Growth And Secondary Metabolite Expression Of Taxus Chinensis In Suspension Cultures In Magnetic Fields

The effects of magnetic field on the growth and secondary metabolism of Taxuschinensis var. mairei in suspension cultures were investigated. The detail studies weredone from the aspects as follows. The natural cells were exposed to two magnetic fields (MF), sinusoidalalternating current magnetic field (ACMF, 50 Hz, 3.5 mT) and direct currentmagnetic field (DCMF, 3.5 mT). The results show the two MFs are both beneficial tothe cell growth and the intensity of bioeffects the DCMF was much stronger than thatof the ACMF. The variations of the cell viability in the two MFs compared to thecontrol are correlated as quadratic relations. The cell biomass and intracellular proteinwere all enhanced by the MFs. Both MFs enhanced taxol production, but themechanism is different. The enhancement of taxol production in ACMF is ascribed tothe increase of the cell biomass, while the abrupt rise of taxol production in the latephase of cell growth in DCMF might indicate an activation of the defense reaction. HCl of different concentration was added to the medium in order to study theinfluences of the physiologic state on the bioeffects of the DCMF. The results showthat the cells in the late growth phase have better endurance to the hurt of the MF. Theobvious change of the medium pH and conductivity indicated that the ion transportunder the intimidation of HCl was easier to be affected by the DCMF. The higher theconcentration of HCl was, the stronger the bioeffects of the magnetic field were. The cooperation of the DCMF and salicylic acid (SA) brought the secondarymetabolism forward. The taxol yields were 3.4 fold (SA) and 1.2 fold (control)respectively in the 2 th days. The maximum of taxol (MF+SA) occurred in the 6 thday, which was 2 days ahead of that of the SA treated cells. But the value was only0.75 fold of that of SA treated ones. We ascribe the enhancement of the cell growth induced by DCMF to the increaseof the cell energy and the promotion of the ion transport brought by the magneticfield. The inhibition of the POD relative activity might account for the enhancementof the malondialdehyde (MDA) and the peroxidation of the cell membrane.