外源褪黑素对采后冷藏番茄硬度变化的影响及调控机制

Effects of exogenous melatonin on firmness of postharvest tomato during cold storage and its regulatory mechanism

番茄不耐冷藏,采后易软化。采用100μmol/L外源褪黑素(melatonin,MT)处理番茄果实,在4℃、90%相对湿度条件下冷藏28 d,分析其采后品质变化,探究MT对采后冷藏番茄硬度变化的影响及调控机制。结果表明:MT处理能有效延缓采后冷藏番茄的失重和软化,推迟可溶性固形物高峰出现,极大地改善冷藏番茄的采后品质。MT处理通过抑制冷藏番茄多聚半乳糖醛酸酶基因(LePG)、纤维素酶基因(LeCel)、β-半乳糖苷酶基因(LeTBG7)、扩展蛋白基因(LeEXP)、富含酪氨酸和赖氨酸的蛋白质基因(LeTLRP)、木葡聚糖内转葡糖基酶/水解酶基因(LeBR1)的相对表达量,从而抑制果胶、纤维素降解和细胞壁松弛。可见,MT处理能够有效缓解番茄果实的软化,保持冷藏品质,延长保质期。

Postharvest tomato does not withstand storage and is easy to soften.In order to investigate the effects of exogenous melatonin(MT)on the firmness change of postharvest tomato during cold storage and its regulatory mechanism,tomatoes were treated with 100μmol/L MT and stored at 4℃ and 90% relative humidity for 28 d to analyze the changes in postharvest cold storage quality.The results showed that MT treatment could effectively delay the weight loss and softening of tomato during cold storage,delay the emergence of the peak of soluble solids.MT treatment inhibited the relative expression levels of polygalacturonase gene(LePG),cellulase gene(LeCel),β-galactosidase gene(LeTBG7)and expansins protein gene(LeEXP),tyrosine and lysine rich protein gene(LeTLRP),xyloglucan endotransglucosylase/hydrolase gene(LeBR1)during cold storage,thereby inhibiting pectin,cellulose degradation and cell wall relaxation.In conclusion,MT treatment can effectively alleviate the softening of tomato fruits,maintain the cold storage quality and extend the shelf life.