| The fruit quality became more and more cruial to consumers with the improvement ofliving standards of people. To improve the fruit inner qualit is the key to raise fruit quality,and the compositions and contents of sugar and acid impact the inner quality significantlybecause they reflect an important indicator of fruit flavor. In this research, using Nanfengtangerine fruit97-2as the experiment materials, we explored the effect of fruit size onsugar and acid content of Nanfeng tangerine and their change during storge, the effect ofleaf/fruit ratio and regulation on sugar and acid content of Nanfeng tangerine.The mainresults were as follows:(1) In the early stage of Nanfeng tangerine fruit development,the sugar content withdifferent leaf/fruit ratio had no significant difference, when the fruit get ripe, the sugarcontent with20:1and40:1was significantly higher the other treatment. Sucrose, glucoseand fructose content increase with the fruits grew, but the speed and style were different.Sucrose was the main sugar when the fruits were ripe, and glucose and fructose contenthad no significant difference. SS and SPS were the key enzymes that effected sugarmatebolism. Effect of leaf/fruit ratio treatment on SPS activity, SS(synthesis direction)activity, AI activity in ripe period and NI activity, SS(cleavage direction) activity in theearly period had differences, other sugar matebolism related enzymes activity wasn’teffected by the leaf/fruit ratio treatment.(2) The total acid, malic acid, citric acid, quinic acid content of Nanfeng tangerinedeclined during the development, but there were some differences in the speed and style.Effect of the leaf/fruit ratio treatment on the citric content was not significant differentduring the Nanfeng tangerine early development,but significant different during the latedevelopment. Effect of the leaf/fruit ratio treatment on the malic and quinic content wassignificant different during all stages of Nanfeng tangerine fruit development. MDHactivity negatively correlated with total acid and malic acid content. PEPC activity hadsignificant positive correlation with malic acid. ACO activity had no significant correlationwith citric acid content of kinds of fruits, besides CK, but had no significant correlationwith total acid content. NAD-IDH activity of fruits with different ratios had significant andnegative correlation with citric acid and total acid content. The greater of the leaf/fruit ratio,the bigger of the correlation coefficient absolute value. CS activity had different changetrend with citric acid and total acid content, the significant correlation was between-0.497and-0.997. Effect of the leaf/fruit ratio treatment on acid metabolism related enzymeactivity also showed different degree of differences.(3) The degree of influence on the sugar content of the Nanfeng tangerine fruit rangefrom handling time down to width of girdling, then leaf/fruit ratio, the optimal combination was4weeks after the flowering，middle leaf/fruit ratio and1/6of the branches diameter.The degree of influence on the acid content of the Nanfeng tangerine fruit range fromhandling time down to leaf/fruit ratio, then width of girdling, the optimal combination was4weeks after the flowering，lower leaf/fruit ratio and1/3of the branches diameter. Thedegree of influence on the sugar/acid ratio of the Nanfeng tangerine fruit range fromleaf/fruit ratio down to handling time, then width of girdling, the optimal combination wassame as the acid. Handling time significantly effected both the sugar and acid of theNanfeng tangerine fruit, but the leaf/fruit ratio and width of girdling did not, they all hadno significant effect on the sugar/acid ratio.(4) When it came to flavor quality, transverse diameter4.0-4.5cm was the best, whiletransverse diameter3.5-4.0cm was the worst. During storage, on the index of sugar contentand titration acid content, transverse diameter4.0-4.5cm were better than the transversediameter3.5-4.0cm and3.0-3.5cm, which had the best and stable fruit quality. |
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