壳寡糖对杏果实采后主要病原菌抑菌作用的研究

Study on Influencing Factors of the Antifungal Activity on the Main Postharvest Disease-producing Fungus of Apricot Fruit by Oligochitosan

【目的】研究壳寡糖对引起杏果实采后病害主要病原真菌抑菌作用的影响因素。【方法】将供试菌种扩展青霉(Penicillium expansum)、胶孢链格孢(Alternaria alternata)和匍枝根霉(Rhizopus stolonifer)活化培养后接种到含有壳寡糖的PDA培养基上,观察不同分子量及不同浓度的壳寡糖对不同病原菌菌落生长的影响。【结果】壳寡糖对3种供试菌均有较好的抑制作用。不同分子量的壳寡糖抑菌效果不同,分子量5 000和10000壳寡糖的抑菌率显著高于分子量3 000的壳寡糖。在供试壳寡糖浓度中,处理效果表现为剂量依赖关系,三种分子量的壳寡糖均以2.0%浓度对三种供试菌的抑菌效果最好。不同病原菌对壳寡糖的敏感性不同,供试壳寡糖对胶孢链格孢(A.alternata)和匍枝根霉(R.stolonifer)的抑制率明显高于扩展青霉(P.expansum)。【结论】不同分子量的壳寡糖对病原菌的菌落生长均有较好的抑制作用,抑制作用的大小因壳寡糖分子量、浓度、病原菌的不同而有差异。

[ Objective] The influencing factors of the antifungal activity on the main postharvest disease - producing fungus of apricot fruit by oligochitosan were studied. [ Method ] Penicillium expansum, Alternaria alternate and Rhizopus stolonifer were inoculated on the potato dextrose agar containing oligochitosan. The effects of oligochitosan of different molecular weight and concentration on the colony growth were evaluated. [ Result] The results from the experiment showed that the oligochitosan had good antifungal activity on the three tested fungi strains. The antifungal activity of 10,000 Da was higher than that of the oligochitosan with molecular weight 3, 000 Da. The antifungal activity of the tested oligochitosan concentration has a concentration dependent manner. Among them, 2.0% oligochitosan was tile most effective. Different strains had different sensitivities to the oligochitosan. A. alternata and R. stolonifer were more sensitive to oligochitosan than P. expansum. The oligochitosan with different molecular weight exhibited significant inhibition effects on the three testing fungi stains. [ Conclusion ] The inhibiting effects of oligochitosan were related to the molecular weight of oligochitosan, concentration and strain species.