蔗糖代谢相关酶在卡因菠萝果实糖积累中的作用

以菠萝品种卡因为材料,测定了不同发育时期果实中蔗糖、葡萄糖和果糖含量以及蔗糖代谢相关酶-酸性转化酶(AI)、中性转化酶(NI)、蔗糖合成酶(SS)和蔗糖磷酸合成酶(SPS)的活性,并对果实中糖积累与酶活性的关系进行了分析.结果表明,卡因果实的发育呈单"S型"曲线,在幼果期到果实迅速生长期,果糖和葡萄糖积累较多,蔗糖积累缓慢,此期蔗糖积累较少与高活性蔗糖转化酶有关;进入成熟期,果实中蔗糖迅速积累,而己糖略有上升,果实蔗糖的显著增加主要与SS和SPS活性有关.酸性转化酶和中性转化酶前期活性很强,后期降低;蔗糖合成酶(合成方向)和蔗糖磷酸合成酶的活性变化趋势相似,前期弱后期强.经过相关性分析:果实中蔗糖含量与SS和SPS活性存在极显著的正相关性(相关系数分别为r=0.97273**和r=-0.91004**),而与NI活性呈极显著负相关(r=-0.76419**),与AI的活性呈显著负相关(r=-0.60594*).

Roles of sucrose-metabolizing enzymes in accumulation of sugars in Cayenne pineapple fruit

The contents of sucrose, glucose and fructose, the activities of sucrose-metabolizing enzymes, including acid in-vertase(AI), neutral invertase (NI) , sucrose synthase(SS) and sucrose phosphate synthase(SPS) during fruit development process and the correlation between the sugar accumulation and the enzymes activity were studied in the fruit of pineapple cv. Cayenne. The results showed that the Cayenne fruit growth was in a sigmoid curve. Fructose and glucose accumulated sharply at the early stages, and sucrose accumulated slightly during the first and second stage of fruit development, which were re-alated to high invertase activities. However, at the ripening stage, sucrose accumulated sharply, while fructose and glucose slightly increased. Accumulation and compositions of sugars were affected evidently by the activities of SS and SPS in Cayenne fruit. The activities of acid invertase and neutral invertase were higher at the early developmental stage than at the late developmental stage; and the activities of sucrose synthase and sucrose phosphate synthase showed a similar change pattern with lower activities at the early developmental stage and higher activities at the late developmental stage. The correlation analyses showed that there was an extremely significant positive correlation between the content of sucrose and the activities of SS and SPS. A significant negative correlation was found between sucrose content and the activities of neutral and acid invertase.