Department of Forest Botany, Warsaw University of Life Sciences, Nowoursynowska 166, 02-776, Warsaw, Poland.
Department of Botany, Warsaw University of Life Sciences, Nowoursynowska 166, 02-787, Warsaw, Poland.
Planta. 2024 Jul 6;260(2):46. doi: 10.1007/s00425-024-04477-0.
Mechanical stress induces distinct anatomical, molecular, and morphological changes in Urtica dioica, affecting trichome development, gene expression, and leaf morphology under controlled conditions The experiments were performed on common nettle, a widely known plant characterized by high variability of leaf morphology and responsiveness to mechanical touch. A specially constructed experimental device was used to study the impact of mechanical stress on Urtica dioica plants under strictly controlled parameters of the mechanical stimulus (touching) and environment in the growth chamber. The general anatomical structure of the plants that were touched was similar to that of control plants, but the shape of the internodes' cross section was different. Stress-treated plants showed a distinct four-ribbed structure. However, as the internodes progressed, the shape gradually approached a rectangular form. The epidermis of control plants included stinging, glandular and simple setulose trichomes, but plants that were touched had no stinging trichomes, and setulose trichomes accumulated more callose. Cell wall lignification occurred in the older internodes of the control plants compared to stress-treated ones. Gene analysis revealed upregulation of the expression of the UdTCH1 gene in touched plants compared to control plants. Conversely, the expression of UdERF4 and UdTCH4 was downregulated in stressed plants. These data indicate that the nettle's response to mechanical stress reaches the level of regulatory networks of gene expression. Image analysis revealed reduced leaf area, increased asymmetry and altered contours in touched leaves, especially in advanced growth stages, compared to control plants. Our results indicate that mechanical stress triggers various anatomical, molecular, and morphological changes in nettle; however, further interdisciplinary research is needed to better understand the underlying physiological mechanisms.
机械应力会导致荨麻发生明显的解剖学、分子和形态变化，影响毛状体发育、基因表达和叶片形态，这些都是在受控条件下观察到的。实验是在普通荨麻上进行的，普通荨麻是一种广泛分布的植物，其叶片形态具有高度变异性，对机械触摸有反应。专门设计的实验设备用于研究机械刺激（触摸）和生长室环境对荨麻的机械应力影响。被触摸的植物的一般解剖结构与对照植物相似，但节间的横截面形状不同。受应力处理的植物表现出明显的四肋结构。然而，随着节间的进展，形状逐渐接近矩形。对照植物的表皮包括刺毛状、腺毛状和简单刚毛状毛状体，但被触摸的植物没有刺毛状毛状体，刚毛状毛状体积累了更多的胼胝质。与受应力处理的植物相比，对照植物的较老节间发生细胞壁木质化。基因分析显示，与对照植物相比，被触摸的植物中 UdTCH1 基因的表达上调。相反，应激植物中 UdERF4 和 UdTCH4 的表达下调。这些数据表明，荨麻对机械应激的反应达到了基因表达调控网络的水平。图像分析显示，与对照植物相比，被触摸的叶片，特别是在生长后期，其叶面积减小，不对称性增加，轮廓发生改变。我们的结果表明，机械应力会引发荨麻的各种解剖学、分子和形态变化；然而，需要进一步的跨学科研究来更好地理解潜在的生理机制。
