In combination of BAP and NAA, callus induction was found to increase with an increase of
the concentration of NAA from 0.1 ppm to 1.0 ppm but the role of BAP was observed to be of very
little or no significance. In general, almost all the concentrations of BAP and NAA in combination
initiated callus. In bud formation, the trend was just opposite to callus induction i.e. an
increase in BAP concentration showed increase in the number of buds per explant until the NAA
concentration was limited up to 0.1 and 0.5 ppm (Fig. 10 and 12) but as the concentration of NAA
was increased to 1.0 ppm and above the bud formation drastically dropped to almost zero. The callus
cultures at these concentrations of NAA gave multiple shoots, buds, abnormal buds and leafy
shoots with 0.1, 0.5, 1.0 and
2.0 ppm of BAP respectively. The multiple shoots were induced mainly at lower concentration
combinations of both the hormones (Fig. 9 and 11). When the concentration of NAA was increased to
1.0 ppm., at lower concentrations of BAP both shoot explants and callus cultures gave few shoots
and roots (Fig. 13) but as the BAP concentration was increased gradually, callus induction and a
few multiple shoots were observed Fig. 14). Here, root induction was completely blocked
although NAA concentration was favorable. Detailed responses of different hormones at different
levels are given in Graphs 1-4.
Root induction was favored by all the concentrations of NAA either singly or in combinations. In
our experiment, other auxins like IAA and IBA did not show any kind of rooting or other remarkable
response both in vitro and in vivo rooting of the micro shoots whereas NAA was effective only
in in vitro condition (Fig. 16). The in vitro rooted micro shoots survived, grew and branched in
the plastic shade house for about 3 months and they gradually died in the winter. The final
survival percentage of both in vitro and in vivo rooted shoots in nature was 60 and 20 respectively
(Fig 17).