3.3. Rooting and acclimatization
Table 3 shows the effect of auxin types and concentrations on in vitro
root production under constant light. No root production was observed
in the control (without any auxin)whereas all the auxin concentrations
evaluated gave root production. In the treatments with NAA, the number
of roots produced increased with an increase in concentration,
reaching the optimum at 2.0 μM. Root length appeared to decrease
(though not significantly) with an increase in NAA concentration. Both
callus and offshoot production was observed at all NAA concentrations,
although the frequency of offshoot production appeared to decrease
with an increase in NAA concentration.On the other hand, no callus production
was observed in all IBA treatments. All the IBA concentrations
tested produced roots and offshoots. Root length increased significantly
in all IBA treatmentswhen compared to NAA treatments. The frequency
of root production in IBA treatments was generally higher than what
was observed in treatmentswith NAA at equimolar level. Callus production
observed at the base of the stems in treatments with NAA makes
the shoots undesirable for acclimatization despite the presence of
roots. Therefore, considering the root length (perhaps indicating the
functionality of the produced roots), frequency of root and offshoot production
and even the number of offshoots produced, the choice of IBA
would be a reasonable option for in vitro rooting of C. albumregenerated
shoots. Superior activity of IBA for root production has been reported in
Rutaceae species such as R. graveolens (Ahmad et al., 2010) and Naringi
crenulata (Singh et al., 2011).