The papers collected in this volume are the contributions of invited speakers to a two-day meeting organised by the Plant Development and Plant Metabolism groups of the SEB and held at Lancaster in April 1992. One of the ideas of the meeting was to try and get away from the stereotyped divisions of ‘hormones and receptors’, ‘signal transduction’, ‘Golgi transport’, ‘protein targeting’, and so on, and look instead at things from the point of view of the proteins involved in these processes, and the effects of post-translational modifications on their activity. The result is a selection of papers on phosphorylation, glycosylation, acylation, ubiquitination, and protein processing, which illustrate the ways in which these modifications are brought about and their effects on cellular processes.

The first chapter, by the volume editors, is an introductory overview of the subject of post-translational modification in plants, in which key advances in the last few years are highlighted. The following chapters by Dixon and Hardie place the work on plant systems in a wider context by reviewing the roles of protein phosphorylation in bacteria and animals; Fallon & Trewavas provide a general discussion of phosphorylation in plant cells and some details on Ca2+/calmodulin regulated and tyrosine kinases in plant systems. In the chapters by Mattoo et al., Soll, and White et al., phosphorylation is discussed with particular reference to chloroplast function; the uses of peptides in the study of G proteins and chloroplast protein kinase are outlined.