Life Science College, Luoyang Normal University, Luoyang, 471934, Henan, China.
Grain and Oil Crops Technology Extension Station, Yongchuan, 402160, Chongqing, China.
Sci Rep. 2023 May 22;13(1):8209. doi: 10.1038/s41598-023-35392-1.
Postharvest senescence and disease development can reduce the nutritional value of fresh jujube fruit. Herein, four different disease-controlling agents (chlorothalonil, CuCl, harpin and melatonin) were separately applied to fresh jujube fruit, and all improved postharvest quality (evaluated by disease severity, antioxidant accumulation and senescence) relative to controls. Disease severity was drastically inhibited by these agents, in the order chlorothalonil > CuCl > harpin > melatonin. However, chlorothalonil residues were detected even after storage for 4 weeks. These agents increased the activities of defense enzymes including phenylalanine ammonia-lyase, polyphenol oxidase, glutathione reductase and glutathione S-transferase, as well as accumulation of antioxidant compounds such as ascorbic acid, glutathione, flavonoids and phenolics, in postharvest jujube fruit. The enhanced antioxidant content and antioxidant capacity (evaluated by Fe reducing power) was ordered melatonin > harpin > CuCl > chlorothalonil. All four agents significantly delayed senescence (evaluated by weight loss, respiration rate and firmness), with the effect ordered CuCl > melatonin > harpin > chlorothalonil. Moreover, treatment with CuCl also increased copper accumulation ~ threefold in postharvest jujube fruit. Among the four agents, postharvest treatment with CuCl could be considered most appropriate for improving postharvest jujube fruit quality under low temperature conditions without sterilization.
采后衰老和疾病的发展会降低鲜枣的营养价值。在此，将四种不同的疾病控制剂（百菌清、CuCl、harpin 和褪黑素）分别应用于鲜枣，与对照相比，所有处理均改善了采后品质（通过疾病严重程度、抗氧化剂积累和衰老来评价）。这些药剂极显著地抑制了疾病的严重程度，抑制效果的顺序为百菌清>CuCl>harpin>褪黑素。然而，即使在贮藏 4 周后，仍检测到百菌清残留。这些药剂提高了苯丙氨酸解氨酶、多酚氧化酶、谷胱甘肽还原酶和谷胱甘肽 S-转移酶等防御酶的活性，以及抗氧化化合物（如抗坏血酸、谷胱甘肽、类黄酮和酚类）在采后枣果中的积累。增强的抗氧化含量和抗氧化能力（通过 Fe 还原力评价）的顺序为褪黑素>harpin>CuCl>百菌清。四种药剂均显著延缓了衰老（通过失重、呼吸速率和硬度评价），效果的顺序为 CuCl>褪黑素>harpin>百菌清。此外，CuCl 处理还使采后鲜枣中的铜积累增加了近三倍。在这四种药剂中，CuCl 处理在低温条件下可作为一种最适宜的方法，用于改善采后鲜枣的品质，且无需进行灭菌处理。
