NO处理对采后映霜红桃果实冷害及呼吸作用的影响

为探究一氧化氮(NO)处理对桃果实冷藏期间冷害及呼吸作用的影响,本研究以映霜红桃果实为试验材料,采用不同浓度NO(0、5、10、15 μL·L^-1)处理,检测桃在4℃贮藏期间冷害症状、冷害指数、硬度、呼吸速率、呼吸途径关键酶的变化。结果表明,10 μL·L^-1NO处理延缓了桃冷害的发生,显著降低了冷害指数、呼吸速率(P<0.05),维持了桃果实的硬度,使果实正常软化后熟。同时,10 μL·L^-1NO处理通过抑制桃果实糖酵解、三羧酸(TCA)循环、细胞色素氧化酶途径关键酶—葡萄糖磷酸异构酶(GPI)、琥珀酸脱氢酶(SDH)和细胞色素氧化酶(COX)的活性(P<0.05),抑制了果实呼吸速率,延缓了果实衰老。10 μL·L^-1 NO处理通过提高磷酸戊糖途径关键酶—葡萄糖-6-磷酸脱氢酶(G-6-PDH)和6-磷酸葡萄糖酸脱氢酶(6-PGDH)的联合活性及抗氰呼吸途径关键酶—交替氧化酶(AOX)的活性,增强了桃果实的抗冷性,减轻了桃果实的冷害。本研究结果为NO在桃果实贮藏保鲜中的应用提供了理论依据。

Effects of Nitric Oxide Treatment on Chilling Injury and Respiration of Postharvest Yingshuanghong Peach Fruit

To explore the effects of nitric oxide (NO) treatment on chilling injury and respiration of peach fruit during cold storage, Yingshuanghong peach fruit was used as the experimental material and treated with different concentrations of NO (0, 5, 10 and 15 μL·L^-1). The quality-related indicators were investigated, including chilling injury index, firmness, respiration rate and enzymes activities of respiratory pathway metabolism. The results showed that 10 μL·L^-1 NO treatment significantly reduced chilling injury index, respiration rate (P<0.05), and maintained the firmness of peach fruits, and enabled peach fruit to soften and ripen normally. At the same time, 10 μL·L^-1 NO treatment significantly inhibited the activities of glucose 6-phosphate isomerase (GPI), succinate dehydrogenase (SDH) and cytochrome oxidase (COX) in peach fruits (P<0.05), which then alleviated the increase of respiration rate and the ripening and senescence of fruits. The total activity of glucose-6-phosphate dehydrogenase (G-6-PDH) and 6-phosphogluconate dehydrogenase (6-PGDH) and the activity of alternative oxidase (AOX) were induced by NO treatment, which can enhance cold tolerance and reduce the chilling injury of peach fruits. This study could provide theoretical basis for the practical application of NO in peach fruit storage and preservation.