不同软化速率山楂果实软化相关酶活性分析

Softening Related Enzymes Activity Analysis of Hawthorn Fruit With Different Softening Progress

以采收期果实硬度迅速下降的‘软肉3号’和仍保持较高硬度的‘秋金星’山楂果实为试材,通过对发育期果实软化相关酶的活性分析,研究了‘软肉3号’果实的软化特点,以期为山楂果实的软化机理研究提供参考依据。结果表明:‘软肉3号’果实在盛花后100 d迅速变软,而‘秋金星’果实的硬度在盛花后120 d缓慢下降,且显著高于‘软肉3号’;多聚半乳糖醛酸酶(PG)在‘软肉3号’中先呈现较低的活性,后伴随果实硬度的快速下降而大幅上升,而其在‘秋金星’中保持较高活性;果胶甲酯酶(PME)在‘软肉3号’中的活性较稳定且均高于‘秋金星’;纤维素酶(Cx)活性在2个品种中均先下降后上升,伴随果实的成熟活性显著升高;β-半乳糖苷酶(β-Gal)在‘软肉3号’的活性较低,在‘秋金星’果实的活性较高,且随果实的成熟急剧上升;脂氧合酶(LOX)均在盛花后60 d出现活性高峰,且伴随果实的成熟出现小幅度上升。综上所述,‘软肉3号’山楂果实质地的改变可能受PG、PME和Cx等多种酶的共同影响和调控。

A special hawthorn germplasm named‘Ruanrou 3#'was used as experimental material as its rapid and remarkable softening characteristic and hawthorn‘Qiujinxing'was used as control.The softening related enzyme activities during fruit development were analyzed.The physiological mechanism in hawthorn fruit softening was studied,in order to provide refernce for the softening mechanism of the hawthorn fruit.The results showed that the fruit firmness of‘Ruanrou 3#'decreased rapidly after 100 days of full bloom,while‘Qiujinxing'started to decrease slowly until after 120 days,which was significantly higher than that of‘Ruanrou 3#'.The activities of polygalacturonase(PG)were lower in the early stage of fruit development for‘Ruanrou 3#',but increased sharply along with the rapid decrease of fruit firmness during the harvest period,instead,it showed relatively low activity in the whole development period in‘Qiujinxing'.The pectin methylesterase(PME)activities in‘Ruanrou 3#'were maintained stable and higher than those in‘Qiujinxing'during all developmental stages.The cellulase(Cx)activity in‘Qiujinxing'and‘Ruanrou 3#'increased significantly at fruit ripening,and there was a significant negative correlation between the Cx activity and fruit firmness.The activities ofβ-galactosidase(β-gal)increased slightly in‘Ruanrou 3#'fruit and then decreased,but increased in‘Qiujinxing'fruit,especially in the stage of fruit maturity.The lipoxygenase activities peaked in the middle and mature stages of‘Qiujinxing'and‘Ruanrou 3#'fruits,and increased slightly at late development stage.In conclusion,the changes of hawthorn fruit softening of‘Ruanrou 3#'might be affected and regulated by PG,PME and Cx.