In vitro propagation of an endangered medicinal plant Saussurea involucrata Kar. et Kir.

An efficient micropropagation system for Saussurea involucrata Kar. et Kir., an endangered Chinese medicinal plant, has been developed. Shoot organogenesis occurred from S. involucrata leaf explants inoculated on medium with appropriate supplements of plant growth regulators. 66.0% of shoot regeneration frequency and 5.2 shoots per leaf explant were achieved when cultured on a medium containing 10 microM 6-benzylaminopurine (BAP) and 2.5 microM 1-naphthaleneacetic acid (NAA). Shoot organogenesis was improved further when the leaf explants were pre-incubated at low temperature, and 80.6% of shoot regeneration frequency was recorded with 9.3 shoots per leaf explant at 4 degrees C by 5-day pretreatment period. Up to 87.0% of the regenerated shoots formed complete plantlets on a medium containing 2.5 microM indole-3-acetic acid (IAA) within 28 days, and 85.2% of the regenerated plantlets survived and grew vigorously in greenhouse condition. The phytochemical profile of the micropropagated plants was similar to that of wild plants. The regeneration protocol developed in this study provides a basis for germplasm conservation and for further investigation of medicinally active constituents of the elite medicinal plant.