Some anatomical factors relating to the penetration of water into xylem of gymnosperms

Abstract

A study has been made of some sapwood specimens of Pinus radiata D. Don and Pinus muricata D. Don known to resist penetration by aqueous preservatives but readily penetrated by creosote oil. A few pits only in these specimens showed aspiration. An arbitrary sinkage time has been used as an indication of the penetrability of the wood and it has been shown that pre-extraction with alcohol and ether greatly reduces the sinkage time in water. In Pinus radiata and Picea spp. the sinkage time was greatly increased by drying but this increase did not take place if the specimens were pre-extracted with alcohol and ether. Extraction after drying at 102°C did not reduce the sinkage time.

A study of staining reactions of the wood with sudan black and sudan IV indicated the presence of fatty material, removable by successive extractions with alcohol and with ether, lining the lumen of pit chambers of the tracheids. This fatty material appeared to be part of a thicker membrane which stained strongly with osmic acid, and could be removed only by extraction with urea. Isolation of this osmiophilic membrane and subsequent electron microscopic examination showed it to have a structure similar to the membrane with "wart-like" texture described by other workers.