A very wide range of plant organ movements have been described and yet it is not clear how each of them is related to the others. This uncertainty has had two undesirable consequences. Firstly, some workers have accepted the idea of a vague unity in the area and have subsequently been misled by information obtained in one system and applied without adequate justification to a study of a quite different system. Secondly, some researchers have evoked a possible diversity to explain why a particular mechanistic explanation may continue to be valid even when the model fails to explain events of a very similar nature in a slightly different system. We argue that this confusion has resulted from a classification of organ movements which has been based on functional rather than on mechanistic considerations. Mechanistic unity is to be expected on evolutionary grounds. This unity, however, may apply only to certain elements of the stimulus-response chain, at certain levels of organization. It follows from this that in seeking this unity, comparisons should be made between equivalent elements of the stimulus-response chain at the same level of organization in different systems. Only when this is done will theories built around the concept of unity provoke meaningful discussion.

中文翻译：

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由差异生长引起的植物运动——机制的统一性还是多样性？

已经描述了非常广泛的植物器官运动，但尚不清楚它们中的每一个如何与其他器官相关联。这种不确定性产生了两个不良后果。首先，一些工作人员接受了该领域模糊统一的想法，随后被在一个系统中获得的信息所误导，并在没有充分理由的情况下将其用于研究一个完全不同的系统。其次，一些研究人员提出了一种可能的多样性来解释为什么即使模型无法解释稍微不同的系统中性质非常相似的事件，特定的机械解释也可能继续有效。我们认为，这种混淆是由基于功能而非机械考虑的器官运动分类造成的。从进化的角度来看，机械统一是可以预期的。然而，这种统一可能仅适用于刺激-反应链的某些元素，在某些组织层次上。因此，在寻求这种统一性时，应该在不同系统中相同组织级别的刺激-反应链的等效元素之间进行比较。只有当这样做时，围绕统一概念建立的理论才会引发有意义的讨论。