外源水杨酸处理对采后蓝莓果实软化的调控作用

为探究外源水杨酸处理对采后蓝莓果实软化的调控作用及最适调控浓度，以‘蓝丰’蓝莓果实为试材，分别采用3 种不同浓度（0.5、1.0、1.5 mmol/L）的外源水杨酸对采后蓝莓果实进行处理，测定常温货架期间果实硬度、腐烂率、失重率、可溶性固形物含量（SSC）的变化，以及果胶酯酶（PE）、多聚半乳糖醛酸酶（PG）和纤维素酶（Cx）等细胞壁水解酶活性的变化。结果表明：外源水杨酸处理能有效延缓采后蓝莓果实硬度下降， 从常温货架2 d开始，1.0 mmol/L 水杨酸处理组蓝莓果实硬度显著高于对照组（P＜0.05），常温货架8 d时，1.0 mmol/L 水杨酸处理组果实硬度比对照组高70%。与对照组相比，1.0 mmol/L 水杨酸处理可将蓝莓果实腐烂发生时间推迟2 d，且能够有效降低果实失重率，并维持果实SSC 稳定。1.0 mmol/L 水杨酸处理显著抑制了蓝莓果实PE 和PG 活性的升高，进而延缓果实软化。综上所述，外源水杨酸处理对采后蓝莓果实软化具有一定的调控作用，其中1.0 mmol/L 为抑制果实软化的最适水杨酸处理浓度，其可通过抑制PE、PG 活性延缓采后蓝莓果实软化。

Regulation Effect of Exogenous Salicylic Acid Treatment on the Softening of Postharvest Blueberry Fruit

To explore the regulatory effect of exogenous salicylic acid treatment on the softening of postharvest blueberry fruit and the optimal regulatory concentration, three different concentrations (0.5, 1.0, 1.5 mmol/L) of exogenous salicylic acid were used to treat the postharvest‘Lanfeng’ blueberry fruits. The regulatory effects of exogenous salicylic acid treatment on the softening of postharvest blueberry fruits were investigated by measuring the changes of fruit firmness, decay rate, weight loss rate and soluble solid content (SSC) and the changes in cell wall hydrolase activities such as pectin esterase (PE), polygalacturonase (PG) and cellulase (Cx) during shelf life at room temperature. The results showed that exogenous salicylic acid treatment could effectively delay the decline of firmness of blueberry fruits. From the 2nd day of shelf life at room temperature, the firmness of blueberry fruits in 1.0 mmol/L concentration of salicylic acid treatment group was significantly higher than that in control group, and on the 8th day of shelf life at room temperature, the firmness of the fruits in 1.0 mmol/L concentration of salicylic acid treatment group was 70% higher than that in control group. Compared with the control group, 1.0 mmol/L sal icylic acid treatment could delay the occurrence of fruit decay for 2 days, effectively reduce the fruit weight loss rate, and maintain stable content of SSC. The 1.0 mmol/L concentration of salicylic acid treatment significantly inhibited the increase of PE and PG activities in blueberries, thereby delay fruit softening. In conclusion, exogenous salicylic acid treatment has a certain regulatory effect on the softening of postharvest blueberry fruit, among which 1.0 mmol/L was the optimal salicylate treatment concentration for inhibiting fruit softening, which can delay the softening of postharvest blueberry fruits by inhibiting the activities of PE and PG.