In vitro plant regeneration from leaf-derived callus of Cimicifuga racemosa.

Cimicifuga racemosa (L.) Nutt., also known as Black Cohosh, is among the top 10 selling medicinal herbs in the United States. The rhizomes have been used to relieve menopausal discomfort. This plant is wild crafted and conservationists have expressed concerns with the sustainability of C. racemosa. Excised tissues from young leaves of C. racemosa were cultured on Murashige and Skoog's medium (MS) supplemented with various concentrations of NAA and TDZ for production of callus. The optimum callus growth and maintenance was in 1.0 microM NAA plus 0.5 microM TDZ. Two-month-old calli were sub-cultured on different concentrations of cytokinins (BA, kinetin, 2ip, TDZ) or in combination with GA(3) for shoot induction. The rate of shoot induction and proliferation was higher in MS media supplemented with 2.0 or 4.0 microM of TDZ. Concentrations of TDZ greater than 4.0 microM suppressed shoot growth. Adding 3.5 microM of GA(3) into media containing BA increased shoot growth. The presence of GA(3) with kinetin or TDZ did not affect shoot production. For rooting, shoots were transferred to MS medium with activated charcoal supplemented with various auxins (IAA, IBA and NAA), roots were noticed 20 days after transference. Activated charcoal was an essential component for vigorous rooting formation. Our results suggest that conservation of C. racemosa is possible through in vitro multiplication of leaf-derived callus.