Dipartimento di Scienze e Tecnologie per l'Ambiente e il Territorio, University of Molise, 86090 Pesche (IS), Italy.
Physiol Plant. 2012 Sep;146(1):39-52. doi: 10.1111/j.1399-3054.2012.01601.x. Epub 2012 Apr 10.
Mechanical stress is a widespread condition caused by numerous environmental factors that severely affect plant stability. In response to mechanical stress, plants have evolved complex response pathways able to detect mechanical perturbations and inducing a suite of modifications in order to improve anchorage. The response of woody roots to mechanical stresses has been studied mainly at the morphological and biomechanical level, whereas investigations on the factors triggering these important alterations are still at the initial stage. Populus has been widely used to study the response of stem to different mechanical stresses and, since it has the first forest tree genome to be decoded, represents a model woody plant for addressing questions on the mechanisms controlling adaptation of woody roots to changing environments. In this study, a morphological and physiological analysis was used to investigate factors controlling modifications in Populus nigra woody taproots subjected to mechanical stress. An experimental model analyzing spatial and temporal mechanical force distribution along the woody taproot axis enabled us to compare the events occurring in its above-, central- and below-bending sectors. Different morphogenetic responses and local variations of lignin and plant hormones content have been observed, and a relation with the distribution of the mechanical forces along the stressed woody taproots is hypothesized. We investigated the differences of the response to mechanical stress induction during the time; in this regard, we present data referring to the effect of mechanical stress on plant transition from its condition of winter dormancy to that of full vegetative activity.
机械应力是由许多环境因素引起的普遍现象，严重影响植物的稳定性。为了应对机械应力，植物已经进化出了复杂的响应途径，能够检测到机械干扰，并诱导一系列的改变，以提高固着性。木本植物根系对机械应力的响应主要在形态和生物力学水平上进行了研究，而触发这些重要变化的因素的研究仍处于初始阶段。杨树被广泛用于研究茎对不同机械应力的响应，由于它是第一个被解码的森林树种，因此代表了一种木质植物模型，可用于解决控制木质植物根系适应不断变化的环境的机制问题。在这项研究中，我们使用形态学和生理学分析来研究控制机械应力下黑杨木质主根发生变化的因素。一个分析木质主根轴上空间和时间机械力分布的实验模型使我们能够比较其上方、中央和下方弯曲部分的发生事件。观察到了不同的形态发生响应和木质素和植物激素含量的局部变化，并假设了与受应力木质主根上机械力分布的关系。我们还研究了随着时间推移对机械应激诱导的响应差异；在这方面，我们提供了有关机械应激对植物从冬季休眠状态向完全营养生长状态过渡的影响的数据。
