| Abstract: | In this report I comment on a small selection of the many interesting papers presented at the European Symposium on Photomorphogenesis in Plants. My major concern arises from problems relating to classical phytochrome treatments versus mutants and transgenic plants as tools in photomorphogenic research on whole plant physiology. Plant responses to visible light are especially evident in etiolated seedlings, although they occur throughout the life cycle of the plant. These characteristics of plant photomorphogenesis in nature can be viewed as representing a continuous developmental series of graded responses to subsequent light exposures. Where the individual, photoautotrophic seedling is moving through this developmental gradient depends on its particular light environment, that is, on both the quality and the quantity of light to which the seedling is exposed. On the contrary, phytochrome treatment of mutants and transgenic seedlings having either deficiency or overexpression of photoreceptors will result in an aberrant kind of physiology. |
