This study utilized physical and in silico experiments to confirm that geometric parameters are far 30 more influential in determining stalk strength than mechanical tissue stiffnesses. Abstract 32The maize (Zea mays) stem is a biological structure that must both balance biotic and structural 33 load bearing duties. These competing requirements are particularly relevant in the design of new 34 bioenergy crops. With the right balance between structural and biological activities, it may be 35 possible to design crops that are high-yielding and have digestible biomass. But increased stem 36 digestibility is typically associated with a lower structural strength and higher propensity for 37 lodging. This study investigates the hypothesis that geometric factors are much more influential in 38 determining structural strength than tissue properties. To study these influences, both physical and 39 in silico experiments were used. First, maize stems were tested in three-point bending. Specimen-40 specific finite element models were created based on x-ray computed tomography scans. Models 41 were validated by comparison with in vitro data. As hypothesized, geometry was found to have a 42 much stronger influence on structural stability than material properties. This information 43 reinforces the notion that deficiencies in tissue strength could be offset by manipulation of stalk 44 morphology, thus allowing the creation of stalks with are both resilient and digestible. 45 46 47 48 49 50 51 52 53

All scientific measurements are affected to some degree by both systematic and random errors. The quantification of these errors supports correct interpretation of data, thus supporting scientific progress. Absence of information regarding reliability and accuracy can slow scientific progress, and can lead to a reproducibility crisis. Here we consider both measurement theory and plant biomechanics literature. Drawing from measurement theory literature, we review techniques for assessing both the accuracy and uncertainty of a measurement process. In our survey of plant biomechanics literature, we found that direct assessment of measurement accuracy and uncertainty is not yet common. The advantages and disadvantages of efforts to quantify measurement accuracy and uncertainty are discussed. We conclude with recommended best practices for improving the scientific rigor in plant biomechanics through attention to the issues of measurement accuracy and uncertainty.

Plant tissues are often heterogeneous. To accurately investigate these tissues, we will need methods to spatially map these tissue stiffness values onto finite element models. The purpose of this research is to develop a method for using specimen-specific computed tomography data to inform the spatial mapping of Young's modulus values on finite element models. The spatial mapping of Young's modulus was calculated and then used to predict the response of specimen tests. Results indicated that this method can be used to obtain spatial distributions of material properties, thus enabling finite element models that account for material heterogeneity.

Plant tissues are often heterogeneous. To accurately investigate these tissues, we will need methods to spatially map these tissue stiffness values onto finite element models. The purpose of this research is to develop a method for using specimen-specific computed tomography data to inform the spatial mapping of Young's modulus values on finite element models. The spatial mapping of Young's modulus was calculated and then used to predict the response of specimen tests. Results indicated that this method can be used to obtain spatial distributions of material properties, thus enabling finite element models that account for material heterogeneity.

The maize (Zea mays) stem is a biological structure that must balance both biotic and structural load bearing duties. These competing requirements are particularly relevant in the design of new bioenergy crops. Although increased stem digestibility is typically associated with a lower structural strength and higher propensity for lodging, with the right balance between structural and biological activities it may be possible to design crops that are high-yielding and have digestible biomass. This study investigates the hypothesis that geometric factors are much more influential in determining structural strength than tissue properties. To study these influences, both physical and in silico experiments were used. First, maize stems were tested in three-point bending. Specimen-specific finite element models were created based on x-ray computed tomography scans. Models were validated by comparison with experimental data. Sensitivity analyses were used to assess the influence of structural parameters such as geometric and material properties. As hypothesized, geometry was found to have a much stronger influence on structural stability than material properties. This information reinforces the notion that deficiencies in tissue strength could be offset by manipulation of stalk morphology, thus allowing the creation of stalks which are both resilient and digestible.