关键词: 荔枝, 果实, 能量调控, 基因表达, 采后衰老

Abstract: To discover the mode of energy regulation and its relationship with senescence in harvested Litchi chinensis Sonn.，three energy charge（EC）levels of seedless litchi fruit including normal EC at ambient temperature（25 ℃）storage（the control），lower EC as affected by 2,4-Dinitrophenol（DNP）and higher EC at low temperature（5 ℃）were investigated to determine effects of EC levels and energy-related genes expression on pericarp browning and senescence. The results showed that low EC level under DNP treatment remarkably promoted fruit senescene；accelerated senescence was observed in the control fruits during post-storage，which was associated with decreased EC；and delayed senescence was noted in 5 ℃-stored litchi fruit with higher EC. DNP treatment resulted in up-regulated expression of LcAOX1 within 6 h，and severe browning in DNP-treated fruit initiated after 24 h of storage. DNP treatment strongly inhibited the expression of LcUCP1. Compared to the control fruits，DNP treatment resulted in earlier and more intense expression in LcSnRK2. During post-storage，lower EC levels were observed in both control and DNP-treated fruits，and expressive levels of LcAAC1，LcAOX1 and LcUCP1 appear to decrease while fruit senescence was aggravated. The expressions of LcAAC1，LcAOX1，LcUCP1 and LcSnRK2 in fruit stored at 5 ℃ were maintained at relatively low levels throughout the storage. The present results indicate that the decline of EC level in harvested litchi fruit might be one of the most important factors to cause rapid senescence. The genes including LcSnRK2 and LcAAC1 were sensitive to energy changes in litchi pericarp，which might respond rapidly to deficit of the energy，and might also be induced to express in up-regulation. The up-regulation of LcAOX1 and LcUCP1 was positively correlated with the senescence of litchi fruit，which might be as reference indicators for postharvest senescence of litchi fruit.

Key words: litchi, fruit, energy regulation, gene expression, postharvest senescence