Department of Collective Behaviour, Max Planck Institute for Ornithology, Konstanz, Germany.
Department of Biology, University of Konstanz, Konstanz, Germany.
PLoS One. 2018 Mar 29;13(3):e0194893. doi: 10.1371/journal.pone.0194893. eCollection 2018.
To grow straight and upright, plants need to regulate actively their posture. Gravitropic movement, which occurs when plants modify their growth and curvature to orient their aerial organ against the force of gravity, is a major feature of this postural control. A recent model has shown that graviception and proprioception are sufficient to account for the gravitropic movement and subsequent organ posture demonstrated by a range of species. However, some plants, including wheat coleoptiles, exhibit a stronger regulation of posture than predicted by the model. Here, we performed an extensive kinematics study on wheat coleoptiles during a gravitropic perturbation (tilting) experiment in order to better understand this unexpectedly strong regulation. Close temporal observations of the data revealed that both perturbed and unperturbed coleoptiles showed oscillatory pulses of elongation and curvature variation that propagated from the apex to the base of their aerial organs. In perturbed coleoptiles, we discovered a non-trivial coupling between the oscillatory dynamics of curvature and elongation. The relationship between those oscillations and the postural control of the organ remains unclear, but indicates the presence of a mechanism that is capable of affecting the relationship between elongation rate, differential growth, and curvature.
为了保持笔直生长，植物需要主动调节自身姿势。向重性运动是植物为抵抗重力而改变生长和弯曲方向的过程，这是植物姿势控制的主要特征。最近的模型表明，向重性感受和本体感受足以解释一系列物种的向重性运动和随后的器官姿势。然而，一些植物，包括小麦胚芽鞘，表现出比模型预测更强的姿势调节。在这里，我们对小麦胚芽鞘在向重性扰动（倾斜）实验期间进行了广泛的运动学研究，以便更好地理解这种出乎意料的强调节。对数据的密切时间观测表明，受扰和未受扰的胚芽鞘都表现出从顶端到空中器官基部的伸长和曲率变化的振荡脉冲。在受扰的胚芽鞘中，我们发现曲率和伸长的振荡动力学之间存在非平凡的耦合。这些振荡与器官的姿势控制之间的关系尚不清楚，但表明存在一种能够影响伸长率、差异生长和曲率之间关系的机制。
