Figure 1.

Schematic depiction of principal steps involved in photosynthesis (light harvesting, photochemistry, involving photosystem II (PSII) and the oxygen-evolving complex (OEC) and carbon fixation in the Calvin cycle (CC)) and in sugar export (phloem loading and sugar transport) to the plant's sinks (solid arrows) as well as (dashed arrows) feedback loops from sugar export and the plant's sinks to photosynthesis and (dotted arrows) feed-forward and feedback loops related to the generation of reactive oxygen species (ROS) in light harvesting and photochemistry. Heat = heat released via thermal dissipation of excess excitation energy in light-harvesting antennae. (Online version in colour.)