View/Open - ResearchSpace - University of KwaZulu-Natal

In vitro corm formation and flowering and ex vitro acclimatization
Table 6.2: Percentage corm induction for Romulea minutiflora shoots cultured on medium
supplemented with growth retardants.
Treatment Basal swelling
(%)
Corm induction
(%)
Corms > 5 mm
(%)
Control 70% 0% 0%
3.4 M PP3 55% 15% 10%
17.0 M PP3 50% 35% 20%
34.0 M PP3 35% 35% 20%
4.9 M ABA 45% 20% 5%
No corm formation was observed for any of the temperature and medium treatments
tested for R. leipoldtii. When 100 bottles of shoots multiplied on media supplemented
with BA placed at 25°C were not subcultured for 6 months no corm formation or
basal thickening was observed. This was not the case with the shoot cultures placed
at 25°C multiplied with media supplemented with kinetin and topolins. Here corms or
basal thickening was observed for all shoots not multiplied after 6 months.
Such basal thickening was observed to a certain extent for non-subcultured shoot
cultures of R. minutiflora and R. sabulosa, but no corm formation was observed in
any cultures placed at 25°C for these species.
The percentage corm induction for R. sabulosa after 6 months was significantly
higher at 10 and 20 °C with all tested sucrose concentrations compared to 15 °C
(Table 6.3). Corm induction was inhibited at 25 °C in this experiment (data not
shown). The largest corm mass was recorded for shoots placed at 15 °C on a MS
medium supplemented with 6% sucrose (Table 6.3). The mass of these corms were
however not significantly different from the mass of the corms obtained for cultures
placed at the same temperature on a medium with 9% sucrose or the mass of corms
produced on a medium with activated charcoal and the mass of corms at 20 °C
placed on a medium with 6% sucrose. Product analysis shows that corms at 15 °C
with 6% sucrose achieved the highest value (Table 6.3).
143