Mechanics and form of the maize leaf: in vivo qualification of flexural behaviour

An in vivo flexural test is designed and conducted on maize leaves. Data processing is based on a local structural definition of longitudinal leaf suppleness, which originates in the theory of pure plane bending of initially curved beams, in large displacements. A specific procedure for curvature and suppleness computation is methodologically discussed. The results presented concern only the elastic flexural behaviour of the leaf (which could be characterized in 59% of the tested leaves). A quasi-exponential increase in suppleness, from the base to the tip of the leaf, was always experienced. It is demonstrated that the midrib plays a major part in bending stiffness. Going up the longitudinal leaf form, it is shown that self weight related elastic bending strains only account for one-third of the actual curvature.