Visible light is the basic energetic driver of plant biomass production through photosynthesis. The constantly
fluctuating availability of light and other environmental factors means that the photosynthetic apparatus must be
able to operate in a dynamic fashion appropriate to the prevailing conditions. Dynamic regulation is achieved
through an array of homeostatic control mechanisms that both respond to and influence cellular energy and
reductant status. In addition, light availability and quality are continuously monitored by plants through photoreceptors.
Outside the laboratory growth room, it is within the context of complex changes in energy and signalling
status that plants must regulate pathways to deal with biotic challenges, and this can be influenced by changes in
the highly energetic photosynthetic pathways and in the turnover of the photosynthetic machinery.