Abstract
Chloroplast position in a cell depends upon light environment. The chloroplasts gather towards incident weak light (accumulation movement) and avoid from the strong light. These phenomena are called as "light dependent chloroplast relocation movement" and well known in plants having green chloroplasts. In Arabidopsis, the accumulation movement is controlled by both phototropins, phot1 and phot2, but the avoidance movement is meditated by only phot2. The plant deficient in the avoidance movement is low resistant from strong light, indicating that the avoidance movement is important to avoid from photo-damage.
The phototropins are photoreceptor for not only the chloroplast relocation movements but also phototropism and stomata opening induced by blue light irradiation. Since the phenomena are important factors for the photosynthesis, a contribution to the photosynthesis will be discussed from view points of the chloroplast movement and phototropin family.
