采前喷施油茶饼粕提取液对火龙果果实采后抗病性的影响

Effect of Preharvest Spraying Extract from Camellia oleifera Cake on the Disease Resistance of Postharvest Pitaya Fruit

为探究采前喷施油茶饼粕提取液对火龙果果实采后抗病性的影响,本研究以紫红龙火龙果为试材,在果实采前喷施不同浓度油茶饼粕提取液,同时以喷施清水为对照(CK),采后果实贮藏于(10±0.5)℃,相对湿度90%~95%条件下,分析各处理的火龙果果实的采后理化、营养成分、活性氧(reactive oxygen species,ROS)代谢及防御酶活力的变化,并对各指标进行相关性分析和综合评分。结果表明:采前喷施油茶饼粕提取液处理均能有效降低火龙果果实的腐烂指数(decay index,DI);贮藏后期,经油茶饼粕提取液处理的火龙果果实的呼吸速率(respiratory rate,RR)、乙烯释放速率(ethylene release rate,ERR)得到有效抑制;油茶饼粕提取液处理能有效延缓其抗坏血酸(ascorbic acid,AsA)含量下降,提高其过氧化氢酶(catalase,CAT)、超氧化物歧化酶(superoxide dismutase,SOD)等抗氧化酶活力,有效促进其过氧化氢(hydrogen peroxide,H_(2)O_(2))代谢,降低果实体内H_(2)O_(2)含量,有效清除其生理代谢过程中积累的自由基。同时,油茶饼粕提取液处理能有效提高火龙果果实的苯丙氨酸解氨酶(phenylalanine ammonialyase,PAL)、过氧化物酶(peroxidase,POD)、多酚氧化酶(polyphenol oxidase,PPO)、β-1,3-葡聚糖酶(β-1,3-glucanase,GLU)及几丁质酶(chitinase,CHI)等防御相关酶活力,从而提高果实抗病能力。相关性分析发现,火龙果果实腐烂指数与ROS积累、膜脂过氧化密切相关,减轻氧化应激、维持细胞膜完整性是提高火龙果果实抗病性的基础,增强果实的抗病能力有助于减轻腐烂。主成分分析发现,采前喷施1.00%油茶饼粕提取液组的火龙果综合评分最高,表明其效果最佳。综上所述,采前喷施1.00%油茶饼粕提取液处理通过提高火龙果果实抗氧化及抗病性来维持其品质。该研究结果为油茶饼粕提取液在火龙果采后贮藏保鲜中的应用提供理论参考。

To explore the effect of the extract from Camellia oleifera cake on the postharvest disease resistance of pitaya,pitaya Zihonglong was sprayed with different concentrations of C.oleifera cake extract before harvest.The fruits were stored at(10±0.5)℃and 90%℃-95%RH after harvest.The changes of physical and chemical properties,nutritional components,reactive oxygen species(ROS)metabolism and defense-related enzyme activities of pitaya fruits after harvest were analyzed,and the correlation between each index and comprehensively scores were analyzed.The results indicated that the preharvest spraying extract from C.oleifera cake could effectively reduce the decay index(DI)of pitaya fruit.The respiratory rate(RR)and ethylene release rate(ERR)of pitaya fruit were effectively inhibited by C.oleifera cake extract at the later storage period.Pitaya fruit treated with C.oleifera cake extract effectively delayed the decrease of ascorbic acid(AsA)content,and increased the activities of catalase(CAT),superoxide dismutase(SOD)and other antioxidant enzymes,effectively promoted the metabolism of hydrogen peroxide(H_(2)O_(2))in fruit,reduced the H_(2)O_(2)content,and effectively removed the ROS accumulation during the fruit physiological metabolism.Meanwhile,the C.oleifera cake extract effectively increased the activities of defense-related enzymes such as phenylalanine ammonialyase(PAL),peroxidase(POD),polyphenol oxidase(PPO),β-1,3-glucanase(GLU)and chitinase(CHI)in pitaya fruit,thus improving its disease resistance.Correlation analysis founded that pitaya fruit DI was closely related to the ROS accu-mulation and membrane lipid peroxidation.Decreasing oxidative stress and maintaining the integrity of cell membrane were the basis for improving the disease resistance of pitaya fruit,and enhancing the disease resistance of pitaya fruit was helpful to reduce decay.Comprehensive evaluation showed that the comprehensive score of pitaya fruit preharvest spraying with 1.00%C.oleifera cake extract was the highest,indicating that its treatment effect was the best.In con-clusion,preharvest spraying with 1.00%C.oleifera cake extract could maintain quality of pitaya fruit by improving the antioxidant and disease resistance.The results provide a theoretical reference for the application of C.oleifera cake extract in the postharvest storage and preservation of pitaya.