FORMATION AND DEPOSITION OF TANNINS IN QUEBRACHO-COLORADO (SCHINOPSIS-BALANSAE ENGL)

In Quebracho colorado heartwood tannins are located in the lumina of m ost parenchyma cells, fibres and vessels. Formation and deposition of the tannins were studied by electron microscopy. In parenchyma cells p henolic compounds first occur at the inner and outer side of the membr anes of vacuoles. Later, these vacuoles are completely filled with dar k stained compounds and fuse together. From parenchyma cells the pheno lic substances migrate into the lumina of fibres and vessels through p its. In pits they penetrate into the compound middle lamella (CML) and diffuse along the CML. Tannins were also found in the cell walls and in fissures within the CML and G-layer of tension wood fibres.