Study On Regulations And Metabolic Mechanism For Inducing Taxol And Taxanes Increment In Taxus Chinensis Var. Mairei

A series of regulation approaches were applied to increase taxol content in plant materials of Taxus chinensis var.mairei,and the metabolic mechanisms for inducing taxol increment were also discussed.1,The method for synchronous determination of taxol and taxanes in Taxus chinensis var. mairei materials was established,including detecting conditions of 10-deacetylbaccatin,7-epi-10 -deacetyltaxol,7-xylosyl-10-deacetyltaxol,10-deacetyltaxol and cephalomannine.The chromatographic column was Curosil-PFP 5μ(4.6mm×250mm);the mobile phase was composed of mobile phase A(acetonitrile:water= 25:75,V:V,from 0 to 17minutes) and mobile phase B(acetonitrile:water= 37:63,V:V,from 17 to 90minutes);flow rate was 1 ml/min and detecting wavelength was 227nm.The results indicated that this method was precise,steady and exact,which was applicable for determination of taxol and taxanes in Taxus plant materials2,Different phytohormone were used for treatments on Taxus cuttings in order to increase taxol content,and their metabolic mechanisms for inducing taxol increment were also discussed.The results indicated that NAA,IBA and ABT had different functions and metabolic mechanisms for inducing taxol increments.After IBA treatments,taxol contents were decreased,which may because of IBA inhibited action for 10-deacetylbaccatin and 7-xylosyl -10-deacetyltaxol biosynthesis;NAA maybe promote biotransformation of 7-epi-10-deacetyltaxol and 7-xylosyl-10-deacetyltaxol into 10-deacetylbaccatin and taxol,so taxol content was increased after NAA treatments;taxol contents were increased after ABT treatments by promoting 10-deacetylbaccatin biosynthesis.3,5mg/L,10mg/L and 20mg/L gibberellin were used for treatments on Taxus in order to increase taxol content,the metabolic mechanisms for inducing taxol increment were also discussed.The results indicated that 10mg/L gibberellin had the best effect on taxol increment on Taxus cuttings,which maybe because low concentration of gibberellin can promote 10-deacetylbaccatin bio-transforming into 7-epi-10-deacetyltaxol,7-xylosyl-10-deacetyltaxol and taxol,but high concentration of gibberellin can induce the biotransformation of cephalomannine,7-epi-10-deacetyltaxol and 10-deacetylbaccatin into 7-xylosyl-10-deacetyltaxol but not taxol.4,100mg/L,300mg/L and 600mg/L salicylic acid were used for treatments on Taxus, and the metabolic mechanisms for inducing taxol increment were also discussed.The results indicated that different concentrations of salicylic acid had various effects on inducing taxol increments.Salicylic acid maybe promote taxol biosynthesis only in a certain concentration range(0～300mg/L),and 300mg/L salicylic acid had induced the most increment of taxol. 5,Special light environments have been constructed for regulating Taxus chinensis var. mairei growth,development and taxol biosynthesis.Either strong light intensity stress or overhead shading didn't benefit of Taxus chinensis var.mairei growth and development.And the best linght environment for Taxus chinensis var.mairei growth and development were in shade at morning and afternoon,in sunshine at noon.The taxol content in Taxus chinensis var. mairei was increased following the enhancement of light intensity.The relationships of taxol contents and light factors were also investigated.It was shown that taxol contents of Taxus seedlings were increased following light intensity enhancement;the contents of 10-deacetylbaccatin, 10-deacetyltaxol and cephalomannine were increased with the enhancement of total light intensity and individual spectrum intensity,but 7-epi-10-deacetyltaxol was decreased.Secondly,the biosynthesis of taxol,10-deacetyltaxol,Cephalomannine and 7-epi-10 -deacetyltaxol in taxus seedlings were mainly regulated by noon light intensity,but the biosynthesis of lO-deacetylbaccatin was also regulated by light intensity of other time.So the best environment for Taxus chinensis var.mairei planting was terrace mode,which can provide conditions of shade at morning and afternoon,sunshine at noon in order to gain the most biomass and taxol content of Taxus chinensis var.mairei.