Tropisms and other movements of a plant organ result from alterations in local rates of cell elongation and a consequent development of a growth differential between its opposite sides. Relative elemental rates of elongation (RELELs) are useful to characterize the pattern of growth along and round an organ. We assume that the value of the RELEL at a given point is dependent on distance from the tip and that the distribution of values along the organ surface can be characterized in terms of the spread and the position of the maximum value. A computer model is described which accommodates these parameters and simulates tropic curvatures due to differential growth. Additional regulatory functions help to return the simulated organ to its original orientation. Particular attention is given to the simulation of root gravitropism because here not only do each of the various growth and regulatory parameters have a known biological counterpart, but some can also be given an actual quantitative value. The growth characteristics relate to the biophysical properties of cells in the elongation zone of the root, while the regulatory functions relate to aspects of the graviperception and transmission systems. We believe that, given a suitably flexible model, computer simulation is a powerful means of characterizing, in a quantitative way, the contribution of each parameter to the elongation of plant organs in general and their tropisms in particular.

中文翻译：

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差异生长和植物嗜性：计算机模拟辅助研究

植物器官的趋向性和其他运动是由局部细胞伸长率的改变和随之而来的相对两侧生长差异的发展引起的。相对元素伸长率 (RELEL) 可用于表征沿器官和围绕器官的生长模式。我们假设给定点的 RELEL 值取决于距尖端的距离，并且沿器官表面的值分布可以根据最大值的扩散和位置来表征。描述了适应这些参数并模拟由于不同生长引起的热带曲率的计算机模型。额外的调节功能有助于将模拟器官恢复到其原始方向。特别注意根向重性的模拟，因为这里不仅各种生长和调节参数中的每一个都有已知的生物对应物，而且有些还可以给出实际的定量值。生长特性与根伸长区细胞的生物物理特性有关，而调节功能与重力感知和传输系统的各个方面有关。我们相信，给定一个适当灵活的模型，计算机模拟是一种强有力的手段，可以定量地表征每个参数对一般植物器官伸长的贡献，特别是它们的向性。生长特性与根伸长区细胞的生物物理特性有关，而调节功能与重力感知和传输系统的各个方面有关。我们相信，给定一个适当灵活的模型，计算机模拟是一种强有力的手段，可以定量地表征每个参数对一般植物器官伸长的贡献，特别是它们的向性。生长特性与根伸长区细胞的生物物理特性有关，而调节功能与重力感知和传输系统的各个方面有关。我们相信，给定一个适当灵活的模型，计算机模拟是一种强有力的手段，可以定量地表征每个参数对一般植物器官伸长的贡献，特别是它们的向性。