Plant biomechanics is an interdisciplinary field that bridges botany, physics, and engineering to understand the mechanical principles underlying plant structure, function, and adaptation. This field explores how plants withstand environmental stresses, such as gravity, wind, and herbivory, and how these mechanical challenges influence plant growth, morphology, and evolution.

Plants may seem stationary and simple compared to animals, but they are remarkably complex organisms that have evolved sophisticated strategies to thrive in their environments. The field of plant biomechanics aims to unravel the mechanical principles underlying plant structure, function and adaptation. By studying how plants withstand forces like gravity and wind, respond to stresses, and generate movements, plant biomechanics is not only advancing our fundamental understanding of plant biology but also inspiring a new wave of nature-inspired innovations.

At its core, plant biomechanics examines the interplay between plant structure and function across scales - from the molecular architecture of cell walls to the mechanical stability of towering tree trunks. This integrative approach has revealed key insights. For example, the remarkable strength yet flexibility of wood arises from the hierarchical arrangement of cellulose microfibrils in cell walls. The ability of plants to grow tall despite their slender structures is enabled by clever mechanical optimization strategies that efficiently distribute resources. 

A central focus of plant biomechanics is the cell wall - a unique structural feature of plant cells that governs growth, provides mechanical support and senses mechanical forces. The cell wall's ability to selectively yield or resist internal turgor pressure is fundamental to plant morphogenesis. Proteins like expansins that modulate cell wall mechanics are of keen interest for understanding growth regulation. Mechanical forces also provide crucial feedback for patterning cell wall properties during development.

Beyond basic biology, the principles of plant biomechanics are increasingly being leveraged for engineering applications. Plant-inspired materials are being developed that combine high strength and toughness, enabled by studying the structural organisation of cellulose and lignin in cell walls.

Read more about this in the First Biomimetic Material…

The fast movements of plants, like the explosive seed dispersal in some species, have guided the design of deployable structures that can rapidly change shape. Even the dense packing of seeds in some fruits has offered inspiration for compact mechanical metamaterials.

Some of the most exciting developments are emerging at the intersection of plant biomechanics and robotics. Researchers are designing soft robots that mimic the movements of climbing vines and the underground navigation of roots, like the work of Bioinspired Soft Robotics Lab led by Prof Barbara Mazzolia.

By incorporating sensing and actuation principles from plants, these plant-inspired robots can adaptively grow, bend, and stiffen to explore constrained environments with minimal energy consumption. Other groups are developing multifunctional materials that can sense and respond to stimuli, borrowing concepts from how plants alter their form in response to mechanical stresses.

The toolkit of plant biomechanics is also being expanded by cutting-edge techniques. Advanced imaging methods allow the visualisation of stress patterns and molecular rearrangements in cell walls with unprecedented resolution. Computational models are helping researchers simulate and predict the complex mechanical behaviour of plant structures across scales. Genetically-encoded biosensors are even letting scientists map the mechanical forces experienced in living tissues. These emerging capabilities are opening new avenues to probe and exploit the biomechanical strategies of plants.

As the field of plant biomechanics continues to grow, it is becoming increasingly interdisciplinary. Collaborations between plant biologists, engineers, physicists and material scientists are yielding fruitful cross-pollination of ideas and approaches. This convergence is not only deepening our appreciation of plants as masterful mechanical problem-solvers but also accelerating the translation of their survival strategies into bio-inspired solutions for human challenges.

From architecture to medicine to robotics, the lessons from plant biomechanics are poised to drive sustainable innovations that seamlessly integrate structure and function. By looking at plants as models of materials and mechanical efficiency, we can design stronger and more resilient buildings, develop adaptive and energy-efficient robots, and create smart materials that respond and adapt to their environment. The potential for plant-inspired innovation is vast and has only begun to be tapped.

Conclusions

Plant biomechanics provides a powerful lens for understanding and emulating nature's engineering successes. As we continue to uncover the mechanical secrets of how plants grow, move and survive, we will gain not only a deeper appreciation of their often-overlooked complexity but also a rich source of inspiration for designing a more sustainable and resilient future. The field of plant biomechanics demonstrates that to innovate, we need only look to the time-tested strategies all around us in nature.

Further Reading

Four Seasons: Air, Earth, Fire, Water...and Kim Kardashian! Biomimicry and the Green Planet.

The rolling moss that gathers no stones.

Learning from a Tropical World

Wegst et al. (2015). Bioinspired structural materials. Nature Materials.

Niklas & Walker (2021). The challenges of inferring organic function from structure and its emulation in biomechanics and biomimetics. Biomimetics.  

Martone et al. (2010). Mechanics without muscle: Biomechanical inspiration from the plant world. Integrative and Comparative Biology.

Speck & Speck (2019). Quo vadis plant biomechanics–Old wine in new bottles or an up-and-coming field of modern plant science? American Journal of Botany.

Mazzolai (2017). Plant-inspired growing robots. Frontiers in Robotics and AI.

Rusin et al. (2022). Plant biomechanics—A natural transition from molecular to organ scale. International Journal of Molecular Sciences.

Speck & Speck (2021). Functional morphology of plants—A key to biomimetic applications. New Phytologist.