Sucrose Synthase Isozymes Related to Sucrose Accumulation During Fruit Development of Japanese Pear (Pyrus pyrifolia Nakai)
Sucrose Synthase Isozymes Related to Sucrose Accumulation During Fruit Development of Japanese Pear (Pyrus pyrifolia Nakai)
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DOI：
10.2503/jjshs.69.671
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发表时间：
2000-11
影响因子：
--
通讯作者：
K. Tanase;S. Yamaki
中科院分区：
文献类型：
--
作者：
K. Tanase;S. Yamaki
以日本梨为试材，研究了果实发育过程中蔗糖代谢相关酶尤其是蔗糖合成酶（SS）同工酶与蔗糖积累的关系。果实中的蔗糖含量在幼嫩阶段很低，随着成熟而急剧增加，蔗糖磷酸合成酶活性也是如此。可溶性和细胞壁结合型酸性转化酶活性在幼果中较高，但在果实成熟过程中迅速下降。同样，SS活性在幼果中较高，但随着果实增大而下降;然而，随着成熟过程中蔗糖的积累，SS活性再次上升。SS活性的波动是由两种SS同工酶（SSI和SSII）引起的，SSI活性在幼果中较高，随果实发育而降低，SSII活性在幼果中很低，随果实发育而升高。这些结果表明，这两种同工酶的功能不同。SSII催化蔗糖的合成，这有助于果实成熟过程中蔗糖的积累，而SSI促进蔗糖裂解与酸转化酶和供应基板的幼果生长。
The relationship between sucrose metabolizing enzymes, especially sucrose synthase (SS) isozymes and sucrose accumulation was investigated throughout fruit development of the Japanese pear. The sucrose content in the fruit which was very low at the young stage, drastically increased with maturation, as did the sucrose phosphate synthase activity. The activities of soluble and cell wall-bound acid invertases, which were high in the young fruit, decreased rapidly during fruit maturation. SS activity was, likewise, high in young fruit but decreased with fruit enlargement ; however, it rose again concomitant with sucrose accumulation during maturation. The fluctuation in SS activity was caused by two SS isozymes (SSI and SSII) ; SSI activity was high in young fruit and decreased with fruit development, while SSII activity, which was very low in young fruit, increased with fruit development. These results indicate that these two isozymes differ in their functions. SSII catalyzes sucrose synthesis which contributes to sucrose accumulation during fruit maturation, whereas SSI facilitates sucrose cleavage together with acid invertases and supplies substrates for growth in young fruits.