Chloroplasts change their intracellular position in response to environmental alterations. What is being most studied is the relocation induced by light. For example, chloroplasts move towards weak light, maximizing photosynthesis. However, when ambient temperature decreases, chloroplasts escape from the weak light. We call the cold-induced phenomenon “the chloroplast cold-avoidance response”. In this review, I would like to summarize the findings on the chloroplast cold-avoidance response during the past over 100 years, and also propose a new hypothesis on biological thermosensing.
