β-半乳糖苷酶及多聚半乳糖醛酸酶对桃果实成熟软化的影响

The effect of β-galactosidase and polygalacturonase on peach ripening and softening

以雨花3号桃果实为试验材料,采用气相色谱法测定不同成熟时期桃果实的乙烯释放量以及ACC合成酶和ACC氧化酶活性的变化,并分析β-半乳糖苷酶(-βG al)和多聚半乳糖醛酸酶(PG)活性的变化,探讨-βG al和PG对桃果实成熟软化的影响。结果表明:在桃果实成熟软化过程中,具有明显的乙烯跃变高峰,ACC合成酶和ACC氧化酶活性变化趋势与乙烯变化相一致;PG活性高峰与乙烯释放高峰同时出现于成熟度Ⅳ,而-βG al活性高峰出现于成熟前期(即成熟度Ⅰ);-βG al不同于PG,其作用主要与桃果实成熟前期果实的软化启动密切相关。

A peach cultivar Yuhua 3 was used to investigate the changes of ethylene production, the activity of ACC synthase and ACC oxidase at five different maturity by GC. The activity of β-galactosidase and polygalacturonase activity were also measured. Their effects on peach softening were discussed. Results showed that there was obvious ethylene peak during peach ripening. Change tendency of ACC synthase and ACC oxidase activities was consistent with ethylene. The peak of polygalacturonase activity and ethylene appeared simultaneously at maturity Ⅳ. While the activities of β-galactosidase were low in the more mature peach fruit and high in maturity Ⅰ . β-galactosidase was different from polygalacturonase and the effect of β-galactosidase on peach softening was mainly on earlier ripening stage.