Figure 6.

Lignin Deposition during C. hassleriana Seed Coat Development.

(A) Seed lignin compositions determined by thioacidolysis. Yields of guaiacyl (G) and catechyl (C) type trithioethylpropylphenols (μmol/g cell wall residues [CWR]) released from the seed coat cell wall preparations are plotted against seed ages (days after pollination).

(B) Extractable CCoAOMT and COMT activities in crude protein extracts from the seeds. Enzyme activity is expressed based on dry seed weight.

(C) Transverse seed sections imaged directly by phenolic autofluorescence or by histochemical lignin staining with toluidine blue O or phloroglucinol-HCl for detection of both G and C lignins or with nitroso reagent for selective detection of C lignin. The two distinguishable sublayers of lignified cells (indicated by yellow and orange arrows) are visible beneath the exotestal cell layers.