Books dealing with climatic change are commonplace, as are those concerned with effects of environmental stresses on plants. The present volume distinguishes itself from earlier publications by highlighting several interrelated environmental stresses that are changing in intensity as the climate warms in response to the accumulation of 'greenhouse' gases. The stresses examined at the NATO Advanced Research Workshop upon which this book is based include atmospheric pollutants, flooding and sub mergence, drought and cold. In future, successful farming or landscape management will ultimately depend on strategies that offset the effects of these and other environmental constraints, while exploiting more favourable features. However, the to predicted speed of climate change may exceed the rate at which new approaches farming, forestry, landscape management and genetic conservation can be developed through experience and retroactive response. The alternative is to anticipate future needs and thus identify appropriate management and legislative strategies by research and discussion. The contents of this volume contribute to these vital processes, upon which the productivity of agroecosystems and conservation of natural ecosystems may increasingly depend. Those with any lingering doubts concerning the gravity of the likely future situation are especially encouraged to read the opening chapter. For convenience, chapters discussing pollution, flooding, drought and cold are grouped in separate sections. However, many authors have taken care to emphasise that interactions between the changing combinations of stresses pose particular problems for plants and plant communities."

This NATO Advanced Research Workshop held 25-30 September, 1988 at the Villa Gualino, Turin, Italy, was the first international meeting of its kind to be devoted solely to cell separation in plants. The partial or complete dissociation of one cell from another is an integral process of differentiation. Partial cell separations are basic physiological components of the overall programme of plant development. Complete cell separations are major events in the ripening of fruits, and the shedding of plant parts. Unscheduled cell separations commonly occur when tissues are subjected to pathogenic invasion. Environmental stresses too, evoke their own separation responses. Over the past five years much new knowledge has been acquired on the regulation of gene expression in specific stages of cell differentiation. Specific molecular markers have been identified that designate the competence of cells for achieving separation. Certain of the chemical signals (hormones, elicitors) that must be emitted or perceived by cells to initiate and sustain separation, are now known to us, and the resulting cell wall changes have come under close chemical scrutiny. The Turin meeting was a focus for those currently involved in such investigations. It assessed factors controlling cell separation in a wide spectrum of different cell types under a variety of conditions.