Study On Sugar Accumulation Of Different Watermelon Germplasms And Correlation Between Sugar Metabolism And Related Enzymes

Accumulation of main soluble sugar: glucose, fructose, sucrose in nine different (early-maturing, middle-maturing, late-maturing) watermelon germplasms was studied. The aim was to breed high quality watermelon ,and provide some academic gist in watermelon cultivation. Moreover, the relation between sugar metabolism and related enzymes was studied, in order to study deeply on watermelon physiology and separate cloning relevant gene of related enzymes. The results were showed as follows:1.The changes of the glucose and fructose content appeared"parabola"in nine germplasms, the content of glucose and fructose were higher and became the main ingredient of soluble sugar during growth prophase,then dropped. The content of glucose and fructose in early-maturing watermelon germplasms reached the tiptop earlier than middle-maturing and late-maturing watermelon germplasms. There was a turning point(16DAA) during sucrose accumulation in all germplams.Sucrose content was lower and it's accumulation was slowly during growing and developing prophase in fruit in all germplasms, then accumulated rapidly and became the main ingredient of soluble sugar after 16DAA .The changes of sucrose content appeared"parabola"in early-maturing watermelon germplasms, reached the tiptop at 28DAA,while that one of middle-maturing and late-maturing increased gradually until maturity. Total sugar of early-maturing watermelon germplams reached peak value at 22DAA,while late-maturing ones reached it at 28DAA.2.Sugar accumulation were together regulated by Acid invertase(AI), Neutral invertase(NI), Sucrose phosphate synthase(SPS), Sucrose synthase(SS). The activity of AI and NI were higer in early developing stage, then dropped.Only that of early-maturing germplasms increased slightly after maturity, correlation between sucrose content and NI,AI...