Photosynthesis under Environmental Fluctuations: A Challenge for Plants, a Challenge for Researchers

The ability of plants to cope successfully with environmental fluctuations is a result of their evolution in subaerial environments, where fluctuations in parameters such as temperature, light, and water availability, are the norm and stable states are the exception. Despite this, most studies have focused on plant responses to stable stress conditions, which are certainly more accessible for experimentation than fluctuating conditions. The concept of environmental fluctuation also includes a sense of predictability: some fluctuations are predictable, dictated, for example, by circadian rhythms, while others are unpredictable. Photosynthetic regulation, which takes place at all levels of organisation, from macroscopic morphology to the biochemical-molecular level, buffers the effects of fluctuations, limiting the over-reduction of the photosynthetic apparatus and the consequent production of reactive oxygen species.