A short item this, but one that has a cytoskeleton dimension and which just goes to show the impact that this cell component has on plant growth and development, and often in surprising ways.
Adding to that catalogue of cytoskeletal contributions to cell biology, Motoki Tominaga et al. propose that the rate of cytoplasmic streaming within cells is a ‘determinant’ of plant size. Cytoplasmic streaming is the term for large-scale active circulation of the entire fluid contents of cells, which is driven by organelles coated with myosin (a component of the cytoskeleton) as they process along actin filament bundles (also cytoskeleton components) fixed at the periphery of the cell. Working with ‘myosin-manipulated’ arabidopsis, the Japan-based team discovered that streaming was slower in plants with ‘slow myosin’, and faster in those with a ‘fast myosin’: as you might predict perhaps. But they also noticed that slow myosin produced smaller-than-usual plants, whereas fast myosin resulted in plants that were larger than wild-type ones. Which led them to – not unnaturally – conclude that their ‘results strongly suggest that cytoplasmic streaming is a key determinant of plant size’. Subsequently, they also mused on the possibility that manipulation of cytoplasmic streaming could be exploited for ‘applications in artificial size control in plants’. Which leads me to muse on how big could you make arabidopsis, that Tom-Thumb of the plant world? This is one story that – like Topsy – could surely grow (and grow…).