三种药用甘草凋落物的水浸提液对根腐病病原菌的影响

Effects of Aqueous Extracts of Three Medicinal Licorice Litters on the Growth of the Root Rot Pathogens

以根腐病病原菌尖孢镰刀菌和腐皮镰刀菌为试材,采用外源添加法,分析了这2种病原菌对3种药用甘草根腐病的致病性能,研究了3种药用甘草凋落物(叶片)的水浸提液对尖孢镰刀菌和腐皮镰刀菌菌丝生长和产孢的影响,以期探究甘草凋落物与根腐病发生之间的内在联系。结果表明:尖孢镰刀菌和腐皮镰刀菌对3种药用甘草具有很强的致病性,可引起典型的根腐病害症状。在0.005~0.020 g·mL^(-1)的浓度范围内,光果甘草和乌拉尔甘草叶片的水浸提液显著促进了2种病原菌的生长和繁殖,二者对尖孢镰刀菌的菌落直径和孢子量的促进效果最高分别可达14.06%、10.58%、24.50%和48.39%,对腐皮镰刀菌的菌落直径和孢子产量的促进效果最高分别可达8.79%、12.25%、17.11%和25.13%。胀果甘草叶片水浸提液对2种病原菌的菌丝生长和产孢则表现出"低促高抑"的特点,其最高使尖孢镰刀菌的菌落直径和孢子量分别显著增加了3.63%和14.86%,使腐皮镰刀菌的菌落直径和孢子量分别显著增加6.64%和16.58%。3种药用甘草叶片水浸提液对该2种病原菌生长和繁殖促进效果的强弱顺序依次为乌拉尔甘草>光果甘草>胀果甘草。综上所述,甘草叶片作为凋落物在农田中的大量积累可能是造成甘草连作背景下根腐病频发的主要原因,建议每年在叶片枯落前进行茎叶收割并及时移出农田。

Taking the pathogenic of Fusarium oxysporum and F.solani as test materials,the pathogenicity of these two pathogens to three kinds of medicinal licorice root rot was analyzed.Then the effects of aqueous extracts of three kinds of medicinallicoroce′s litters(leaves)on the mycelial growth and sporulation of F.oxysporum and F.solani were detected by the exogenous addition method,in order to explore the mechanism of the frequent occurrence of licorice root rot under continuous cropping condition.The results showed that F.oxysporum and F.solani had strong pathogenicity to the three kinds of medicinal licorices,and could cause typical symptoms of root rot disease.In the concentration range of 0.005-0.020 g·mL^(-1),the aqueous extracts of G.glabra and G.uralensis leaves significantly promoted the growth and reproduction of the two pathogens,which significantly increased the colony diameter and spore amount of F.oxysporum by 14.06%,10.58%,24.50%and 48.39%,and significantly increased the colony diameter and spore amount of F.solani by 8.79%,12.25%,17.11%and 25.13%,respectively.The aqueous extract of G.inflata leaves showed the characteristics of low promotion and high inhibition on the mycelial growth and spore production of the two pathogens,and its maximum increased the colony diameter and spore volume of F.oxysporum by 3.63%and 14.86%,which significantly increased the colony diameter and spore volume of F.solani by 6.54%and 16.58%.The order of the influence rate of the aqueous extracts of three kinds of medicinal licorice leaves on the growth and reproduction of two kinds of pathogens was G.uralensis>G.glabra>G.inflata.In conclusion,the large accumulation of leaves of three kinds of medicinal licoriceas litter in the farmland may be the main reasons for the frequent occurrence of root rot of licorice under continuous cropping condition.It is suggested that the licorice leaves should be harvested and removed annually before they turn into yellow and fall off.