【目的】红树莓(Rubus idaeus)富含多种营养成分,其中,总酚、类黄酮和维生素C(VC)等天然抗氧化活性物质备受关注。为更有效开发利用该资源,本研究拟对红树莓不同发育阶段的外观品质、抗氧化物含量变化及抗氧化酶相关基因表达规律进行系统研究。【方法】以优良红树莓栽培品种‘秋福'(‘Autumn Bliss')为试材,运用蒽酮比色法、氢氧化钠滴定法、羟胺法和qRT-PCR等方法对其不同发育阶段果实的外观、品质、抗氧化指标和抗氧化酶活性进行测定,对其抗氧化酶基因的表达特性进行分析,并对各指标进行相关性和主成分分析。【结果】红树莓果实的质量和横纵径随着果实的成熟而逐渐增加,果实亮度则逐渐降低,饱和度的变化趋势为先增加后减少。随着红树莓果实的逐渐成熟,糖酸比呈现逐渐升高的趋势,在35 DAF(开花后天数)时达到最高,为5.91。总酚、类黄酮和维生素C(VC)含量在红树莓果实发育过程中整体呈下降趋势,青果时期含量最高,与总抗氧化能力呈正相关;花色苷含量呈上升趋势,成熟期达到最高,质量分数为802.42 μg/g。此外,果实的抗氧化酶中POD活性(62.58 U/g)和GSH质量分数(1.01 mg/g)均在青果时最高,与总抗氧化能力呈极显著正相关;而SOD活性、MDA含量和 O_2^{-}产生速率则在成熟时最高,与总抗氧化能力呈负相关。SOD活性相关基因RuSOD1和RuSOD2在果实发育中的表达量整体呈上升趋势,RuSODCP.2表达量前期也呈上升趋势,成熟阶段略有下降,RuFSD的表达量整体变化幅度不大,与SOD活性均呈正相关;POD活性的相关基因RuPOD表达量逐渐下降,RuPER5在7~14 DAF时期表达量下降,14~35DAF时期上升,RuPER25则是7~21 DAF时期表达量上升,21~35 DAF时期下降,而RuPROX6表达量逐渐上升,RuPER17表达量变化并不显著,POD活性与RuPOD、RuPER5、RuPER17和RuPER25表达量均呈正相关,而与RuPROX6呈负相关。【结论】红树莓青果时期抗氧化能力最强,其中总酚、类黄酮、POD和GSH是主要的抗氧化物成分,研究结果将为后续深入探讨红树莓果实抗氧化物质的变化规律及作用机制奠定基础。

【Objective】Rubus idaeus (red raspberry) fruits are renowned for their rich nutritional profile, particularly their high content of natural antioxidant compounds such as total phenols, flavonoids, and vitamin C (VC). To optimize the development and utilization of this valuable resource, this study aims to systematically investigate the appearance quality, dynamic changes in antioxidant content, and expression patterns of antioxidant enzyme-related genes of red raspberry at different developmental stages.【Method】The study employed the superior red raspberry cultivar ‘Autumn Bliss' as the experimental material. A comprehensive analysis was conducted to measure the fruit's appearance, quality, antioxidant indicators and antioxidant enzyme activity at different developmental stages. Methods such as anthrone colorimetry, sodium hydroxide titration, hydroxylamine method and quantitative real-time PCR (qRT-PCR) were utilized. The expression characteristics of antioxidant enzyme genes were analyzed, and the correlation and principal component analysis were performed to elucidate the relationships among the measured indicators.【Result】The fresh weight and transverse and longitudinal diameter of red raspberry fruit gradually increased with fruit maturity, while the fruit luminosity gradually decreased, and the trend of chroma change was initially increasing and then decreasing. As the red raspberry fruit gradually matures, the sugar acid ratio showed a gradually increasing trend, reaching its highest value of 5.91 at 35 days after flowering (DAF). The contents of total phenol, flavonoid and VC content showed an overall downward trend during the development of red raspberry fruits, with the highest content during the green fruit stage and a positive correlation with total antioxidant capacity. The content of anthocyanins showed an upward trend and reached its highest point during the mature stage, with a mass fraction of 802.42 μg/g. In terms of antioxidant enzyme activity, the POD activity (62.58 U/g) and glutathione (GSH) mass fraction (1.01 mg/g) were highest during the green fruit stage, respectively, showing an extremely significant positive correlation with the total antioxidant capacity. In contrast, SOD activity, MDA content, and {\mathrm{O}}_2^{-} production rate were highest at maturity and negatively correlated with total antioxidant capacity. The expression levels of SOD activity related genes RuSOD1 and RuSOD2 showed overall upward trends during fruit development, while the expression levels of RuSODCP.2 also showed an upward trend in the early stage and slightly decreased in the mature stage. The overall change in the expression level of RuFSD was not significant. And they were positively correlated with SOD activity. The expression level of the genes related to POD activity, RuPOD, gradually decreased. The expression level of RuPER5 decreased during the 7-14 DAF period and increased during the 14-35 DAF period, while the expression level of RuPER25 increased during the 7-21 DAF period and decreased during the 21-35 DAF period. The expression level of RuPROX6 gradually increased, while the expression level of RuPER17 did not change significantly. POD activity was positively correlated with the expression levels of RuPOD, RuPER5, RuPER17 and RuPER25, while it was negatively correlated with RuPROX6.【Conclusion】The findings indicate that red raspberry fruits exhibit the highest antioxidant capacity during the green fruit stage, with total phenols, flavonoids, POD and GSH identified as the primary antioxidant components. This research provides a foundation for further exploration into the dynamics changes and action mechanisms of antioxidant substances in red raspberry fruits, offering valuable insights for their potential applications in nutrition and health.