Studies On Kinetics Of SOD Production By Garlic Cell Cultivation

Induction of garlic callus and selection of highly producing SOD garlic suspension cell line were studied. When the explant size with epidermis was 0.5cm×0.3cm× 0.2cm, more loose callus could be induced from the Guangzhou white peel garlic in the medium of MS+ 3.0mg/L 2,4-D + 1.2mg/L 6-BA under condition of 600 lux 12 hours circular illumination. The maximum biomass was 22.12 g.DW/L while the maximum total SOD activity was 10.81×10⁴U/L by selected garlic cell line suspension after 18 days' culture.The effects of major nutrients on garlic cell growth and Superoxide dismutase (SOD) production were discussed. Sucrose was better for cell growth and SOD production among different carbon sources. In the range of 10⁶0 g/L sucrose concentration, highest biomass and SOD production were achieved on 30 g/L. Standard nitrogen concentration in MS medium was enough for garlic cell growth and SOD production. Mineral nitrate source and urea were suitable for cell growth. Phosphate was necessary for cell growth and SOD production. Different initial phosphate concentration had remarkable effect on SOD production. The standard phosphate concentration appeared more suitable for cell growth and SOD production.The suspension culture process of garlic cell could be divided into three phases: lag phase, rapid growth phase, stationary phase. Sucrose was growth limiting nutrient on low concentration condition. Increase of sucrose concentration stimulated cell growth, extended rapid growth phase and increased the final cell harvest. Substrate inhibition was observed when the concentration was above 30 g/L. The influence of different NH₄⁺ to NO₃^- ratio on cell growth was mainly reflected by the inhibition of high ammonium. Phosphate was also the growth limiting nutrient on low concentration condition. Increase of phosphate concentration increased cell growth rate and shortened the culture period. Under the standard culture condition, the specific cell growth rate was 0.22 0.26 day^-1, and the doubling time was 2.7³.2 days.The trends of SOD production variation under different initial sucrose concentration were the same. Increase of sucrose concentration could also improve SOD production to some extent, while higher sucrose concentration inhibited SOD production. SOD production was the lowest when used ammonium as only nitrate source. The maximum total SOD activity could be achieved while the ratio of NH₄⁺ to NO₃^- was 20...