SOMATIC EMBRYOGENESIS IN CELL-CULTURES OF THAPSIA-GARGANICA - CORRELATION BETWEEN THE STATE OF DIFFERENTIATION AND THE CONTENT OF THAPSIGARGINS

Cell cultures from different species of the genus Thapsia (Apiaceae) h ave been investigated. In one 4-year-old line of T. garganica L. spont aneous somatic embryogenesis up to the globular stage occurred in a su spension culture containing 1 mg l-1 2,4-dichlorophenoxyacetic acid (2 ,4-D). Also callus cultures of this line, previously maintained on a m edium containing 1 mg 1-1 2,4-D, when transferred to various media dep rived of 2,4-D, produced somatic embryos that developed into plantlets . Cell culture, embryos and regenerated organs were analysed for their content of thapsigargins. The undifferentiated cell culture did not s ynthezise thapsigargins, but was found to produce a yet unidentified c ompound not present in planta. White embryos in the pre-cotyledonary s tage did not synthezise thapsigargins either, but when the embryos dev eloped to the cotyledonary stage and became green, the synthesis start ed. Regenerated roots and shoots also contained thapsigargins.