高能电子束辐照对猕猴桃细胞壁降解相关酶活性和基因表达的影响

以‘海沃德’猕猴桃为试材，经剂量0（对照）、300、400和500 Gy高能电子束辐照后，于0~1 ℃、RH 90%~95%冷库中贮藏90 d，研究电子束辐照对果实硬度、细胞壁组分、软化相关酶活性及其基因表达量的影响。结果表明:高能电子束辐照显著维持了果实的硬度，有效抑制了细胞壁骨架物质原果胶和纤维素的分解，延迟了果实后熟软化。同时，辐照抑制了多聚半乳糖醛酸酶（polygalacturonase，PG）、果胶甲酯酶（pectin methylesterase，PME）、β-半乳糖苷酶（β-D-galaetosidase，β-Gal）和纤维素酶（cellulase，Cx）的活性，降低了PG、PME、β-Gal和Cx编码基因的表达。综合认为，以400 Gy高能电子束辐照对抑制细胞壁降解相关酶活性及基因表达，保持细胞结构的完整性，维持贮藏期间果实硬度效果最好。研究结果为高能电子束用于猕猴桃采后保鲜提供理论依据。

Effect of High Energy Electron Beam Irradiation on Cell Wall Degradation Related Enzyme Activities and Gene Expressions of Kiwifruit

‘Hayward’ kiwifruits were used as the test materials to be irradiated with high energy electron beams at doses of 0 (control), 300, 400 and 500 Gy. The fruits were stored at 0~1 ℃, RH 90%~95% for 90 d. The effects of electron beam irradiation on fruit firmness, cell wall components, softening-related enzyme activities and gene expressions were analyzed. The results showed that the high energy electron beam irradiation kept the firmness, effectively inhibited the degradation of cell wall skeletal material (protopectin and cellulose) and delayed the postharvest ripening and softening of kiwifruits. In further, high energy electron beam irradiation significantly inhibited the activities of polygalacturonase (PG), pectin methylesterase (PME), β-D-galaetosidase (β-Gal) and cellulase (Cx), and reduced the expressions of genes encoding PG, PME, β-Gal and Cx. Among the three treatments, 400 Gy high-energy electron beam irradiation showed the best effect on inhibiting cell wall degrading enzyme activity and gene expression, retaining the integrity of cell structure, and maintaining fruit firmness during storage. The study provided a theoretical basis for the use of high-energy electron beams in postharvest kiwifruit preservation.