壳聚糖复合磷酸钠处理对苹果青霉病的影响及部分机理

以“金冠”苹果为试材,研究不同浓度壳聚糖复合0.5 mg/mL磷酸钠浸泡处理对损伤接种扩展青霉(Penicillium expansum)果实病斑扩展的影响,研究最佳复合处理对果实抗氧化酶活性及苯丙烷途径关键酶活性和产物积累的影响。结果表明,1.0%壳聚糖复合磷酸钠处理对果实青霉病的控制效果最佳,处理显著降低病斑直径,激活过氧化物酶和苯丙氨酸解氨酶活性,促进果实总酚、类黄酮及木质素的积累。此外,复合处理可提高果实过氧化氢含量、过氧化氢酶、抗坏血酸过氧化物酶和谷胱甘肽还原酶活性。由此表明,壳聚糖复合磷酸钠处理抑制苹果果实青霉病的发生与提高抗氧化能力和激活苯丙烷代谢途径密切相关。

Effects of the Combination of Chitosan and Trisodium Phosphate on the Development of Blue Mold in Apple Fruits and the Partial Mechanism Underlying These Effects

The effects of different concentrations of chitosan combined with 0.5 mg/mL trisodium phosphate at ambient temperatures on the development of lesions in apples(cv.Golden Delicious)inoculated with Penicillium expansum was investigated.The effects of an optimal combination of chitosan and trisodium phosphate on the activity of antioxidant enzymes,as well as other enzymes,and on the accumulation of metabolites in the phenylpropanoid pathway were also studied.The results indicated that 1.0%chitosan combined with 0.5 mg/mL trisodium phosphate was the most effective treatment for the inhibition of the growth of blue mold in apples.Importantly,the combination of chitosan and trisodium phosphate significantly reduced the lesion diameter in the inoculated fruits and increased the contents of total phenolic compounds,flavonoids,and lignin,and the activities of peroxidase and phenylalanine ammonia-lyase in apples.Furthermore,this combination increased the H2O2 contents,and the catalase,ascorbate peroxidase,and glutathione reductase activities in apples.Collectively,these findings suggested that the combination of chitosan and trisodium phosphate inhibits the formation of blue mold in apples via the enhancement of antioxidant capacity and the activation of the phenylpropanoid pathway.