The optimal type and concentration of elicitors were determined
based on their effect on productivity. Addition of elicitors
on day 21 of the root cultures, which corresponded to the late linear
or early stationary growth phase. There was almost no significantly
difference in growth patterns between the control and all
the treatment groups. This may be due to the fact that treatment
with elicitors was during the early stationary growth phase. Measurement
of production of NQs in the untreated root cultures revealed
that (1) and (3) were the major NQs (0.79 mg/g DW and
0.15 mg/g DW), while (2) was a minor product (0.03 mg/g DW).
Different elicitor types and concentrations exerted different effects
on NQ production by the root cultures. The effect of all elicitors
was positive and dose dependent on the production of NQs
(Fig. 2). However, the specificities and optimum concentrations
of the elicitors were different. Treatment with YE, CAH and TRH resulted
in only slight, but statistically significantly, increased production
of (1) and (2) (Fig. 2a and b).