| Cyclocarya paliurus is an endemic woody medicinal plant in China,which contains a large number of secondary metabolites such as flavonoids and triterpenes,which has important health value.However,the application of fertilizer(especially nitrogen fertilizer)during the artificial cultivation of Cyclocarya paliurus promoted the growth and increased the accumulation of leaf biomass,but it also greatly reduced the content of secondary metabolites and affected the quality of raw materials.Arbuscular mycorrhizal(AM)is a widely associated with plant roots,which promotes plant growth and provides synthesis and accumulation of secondary metabolites to a certain extent.In order to reduce the use of chemical fertilizer and balance the contradiction between yield and quality of the medicinal plantation of Cyclocarya paliurus,this study used inoculation of arbuscular mycorrhizal fungi to improve the growth of medicinal plants and increase the yield of secondary metabolites.The inoculation experiments were carried out on the inoculated soil under the natural forest of Cyclocarya paliurus to study the effects of AM fungi on the growth characteristics,biomass accumulation,plant tissue C and N contents,mineral nutrient absorption,secondary metabolite content and yield of Cyclocarya paliurus.The results are as follows:(1)The seedling height and ground diameter growth of Cyclocarya paliurus seedlings were significantly higher than those of the control group after mycorrhiza inoculation(P ＜ 0.05).The total growth of seedling height in the experimental group from August to October was significantly higher than that in the control group.And the total growth of ground diameter was similar to that of seedling height,but the significant difference was not reached until September.The net growth of seedling height and ground diameter in experimental group was significantly higher than that in control group,and the net growth of seedling height was approximately to 8-9 > 9-10 > 7-8 > 4-7.The trend of net growth of ground diameter in experimental group was consistent with that of seedling height,while the net growth of the control group in 8-9 was lower than that in 9-10.(2)The contents of N(27.87 mg/g),K(7.48 mg/g),Ca(26.63 mg/g),Mg(2.82 mg/g)in leaves of Cyclocarya paliurus in experimental groups were higher than those in control group after mycorrhizal inoculation,and the N content was significantly higher than that in control group(P ＜ 0.05).The contents of P(1.51 mg/g)and Mg(2.86 mg/g)were the highest in roots of Cyclocarya paliurus in experimental groups.After mycorrhizal inoculation,N content in stem and leaf,K content in root and stem,Ca content in stem and Mg content in stem in experimental groups were significantly higher than those in control group(P ＜ 0.05),so the mycorrhizal fungi can promote the absorption of mineral nutrients in Cyclocarya paliurus seedlings.(3)The contents of quinic acid,total flavonoids,quinic acid,quercetin and kaempferol were not significantly different after mycorrhizal inoculation,but the content of quercetin in the root of Cyclocarya paliurus in experimental groups was significantly lower than that in control group(P ＜ 0.05).These indicating that the accumulation of quercetin was inhibited by mycorrhizal fungi inoculation.The total triterpenes in stem,Pterocaryoside B,Pterocaryoside A and Oleanolic acid in leaves of Cyclocarya paliurus were significantly different after after mycorrhizal inoculation(P ＜ 0.05).The contents of total triterpenoids in stem and leaves(Pterocaryoside B,Pterocaryoside A and olenolic acid)in experimental groups were significantly higher than those in control group(P ＜ 0.05),and the corresponding contents were 3.74 mg/g,0.26 mg/g,0.09 mg/g and 0.05 mg/g,respectively.The effect of mycorrhizal fungi on the content of triterpenes was greater than that on the content of flavonoids.(4)The yields of quinic acid(0.87 mg/g),quercetin(0.32 mg/g)and kaempferol(0.65 mg/g)in leaves of Cyclocarya paliurus were higher than those in the control group after mycorrhizal inoculation,but there was no significant difference between the two groups.The yields of quinic acid,quercetin and kaempferol in the stem of Cyclocarya paliurus were significantly higher than those in the control group(P ＜ 0.05).The yield of triterpenoids(Pterocaryosideb,Pterocaryoside A,olenolic acid)in leaves of Cyclocarya paliurus in experimental group was significantly higher than that in control group after mycorrhizal inoculation(P ＜ 0.05).However,the yield of argyranic acid in leaves only0.11 mg/g where was detected in the experimental group.There was no significant difference in the yield of cycaloylic acid B between the two groups.Inoculation of mycorrhizal fungi could significantly promote the yield of flavonoids and triterpenoids in the corresponding parts of Cyclocarya paliurus.(5)Kaempferol in the root of Cyclocarya paliurus in the test group was significantly positively correlated with C/N,so as quinic acid in the leaves correlated with C content after mycorrhizal inoculation(P ＜ 0.05).There was no significant correlation between flavonoids and N content in various parts of Cyclocarya paliurus and no significant correlation between triterpenes and C,N,C/N in experimental group,while there was a significant negative correlation between Pterocaryoside A and C content in leaves of Cyclocarya paliurus in control group(P ＜ 0.05).(6)Kaempferol in leaves of Cyclocarya paliurus in experimental groups was positively correlated with K content after mycorrhizal inoculation(P ＜ 0.05).There was a significant positive correlation between quercetin and K content in the stem of Cyclocarya paliurus in experimental groups(P ＜ 0.05),and there was a negative correlation between kaempferol and Mg content in the same part.The contents of P,K,Ca,Mg were positively correlated with the total flavonoids and quinic acid in the roots of Cyclocarya paliurus in experimental groups,but this were not significant.The oleanolic acid content in the stem and root of Cyclocarya paliurus in experimental groups was significantly positively correlated with P and Ca content after mycorrhizal inoculation(P ＜ 0.05). |
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