宿主和培养基质对根内根生囊霉菌剂扩繁的影响及菌根化魔芋栽培

Effects of host and cultivating substrates on propagation of Rhizophagus irregularis and cultivation of Amorphophallus konjac with mycorrhization

【目的】研究不同宿主和培养基质对丛枝菌根真菌(arbuscular mycorrhizal fungi,AMF)根内根生囊霉(Rhizophagus irregularis)菌剂扩繁的影响,以及扩繁菌剂对正茬和重茬魔芋生长的影响,为利用AMF缓解魔芋连作障碍,实现绿色栽培提供科学依据。【方法】在室内盆栽条件下,研究不同宿主植物(玉米、魔芋)和培养基质(纯沙、纯土和沙土混合)对根内根生囊霉的侵染程度、菌丝密度、产孢量及宿主地上部干质量和地下根系干质量的影响。利用扩繁的根内根生囊霉菌剂进行正茬和重茬盆栽魔芋菌根化栽培,以不接种AMF为对照,研究不同处理对魔芋产量、植株含磷量和魔芋软腐病发病率的影响。【结果】(1)根内根生囊霉以魔芋为宿主植物在纯土基质中的扩繁效果最佳,魔芋的菌根侵染强度、产孢量和菌丝密度分别为86.17%,76个/cm^(3)和0.93 m/g,同时魔芋的地上部干质量和地下根系干质量也高于其他处理。(2)在盆栽条件下,接种根内根生囊霉菌剂的正茬和重茬魔芋软腐病相对防效分别为100.0%和77.9%。正茬菌根化的魔芋单株块茎鲜质量、单株根系数、茎和叶中磷含量分别较正茬对照显著增加18.2%,18.4%,7.5%和6.3%(P<0.05);重茬菌根化的魔芋单株块茎鲜质量、单株根系数、根和茎中磷含量分别较重茬对照显著增加19.0%,20.9%,3.7%和17.6%(P<0.05)。【结论】在本试验条件下,根内根生囊霉扩繁的最适宿主是魔芋,最适基质是纯土。接种自繁的根内根生囊霉菌剂可以增强正茬和重茬魔芋软腐病的防治效果,促进魔芋生长,改善植株磷营养。

【Objective】This study investigated the effects of different host plants and cultivating substrates on propagation of arbuscular mycorrhizal fungus Rhizophagus irregularis and the effects of propagated agent on growth of first and repeated konjac(Amorphophallus konjac)to provide basis for alleviating continuous cropping obstacle of konjac and exploring green cultivation by arbuscular mycorrhizal fungi(AMF).【Method】A pot experiment was conducted to study the effects of different host plants(maize and konjac)and cultivating substrates(pure sand,pure soil,and sandy soil)on mycorrhizal infection level,mycellial density,Rhizophagus irregularis sporulation,as well as dry mass of aboveground and underground roots of konjac in greenhouse condition.The effects of different treatments on yield,phosphorus content and incidence of konjac soft rot disease were studied by mycorrhizal cultivation of first and repeated konjac with self-reproduced microbial inoculum.【Result】(1)The propagation of R.irregularis with konjac as host plant in soil substrate had the best mycorrhizal response,with mycorrhizal infection intensity of 86.17%,sporulation of 76 per cm^(3),and mycelial density of 0.93 m/g,respectively.The dry masses of aboveground and underground roots of konjac were also higher than those of other treatments.(2)Under greenhouse pot conditions,the relative efficacy of soft rot disease of konjac inoculated with R.irregularis was 100.0%and 77.9%in the first and repeated cropping,respectively.Compared with the control,fresh mass of tuber,number of roots per plant,phosphorus contents in stem and leaf of mycorrhizal konjac in the first cropping were significantly increased by 18.2%,18.4%,7.5%,and 6.3%(P<0.05),respectively.Inoculation with R.irregularis increased fresh mass of tuber,number of roots per plant,as well as phosphorus contents in root and stem of repeated konjac by 19.0%,20.9%,3.7%,and 17.6%(P<0.05),respectively.【Conclusion】Under the condition of this study,the combination of konjac and pure soil was optimal for propagation of R.irregularis.Inoculation with self-reproduced inoculum R.irregularis decreased the incidence of soft rot disease,promoted plant growth,and enhanced phosphorus nutrition of konjac in the first and repeated cropping soils.