Despite extensive knowledge about vessel element growth and the determination of the axial course of vessels, these processes are still not fully understood. They are usually explained as resulting primarily from hormonal regulation in stems. This review focuses on an increasingly discussed aspect – mechanical conditions in the vascular cambium. Mechanical conditions in cambial tissue are important for the growth of vessel elements, as well as other cambial derivatives. In relation to the type of stress acting on cambial cells (compressive versus tensile stress) we: (i) discuss the shape of the enlarging vessel elements observed in anatomical sections; (ii) present hypotheses regarding the location of intrusive growth of vessel elements and cambial initials; (iii) explain the relationship between the growth of vessel elements and fibres; and (iv) consider the effect of mechanical stress in determining the course of a vessel. We also highlight the relationship between mechanical stress and transport of the most extensively studied plant hormone – auxin. We conclude that the integration of a biomechanical factor with the commonly acknowledged hormonal regulation could significantly enhance the analysis of the formation of vessel elements as well as entire vessels, which transport water and minerals in numerous plant species.

中文翻译：

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我们对木本植物次生木质部血管元素的生长了解多少？

尽管对血管元素生长和血管轴向路线的确定有广泛的了解，但这些过程仍未完全了解。它们通常被解释为主要由茎中的激素调节引起。这篇评论集中在一个越来越多的讨论方面——血管形成层的机械条件。形成层组织中的机械条件对于血管元素以及其他形成层衍生物的生长很重要。关于作用在形成层细胞上的应力类型（压缩应力与拉伸应力），我们：（i）讨论在解剖切片中观察到的扩大血管元素的形状；（二) 提出关于血管元素和形成层声母侵入生长位置的假设；( iii ) 解释血管元素的生长与纤维的关系；( iv ) 考虑机械应力对确定船只航向的影响。我们还强调了机械应力与研究最广泛的植物激素 - 生长素的运输之间的关系。我们得出结论，将生物力学因素与公认的激素调节相结合可以显着增强对血管元素以及整个血管形成的分析，这些血管元素在许多植物物种中运输水和矿物质。