Table 1.

Glossary of terms

Term	Definition
Bending Moment	The result of multiplying a force by the perpendicular distance from the force to the axis about which the bending moment is being calculated. Conceptually can be thought of as a torque
Bending Stress	A measure of the force experienced by the plant tissues that is normalized to size and geometry
Body Forces	Forces acting on the plant due to the gravity
Contact Forces	Forces that occur when other solid materials contact the plant
External Forces	Forces that are applied to the plant from an external source (e.g. Contact Forces or Surface Forces). Body Forces are not an External Force
Stalk Flexural Stiffness	Flexural stiffness is a standard structural engineering quantity for measuring the flexural (i.e., bending) deformability of objects. It is equal to the elastic modulus of the material multiplied by the moment of inertia (a geometric term which quantifies the distribution of mass about the object’s centroid). During mechanical phenotyping tests of plant stalks flexural stiffness is typically calculated by applying a force, measuring deflection and using Castigliano’s energy method to indirectly solve for flexural stiffness
Stalk Bending Strength	The maximum bending moment the plant can support before structural failure occurs (i.e., before breaking)
Surface Forces	Forces that are distributed across the plant’s surface