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 matrix in higher plants. This is the initial article in the series and it alludes only briefly to differences and similarities between the extracellular matrices of higher plants and animals. For more detailed information, the reader is referred to two recent surveys (1, 2) that provide expert and comprehensive coverage of recent advances, and summarize our current understanding of the extracellular matrix in higher plants. Oxalate, in the form of its water-insoluble calcium salt, is a familiar source of pathology in the 'stone' diseases of animals (3) and is important in regulating the levels of tissue calcium in at least some higher plants (4-6). Only recently, the significance of oxalate as a possible source of the H2O2 that is needed to fuel peroxidase reactions and cross-link polymers in the extracellular matrix of higher plants has become apparent, and this will be the principal subject of the article.