| Continuous cropping obstacle problem seriously affects the yield and quality of Panax notoginseng,and restricts its cultivation and development.The studies mostly focused on the effects of fresh roots or rhizosphere soil extracts of Panax notoginseng on its seed germination and seedling morphological index.The research about impact of allelochemicals on its physiological indexes and rotation crop choice were less.As a result,this article studied the effects of ferulic acid,p-coumaric acid,syringic acid,p-hydroxybenzoic acid,vanillic acid,PNS,ginsenosides Rg1 and notoginsenoside R1 at different concentrations on the morphological and physiology index of Panax notoginseng,wheat,maize and Chinese cabbage seedlings,in order to provide some references for further research of allelopathic autotoxicity of Panax notoginseng,as well as provide some theoretical basis for screening proper rotation crops of Panax notoginseng.The primary results of research are as follows:1.After treated by five phenolic acids,shoot height,main root length,soluble protein content,CAT and POD activity of Panaxnotoginseng seedlings were decreased.Among them,shoot height and POD activity of seedlings were decreased obviously by ferulic acid;and the shoot height of 50,100mg·L-1 p-coumaric acid and 100mg·L-1 vanillic acid were 16.19%,16.67% and 29.29% dramatically lower than that of the control group.The main root length of seedlings were also reduced significantly by p-coumaric acid,syringic acid and p-hydroxybenzoic acid,meanwhile the CAT activity of seedlings were decreased by 10,50,100 mg·L-1 syringic acid,p-hydroxybenzoic acid and vanillic acid.Besides that,the SOD activity of seedlings increased when treated with syringic acid,vanillic acid,p-hydroxybenzoic acid and higher concentrations of p-coumaric acid,moreover vanillic acid increased them significantly.The results suggested that five phenolic acids had some certain allelopathic inhibitory effects on Panax notoginseng seedlings,but the effects were not completely consistent.Among them,ferulic acid had greater influence.2.After dealt with three saponins,shoot height,main root length,soluble protein content,soluble sugar content and CAT activity of Panaxnotoginseng seedlings were decreased.Among them,shoot height and main root length of seedlings were decreased obviously by PNS and ginsenosides Rg1;and the soluble protein content of 0.01,0.10,1.00 mg·L-1 PNS were 28.83%,17.07% and 23.21% dramatically lower than that of the control group.The POD and SOD activity of seedlings were also reduced by PNS,meanwhile SODactivity of seedlings were increased by ginsenosides Rg1 and notoginsenoside R1.The comprehensive sensitive index suggested that three saponins had some certain allelopathic inhibitory effects on Panax notoginseng seedlings,and the effects of PNS were bigger than the others.3.After dealt with five phenolic acids,the soluble sugar content of wheat seedlings was increased.The shoot height and main root length was reduced by ferulic acid,p-coumaric acid and vanillic acid;meanwhile the main root length was increased by p-hydroxybenzoic acid,but they were all not significant.The p-coumaric acid decreased the soluble protein content,CAT,POD and SOD activity of seedlings;and the syringic acid increased their soluble protein content,CAT and POD activity.Besides that,the soluble protein content,CAT and SOD activity of seedlings were also increased when treated with vanillic acid.The results suggested that ferulic acid and p-coumaric acid had some certain allelopathic inhibitory effects on wheat seedlings,while syringic acid,p-hydroxybenzoic acid and vanillic acid had some promoting impact,but their allelopathic index were all not big.4.In the range of 0.01-100 mg/L concentration,PNS increased shoot height,soluble sugar content,CAT and POD activity of wheat seedlings;meanwhile reduced their main root length,soluble protein content and SOD activity,but they were all not significant.Ginsenosides Rg1 increased shoot height and POD activity of seedlings;and decreased their soluble protein content,soluble sugar content and CAT activity.In addition,the impact of ginsenosides Rg1 to the main root length and CAT activity of seedlings showed low concentrations promoted and high concentrations inhibited trend.Besides that,the shoot height,main root length,soluble protein content,soluble sugar content,POD and SOD activity of seedlings were all decreased when treated with notoginsenoside R1,and some reached the significant level.The results suggested that ginsenosides Rg1 and notoginsenoside R1 had some certain allelopathic inhibitory effects on wheat seedlings,but their allelopathic index were all not big.5.After handled by five phenolic acids,the shoot height,main root length,soluble protein content,POD and SOD activity of maize seedlings were all decreased.The CAT activity of seedlings was reduced by ferulic acid,p-coumaric acid,p-hydroxybenzoic acid and vanillic acid,but increased by syringic acid.Besides that,the soluble sugar content of seedlings was also decreased when treated with p-hydroxybenzoic acid,and increased by ferulic acid,p-coumaric acid,syringic acid.The impact of ginsenosides Rg1 to the main root length and CAT activity of seedlings showed low concentrations promoted and high concentrations inhibited trend.The results suggested that five phenolic acids showed allelopathic inhibitory effects on maize seedlings in general,and they were larger than theeffects on wheat seedlings.6.The main root length,soluble protein content,CAT,POD and SOD activity of maize seedlings were all decreased after treated by three saponins.Meanwhile soluble sugar content was increased by PNS,and decreased by ginsenosides Rg1 and notoginsenoside R1,but they were all not significant.Shoot height of seedlings was decreased by PNS;and increased by ginsenosides Rg1.In addition,the impact of notoginsenoside R1 to shoot height of seedlings showed low concentrations promoted and high concentrations inhibited trend.The comprehensive sensitive index showed that three saponins had allelopathic inhibitory effects on maize seedlings,and they were larger than the effects on wheat seedlings,too.7.After treated by five phenolic acids,the shoot height,main root length and SOD activity of Chinese cabbage seedlings were all decreased,and some of them reached the significant level,meanwhile the soluble protein content of seedlings was increased.The CAT activity of seedlings was reduced by ferulic acid,p-coumaric acid,and POD activity of seedlings was decreased by p-coumaric acid.The impact of ferulic acid to POD activity of seedlings showed low concentrations promoted and high concentrations inhibited trend.P-hydroxybenzoic acid and vanillic acid reduced the POD content of seedlings.Besides that,syringic acid increased the soluble sugar content and POD activity,and showed low concentrations promoted and high concentrations inhibited trend to CAT activity of seedlings.The comprehensive sensitive index suggested that five phenolic acids all showed allelopathic inhibitory effects on Chinese cabbage seedlings,and their strength was between in wheat and maize.8.In the range of 0.01-100 mg/L concentration,PNS increased soluble protein content,CAT and SOD activity of Chinese cabbage seedlings;meanwhile reduced their main root length and POD activity,but showed low concentrations promoted and high concentrations inhibited trend to shoot height and soluble sugar content of seedlings.Ginsenosides Rg1 and notoginsenoside R1 all increased soluble protein content,soluble sugar content and CAT activity of seedlings;and decreased their shoot height,main root length,POD and SOD activity.The results showed that three saponins all had some certain allelopathic inhibitory effects on Chinese cabbage seedlings,and the allelopathic strength of ginsenosides Rg1 and notoginsenoside R1 was also between in wheat and maize.As we can see from the above results,these several allelochemicals all had allelopathic inhibition effects on the morphology and physiology indexes of Panax notoginseng seedling in different degrees,and the effects of ferulic acid and PNS were larger relatively.And there was different intensity of allelopathic inhibition impact on wheat,maize,Chinese cabbage.The intensity of allelopathic inhibition from high to low in order was maize,Chinese cabbage,wheat.This provided some certain reference for the choice of rotation crops for Panax notoginseng. |
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