Hydromechanical field theory of plant morphogenesis
Abstract
The growth of plants is a hydromechanical phenomenon in which cells enlarge by absorbing water, while their walls expand and remodel under turgor-induced tension. In multicellular tissues, where cells are mechanically interconnected, morphogenesis results from the combined effect of local cell growths, which reflects the action of heterogeneous mechanical, physical, and chemical fields, each exerting varying degrees of nonlocal influence within the tissue. To describe this process, we propose a physical field theory of plant growth. This theory treats the tissue as a poromorphoelastic body, namely a growing poroelastic medium, where growth arises from pressure-induced deformations and osmotically-driven imbibition of the tissue. From this perspective, growing regions correspond to hydraulic sinks, leading to the possibility of complex non-local regulations, such as water competition and growth-induced water potential gradients. More in general, this work aims to establish foundations for a mechanistic, mechanical field theory of morphogenesis in plants, where growth arises from the interplay of multiple physical fields, and where biochemical regulations are integrated through specific physical parameters.
Summary
This paper extends the gradient concept beyond hormones to include water, pressure, and mechanical fields. It presents a unified physical theory where plant tissues respond to multiple overlapping gradients.
Key insights on gradient-driven tissue behavior:
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Multiple field gradients: Plant morphogenesis is not driven by a single gradient but by the interplay of chemical (hormones), hydraulic (water), and mechanical (stress) fields.
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Water potential gradients: Growing regions act as “hydraulic sinks” - they draw water from surrounding tissues, creating water potential gradients that influence neighboring cell behavior.
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Non-local effects: A cell’s growth depends not just on its local environment but on the entire field of water potential, stress, and chemical signals across the tissue.
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Competition through gradients: Multiple growing regions compete for water through the gradient field - a faster-growing region creates a stronger sink, potentially starving competitors.
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Poromorphoelastic framework: The tissue is treated as a porous, elastic, growing medium where all these gradients interact through fundamental physics.
This work fundamentally validates the “tissues in gradients” view by showing that multiple physical fields - not just hormones - create the gradients that instruct tissue behavior.