Manchanda et al.
These media were fortified with 3.0% sucrose and
This might be due to the fact that when ethylene is
0.8% agar. A single explant was inoculated per test
produced through cell division during establishment
tube (Figure 1A) and the cultures were incubated
phase of leaf roll segments under in vitro conditions,
at 25 ± 2°C in an air-conditioned incubation room
Ag + ions are produced in the medium and an ethylene
with 16:8 hours light: dark photoperiod regime.
receptor, ETR1, contains one ethylene-binding site
For rooting, 5-7 cm long shoots were cultured on
per homodimer which is further mediated by a single
MS medium + NAA (3.0 mgl -1 ) + Indole-3-butyric
copper ion (Cu + ) present in the ethylene-binding site.
acid (IBA; 2.0 mgl -1 ) + sucrose (7%). The pH of the
The replacement of the copper co-factor by silver
medium was set at 5.8 prior to autoclaving at 121°C
for 20 min.
In order to investigate its effect, ethylene production
was inhibited in the culture bottles using ethylene
inhibitors i.e. AgNO 3 . A stock solution of silver
nitrate was prepared, autoclaved and poured
into the autoclaved medium at their respective
concentrations. Data was analysed using the CPCS-1
software (Cheema and Singh 1990). Fifteen leaf roll
segments (three replicates for each concentration)
were used for the present study.
Figure 2. Per cent leaf roll segments responding with an
Results and Discussion
increase in concentration of ethylene inhibitor (AgNO3; mgl-1)
in the medium in two cultivars of sugarcane i.e. CoJ 83 and
The aim of this work was to study the influence of the
CoH 119
ethylene inhibitor, AgNO 3 on shoot organogenesis
and regeneration in sugarcane. For tissue culture
also serves to lock the receptor into a conformation
studies of sugarcane, leaf roll segments served
such that it continuously represses ethylene
as a good source of explants (Figure 1A). After
responses (Zhao et al. 2002). Further, perusal of data
placing the leaf roll segments of sugarcane on shoot
from Table 1 shows that average number of shoots
organogenesis medium, unwhorling occurred and
increased to 7 and 6.25 in case of CoJ 83 and CoH
the segments showed direct shoot regeneration
119, respectively, which were significantly different
[Figure 1 (B,C)] within 14-15 days of culturing. Both
from control as well as significant difference was
the cultivars exhibited extreme variation in response
observed between varieties. Similar observations
were made for shoot length which was significantly
to ethylene inhibitor, silver nitrate (AgNO 3 ) with
respect to the percentage of responding leaf roll
higher in CoJ 83 in medium supplemented with
segments, number of shoots formed per leaf roll
3 mgl -1 of AgNO 3 as compared to control and higher
segment, shoot length, number of roots and root
in COH 119 in medium supplemented with 5
length. The perusal of the data from Figure 2 showed
mgl -1 of AgNO 3 . Fei et al. (2000) observed that
that the percentage of responding explants increased
addition of the ethylene antagonist, silver nitrate
to 82.3% (6.3% increase from control) in CoJ 83 variety
(AgNO 3 ), into callus induction medium significantly
enhanced embryogenic callus production (both
on medium [MS+ NAA (5 mgl -1 ) + Kin (0.5 mgl -
1 ) + 3.0% sucrose + 0.8% agar] supplemented with
induction frequency and callus growth) of field-
collected male immature inflorescence cultures of
3 mgl -1 of AgNO 3 and in case of CoH 119, increased
buffalograss NE84-45-3 and ‘Texoka’.
to 79.16% (9.86% increase from control) on medium
[MS+ NAA (5.5 mgl -1 ) + Kin (0.5 mgl -1 ) +3.0% sucrose
Earlier, silver nitrate has been known to influence
+ 0.8% agar] supplemented with 5 mgl -1 of AgNO 3 .
in vitro shoot multiplication and root formation in
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