氨基寡糖素对苦瓜枯萎病的抗性诱导作用.

【Objective】The present paper aimed to explore the induction of amino-oligosaccharides resistance to Fusarium wilt of bitter gourd, so as to provide reference for improving the technology of amino-oligosaccharide-induced resistance to F. wilt.【Method】Leaves and bitter gourd seedlings were sprayed with different concentrations of amino-oligosaccharins and roots of bitter gourd seedlings were watered with different concentrations of amino-oligosaccharins. Four treatments were set: Induction without inoculation, induction with inoculation, no induction but with inoculation, no induction and no inoculation. After 15 days of treatment, activities of β-1, 3-glucanase (β-1, 3-GLU), peroxidase (POD), polyphenol oxidase (PPO) and phenylalanine ammonia lyase (PAL) were determined to analyze the changes of lignin, phenolic compounds and callose in the root, stem and leaf of bitter gourd, thus, exploring the induced resistance of amino-oligosaccharide to F. wilt of bitter gourd.【Result】Induction of 5% amino-oligosaccharide by foliar spray and root watering both could induct the resistance to F. wilt on bitter gourd seedlings. The disease index by 1500 times solution foliar spray with 5% amino-oligosaccharide was 30.83, 23.34 lower than that of the control (CK1), reaching the disease resistance level (R), and the induced disease resistance index was 43.09. The disease index by 1000 times solution root irrigation with 5% amino-oligosaccharide was 25.00, 59.44 lower than that of the control (CK2), reaching the disease resistance level (R), and the induced disease resistance index was 70.39. The results of ANOVA showed that the difference of inducted effect on disease resistance reached a very significant level (P<0.01,the same as below) between 5% amino-oligosaccharide and 0.5% chitosan, 6% oligosaccharide. After induction and inoculation of 5% amino-oligosaccharide, a small amount of mycelia was observed in the root system from 6 days to 14 days, while the production of mycelia was found in the control group after 2 days, a large number of mycelia appeared on 8 days, and spores were found after 14 days, indicating that the induction of amino-oligosaccharide could delay the infection time of F. oxysporum. At the same time, it could prevent the further development of mycelia and inhibit the formation of spores.【Conclusion】5% amino-oligosaccharide could make immune system work, induce the expression of disease-course-related protease activity, promote the formation of secondary metabolites, and effectively enhance the resistance of bitter gourd to F. wilt. [ABSTRACT FROM AUTHOR]