西瓜果实发育过程中番茄红素、瓜氨酸和V_C等功能物质含量的变化

Changes of the Contents of Functional Substances Including Lycopene,Citrulline and Ascorbic Acid During Watermelon Fruits Development

【目的】对不同品种西瓜果实发育过程中番茄红素、瓜氨酸和VC等功能物质含量的动态变化进行分析,以探讨西瓜功能物质的变化规律,旨在为西瓜品质改良、功能西瓜育种提供依据。【方法】本研究以不同西瓜品种为对象,对不同发育阶段果实中番茄红素、瓜氨酸和VC等功能物质含量进行测定。【结果】(1)红瓤西瓜果实番茄红素在果实发育过程中的积累呈"S"型曲线变化;幼果番茄红素含量较低,着色期急剧增加,完熟期达到峰值。(2)西瓜幼果瓜氨酸含量较低,随果实发育瓜氨酸缓慢积累,果实膨大期含量有所减少,随后大幅度增高,接近完熟达到峰值,过熟期含量缓慢减少。(3)幼果期总VC含量较高,随着果实发育有所积累并达到第1个峰值,果实膨大期迅速下降到最低值,随后迅速积累,完熟期达到第2个峰值,过熟期缓慢下降;还原型VC和氧化型VC也符合同样规律,即西瓜果实发育过程总VC、还原型VC(AA)和氧化型VC(DHAA)的含量均呈"M"曲线变化,第2峰值大于第1峰值;达到峰值时,不同品种西瓜果实还原型VC﹕氧化型VC≈1—2﹕1。【结论】西瓜果实中番茄红素和VC含量在完熟期达到峰值,瓜氨酸含量在接近完熟期达到峰值。

[ Objective] The changes of the contents of the functional substances including lycopene, cltrulline and ascorbic acid （Vc） of watermelon during fruit development were studied in order to provide a theoretical basis for optimization of watermelon breeding. [Method] The contents of lycopene, citrulline and ascorbic acid （Vc） of watermelon during fruit development were analyzed, The lycopene, citrulline and total ascorbic acid （TAA） contents were determined by spectrophotometry methods and ascorbic acid （AA） was determined by 2,6 - dichlorophenolindophenol titration. [Result] The lycopene accumulation during fruit development of red flesh watermelon fruit was a S-type curve. The lycopene content of young fruit was low, and slow accumulation during fruit development, then lycopene content increased dramatically with the red flesh coloring and achieved the highest value at ripening stage. Decreasing tendency in lycopene contents was observed during overripening. The citrulline contents of young fruits were lower, then it accumulated slowly during fruit development and decreased in fruit enlargement. Then it increased rapidity and achieved the peak value before maturity. The decreasing tendency in citrulline content was noticed in maturity phase. The change of Vc contents in different color flesh of watermelons were showed a M-curve shape during fruit development： The content of tota1 ascorbic acid （TAA） in young fruit was high, then reached the first peak of TAA content with the enlargement of the fruit, The TAA contents decreased rapidly to the lowest level and then increased rapidly to achieve the second peak at ripening stage. The decreasing tendency in content was noticed during overripening. Both ascorbic acid （AA） and dehydroascorbic acid （DHAA） contents showed the same change. When achieved the peak, the ratio of TAA ： AA contents in different fruits of watermelon varieties were about 1-2 ： 1. [ Conclusion ]The contents of lycopene and Vc in ripe fruits of watermelon achieved the peak value and the contents of citrilline in nearly mature of watermelon fruit achieved the peak value.