蔗糖酶活力与甜菜块根贮藏质量的关系

可溶性酸性蔗糖酶是决定甜菜块根贮藏质量的关键酶。贮藏期间其活力的提高是由于蛋白质重新合成所致。不良的贮藏条件使块根汁液pH降低,膜透性增加,这两种因素与可溶性酸性蔗糖酶活力成正相关,与贮藏质量成负相关。

Relationship Between Invertase Activities and Quality of Sugarbeet Roots During Storage

In order to elucidate the relationship between the activities of invertases and the quality of stored sugarbeet roots, the changes of invertase activities and the quality of sugarbeet roots under different storage conditions were studied. Invertases of the roots were divided into four kinds according to their optimal pH and existing forms, i. e., soluble acid invertase (SAI), binding acid invertase (BAI), soluble neutral invertase (SNI) and binding neutral invertase (BNI). The activity of soluble acid invertase increased rapidly during storage, especially after thawing (Table 1, Fig. 1). It was mainly due to the synthesis of new protein (Fig. 2). However, the activity of soluble neutral invertase decreased under the same conditions. Of four invertases, the soluble acid invertase had the greatest influence on the root quality. Under poor storage conditions, the content of sucrose decreased, and the reducing sugar content increased (Fig. 3, 4), which resulted in the deterioration of the roots. It was also found that the sap acidity and the membrane permeability of roots increased gradually during storage. From these results, it could be concluded that there was a significant negative correlation between the quality of stored roots and the sap acidity, the membrane permeability as well as the soluble acid invertase activity.