A Cytochemical Study of Differentiation and Breakdown of Vessel End Walls

A cytochemical approach was used to study the architecture ofthe end wall and its modifications during vessel differentiationin Populus italica and Dianthus caryophyllus. The combinationof cytochemical techniques with selective extractions to removeend wall subunits provides information on the different componentsof the end wall and on the method of perforation. The end wallappears to be formed mainly from pectins and hemicelluloses.No cellulosic components nor lignin were found though the 3,3'-diaminobenzidine assay revealed the presence of peroxidases.That the method of perforation may depend on the species isdiscussed. Dianthus caryophyllus L., carnation, Populus italica, poplar, xylem vessel, cell wall, cytochemistry, vessel differentiation