3.4 Effect of NH4+ to NO3- ratio on hairy root growth
Different ratios of NH4+ to NO3- in MS medium were used for supplying the nitrogen requirement of the hairy roots. Figure 4 shows the effect of different nitrogen forms ratios on hairy root growth of V. officinalis. MS media supplemented with a 20:20 mM and 20:40 mM ratio of NH4+ to NO3- produced the maximum biomass after 21 days, 1.80 and 1.62 g l-1, respectively. MS medium with a 20:20 ratio of NH4+ to NO3- slightly had greater influence on the growth of hairy roots than basal MS medium (20:40 mM), but this difference was not statistically significant.