Tsugawa Satoru, Sano Tomohiko G, Shima Hiroyuki, Morita Miyo Terao, Demura Taku
Graduate School of Science and Technology, Nara Institute of Science and Technology, Ikoma, Japan.
Flexible Structures Laboratory, Institute of Mechanical Engineering, EPFL, Lausanne, Switzerland.
Quant Plant Biol. 2020 Dec 15;1:e4. doi: 10.1017/qpb.2020.5. eCollection 2020.
Plant shoot gravitropism is a complex phenomenon resulting from gravity sensing, curvature sensing (proprioception), the ability to uphold self-weight and growth. Although recent data analysis and modelling have revealed the detailed morphology of shoot bending, the relative contribution of bending force (derived from the gravi-proprioceptive response) and stretching force (derived from shoot axial growth) behind gravitropism remains poorly understood. To address this gap, we combined morphological data with a theoretical model to analyze shoot bending in wild-type and mutant . Using data from actual bending events, we searched for model parameters that minimized discrepancies between the data and mathematical model. The resulting model suggests that both the bending force and the stretching force differ significantly between the wild type and mutant. We discuss the implications of the mechanical forces associated with differential cell growth and present a plausible mechanical explanation of shoot gravitropism.
植物茎的向重力性是一种复杂的现象，它源于重力感知、曲率感知（本体感受）、支撑自身重量的能力以及生长。尽管最近的数据分析和建模揭示了茎弯曲的详细形态，但重力向性背后弯曲力（源自重力本体感受反应）和拉伸力（源自茎轴向生长）的相对贡献仍知之甚少。为了填补这一空白，我们将形态学数据与理论模型相结合，以分析野生型和突变体的茎弯曲情况。利用实际弯曲事件的数据，我们寻找能使数据与数学模型之间差异最小化的模型参数。所得模型表明，野生型和突变体之间的弯曲力和拉伸力均存在显著差异。我们讨论了与细胞差异生长相关的机械力的影响，并对茎的向重力性提出了一个合理的力学解释。
