氣調貯藏對蘋果果實糖代謝的調控機制研究

田世平　朱竹

摘 要：糖是決定果實風味的關鍵物質。氣調貯藏（CA）可以保持果實采后的品質。為研究氣調貯藏對果實糖代謝的調控機制，該研究克隆了參與蘋果果實糖代謝的多個基因，并研究了這些基因在不同貯藏條件下果實中的表達，及相關酶的活性變化。結果表明貯藏在CA條件下的蘋果果實可以維持較高的糖含量，包括蔗糖、果糖和葡萄糖。一些關鍵基因例如蔗糖合酶（SS），蔗糖磷酸合酶（SPS），果糖激酶（FK）和己糖激酶（HK）的表達水平與酶活變化一致。在氣調條件下中性轉化酶（NI），液泡轉化酶（VI），果糖激酶和己糖激酶的活性受到抑制，而蔗糖磷酸合酶的活性增強，表明CA可以增強蔗糖的合成，減少蔗糖和己糖的分解。上述結果為解釋氣調貯藏保持果實糖含量提供了分子水平的證據。

關鍵詞：蘋果 采后 糖代謝 氣調

Abstract：Sugars are essential contributors to fruit flavour. Controlled atmosphere （CA） storage has been proved to be beneficial for maintaining harvested fruit quality. To explore regulatory mechanism of sugar metabolism in fruit stored in CA condition， we cloned several genes， encoding key enzymes， involved in sugar metabolism in apple fruit， and analyzed sugar contents， along with gene expression and enzyme activities in fruits stored in air and CA. The results indicated that CA could maintain higher contents of sugars， including sucrose， fructose and glucose. Expression levels of key genes， such as sucrose synthase （SS）， sucrose phosphate synthase （SPS）， fructokinase （FK） and hexokinase （HK）， were shown to be correlated with the corresponding enzyme activities. We found that activities of neutral invertase （NI）， vacuolar invertase （VI）， FK and HK were inhibited， but SPS activity was promoted in apple fruit stored in CA， suggesting that CA storage could enhance sucrose synthesis and delay hydrolysis of sucrose and hexose. These findings provided molecular evidence to explain why higher sugar levels in harvested fruit are maintained under CA storage.

Key Words：Apple； Postharvest； Sugar metabolism； Controlled atmosphere

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