The Relation Between Endogenous Hormones and Late-Germination in Buds of Avrolles Apple

In order to provide the physiological bases for selecting late-germination cultivars that can avoid late frost damage,the very late-germination variety Avrolles (Malus domestica) was used to study the relation between the dynamic changes and balance of endogenous hormones and germination time.The concentrations of endogenous GA3,ABA,IAA,and ZR were determined in buds of Avrolles and Judeline (Malus domestica) from dormancy releasing to germination by capillary electrophoresis.The dynamic changes of endogenous hormones concentration in buds of Avrolles and Judeline were similar; but the magnitude and time of the change were significantly different between the two varieties,especially for GA3.GA3 concentration increased with dormancy releasing,then decreased,and increased again before germination in the two varieties.GA3 concentration in Avrolles was 1.72 times that in Judeline at the first peak,the gap increased to 2.22 times at germination.ZR concentration exhibited a continuous increase trend,but it decreased sharply before germination.ZR accumulation in Avrolles took 36 days longer than in Judeline,the peak value was 44% higher than in Judeline.Before germination,ZR concentration in Avrolles was 2.12 times that in Judeline.The differences between IAA and ABA concentration were relatively small in the two varieties,while the ratios of GA3/ABA and (GA3 + IAA + ZR)/ABA in Avrolles were 2.08 and 1.58 times those in Judeline,respectively.The germination of apple bud was regulated by the endogenous hormones.For the late-germination apple Avrolles,its germination requires higher concentration of GA3 and ZR,which leads to the high ratios of GA3/ABA and (GA3 + IAA + ZR)/ABA.