Fig. 2. Labeling of lignin and monolignol pathway intermediates with ¹³C–l-phenylalanine during C. hassleriana seed coat development.

(A) Total lignin monomer thioacidolysis yields from isolated cell walls after feeding seed coats with ¹³C-Phe for the times shown (DAP). (B) Total thioacidolysis yields of labeled lignin monomers in the preparations in (A). Yields were calculated for the M + 7 ions by the method described previously (12). (C) Percentage labeling of individual pathway intermediates as determined by LC-MS analysis. (D) Total phenylalanine amount as determined by LC-MS analysis. Approximately 100 mg of seed coats isolated from seeds harvested from each individual Cleome plant were counted as one biological replicate. Data are means ± SE derived from three biological replicates. CWR, cell wall residue.