OXALATE, GERMIN, AND THE EXTRACELLULAR-MATRIX OF HIGHER-PLANTS

In forthcoming issues of The FASEB Journal, there will be a series of articles, each dealing with a selected aspect of the extracellular mat rix in higher plants. This is the initial article in the series and it alludes only briefly to differences and similarities between the extr acellular matrices of higher plants and animals. For more detailed inf ormation, the reader is referred to two recent surveys (1, 2) that pro vide expert and comprehensive coverage of recent advances, and summari ze our current understanding of the extracellular matrix in higher pla nts. Oxalate, in the form of its water-insoluble calcium salt, is a fa miliar source of pathology in the 'stone' diseases of animals (3) and is important in regulating the levels of tissue calcium in at least so me higher plants (4-6). Only recently, the significance of oxalate as a possible source of the H2O2 that is needed to fuel peroxidase reacti ons and cross-link polymers in the extracellular matrix of higher plan ts has become apparent, and this will be the principal subject of the article.