Putrescine Influences Growth and Production of Coumarins in Hairy Root Cultures of Witloof Chicory (Cichorium intybus L. cv. Lucknow Local)

The effect of putrescine (Put) on the growth
and production of two coumarins, esculin and esculetin,
in hairy roots of chicory (Cichorium intybus L. cv. Lucknow
local) was examined. To study the role of Put on
growth and production of coumarins, polyamine inhibitors,
namely a-DL-difluromethylornithine and a-DLdifluromethylarginine were used at 1 mM concentration.
Put treatment at 1.5 mM produced a 1.9-fold increase in
the growth of hairy roots, as well as the production of
esculin and esculetin. The treatments with polyamine
(PA) inhibitors resulted in much lower growth and production of coumarins compared with both 1.5-mM Put
treatment and the control. Both free and conjugated PAs
were studied over the whole culture period, and conjugates
of all three PAs, namely Put, spermidine, and spermine,
were higher than free PAs throughout the culture
period. The treatments with PA inhibitors showed lower
levels of endogenous PAs compared with Put-treated
samples. The treatment with 1.5 mM Put showed maximum
accumulation of endogenous conjugated Put (2,098
± 157 nmoles gm-1 fresh weight). The production of
esculin and esculetin was strictly correlated with growth
in all treatments. Put at 1.5 mM resulted in greater length
of primary root (18.3 ± 1.4 cm) as compared with the
control (11 ± 0.9 cm) and larger numbers of secondary
and tertiary roots.