Wound periderm, suberin layers

The time course of deposition of aromatic monomers into the phenolic portion of suberin in wound-healing slices of Solanum tuberosum tubers was determined using the amount of / -hydroxybenzaldehyde and vanillin generated by alkaline nitrobenzene oxidation as a measure of aromatic deposition (85). The deposition of such phenolics into the polymer exhibited a lag period of about three days after wounding followed by several days when the deposition of phenolics increased rapidly, and subsequently the process ceased. Exogenous L-[U- C]-phenylalanine and [U- Clcinnamic acid were incorporated into the insoluble polymeric material by wound-healing slices of S. tuberosum (85). Nitrobenzene oxidation of the polymeric material derived from labeled cinnamic acid released labeled /7-hydroxybenzaldehyde and vanillin. The time course of incorporation of phenolics into the suberin polymer correlated with the time course for the deposition of aliphatic monomers into the polymer, the deposition of suberin-associated waxes into the periderm layer and the development of diffusion resistance (Fig. 6.4.12) (86). 

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