不同时期套袋对幸水梨果实品质、石细胞发育及其相关酶活性变化的影响

以幸水梨为试材分不同时期进行套袋处理,采集各个发育时期的果实,对其果实品质、石细胞团的密度、大小、含量及几种相关酶活性进行了分析.结果表明:(1)不同时期套袋后,幸水梨的硬度、可滴定酸含量均比对照显著增加,可溶性固形物、可溶性总糖含量以及单果重均有不同程度的降低.(2)不同时期套袋果的石细胞含量显著低于对照;与对照果相比套袋果果实表面光洁,果点小而稀,外观品质明显改善.(3)果实石细胞团的密度在幼果期较高,随着果实的发育膨大,密度逐渐减小,成熟前1个月左右基本稳定,石细胞团的纵横径随果实发育先逐渐增大而后减小,石细胞含量也表现出先增加后减少的趋势,在花后第49 d达到最大值.(4)果实内苯丙氨酸解氨酶在果实发育初期的活性较高,随着果实发育逐渐降低;多酚氧化酶活性变化与苯丙氨酸解氨酶相似;过氧化物酶活性随果实的生长呈现先上升后下降的趋势,其活性峰值在盛花后第28 d,其后缓慢下降.(5)不同时期套袋处理后,苯丙氨酸解氨酶、过氧化物酶以及多酚氧化酶活性整体上均比对照降低,与石细胞含量呈正相关关系.

Effects of Fruit Bagging at Different Stages on Pear Quality and Sclereid Development and the Activities of Their Related Enzymes in the Pear Variety Kousui

The fruits of kousui were bagged at different fruit stages and collected to examine the effects of fruit bagging on their quality and sclereid-agglomerate density,size and content and the activities of their related enzymes.It was shown that(1)after they were bagged at different stages,the fruits increased their hardness,titratable acid content and decreased their solids content,soluble sugar content and weight per fruit in various degrees compared with the control fruits;(2)the bagged fruits got remarkably improved in appearance having a smooth and even surface with sparse and smaller fruit dots compared with the control fruits;(3)the sclereid agglomerate density of the fruits appeared high at their young stage,then increased and decreased later on,and their sclereid content tended to increase at first,peak 49 days after flowering and then decline;(4)in the fruits,the PAL activity appeared high at the early stage and then gradually declined with fruit development and the PPO activity varied similarly to the PAL activity;the POD activity appeared to rise at first,reached its peak 28 days after full blooming and then slowly declined;(5)The PAL,PPO and POD activities in the bagged fruits were higher than those in the control fruits and appeared to be positively related to the sclereid content