Fine-tuned far-red light responses in plants

A plant’s light environment varies throughout the day and from season to season, both through changes in the external conditions (e.g. weather, photoperiod) and through growth and development of neighboring plants. Since light drives photosynthesis and is therefore critical for plant growth and development, being able to escape from a shaded environment creates a key competitive advantage. In shade, the light environment is relatively depleted in blue and red (R) light and relatively enriched in far-red light (FR), resulting from the absorption properties of chlorophyll. Using their photoreceptors, plants can detect specific wavelengths of light, including the ratio of red to far-red light (R:FR). Upon detection of a reduction in the R:FR, plants display a suite of responses, collectively termed the shade avoidance syndrome. In this thesis we aimed to answer how spatial and temporal alterations in the light environment affect shade avoidance responses and (how) FR affects photosynthetic rates and biomass in Arabidopsis thaliana.