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17. Sept. 2025
A research team led by CEITEC Masaryk University (MUNI) has discovered that plant hormones called cytokinins prevent the premature stiffening of cell walls in vascular tissues, ensuring the optimal development of water-conducting tissues. If the cell wall gets fortified too early, the resulting vessels have a smaller diameter and carry less water. This finding, made possible through globally unique research approaches, could be important not only for understanding plant growth but also for breeding and adapting plants to drought.
Proper timing of development is crucial for plants. The team led by Jan Hejátko from CEITEC Masaryk University has revealed a new role for plant hormones known as cytokinins: these substances stop cells from “stiffening” before they reach their full size. Cytokinins act like an internal timer – giving the plant a signal when it is the right moment for growth, cell division, or maturation.
The researchers focused on the stem development of Arabidopsis thaliana, a widely used model organism. Using genetic modifications, gene activity analysis, and measurements of vascular tissue properties, they examined how cytokinin signalling influences the formation of the secondary cell wall – a rigid layer that provides strength and stability to plant cells, especially in vascular tissues.
During the development of vessels, the cells must first expand to the required size. Only then can their walls thicken and strengthen enough to withstand high pressure and efficiently transport water throughout the plant. This developmental adaptation has been crucial – it enabled the terrestrial life expansion from the water environment. The study showed that if a plant lacks sufficient cytokinins, or if their perception is disrupted, it starts strengthening its cell walls too soon. As a result, the vascular cells do not have enough time to grow, producing smaller water-conducting tissues with significantly reduced water transport capacity.
“Our research shows that cytokinin signalling acts as a safeguard against the plant’s ‘rash’ development,” says first author Vojtěch Didi. “Without it, the plant starts preparing for mechanical stress too early, even before it is fully developed.”
Co-author Dominique Arnaud adds: “It was fascinating to see that even relatively mild changes in the cytokinin signalling pathway had a strong impact on gene activity and the functionality of vascular tissues. This shows just how precisely plants time their developmental processes.”
At the molecular level, the research revealed that cytokinins in plants suppress the activity of genes carrying the instructions for the so-called NST transcription factors – the main switches that trigger the process of cell wall strengthening. Once the activity of these genes is suppressed, the plant delays the transition to the cell-strengthening phase, ensuring that water-conducting tissues reach the right size and function.
“Understanding this mechanism helps us better grasp how plants control the growth of their tissues in time and space,” adds corresponding author Jan Hejátko. “This could be important, for example, in developing crop varieties that use water more efficiently.”
The study brought together molecular biologists from CEITEC and the National Centre for Biomolecular Research with botanists from the Department of Experimental Biology and computer scientists from RECETOX and the Faculty of Informatics at MUNI. Combining advanced molecular techniques with “classic” methods for studying water transport in plants made it possible to experimentally characterise water transport in specific cell types, even in a plant as small as Arabidopsis. In addition to MUNI researchers, the study involved scientists from the Institute of Biophysics in Brno, Palacký University in Olomouc, and the University of British Columbia in Canada.
The full study has been published in the scientific journal Development.
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