Twenty-nine, prominent, international researchers provide contributions which deal with understanding the basic ecophysiological and molecular principles governing the functioning of plant systems in relation to their environment. Divided into two headings: biotic and abiotic; the first consists of abiotic, natural environmental factors--light, ultraviolet radiation, chilling and freezing, high temperatures, drought, flooding, salt and trace metals. The latter half presents anthropogenic aspects including allelochemicals, herbicides, polyamines, air pollutants, carbon dioxide, radioisotopes and fire.