1. Cells and protoplasts were isolated from the tapetum in order to demonstrate the importance of this tissue in the phenylpropanoid metabolism of the anther loculus. It was our purpose to investigate the localization of the key phenylpropanoid enzyme, phenylalanine ammonia-lyase, within the tapetum and the other anther tissues. 2. The isolation of tapetum protoplasts proved to be possible only from tissue of the early developmental stage, and even then only with difficulties. It was not possible to obtain enough protoplasts for enzymatical studies. The cell walls of the tapetum from later developmental stages contain components which resist the attack of the hydrolytic enzymes. 3. Tapetum tissue, on the other hand, could be isolated in much greater quantities such that enzymatical studies were possible. Contamination of this isolated tissue with cells, protoplasts or traces of other anther tissues could not be detected. 4. The anther tapetum showed a very high specific PAL activity, whereas the pollen and other anther tissues contained only marginal activity. This result illustrates the dominant role of the tapetum in the anther phenylpropanoid metabolism. 5. IR-spectroscopy and acetolysis resistance revealed that sporopollenin is a building material of the newly formed tapetal and peritapetal cell walls.