The video shows birch (Betula pendula) pollen grains immersed in water. It can be seen that the pollen grains rupture and expel cytoplasmic material including starch granules. These materials are also referred to as subpollen particles. The video is a supplement to the article "Isolation of sub-pollen particles (SPPs) of birch: SPPs are potential carriers of ice nucleating macromolecules" in Biogeosciences. Full reference: Burkart, J., Gratzl, J., Seifried, T. M., Bieber, P., and Grothe, H.: Isolation of subpollen particles (SPPs) of birch: SPPs are potential carriers of ice nucleating macromolecules, Biogeosciences, 18, 1–15, 2021.