套袋苹果果实质地及其显微结构与果面裂纹的关系

Relationships between the Texture and Microstructure of Bagged Apple Fruit and Cracking

以套白色单层纸袋的着色富士系‘天红2号’和短枝富士后代优系4-1-103,以及不着色姊妹系‘冀苹4号’和‘冀苹5号’4个苹果品种(系)为试验材料,利用质构仪整果穿刺和质地多面分析法(texture profile analysis,TPA)测定果实质地,光学显微镜观察果实显微结构,探讨苹果果实质地及其显微结构与果面裂纹的关系,为抗裂纹品种的选育和潜在裂纹机制提供理论依据。结果表明:(1)盛花后132~185 d,‘天红2号’和‘冀苹4号’裂纹率和裂纹指数始终高于4-1-103和‘冀苹5号’,其裂纹主要部位为果肩部。(2)‘天红2号’和‘冀苹4号’的果肉脆裂性、果肉硬度分别显著小于4-1-103和‘冀苹5号’。(3)‘天红2号’和‘冀苹4号’的表皮细胞密度显著小于4-1-103和‘冀苹5号’,其果肉细胞间隙率显著大于4-1-103和‘冀苹5号’,且其角质膜有“V”型凹陷,并发生龟裂,而4-1-103和‘冀苹5号’角质膜完整均一。(4)主成分和灰色关联度分析表明,果肉硬度、果皮果肉硬度比和果肉细胞间隙率是解释裂纹的主要指标。研究发现,果实角质膜完整均一、果肉硬度大、果肉细胞间隙率小的苹果品种不易发生果面裂纹。

Colored Fuji‘Tianhong 2’and short shoot Fuji progeny 4-1-103,non-colored‘Jiping 4’and‘Jiping 5’in white single paper bag were used as experimental materials.Fruit texture was determined by whole-fruit puncture and texture profile analysis(TPA).The fruit microstructure was observed by light microscope.The relationships between the texture and microstructure of apple fruit and cracking were discussed to provide a theoretical basis for the breeding of anti-cracking cultivars and cracking mechanism.The results showed that:(1)from 132 to 185 days after full bloom,the cracking rate and cracking index of‘Tianhong 2’and‘Jiping 4’were always higher than those of 4-1-103 and‘Jiping 5’,and fruit shoulder was the main cracking part.(2)Flesh fracturability and firmness of‘Tianhong 2’and‘Jiping 4’were significantly lower than those of 4-1-103 and‘Jiping 5’,respectively.(3)The epidermal cell density of‘Tianhong 2’and‘Jiping 4’was significantly lower than that of 4-1-103 and‘Jiping 5’,and the flesh cell voids of‘Tianhong 2’and‘Jiping 4’was significantly higher than that of 4-1-103 and‘Jiping 5’.The cutin membrane of‘Tianhong 2’and‘Jiping 4’had v-shaped depressions and cracking,while the cutin membrane of 4-1-103 and‘Jiping 5’was intact and uniform.(4)Principal component and gray correlation analysis showed that flesh firmness,firmness ratio of skin and flesh and flesh cell voids were the main indicators to explain the cracking.In the paper,the study found that the apple cultivars with intact and uniform cutin membrane,large flesh firmness and small flesh cell voids are less prone to cracking.