Micropropagation for mass multiplication and enriched production of ascorbic acid in tissue culture foliage of roselle (Hibiscus sabdariffa L.)

An efficient protocol was developed for the
micropropagation of Hibiscus sabdariffa through nodal explants
(auxillary bud cultures) of in vitro seedlings. Nodal
explants were able to induce multiple shoots on Murashige
and Skoog (MS) basal medium supplemented with
2.0 mg L−1 6-benzylaminopurine, 0.5 mg L−1 indole-3-
acetic acid, and 10 μM silver nitrate (AgNO3; 7–8 shoots/
explant) or 20 μg L−1 triacontanol (TRIA; 4–5 shoots/explant).
Medium devoid of AgNO3 that was supplemented with
0.1–0.5 mg L−1 gibberellic acid (GA3) induced the proliferation
of up to two shoots/explant, but supplementation with 1–
5 mg L−1 GA3 induced a single shoot. The highest frequency
of shoot elongation and rooting was obtained on 0.5-strength
MS medium supplemented with 0.1 or 0.5 mg L−1 GA3, and
on this medium, further proliferation of shoots was also evident.
Micropropagated plants were hardened in the greenhouse
and successfully established in soil. Ascorbic acid level
in leaves of micropropagated plants from AgNO3- and TRIAsupplemented
media was highest (2.24 ± 0.14 and
2.18 ± 0.13 mg g−1 fresh weight, respectively), which was
2.8-fold more than normal ex vitro leaves of the same age
(0.79 ± 0.03 mg g−1 fresh weight).