Studies On Changes Of Soluble Sugar And Organic Acid Accumulation And Sugar Related Enzyme Activities In Several Apple Cultivars Fruit

The variety, content, composition ratio and the formation of dynamic were importantfoundation for the formation of apple fruit flavor. In order to explore the variation regularityand the difference of sugar and organic acid accumulation in apple fruits from different flavorvarieties, clear the key enzymes of the accumulation of soluble sugar, lay the theoretical basisfor the accumulation, metabolism and regulation of apple fruit.4varieties of ‘Granny’,‘Pinklady’,‘Fuji Ⅱ’(cultivated in large area) and ‘Gala Ⅱ’(cultivated in large area)were used as theexperimental materials in this experiment. The apple were picked up regularly and weighedaccurately, HPLC(High Performance Liquid Chromatography) method was used to measurethe soluble sugar and organic acid contents, and colorimetry was used to measure sugarrelated enzyme activities in this study. The mission of this experiment was to researchdynamic changes of sugar and acid accumulation and sugar related enzyme activities, analysethe relationship of soluble sugar and organic acid, and the relationship of soluble sugar andsugar related enzyme activities. The main results were as follows:1. The chromatographic condition of the determination of soluble sugar and organic acidby HPLC.(1) The chromatographic condition of soluble sugar determination: Sugar-PakTMIcolumn and protection column (Waters) were adopted.The column temperature was80℃,mobile phase was ultrapure water, and the flow rate was0.6ml/min.The detector wasdifferential refraction detector (Waters2998), and the temperature of detection cell was35℃.(2) The chromatographic condition of organic determination acid: IC PAKTM IONExclusion column and protection column (Waters) were adopted. The column temperaturewas50℃, mobile phase was0.01mol·L-1H2SO4, and the flow rate was0.5ml/min. The UVdetection wavelength was210nm. The detector was diode-array detector (Waters2998).2. Variation regularities of soluble sugar contents in apple fruits from different flavorvarieties during fruit development.(1) Sucrose: The sucrose contents in4apple varieties fruits were lower and increasedslowly at early developmental stage. There were two rapid accumulation periods in the more acid varieties apple fruits (‘Granny’ and ‘Pink lady’), that were the period on75d～109d andthe period on129d～189d. The more sweet varieties apple fruits (‘Fuji Ⅱ’ and ‘GalaⅡ’)hadonly one rapid accumulation period, that is129d～189d.(2) Glucose: The glucose contents in4apple varieties fruits were all accumulated rapidlyfrom15days after anthesis, and there had difference between4apple cultivars：The increasedtrends of the more sweet varieties apple fruits (‘Fuji Ⅱ’ and ‘Gala Ⅱ’) continued to75daysand85days after anthesis respectively, and had a increased trend on one month beforematurity. The increased trends of the more acid varieties apple fruits (‘Granny’ and ‘Pinklady’) continued to53days after anthesis,and had no increased trend on one month beforematurity.(3) Fructose: The fructose contents in4apple varieties fruits were increased rapidly inthe early developmental stage, and tended to be stable in the late stage of fruit development.The rapid accumulation periods in the more sweet varieties apple fruits (‘FujiⅡ’and ‘Gala Ⅱ’)was longer than it in the more acid varieties apple fruits (‘Granny’ and ‘Pink lady’).(4) Sorbitol: The concentrations of sorbitol decreased with fruit development in4applevarieties fruits.(5) Total sugar: The total sugar contents in4apple varieties fruits were increased rapidlyin the early developmental stage, the increase speed at the late developmental stage wasslower than it in the early developmental stage.(6) The sucrose content in the more acid varieties of fruit (‘Granny’ and ‘Pink lady’) hasbeen higher than it in the more sweet varieties apple fruits (‘Fuji Ⅱ’) throughout thedevelopmental period, and was significantly higher than it in the ‘GalaⅡ’ before44days afteranthesis. The contents of glucose, fructose and total sugar were significantly higher than it inthe more acid varieties of fruit (‘Granny’ and ‘Pink lady’) in the middle and late stage of fruitdevelopment.3. Variation regularities of organic acid contents in apple fruits from different flavorvarieties during fruit development.(1) Malic and oxalic: The overall trend of malic and oxalic in4apple varieties fruitswere increased in the early developmental stage, and then decreased with fruit development.The malic content in ‘Pink lady’ and ‘Granny’ reached the highest point at35days and53days after anthesis respectively, and the highest point of ‘FujiⅡ’ and ‘GalaⅡ’ was at44daysafter anthesis.(2) Succinic, acetic, citric and tartaric: The contents of succinic, acetic, citric and tartaricin4apple varieties fruits all decreased gradually with fruit development.(3) Total acid: The total acid contents in4apple varieties fruits were all decreased in the early developmental stage, then increased rapidly, and then decreased with fruit developmentafter the formation of peak.(4) The contents of malic, citric and tartaric in the more acid varieties of fruit (‘Granny’and ‘Pink lady’) were significantly higher than it in the more sweet varieties applefruits(‘Fuji Ⅱ’and ‘GalaⅡ’) throughout the development period or most time of thedevelopment period.4. Variation regularities of sugar related enzyme activities in apple fruits from differentflavor varieties during fruit development.In the early developmental stage of4apple varieties fruits, the activity of AI,NI andSS-C were high, the activity of SPS, SS-S and NAD-SDH were low relatively, then theactivity of AI,NI and SS-C decreased, and the activity of SPS SS-S and NAD-SDHincreasedduring fruit development. In the middle developmental stage, the activity of SDH in4applevarieties fruits all formed a apparent peak, and the activity of SDH in the more sweet varietiesapple fruits (‘Fuji Ⅱ’ and ‘GalaⅡ’) was significantly higher than it in the more acidvarietiesapple fruits (‘Granny’ and ‘Pink lady’). The activity of AI in the more sweet varieties applefruits(‘Fuji Ⅱ’ and ‘Gala Ⅱ’) was twice of that in the more acidvarieties of fruits (‘Granny’and ‘Pink lady’) throughout the development period. In the middle and late developmentalstage of fruits, the activity of SPS and SS-S in the more acid varieties of fruits (‘Granny’ and‘Pink lady’) was significantly higher than it in the more sweet varieties apple fruits(‘FujiⅡ’and‘Gala Ⅱ’).5The difference of the accumulation of soluble sugars in different flavors of applevarieties fruit was mainly affected by the accumulation differences in sucrose, glucose andfructose, and was less affected by sorbitol accumulation.6The differences of the sucrose accumulation in different flavors of apple varieties fruitwas mainly affected by the regulation and control of SPS, SS-S and AI, glucose and fructoseaccumulation differences were mainly affected by the regulation and control of AI andNAD-SDH.