Intracellular Photomorphogenesis

Abstract

Growth, differentiation and the integration of these processes ( = morphogenesis) in the multicellular plant is profoundly influenced by light acting through photomorphogenetic sensor and effector molecules, from which phytochrome is the one most widely known. It is obvious that a similar situation exists at the next lower level in the hierarchy of complexity, i.e., at the level of the cell which functions as an integrated system of numerous subcellular compartments. A major reason for studying the functional and structural changes within the cell during photomorphogenesis is the hope that the regulatory processes governing the coordinate development of subcellular compartments may, at the present state of experimental arts, be more open for a successful attack than those directing photomorphogenesis of the whole plant. (In its strict sense this problem has been hardly addressed up till now). Indeed the last few years have seen the advent of powerful new techniques for the in vitro investigation of basic cellular processes such as DNA transcription and RNA translation by the various genetic systems, or the specific transport of functional proteins from one cell compartment to another. These techniques are now being explored in the research on intracellular photomorphogenesis. It appears appropriate, therefore, to devote this chapter mainly to a critical review of the recent molecular approaches in this field.