Effects Of Different Hormone Treatment On Sugar Accumulation In Fruit Of Grafted Watermelon

Grafting is an important technique to control continuous cropping disturbance and to prevent the occurrence of soil-brane diseases and to increase stress resistance of watermelon plant in china. But, the qualities and sugar contents of grafted watermelon fruit,decreased when resistance of watermelon plant increased. In recent years, Many studies had declared that GA and ABA play important regulative roles on the level of hormones,Sucrose metabolism enzymes and expression of many genes. GA and ABA can improve the transportation and download and accumulation of sugar in fruits of plant. But, the studies on effect of exogenous GA and ABA on sugar accumulation of grafted watermelon fruit,were rare..In the present study ,we investigated the effects of different GA and ABA concentrations on sugar accumulation of grafted watermelon fruits, the main purpose was to clarify the physiological mechanisms of GA and ABA concentrations on sugar accumulation of grafted watermelon fruits and give help to improve the fruit quality of grafted watermelon.The results were showed as follows:Firstly, Exogenous GA can improve the fructose and glucose content of grafted watermelon fruit,but it reduced the sucrose content;Exogenous ABA has advance in these three sugars.It is different between exogenous GA and ABA effect to sugars,but they let the soluble sugar content rised at the middle and latter period of grafted watermelon fruit.It is important to fruit sugar accumulated and quality formed. The treatment of 50ppmABA is best in all.Secondly, Exogenous GA can improve endogenous GA and ABA content of grafted watermelon fruit. Exogenous ABA only increased endogenous ABA content and restrained endogenous GA content of grafted watermelon fruit.The different of exogenous hormone made the content and proportion of endogenous GA and ABA had changed.So the effect of sugar composing and accumulation also had changed.Finally, The sucrose metabolism of grafted watermelon fruits can be adjusted by AI,NI,SPS and SS. The treatment of Exogenous Hormones can effect the activity of sucrose metabolism enzyme,for this the sugars of grafted watermelon fruits can be controlled.The raise of AI and NI activity is beneficial to sucrose analyzed and fructose or glucose accumulated.The raise of SPS and SS activity is beneficial to sucrose accumulated. Exogenous GA can improve Invertase activity of grafted watermelon fruit and restricted the SPS and SS activity.So the fructose or glucose content has increasing and the sucrose has reducing. Exogenous ABA can improve this four Sucrose Metabolism Enzyme activity at all.So the content of these three sugar has increased.