PhD student Nico Schramma wins the first price of the BioPM Posterawards during the NWO Biophysics conference in Veldhoven with his poster entitled “Collective chloroplast dynamics in plant cells”
On his poster the PhD student presents his work on a dynamical phase transition observed during the photo-adaptation of the water plant Elodea densa. Inside every leaf-cell of the plant one can find up to 100 chloroplasts, the photosynthetic organelles which contain chlorophyll.
Those organelles can actively and individually move in a light-dependent manner. Under dim light conditions, chloroplasts sit in a single layer to absorb as much sunlight as possible. The dynamics in this dense two-dimensional configuration of these hemispherical organelles has striking similarities to systems close to a glass transition or supercooled liquids: occasionally a single or several organelles can change neighbors by “hopping” between cages, whereas in other regions nothing moves. However, if strong light is turned on the chloroplasts agitate and ‘break’ out of their local confinement and can re-arrange towards a light-avoidance state.
The proximity to a transition from an arrested to a ‘fluid’-like state serves a biological role: chloroplasts arrange in a way to receive as much light as possible, while maintaining the ability to break out of a two-dimensional glass-like configuration in order to actively re-arrange to avoid photo damage.
More can be read here: https://doi.org/10.1101/2022.04.15.488438