能量供应对‘南岛无核’荔枝果实采后能量代谢及衰老的影响

Effects of Energy Supply on Energy Metabolism and Postharvest Senescence of 'Nandao wuhe' Litchi Fruit

以‘南岛无核’荔枝果实为材料,研究促进和抑制能量水平条件下,荔枝果实采后贮藏过程中呼吸、失水、果皮细胞膜损伤、能量产生及其关键酶活性与衰老的关系。结果表明:2,4-二硝基苯酚(DNP)解偶联剂抑制了能量供应,可促进荔枝果皮失水,加速果皮细胞膜损伤,能荷下降快,明显促进了荔枝果实衰老。而外源ATP处理降低了果皮失水和细胞膜损伤,果实贮藏期间保持了相对较高的能荷,延缓了荔枝果实采后衰老。DNP的解偶联作用使线粒体制造ATP受阻,直接诱导了贮藏前期细胞色素C氧化酶(COX)、H^+-ATPase和Ca^(2+)-ATPase活性增强,贮藏后期这些ATP关键酶活性下降,对延缓果实衰老不利。而外源ATP处理,果实贮藏前期COX活性较低,贮藏后期COX、H^+-ATPase和Ca^(2+)-ATPase活性增强,均对延缓荔枝果实衰老具有积极作用。总之,荔枝采后贮藏后期energy charge(EC)下降、ATP供应不足是导致荔枝果实衰老的重要因素,适当提高贮藏后期果实电子传递与氧化磷酸化过程中COX、H^+-ATPase和Ca^(2+)-ATPase等ATP相关酶的活性,对抑制荔枝果皮衰老、延长贮藏期更有利。

In the test, seedless litchi fruits were soaked in the solution with ATP and DNP. The relationship between browning induced by senescence and respiration, cell membrane damage, mitochondrial electron transport and energy production of oxidative phosphorylation, the key enzyme activities of litchi fruits in the postharvest storage were studied. The results showed that uncouple agent DNP treated inhibited energy supply, promoted dehydration of litchi pericarp, accelerated damage of cell membrane, decreased energy charge, and promoted senescence of litchi fruit browning. ATP treated decreased dehydration and cell membrane damage of pericarp, relative high energy charge were kept during storage, and the senescence and browning of litchi fruit were delayed. At earlier storage, the production of ATP in mitochondrial was blocked by the uncoupling effect of DNP, and the activities of eytochrome c oxidase（COX） , H＋-ATPase, and Ca2＋-ATPase induced and enhanced directly, and the utilization of energy-yielding material increased. At later storage, the activities of COX, H＋-ATPase, and Ca2＋-ATPase decreased, which were adverse to delaying fruit senescence. The activity of COX in litchi pericarp soaked in the solution with ATP at earlier storage reduced, and the utilization of energy-yielding material decreased. And the activities of COX, H^-ATPase, and Ca2＋-ATPase were stimulated in pericarp by ATP, which were conducive to delaying fruit senescence. According to the results, measures in appropriately increasing the enzymes＇ activities of ATP production such as COX, H＋-ATPase, and Ca2＋-ATPase in pericarp of litchi at later storage to inhibit browning and prolong storage time were suggested.