Fig. 3. Incorporation of ¹³C–l-phenylalanine, ¹³C-coniferyl alcohol, and ¹³C-caffeyl alcohol into lignin and monolignol pools in developing seed coats of C. hassleriana.

(A to C) Thioacidolysis yields of total G- and C-monolignols from lignin isolated from Cleome seed coats fed ¹³C-Phe (A), ¹³C-coniferyl alcohol (B), or ¹³C-caffeyl alcohol (C) at the times shown. (D to F) Thioacidolysis yields of ¹³C-labeled G- and C-monolignols from lignin isolated from Cleome seed coats fed ¹³C-Phe (D), ¹³C-coniferyl alcohol (E), or ¹³C-caffeyl alcohol (F) at the times shown. (G to I) ¹³C-labeled coniferyl alcohol extracted from Cleome seed coats fed ¹³C-Phe (G), ¹³C-coniferyl alcohol (H), or ¹³C-caffeyl alcohol (I) at the times shown. (J and K) ¹³C-labeled caffeyl alcohol extracted from Cleome seed coats fed ¹³C-Phe (J) or ¹³C-caffeyl alcohol (K) at the times shown. Amounts of labeled monomers in cellular pools, or as components of lignin, were calculated for the M + 7 ions (¹³C-Phe) or M + 6 ions (¹³C-coniferyl alcohol and ¹³C-caffeyl alcohol) by the method described previously (12). Approximately 100 mg of seed coats isolated from seeds harvested from each Cleome plant were counted as one biological replicate. Data are means ± SE derived from three biological replicates.