Multiscale structural anisotropy steers plant organ actuation.

Area of Science:

• Plant biology
• Biomechanics
• Morphology

Background:

• Leaf movement in vascular plants is mediated by pulvini.
• Understanding the influence of hierarchical tissue architecture on pulvinus function is limited.

Purpose of the Study:

• Investigate how multiscale structure affects turgor-driven pulvinus movements.
• Analyze the relationship between structural organization and mechanical properties.

Main Methods:

• Visualized Mimosa pudica pulvinus morphology and anatomy across hierarchical scales.
• Used osmotic perturbations to swell dissected pulvini.
• Observed cell geometry, microfibril reinforcement, and epidermal cell orientation.

Main Results:

• Identified directional cellulose microfibril reinforcement and anisotropic swelling in parenchyma.
• Observed oblong epidermal cells oriented transverse to the pulvinus long axis.
• Demonstrated that multiscale structural specializations guide hydraulic deformation.

Conclusions:

• Multiscale mechanics are crucial for translating cell-level turgor changes into organ-scale pulvinus motion.
• Hierarchical architecture of plant tissues significantly influences pulvinus-mediated actuation.
• Structural specializations across multiple scales guide hydraulic deformation in pulvini.