Eight years have elapsed since the first International Meeting on Plant Mitochondria was held in Marseilles. Since this date numerous important developments have occurred within the field and hence a further conference on this fundamental area of research was considered well overdue. This volume summarises the lecture and poster sessions of the second International Meeting on Plant Mitochondria held in Aberystwyth, July 20- 24th, 1986. The meeting was held not only to bring together plant scientists interested in the bioenergetics of plant mitochondria but also those who are interested in the regulatory role of mitochondria in plant growth and respiration. A further important aspect of this conference was to introduce plant physiologists and biochemists to the plant molecular biologists in an attempt to not only discuss problems of mutual interest but to also learn much more about the real questions which the biochemists and physiologists wish to answer. Hopefully the volume reflects much of the current excitement and advances being made in the field. Although many of the participants of the first meeting were present the expertise of Walter Bonner, Jack Hanson and Gaston Ducet, to name but a few, was sorely missed. The conference consisted of forty-five minute review lectures followed by thirty minute research lectures, the summaries of which are found in the longer articles. The meeting was divided into four seSSions, namely, organisation of the electron transport chain; mitochondrial interactions; mitochondrial biogenesis and plant growth and development.