柠檬酸处理对厚皮甜瓜黑斑病的抑制及苯丙烷代谢的作用

Control of black spot and potentiating of phenylpropanoid pathway in muskmelon fruit treated by citric acid

以"银帝"甜瓜果实为试材,研究采后不同浓度柠檬酸处理对厚皮甜瓜损伤接种Alternaria alternata病斑直径的抑制,以及对果实苯丙烷代谢相关酶和产物积累的影响。结果表明,2%的柠檬酸处理显著(p≤0.05)降低了果实损伤接种A.alternata的病斑直径。柠檬酸处理明显提高了果实体内的过氧化物酶(POD)和苯丙氨酸解氨酶(PAL)活性,促进了总酚、类黄酮和木质素含量的积累。由此表明,采后柠檬酸处理可通过促进苯丙烷代谢途径来提高厚皮甜瓜果实对采后病害的抗性。

Effect of postharvest citric acid dipping on black spot, reactive oxygen species and phenylpropanoid pathway in muskmelon fruit was investigated.Muskmelon（ Cucumis melo L.cv.Yindi）fruit were dipped at different concentrations of citric acid and inoculated with Alternaria alternat＆The inhibition effect of citric acid dipping on the lesion diameter, the key enzyme activities and phenylpropanoids accumulation of phenylpropanoid pathway in muskmelon fruits were investigated.The results indicated that citric acid at 2% significantly reduced the lesion diameter of fruit inoculated with A.alternata.Citric acid treatment increased the activities of peroxidase（POD） and phenylalanine ammonia-lyase（ PAL）.Citric acid also increased the content of total phenolic compounds,flavonoids and lignin in the fruit.The results also suggested that postharvest citric acid decreased postharvest diseases of muskmelon fruit by accelerating phenylpropanoid pathway.