text: *UVR8: UV-B light reception
  *Cryptochrome: blue and UV-A light reception
  *Phototropin: blue and UV-A light perception (to mediate phototropism and chloroplast movement)
  *Zeitlupe: blue light entrainment of the circadian clock
  *Phytochrome: red and far-red light reception
  All the photoreceptors listed above allow plants to sense light with wavelengths range from 280 nm (UV-B) to 750 nm (far-red light). Plants use light of different wavelengths as environmental cues to both alter their position and to trigger important developmental transitions. The most prominent wavelength responsible for plant mechanisms is blue light, which can trigger cell elongation, plant orientation, and flowering. One of the most important processes regulated by photoreceptors is known as photomorphogenesis. When a seed germinates underground in the absence of light, its stem rapidly elongates upwards. When it breaks through the surface of the soil, photoreceptors perceive light. The activated photoreceptors cause a change in developmental program; the plant starts producing chlorophyll and switches to photosynthetic growth.