History and insights

Abstract

Human beings have always relied on plants to provide their staple foods and raw materials for diverse tools, and since prehistoric times must have known that sunlight greatly influences plant development and reproduction. From the Renaissance onwards, careful observations of nature led to a growing awareness that both higher and lower plants respond variously to light in terms of irradiation dosage for photosynthesis, direction for phototropism, timing and duration for photoperiodism, and wavelengths for photomorphogenesis. [Joseph Priestley (1772)] discovered that green plants utilize light as their source of energy for the production of complex organic substances. Julius Sachs (1864) demonstrated that only the blue region of visible light resulted in phototropic bending of plants. [Charles Darwin and his son (1881)] carried out a pioneering experiment on lightsignal transduction of phototropism, in which they separated the photoreceptive site from the responding growth region in monocot seedlings. In 1910, Georg Klebs gathered a lot of evidence that the environmental light greatly influences growth and development of seed plants and ferns. However, the molecular basis of light perception and signal transduction in plants was not elucidated until quite recently.