier in the AGPP,SSS and SBE activities and had higher GS activity at the early grain filling stage than those with low amylose content.The GS activity peaked earlier and was higher at the late stage of grain filling in the progeny with high protein content than in that with low protein content.It is suggested that the activities of key enzymes for starch synthesis and glutamin synthetase could be changed in oriented breeding for amylose and protein contents in grains.