Cellular Distribution of Extractives in Redwood and Incense Cedar - Part II. Microscopic Observation of the Location of Cell Wall and Cell Cavity Extractives

Many redwood and incense cedar heartwood tracheid walls and pit structures were deposited with extractives but in varying amounts. Latewood tracheids contained more extractives than earlywood tracheids. Polyphenolic extractives in the cell wall were concentrated in the S 2 layer of the secondary wall. Within the S 2 layer, the inner and outer portions had a higher extractive concentration than the central portion of the layer. There was a general trend for the concentration of extractives to decrease from the lumen inward towards the middle lamella, suggesting that extractives, when they are deposited, infiltrate into the cell wall in the same sequence.