Effect Of Elicitor On Callus Growth And Triterpenoid Saponins Synthesis In Ardisia Crenata Sims Callus

Ardisia crenata Sims is an excellent plant resource with many ecological and economic uses,which has both ornamental and medicinal value.It has wide application prospect in the eco-city construction.Triterpenoid saponin,the main active component of Ardisia crenata Sims,contributes to the prevention of cardiovascular disease and cancer.In this study,first of all,the culture system of Ardisia crenata Sims callus was established.Then,to establish the best inducer and combination resulted in Triterpenoid saponins synthesis,we used Ardisia crenata Sims callus as research material and used six kinds of inducers,such as yeast extract,Aspergillus nigergerum,Chitosanum,Methyl jasmonate,lanthanum and Co2+ as research object to screen inducers.Finally,the effect of inducers on callus metabolism of Ardisia crenata Sims was analysed and the mechanism of inducible regulating Triterpenoid saponins synthesis was explored.The results of this study not only provide scientific basis and technical support for the industrial production of Triterpenoid saponins,but also have great theoretical and practical significance for the conservation of Ardisia crenata Sims and the protection of ecological environment.The main results are as follows:(1)When the stem of Ardisia crenata Sims aseptic seedling was used as explant,the induction rate of callus was the highest and the biomass of callus proliferation was significantly higher than that of root and leaf.But Triterpenoid saponins content was lower than that of callus with roots as explants.Therefore,using stem as explant was beneficial to the growth of callus and using root as explant was beneficial to the synthesis of Triterpenoid saponins synthesis.The callus induction from stem was considered as the optimal treatment.(2)Three biological inducers(YE,Aspergillus nigergerum,Chitosanum)had different physiological effects on callus growth.Aspergillus nigergerum significantly promoted growth and Chitosanum inhibited the growth of callus.However,the three biological elicitors showed significantly stimulative effects on Triterpenoid saponinssynthesis,of which Aspergillus nigergerum was the most able to promote Triterpenoid saponins synthesis in the callus of Ardisia crenata Sims.By screening concentration of Aspergillus nigergerum,it was found that Aspergillus nigergerum at different concentrations can increase the content of Triterpenoid saponins in callus,and the optimum concentration was 50 mg/L.But the optimum concentration of callus growth was 100 mg/L.Therefore,Triterpenoid saponins synthesis was most favorable for Aspergillus nigergerum 100 mg/L.(3)Three kinds of abiotic elicitor(MeJA?La?Co2+)were beneficial to the growth of callus and Triterpenoid saponins synthesis in Ardisia crenata Sims,of which La was the most able to promote Triterpenoid saponins synthesis in the callus of Ardisia crenata Sims.By screening concentration of La,it was found that La at different concentrations was beneficial to the growth of callus and Triterpenoid saponins synthesis.And the optimal induction concentration was 30?mol/L.(4)By orthogonal experiment on combination of different concentrations of La and Aspergillus nigergerum,it was found that each combination has a certain effect on the Triterpenoid saponins synthesis.Among them,100mg/L Aspergillus nigergerum+ 30?mol/L La had the best stimulated effect,which was higher than that of 100mg/L Aspergillus nigergerum and 30?mol/L La alone.(5)La,Aspergillus nigergerum and combinations of Aspergillus nigergerum and La can significantly activate the antioxidant defense system and Triterpenoid saponins synthesis pathway of Ardisia crenata Sims callus.However,the induction effect was different and the induction effect of combination was better than that of two elicitors alone.The activities of superoxide dismutase(SOD),peroxidase(POD),catalase(CAT),?-vanillin synthase(?-AS)and accumulation of Triterpenoid saponinswere better increased by the synergism of the two elicitors.Aspergillus Niger,La as an exogenous inducer,were transfered into cells by signal and stimulated the oxidative stress defense system of Ardisia crenata Sims callus rapidly.The synthesis pathway of Triterpenoid saponins was activated,which promoted the accumulation of Triterpenoid saponins.