一氧化氮对无核白葡萄果梗贮藏品质和微观结构的影响

为研究NO处理对贮藏过程中无核白葡萄理化品质、色素物质积累和微观结构的影响，本实验以无核白葡萄为研究试材，分别采用500 μL/L NO和空气熏蒸葡萄2 h，在0±0.5 ℃下冷藏25 d后，并模拟货架条件下放置3 d，货架温度分别为8±0.5 ℃和20±0.5 ℃。结果表明，与对照组相比，NO熏蒸处理显著减缓了葡萄果梗失重和电导率的增加，抑制了叶绿素降解和花青素的积累；NO处理减少了果梗表面裂纹数量、开裂强度、木质部中无机物的消耗，从而减缓了局部组织的凹陷程度。组织染色分析发现，NO维持了果梗表皮细胞的体积，减缓了细胞壁增厚及其木栓化，抑制了表皮棕色物质的积累。综上所述，NO处理有利于保持葡萄果梗品质，通过抑制叶绿素降解和花青素积累来延迟果梗的褐变，保持葡萄果梗微观结构的完整性。

Effects of Nitric Oxide on Storage Quality and Microstructure of Seedless White Grape Stem

In order to study the effect of nitric oxide (NO) on the physicochemical quality, pigment accumulation and microstructure of thompson seedless grape during storage. The grapes were fumigated with 500 μL/L NO or air for 2 h and then stored at 0±0.5 ℃ for 25 days, afterwards the grapes were separately moved to simulated shelf conditions for 3 days at 8±0.5 ℃ and 20±0.5 ℃ at the same time. The results showed that NO significantly slowed down the weight loss of grape rachis and the increase of electrical conductivity, inhibited the degradation of chlorophyll and the accumulation of anthocyanin in grape rachis compared with the control group. NO reduced the quantity and strength of cracks on the surface of spine, but also helped to maintain the tightness of intercellular space arrangement, slowed down the depletion of inorganic matter in the xylem, thus reducing the degree of partial depressions in the tissues. Tissue staining analysis showed that NO maintained the volume of rachis epidermal cells, slowed down the cell wall thickening and corkification, in addition, inhibited the accumulation of brown matter in the epidermis. In conclusion, NO fumigation was conducive to maintaining the quality of grape rachis, delaying the browning by inhibiting chlorophyll degradation and anthocyanin accumulation, moreover, maintaining the integrity of the rachis microstructure.