Influence of polyamines on growth and formation of secondary metabolites in hairy root cultures of Beta vulgaris and Tagetes patula

Growth of hairy roots of Beta vulgaris, which produces betalaines, and of Tagetes patula, which produces thiophenes, was studied under the influence of externally treated polyamines. Of the three polyamines, viz. putrescine, spermidine and spermine, administered singly at 1.5 mM concentration, putrescine and spermidine at 0.75 mM concentration influenced increase in the accumulation of biomass of B. vulgaris and T. patula hairy roots by 1.42 and 1.30 fold over the control. Whereas, the treatment of spermine (1.5 mM) alone resulted in decrease in the biomass in both the systems, Combined administration of putrescine (0.75 mM) and spermidine (0.75 mM) enhanced growth in both B. vulgaris and T, patula than that observed in individual treatments. Polyamines administered alone or in combination did alter production of betalaine and thiophene content. Dose response experiments showed that, when putrescine and spermidine was administered at 0.75 mM concentration, it resulted in maximum biomass and production of betalaine and thiophene in B. vulgaris and T. patula respectively as compared to the control and the media treated with double and triple strength of nitrates and in combination with putrescine and spermidine at equimolar concentration. In B. vulgaris and T. patula hairy root cultures, endogenous spermine titers were maximum in putrescine and spermidine 0.75 mM each treated, cultures, which was 1.63 and 2.0 fold higher than in control on 28(th) and 35(th) days respectively.