Changing trends of sugar,pH and ABA during strawberry fruit development

To uncover the physiological mechanism of strawberry development and ripening,seven-stage fruits of Fugilia strawberry(Fragaria ananassa) were used to research the changes of pH value,soluble sugar content and ABA level.The main results showed that soluble sugars were mainly glucose and fructose at the former period of fruit development,and sucrose was relatively lower.After the onset of berry ripening,sucrose had two rapid accumulations,and finally the amount of sucrose was 1.25 times than that of glucose and fructose.A decline-rise 'V' curve of changes of pH values was coupled with fading-green stage and coloring-up stage,respectively,between of which was the lowest pH point at white berry stage.The changing patterns of ABA in achene and receptacle showed 'W' and 'V' curves,respectively,and ABA contents in the former were three times than that in the latter.In addition to initial red stage,ABA contents in receptacle displayed continual rise during strawberry fruit development.In conclusion,compared with glucose and fructose,the accumulation of sucrose showed a distinct change;ABA accumulation in achene and in receptacle is complex with unremarkable correlation coefficient;soluble sugar contents had a close relationship with ABA level in receptacle.