丛枝菌根真菌对接种尖孢镰刀菌后黄瓜 根系次生代谢物的影响

采用灌根法对4周龄的黄瓜幼苗接种尖孢镰刀菌Fusarium oxysporum f.sp.cucumerinum,研究了不同取样时期AM真菌Glomus versiforme对植株根系黄酮和总酚含量及叶片中POD和PPO酶活性的影响.结果表明:菌根化植株可通过生物量的补偿和体内次生代谢物含量的改变来提高抗病性.即接种F.oxysporum f. sp. cucumerinum的第9天,菌根化植株根系和地上部生物量分别比对照高出50%和31.7%,此时,对照发病率达15%,而菌根化植株生长始终正常;在病原菌的侵入初期和后期,菌根化植株根系中黄酮和总酚含量高于对照;在植株发病期,菌根化植株仍可通过根系中含量相对较低的黄酮和总酚来抵御病原菌的侵害;与对照相比,抗病性较强的菌根化植株叶片中POD酶活性变化较为缓和,且PPO酶活性一直较高.

Effects of arbuscular mycorrhizal fungus, Glomus versiforme, on secondary metabolites in cucumber roots infected with F.oxysporum f. sp. cucumerinum

Cucumber seedlings were infected with Fusarium oxysporum f.sp.cucumerinum (the density of spores was 10~4 cfu/mL),after 4 weeks growth.The effects of Glmous versiforme on the flavone and total phenol concentration in the roots and POD and PPO activity in the leaves were investigated.The results indicated that resistance of mycorrhizal plants to wilt can be improved by compensating biomass and chan- ging in secondary metabolites.On the 9th day,compared with control,biomass of roots and shoots in- creased by 50% and 31.7% respectively in mycorrhizal plants inoculated with G.v.,for control the dis- ease incidence had reached 15%;mycorrhizal plants were healthy during all the sampling times.On the early and later stages of pathogen invasion,the concentration of flavone and total phenol in roots of my- corrhizal plants were higher than those of control,when the control began to show visible disease symp- toms,the mycorrhizal plants can protect from being further attacked with lower flavone and total phenol concentrations.Compared with control the changes of POD activity were stable in leaves of mycorrhizal plants and PPO activity was higher than that of control.