韭菜化感物质草莓酸对香蕉枯萎病菌的影响

nutrient on banana growth and root morphology

关键词:  草莓酸, 化感物质, 香蕉枯萎病, 尖孢镰刀菌4号生理小种, 土壤微生物数量, 土壤酶活性

Key words:  strawberry acid, allelochemical, banana wilt, Foc4, soil microbial quantity, soil enzyme activity

摘要:

香蕉枯萎病主要由尖孢镰刀菌 4 号生理小种(Fusarium oxysporum f. sp. cubense,Foc4)引起的一种土传病害,严重威胁香蕉产业的可持续发展。为寻求一种经济有效且环保的防治措施,以韭菜化感物质的衍生物草莓酸(strawberry acid,SA)为材料,通过平板和盆栽实验,研究了SA对Foc4的菌丝生长、香蕉枯萎病病情指数、土壤微生物数量、土壤酶活性的影响。结果表明:(1)随着SA浓度的增加,Foc4的菌落生长直径显著减小,第5天时菌落直径在SA浓度为300、450 μL·L^-1时比150 μL·L^-1分别减小了49.15%、70.89%; 液体培养条件下SA浓度为600 μL·L^-1时Foc4的分生孢子数量显著低于对照处理(相差 470 多倍); pH为5时SA对Foc4的抑制效果显著比pH为7和9时好。(2)随实验处理时间的延长,添加 SA后香蕉幼苗的病情指数显著低于对照。(3)土壤细菌、真菌数量和微生物总量在SA为600 μL·L^-1时均为最高; Foc4数量随SA浓度升高而降低,在1 200 μL·L^-1时显著降低。(4)各土壤酶在浓度(300～600 μL·L^-1)SA处理时活性较高; 1 200 μL·L^-1时显著降低,过氧化氢酶和多酚氧化酶较对照分别降低了41.88%、54.82%。(5)相关性分析得出,土壤微生物总量与细菌、真菌数量极显著正相关; 土壤真菌与放线菌显著负相关; 土壤细菌、真菌和放线菌数量均与蔗糖酶、多酚氧化酶显著正相关; 蔗糖酶与脲酶、过氧化氢酶与多酚氧化酶均显著正相关。综上认为,添加SA浓度为600 μL·L^-1能较好地抑制Foc4的菌丝生长且能提高其抑制率,病情指数明显降低,有利于改善香蕉的生长环境。该研究结果为有效利用SA防治香蕉枯萎病提供了科学依据。

Abstract:

Banana Fusarium oxysporum f. sp. cubense is a soil-borne disease, which seriously threatens the sustainable development of banana industry. In order to seek an economic, effective and environmental protection measures, plate and pot experiments were carried out by using allelochemical strawberry acid(SA)to investigate the effects on hypha growth, disease severity index of banana wilt, soil microorganism quantity and soil enzyme activity. The results were as follows:(1)With the increase of SA concentration, the colony growth diameter of Foc4 decreased significantly, which decreased by 49.15% and 70.89% when SA concentrations were 300 μL·L^-1 and 450 μL·L^-1 compared with 150 μL·L^-1, respectively, on the fifth day. The number of spores were significantly lower than that of the control treatment(more than 470 times)when SA concentration was 600 μL·L^-1 under liquid medium condition. SA had a better inhibitory effect on Foc4 at pH 5 and was significantly better than that at pH 7 and pH 9.(2)As time going, the disease severity index of banana seedlings was significantly lower than that of the control after adding SA.(3)The numbers of soil bacteria, fungi and the total amount of microorganisms were all the highest when SA was 600 μL·L^-1; The number of Foc4 decreased with the increase of SA concentration, and significantly decreased when SA concentration was 1 200 μL·L^-1.(4)The soil enzyme activity was higher when SA concentration was 600 μL·L^-1,and was significantly decreased when SA concentration was 1 200 μL·L^-1, the activity of catalase and polyphenol oxidase were lower by 41.88% and 54.82% compared with the control, respectively.(5)Correlation analysis showed that the total amount of soil microorganisms was extremely significantly positively correlated with the numbers of bacteria and fungi. Soil fungi was significantly negatively correlated with actinomycetes. The numbers of soil bacteria, fungi and actinomycetes were all significantly positively correlated with invertase and polyphenol oxidase. Invertase and urease, catalase and polyphenol oxidase were all significantly positively correlated. In general, adding SA at a concentration of 600 μL·L^-1 can better inhibit the hypha growth of Foc4, increase its inhibition rate, and significantly reduce the disease severity index. Meanwhile, it can improve the growth environment of bananas. This study provides an academic reference for the effective use of SA to control banana wilt.