Optimization Of Culture Condition And Saponin Metabolism Of Psammosilenet Unicoides Callus

In this research,young shoots of Psammosilenet unicoides was taken as sample for theinduction and proliferation of callus,and meanwhile, the changes in saponin content in calluswith culture time under various conditions were detected. The results are as follows.1. Effects of growth regulators on callus induction and proliferation were investigatedthrough combinations of2,4-D、6-BA、NAA and KT in the levels of simple and multi-factorwith the method of orthogonal design. The results of statistic analysis indicated that theprescription of2,4-D0.5mg.L^-1was the optimal hormone concentration for callus induction，and6-BA0.5mg.L^-1+2,4-D0.5mg.L^-1for callus growth, and2,4-D1.5mg.L^-1+6-BA1.5mg.L^-1+NAA1.5mg.L^-1for saponin accumulation with basic medium MS.2. Optimization of culture components were conducted on the base of above-stated results.Firstly, MS was proved to be the best for callus growth and saponin accumulation, and theother parameters were4%sucrose, KNO3:NH4NO3(1.9:1.65, total was60mmol.L^-1),1mmol.L^-1KH2PO4and4.5mmol.L^-1CaCl2, respectively.3. In this case, we next studied the effects of light, pH, temperature and quantity ofinoculum on callus growth and saponin accumulation, and the results showed that8h d^-1oflumination, pH5.8,24℃and3～4g/bottle of inoculum quantity were the best.4. We also tested the effects of some elicitors including oxalic acid, H₂O₂and salicylicacid on callus growth and saponin accumulation of Psammosilenet unicoides. It showed thatthe best culture conditions were adding10-3mmol.L^-1oxalic acid at15d and10-4mmol.L^-1H₂O₂at1d into medium after inoculation respectively.In addition,the concentration ofsalicylic acid between10-3and1mmol.L^-1was not suitable for callus cuture. The enzymeactivity of phenylalanine, polyphenol oxidase and peroxidase become to the peak value afteradding oxalic acid at48h,60h and36h,respectively17.6%,8.74%and49.04%higher thancontrol group.