欧李果实发育期糖和酸组分及其含量的动态变化特性

以农大3号、农大4号、农大5号3个欧李品种为材料,测定果实发育过程中各组分糖、酸及总糖、总酸的含量,以明确欧李果实糖酸积累的动态变化特性.结果显示:(1)3个欧李品种果实成熟期糖含量、酸含量及糖酸比存在明显差异,其中农大3号品种的总糖含量最高,总酸含量最低,糖酸比值最高.(2)成熟期3品种各糖组分中均以果糖含量较高,葡萄糖和蔗糖含量较低,山梨醇含量微量;酸组分中均以苹果酸为主,柠檬酸少量.(3)3个品种果糖、蔗糖、葡萄糖、山梨醇含量在整个果实发育期均呈持续增加态势,并以果糖积累为主;农大3号果糖含量在8周后增幅明显高于另2个品种,且一直保持到果实成熟;3个品种蔗糖含量的变化趋势相近,在前期和中期增加缓慢,接近成熟的2～3周则迅速增加并占整个发育期积累量的70%以上.(4)3个品种酸含量的变化趋势较为相似,苹果酸和柠檬酸在果实发育的前期和中期含量均较低,在果实发育后期迅速增加,但接近果实成熟时又大幅下降.研究表明,果糖与苹果酸的含量及其动态变化是影响欧李果实糖酸比、决定果实风味的主要因素.

Composition and Dynamic Changes of Sugars and Acids in ChineseDwarf Cherry (Cerasus humilis Bunge) during Fruit Development

The contents of sugars and organic acids during fruit development were investigated and the dynamic changes of sugars and organic acids were analyzed in the fruit of Chinese dwarf cherry cultivars ‘Nongda 3’,’Nongda 4’ and ’Nongda 5’.The results showed that:(1)The content differences of total sugars,total acids and sugar acid ratio in three cultivars were obvious.(2)The content of fructose was at higher level,glucose and sucrose were at lower level,and only a little sorbitol was found in the ripening stage of three cultivars.The malic acid was the main acid in the the ripening stage of three cultivars,compared to the low content of citric acid.(3)The contents of fructose,surcose,glucose and sorbitol were increasing in the whole fruit development period in three cultivars.Fructose was the major sugar in the fruit.The content of fructose increased quickly in the mid-period of fruit development in ‘Nongda 3’,and was obviously higher than that in other two cultivars.The changing trends of sucrose were similar during the different cultivars,which was increasing slowly in the early-period and mid-period and was increasing quickly(above 70 percent of total sugars) in the late-period of fruit development.(4)The changing trends of acids were similar in three cultivars.The contents of malic acid and citric acid was lower in the early-period and mid-period of fruit development,and increasing rapidly in the late-period,but reducing dramatically when the fruit was close to mature.To sum up,the contents and the dynamic changes of frutose and malic acid were main factors which affect the sugar acid ratio and determine the fruit flavor.