Plant tropism refers to the directed movement of an organ or organism in response to external stimuli. Typically, these stimuli induce hormone transport that triggers cell growth or deformation. In turn, these local cellular changes create mechanical forces on the plant tissue that are balanced by an overall deformation of the organ, hence changing its orientation with respect to the stimuli. This complex feedback mechanism takes place in a three-dimensional growing plant with varying stimuli depending on the environment. We model this multiscale process in filamentary organs for an arbitrary stimulus by explicitly linking hormone transport to local tissue deformation leading to the generation of mechanical forces and the deformation of the organ in three dimensions. We show, as examples, that the gravitropic, phototropic, nutational, and thigmotropic dynamic responses can be easily captured by this framework. Further, the integration of evolving stimuli and/or multiple contradictory stimuli can lead to complex behavior such as sun following, canopy escape, and plant twining.

植物向性是指器官或生物体响应外部刺激的定向运动。通常，这些刺激会诱导激素转运，从而引发细胞生长或变形。反过来，这些局部细胞变化在植物组织上产生机械力，该机械力通过器官的整体变形来平衡，从而改变其相对于刺激的方向。这种复杂的反馈机制发生在三维生长的植物中，根据环境的不同刺激也不同。我们通过明确地将激素转运与局部组织变形联系起来，从而在任意刺激下对丝状器官中的这种多尺度过程进行建模，从而导致机械力的产生和器官在三个维度上的变形。作为例子，我们表明，该框架可以轻松捕获向地性、向光性、章动和触触性动态响应。此外，不断发展的刺激和/或多种矛盾刺激的整合可能导致复杂的行为，例如追日、树冠逃逸和植物缠绕。