Experiment Measurement of Cytoplasmic Streaming Velocity within a Single Plant Cell

Cytoplasmic streaming, driven by myosin movement on actin filaments, is believed to play a major role in substance transportation and cell metabolism within plant cells. For example, it has been suggested that the cytoplasmic streaming velocity has a correlation with a plant growth rate, such that a faster streaming velocity leads to a larger plant growth. However, this observation has been made only in Arabidopsis and has not been generalized to other plant species. In this study, we measure cytoplasmic streaming velocity by tracking the movement of vesicles along actin filaments in various plant species and phenotypes with different growth rates and growth heights to confirm the correlation between a plant growth and a streaming velocity. Furthermore, we study how the environmental conditions such as temperature and salinity affect the cytoplasmic streaming, while correcting the influence of viscosity change with the temperature based on an in-situ micro-rheology technique. We hope that our results may serve as a cornerstone for future studies to assess the environmental resistance of genetically modified plants at the cellular level.