贮前外源水杨酸处理对桃果冷贮性的影响

选择商品成熟期的桃(PrunuspersicaL.cv.Beijing24),采摘后分别用0、0.35、0.7、1.0mmol/L水杨酸(Salicylicacid,SA)溶液浸泡5min,在0℃的低温下贮藏28d,然后转到20℃下3d(模拟货架期)。货架期结束时,观察果实冷害和腐烂发生状况并计算果实冷害指数和腐烂指数,测定果实的硬度和丙二醛含量。结果表明,与对照相比,1mmol/LSA处理对维持果实硬度具有显著的效果,同时显著降低了冷害指数、腐烂指数和丙二醛含量,其他两种浓度的SA处理与对照之间不存在显著差异。说明1mmol/LSA能够减轻桃果的冷害。进一步研究发现,在冷藏中期(14d)、冷藏结束时(28d)和货架期结束时,1mmol/LSA预处理的桃果肉的还原性抗坏血酸与氧化性抗坏血酸含量之比(AsA/DHAsA)分别比对照高39%,61%和55%。在冷藏中期(14d),还原性谷胱甘肽与氧化性谷胱甘肽含量之比(GSH/GSSG)比对照高68%。在贮藏和货架期结束时,抗坏血酸氧化酶和谷胱甘肽还原酶活性显著高于对照。上述结果说明,水杨酸能减轻桃果由于冷贮发生的冷害与诱导提高抗氧化系统抗抗坏血酸—谷胱甘肽循环的活性有关,适宜浓度的水杨酸处理可能是提高桃果实冷藏性的有效措施。

Salicylic Acid Alleviates Chilling Injury and Effects Antioxidant System of Peach Fruit during Cold Storage

Peach Prunus persica (L.) Batch. cv. Beijing 24] fruit at commercial maturity were immersed in 0, 0.35, 0.7 and 1 mmol/L salicylic acid (SA) solution for 5 min, stored at 0°C for 28 days, then moved to 20°C for 3 days to simulate shelf life. Chilling injury (CI) index, decay index (DI), firmness and malondialdehyde (MDA) content of fruit were measured at the end of shelf life. The results showed that only 1 mM SA significantly maintained higher firmness and lower CI, DI, and TBARS content of fruit compared with the control. Studies were then conducted to determine if 1 mmol/L SA alleviated chilling injury by influencing antioxidant systems of the fruit. Reduced-to-oxidized ascorbate ratio (AsA/DHAsA) in 1 mmol/L SA-treated fruit was 39%, 61%, and 55% higher than that in controls at the midpoint of storage, the end of storage and after 3 days of shelf life, respectively. The reduced-to-oxidized glutathione ratio (GSH/GSSG) in SA treated-fruit was 68% higher than that in controls at the midpoint of storage. Ascorbate peroxidase and glutathione reductase activities in SA-treated fruit were significantly greater than those in controls during cold storage. The effect of SA on alleviating chilling injury of peaches during cold storage may be related to its ability to induce antioxidant systems .