Department of Physics, Ritsumeikan University, Kusatsu, Shiga, Japan.
Phys Rev Lett. 2012 Sep 21;109(12):128104. doi: 10.1103/PhysRevLett.109.128104. Epub 2012 Sep 19.
The molecular and cellular basis of left-right asymmetry in plant morphogenesis is a fundamental issue in biology. A rapidly elongating root or hypocotyl of twisting mutants of Arabidopsis thaliana exhibits a helical growth with a handedness opposite to that of the underlying cortical microtubule arrays in epidermal cells. However, how such a hierarchical helical order emerges is currently unknown. We propose a model for investigating macroscopic chiral asymmetry in Arabidopsis mutants. Our elastic model suggests that the helical pattern observed is a direct consequence of the simultaneous presence of anisotropic growth and tilting of cortical microtubule arrays. We predict that the root helical pitch angle is a function of the microtubule helical angle and elastic moduli of the tissues. The proposed model is versatile and is potentially important for other biological systems ranging from protein fibrous structures to tree trunks.
植物形态发生中左右不对称的分子和细胞基础是生物学中的一个基本问题。拟南芥扭转变体的快速伸长的根或下胚轴表现出具有与表皮细胞中皮层微管阵列相反的手性的螺旋生长。然而，目前尚不清楚这种分层螺旋秩序是如何出现的。我们提出了一个用于研究拟南芥突变体中宏观手性不对称的模型。我们的弹性模型表明，观察到的螺旋模式是各向异性生长和皮层微管阵列倾斜同时存在的直接结果。我们预测根的螺旋螺距角是微管螺旋角和组织弹性模量的函数。所提出的模型是通用的，对于从蛋白质纤维结构到树干的其他生物系统可能很重要。
