Root hair growth: it's a one way street

Over the last few decades, our understanding of directed cell growth in different organisms has substantially improved. Tip-growing cells in plants elongate rapidly via targeted deposition of cell wall and membrane material at the cell apex, and use turgor pressure as a driving force for expansion. This type of polar growth requires a high degree of coordination between a plethora of cellular and extracellular components and compounds, including calcium dynamics, apoplastic reactive oxygen species and pH, the cytoskeleton, and vesicular trafficking. In this review, we attempt to outline and summarize the factors that control root hair growth and how they work together as a team.