Fig. 2.

Secondary metabolites in roots of transgenic Taraxacum koksaghyz plants that either exude latex (barstar, bs, and the near-isogenic line, NIL) or do not exude latex (barnase, bn/bs). Roots were sampled at 8, 12, and 24 weeks old. Data are means (±SD): for the 8th week five pooled samples of four plants each were sampled, and for the 12th and 24th weeks six individual plants were sampled. Metabolite concentrations and total contents per root were determined for (A) poly(cis-1,4-isoprene), (B) squalene/2-3-oxidosqualene, (C) pentacyclic triterpenes, and (D) sterols. Pentacyclic triterpene concentrations and contents were calculated based on the detection of α- and β-amyrin, lupeol, lup(19,21)-en-3-ol, taraxasterol, and a further two unidentified triterpenes. Sterol concentrations and contents were calculated based on the detection of campesterol, stigmasterol, and sitosterol. Due to non-normal distribution of the data, significance levels among the genotypes at each time-point were assessed using non-parametric Mann–Whitney U-tests (*P<0.01).