超声波联合水杨酸处理对冬枣采后黑斑病的防控研究

Prevention and control of postharvest black spot disease of jujube by ultrasonic combined with salicylic acid treatment

为探究超声波(ultrasound,US)联合水杨酸(salicylic acid,SA)处理对冬枣采后黑斑病的防控效果及其机理,该文使用US单独或联合SA处理冬枣果实,测定发病率、自然腐烂率,筛选出最佳的处理条件,并从其对病原菌的直接作用、诱导枣果实抗病性等方面对其防治机制进一步研究。结果表明,US单独或联合SA处理均能有效控制冬枣采后黑斑病,并显著降低自然腐烂率,且联合处理的防治效果显著优于单独处理(P<0.05)。对其作用机制进一步探究,US联合SA处理能显著抑制Alternaria alternata的菌丝生长(P<0.05)。US处理不仅能降低A.alternata在冬枣伤口处的附着量,还能使冬枣果皮表面形成微裂纹,从而利于SA与果实接触,促进SA向果实渗透。此外,US与SA联合处理可以显著提高果实过氧化物酶、多酚氧化酶、苯丙氨酸解氨酶、4-香豆酸辅酶A连接酶活性(P<0.05),促进冬枣中的总酚、黄酮、游离酚、结合酚的积累(P<0.05),诱导枣果实抗病性,提高枣果实对病害的防御能力,从而降低果实腐烂率。综上所述,US联合SA作为一种绿色安全的处理方式对于控制冬枣采后黑斑病具有良好的研究潜力和开发前景。

This study aimed to investigate the effects and mechanism of ultrasonic(US)combined with salicylic acid(SA)treatment on the postharvest black spot of jujube during storage.This paper used the US alone or combined with SA to treat jujube fruits,determined the incidence rate and natural decay rate,then screened the best treatment conditions,and further investigated its control mechanism in terms of its direct effect on pathogenic bacteria and induced disease resistance in jujube fruits.Results showed that the US alone or combined SA treatment significantly controlled the disease incidence of black spots and reduced the natural decay rate of jujube,and the combined treatment was significantly better than that alone(P<0.05).Furthermore,US combined with SA treatment significantly inhibited the mycelial growth of Alternaria alternata in vitro(P<0.05).US treatment not only reduced the attachment of A.alternata at the wound of the jujube but also caused microcracks to form on the surface of the jujube fruit skin,which facilitated the contact between SA and fruit and promoted the penetration of SA into the fruit.In addition,the combined treatment significantly increased the activity of peroxidase,polyphenol oxidase,phenylalanine deaminase,and 4-coumarate coenzyme A ligase(P<0.05),promoted the accumulation of total phenols,flavonoids,free phenols,and bound phenols(P<0.05),induced disease resistance,and improved the defense ability of jujube fruit against diseases,thus reducing fruit decay rate.In conclusion,the US combined with SA has good research potential and development prospects as a green and safe treatment for the control of postharvest black spot disease of jujube.