Quantification of temperature dependence of forces involved in cytoplasmic streaming using optical tweezers

Abstract Cytoplasmic streaming is a phenomenon observed in plants where the circulation of cellular components occurs around the central vacuole. It is crucial for the spatio-temporal distribution of organelles in plant cells and thus has an important role in plant growth. It has been found that enhanced cytoplasmic streaming yielded higher growth and better foliage in plants. While cytoplasmic streaming in plants has been extensively studied, the in vivo quantification of the forces involved remains unexplored. In this study, in vivo optical trapping has been performed in onion cells, and the forces responsible for transporting organelles by cytoplasmic streaming have been measured. In plants, cytoplasmic streaming speeds have previously been shown to decrease with a decrease in temperature; however, their temperature dependence has not been studied at higher temperatures. Using optical tweezers, this study measures collective transport properties such as the forces exerted by cargoes and their speeds during cytoplasmic streaming at different temperatures. A better understanding of how cytoplasmic streaming is regulated at different temperatures can help develop plants that can utilize nutrients more efficiently, thus increasing their yield and survival.