黄冠梨是我国生产的优质梨品种之一。然而,“黄冠梨”的袋装果实在成熟期下雨后经常遭受果皮褐变。在这项研究中,为了发现套袋处理对果皮褐变斑点的发生和果实品质的影响,水果被单层覆盖,两层,或三层纸袋达到盛开后六周。结果表明,与未袋装水果相比,袋装水果的特征是表面光滑,皮孔减少。未装袋和两层装袋的水果有黄色/绿色果皮,而单层和三层袋装的袋装有黄色/白色果皮。与未袋装的水果相比,套袋水果的维生素C(Vc)含量和果皮颜色指数L和a值较高,可溶性固形物含量(SSC)较低,可滴定酸(TA)含量,吸光度指数差异(IAD),B值。此外,三层袋装组在果实品质方面优于其他组,但是它也有最大的果皮褐变斑点的发生率。在出现果皮褐变斑点之前和之后,与未袋装的水果相比,袋装水果的角质层更光滑,更薄。此外,三层袋装水果的果皮中木质素含量最低,酚类含量最高,与木质素合成相关的酶如苯丙氨酸解氨酶(PAL)的活性最低,过氧化物酶(POD),和多酚氧化酶(PPO),以及相关基因的最小表达,如肉桂醇脱氢酶(CAD),肉桂酰辅酶A还原酶(CCR),4-香豆酸:辅酶A连接酶(4CL6),和肉桂酸4-羟化酶(C4H1)。推测POD活性和CAD9,CCR3,CCR4和CCR5的相对表达可能在果皮褐变斑点的发生中起关键作用。总之,木质素合成影响袋装梨果皮褐变斑点的发生率。本研究为了解黄冠梨果皮褐变斑的发生率提供了理论依据。
The \'Huangguan\' pear is one of the high-quality pear cultivars produced in China. However, the bagged fruit of the \'Huangguan\' pear often suffers from peel browning spots after rain during their mature period. In this study, in an effort to discover the impact of
bagging treatments on the occurrence of peel browning spots and fruit quality, fruits were covered by single-layer, two-layer, or triple-layer paper bags six weeks after reaching full bloom. The results showed that the bagged fruits were characterized by smooth surfaces and reduced lenticels compared with the unbagged ones. The unbagged and the two-layer bagged fruits had yellow/green peels, while the single- and triple-layer bagged ones had yellow/white peels. Compared with the unbagged fruits, the bagged fruits had higher vitamin C (Vc) contents and values of peel color indexes L and a and lower soluble solid contents (SSCs), titratable acid (TA) contents, absorbance index differences (IAD), and b values. Additionally, the triple-layer bagged group was superior to other groups in terms of fruit quality, but it also had the maximum incidence of peel browning spots. Before and after the appearance of peel browning spots, the bagged fruits had smoother and thinner cuticles compared with the unbagged ones. Furthermore, the triple-layer bagged fruits had minimum lignin contents and maximum phenolic contents in their peels, with minimum activity of lignin synthesis-related enzymes such as phenylalanine ammonia lyase (PAL), peroxidase (POD), and polyphenol oxidase (PPO), as well as minimum expressions of relevant genes such as cinnamyl alcohol dehydrogenase (CAD), cinnamoyl CoA reductase (CCR), 4-coumarate: coenzyme A ligase (4CL6), and cinnamate 4-hydroxylase (C4H1). It was deduced that POD activity and the relative expressions of CAD9, CCR3, CCR4, and CCR5 may play key roles in the occurrence of peel browning spots. In summary, lignin synthesis affected the incidence of peel browning spots in bagged \'Huangguan\' pears. This study provides a theoretical basis for understanding the incidence of peel browning spots in \'Huangguan\' pears.