Stiffness transitions in new walls post-cell division differ between Marchantia polymorpha gemmae and Arabidopsis thaliana leaves

Abstract

Plant morphogenesis is governed by the mechanics of the cell wall—a stiff and thin polymeric box that encloses the cells. The cell wall is a highly dynamic composite material. New cell walls are added during cell division. As the cells continue to grow, the properties of cell walls are modulated to undergo significant changes in shape and size without breakage. Spatial and temporal variations in cell wall mechanical properties have been observed. However, how they relate to cell division remains an outstanding question. Here, we combine time-lapse imaging with local mechanical measurements via atomic force microscopy to systematically map the cell wall’s age and growth, with their stiffness. We make use of two systems, Marchantia polymorpha gemmae, and Arabidopsis thaliana leaves. We first characterize the growth and cell division of M. polymorpha gemmae. We then demonstrate that cell division in M. polymorpha gemmae results in the generation of a temporary stiffer and slower-growing new wall. In contrast, this transient phenomenon is absent in A. thaliana leaves. We provide evidence that this different temporal behavior has a direct impact on the local cell geometry via changes in the junction angle. These results are expected to pave the way for developing more realistic plant morphogenetic models and to advance the study into the impact of cell division on tissue growth.

Assessing the hydromechanical control of plant growth

“…For 179 individuals among the control experiments, we had access to both hydromechanical properties and growth rate, which allowed us to show that there is a correlation between the bulk elasticity of the gemmae and their instantaneous growth rate, in line with previous reports of stiffer regions of the shoot apical meristem of tomato growing slower [30] and softer regions of roots growing faster [33]. A similar correlation was recently observed at the cell wall level in Marchantia [47]. The weaker correlation between hydraulic conductivity and growth rate suggests that growth rate is partially limited by the plant water conductivity.…”

Assessing the hydromechanical control of plant growth

“…For 179 individuals among the control experiments we had access to both hydromechanical properties and growth rate, which allowed us to show that there is a correlation between bulk elasticity of the gemmae and their instantaneous growth rate, in line with previous reports of stiffer regions of the shoot apical meristem of tomato growing slower [30] and softer regions of roots growing faster [33]. A similar correlation was recently observed at cell wall level in Marchantia [47]. The weaker correlation between hydraulic conductivity and growth rate suggests that growth rate is partially limited by the plant water conductivity.…”

The interplay between cell wall integrity and cell cycle progression in plants

“…Yet, the technical challenges associated with studying dynamic processes remain substantial, due to the lack of spatial and temporal resolution of the employed methods (Alonso Baez and Bacete 2023 ). A nice example of how high-resolution techniques can shed light into how cell wall properties relate to cell division and morphogenesis is the recent study by (Bonfanti et al 2023 ). By employing time-lapse imaging and atomic force microscopy, the authors systematically mapped the stiffness of cell walls in relation to their age and growth in Marchantia polymorpha and A. thaliana .…”