In Vitro Mass Multiplication and Production of Roots in Plumbago rosea

Abstract

Mass multiplication of Plumbago rosea was achieved by indirect organogenesis in young stem, leaf and root explant cultures of 6 - 9-month-old plants. All the explants responded similarly in a hormonal regime of 2.5 mg/L BA and 1.5 mg/L NAA with the formation of nodular callus in 4 weeks; the callus was divided and subcultured at 4-week intervals in the presence of 3.0 mg/L BA to produce up to 23.5 ± 1.6 shoots in 18 weeks and then at 2.0 mg/L BA to produce up to 79.6 ± 1.5 shoots in 23 weeks. The shoots of 2.0 - 3.5 cm length were rooted easily in half-strength MS agar medium supplemented with 0.1 mg/L IBA and rooted plants established within 4 weeks at a 95 - 98 % rate without hardening. Eight weeks after establishment, the micropropagated plants were transferred to experimental plots and cultivated for 10 months to obtain a significantly higher number (18.0 ± 0.5) of larger tuberous roots (137.4 ± 3.4 g fw/plant) compared to conventional rooted cuttings (14.0 ± 1.7, 47.9 ± 1.6 g fw/plant). During this period, the concentration of the root-specific compound, plumbagin recorded per g dw (1.5 %), was higher than that of conventionally propagated plants (0.9 - 1.0 %). The early formation of plumbagin-rich tuberous roots holds significant potential for the commercial cultivation of the micropropagated plants.

Abbreviations

fw:fresh weight

dw:dry weight

2,4-D:2,4-dichlorophenoxyacetic acid

KN:Kinetin

NAA:α-naphthaleneacetic acid

BA:benzylaminopurine

IBA:indole 3-butyricacid

IAA:indole 3-aceticacid

References

• 1 Dinda B, Hajra A K, Chel G. Naphthoquinones of Plumbago species: a review.  Indian Chemical Society. 1997;  74 974-9
• 2 Survey R eport. Tropical Botanic Garden & Research Institute. Trivandrum, Kerala India; 1997
• 3 Satheeshkumar K, Bhavanandan K V. Micropropagation of Plumbago rosea L.  Plant Cell, Tissue & Organ Culture. 1988;  15 275-8
• 4 Satheeshkumar K, Bhavanandan K V. Regeneration of plants from leaf callus of Plumbago rosea L.  Indian Journal Experimental Biology. 1989;  27 368-9
• 5 Harikrishnan K N, Hariharan M. Direct shoot regeneration from nodal explants of Plumbago rosea L.  Phytomorphology. 1996;  46 53-8
• 6 Hiraoka N. Bupleurum falcatum L. Embryogenesis and production of saikosaponins. In: Bajaj YPS (editor) Biotechnology in agriculture and forestry; 7. Medicinal and aromatic plants II. Springer Verlag Berlin; 1989: pp 69-81
• 7 Ikuta A, Itokawa H. Coptis; in vitro regeneration of plants and the production of berberin. In: Bajaj YPS (editor) Biotechnology in agriculture and forestry; 7. Medicinal and aromatic plants II. Springer Verlag Berlin; 1989: pp 110-28
• 8 Sreekumar S, Seeni S, Pushpangadan P. Micropropagation of Hemidesmus indicus for cultivation and production of 2-hydroxy-4-methoxybenzaldehyde.  Plant Cell, Tissue & Organ Culture. 2000;  62 211-8
• 9 Murashige T, Skoog F. A revised medium for rapid growth and bioassay with tobacco tissue cultures.  Physiologia Plantarum. 1962;  15 473-97
• 10 Heble M R, Narayanaswamy S, Chadha M S. Tissue differentiation and plumbagin synthesis in variant cell strains of Plumbago zeylanica L. in vitro .  Plant Science Letters. 1974;  2 405-9
• 11 Crouch I J, Van Staden J. Studies on the isolation of plumbagin from in vitro and in vivo grown Drosera species.  Plant Cell, Tissue & Organ Culture. 1990;  21 79-82
• 12 Raghava Rao D. Statistical techniques in agriculture and biological research. Oxford and IBH Publ. Co New Delhi; 1987: pp 85