Factors affecting somation embryogenesis in long term callus cultures of 'safed musli' (Chlorophytum borivilianum), an endangered wonder herb
1999; NISCAIR; Volume: 37; Issue: 1 Linguagem: Inglês
ISSN
0975-1009
AutoresD. K. Arora, Sheenam Suri, K. G. Ramawat, Jean‐Michel Mérillon,
Tópico(s)Plant tissue culture and regeneration
ResumoChiorophYlU lIl boriniianu7Il, commonly known as ' safed musli' , has become an endangered species due to ,t s ,,:cr-exploitation for tuberous roots, used as tonic and aphrodisiac. An improved method has been ut ,' cl oped fo r large-scale rapid multiplication of C. borivilianum through somatic embryogenesis in callus cu ltures. Somatic embryos were obtained on MS medium containing 2.25 J..lM 2,4-D and 1.15 ~lM kinetin . The concentration and com ination of KNO) and (NH4)2S04 in the medium had a marked effect on the somatic embryogenesis . Anunonium to nitrate nitrogen in the ratio of 1:4 at low total ni trogen level (250 or 500 mgNL ) in th e medium was favourable for the growth and somatic embryo genesis. Among th e various cytokinins tested, 2-iP had a maximum stimulatory effect on somatic em bryogenesis. Decreasing order of the effectiveness of various cytokinins incorporated in MS-9 medium (i .e., MS medium containing 100 mgNL' 1 (NH4)2S0 4 and 400 mgNL' 1 KJ~03) supplemented with 2.25 J..lM 2,4-0 was 2-iP > TDZ >kinetin >BAP. Incorporation of amino acids, viz. glutamine and proline, promotes embryogenesis. Maximum number of somatic embryos (63 per inoculum) were observed on MS-9 medium supplemented with 100 mgL' proline, 1. 12 J..lM 2,4-D and 7.42 J.1M 2-iP. Germination of somatic embryos, isolated from young cultures (1-5 months-old) was maximum (48%) on MS-9 me d ium supplemented with 17.6 J.1M BAP. On the other hand, somatic embryos developed in long-term cultures were abnormal and showed a wide range of variation in the number of chromosomes, ranging from 23 to 58 (i.e 3X-3 to 7X+2) along with several structural chromosomal abnormalities. This may be the reason fo r the decline in the germination potential of somatic embryos in long-term cultures. Thus, callus produced from shoot cultures obtained from stem-disc explants on B5 medium containing 2 J..lM TDZ and 0 .18 mM adenine, provides an excellent source for obtaining fresh cytologically-stable embryogenic cultures. Plamlets developed in vitro through embryo germination were successfully trans ferre d to soil with 90% survivability . The technique developed is highly efficient to get miniature plantlets for fiel d transfer in 2 months, starting from the callus .· Chlorophytum borivilianum (liliaceae) and a few other species are commonly known as 'safed musli'. Tuberous roots of the plant are widely used as tonic and aphrodisiac due to the presence of steroidal saponins, viz . neotigogenin, neoheco geni n, sti gmasterol and tokorogenin I. 2. C. borivilianum has been used along with other plants such as Asparagus ascendense, A. racemosum, Curculigo orchioides and Withania somnifera in several formulations in the Indian system of medi ci ne 3 . 4 • Pharmocological investigations of saponin
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