All kingdoms of life have evolved tip-growing cells able to mine their environment or deliver cargo to remote targets. The basic cellular processes supporting these functions are understood in increasing detail, but the multiple interactions between them lead to complex responses that require quantitative models to be disentangled. Here, I review the equations that capture the fundamental interactions between wall mechanics and cell hydraulics starting with a detailed presentation of James Lockhart’s seminal model. The homeostatic feedbacks needed to maintain a steady tip velocity are then shown to offer a credible explanation for the pulsatile growth observed in some tip-growing cells. Turgor pressure emerges as a central variable whose role in the morphogenetic process has been a source of controversy for more than 50 yr. I argue that recasting Lockhart’s work as a process of chemical stress relaxation can clarify how cells control tip growth and help us internalise the important but passive role played by turgor pressure in the morphogenetic process.

中文翻译：

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花粉管生长的力学和水力学

所有生命王国都进化出了尖端生长细胞，能够挖掘环境或将货物运送到远程目标。人们越来越详细地了解支持这些功能的基本细胞过程，但它们之间的多重相互作用会导致复杂的反应，需要解开定量模型。在这里，我从详细介绍 James Lockhart 的开创性模型开始，回顾捕捉壁力学和单元水力学之间基本相互作用的方程。然后显示维持稳定尖端速度所需的稳态反馈为在某些尖端生长细胞中观察到的脉动生长提供了可信的解释。50 多年来，Turgor 压力作为一个中心变量出现，其在形态发生过程中的作用一直是争议的根源。