The Overlooked Biomechanical Role of the Clasping Leaf Sheath in Wheat Stalk Lodging.

Joseph Cornwall,Christopher S. McMahan,Daniel J. Robertson,Christopher J. Stubbs

doi:10.3389/fpls.2021.617880

Joseph Cornwall, Christopher S. McMahan + Show 2 more

Open Access

https://doi.org/10.3389/fpls.2021.617880

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Abstract

The biomechanical role of the clasping leaf sheath in stalk lodging events has been historically understudied. Results from this study indicate that in some instances the leaf sheath plays an even larger role in reinforcing wheat against stalk lodging than the stem itself. Interestingly, it appears the leaf sheath does not resist bending loads by merely adding more material to the stalk (i.e., increasing the effective diameter). The radial preload of the leaf sheath on the stem, the friction between the sheath and the stem and several other complex biomechanical factors may contribute to increasing the stalk bending strength and stalk flexural rigidity of wheat. Results demonstrated that removal of the leaf sheath induces alternate failure patterns in wheat stalks. In summary the biomechanical role of the leaf sheath is complex and has yet to be fully elucidated. Many future studies are needed to develop high throughput phenotyping methodologies and to determine the genetic underpinnings of the clasping leaf sheath and its relation to stalk lodging resistance. Research in this area is expected to improve the lodging resistance of wheat.

Highlights

Wheat stalk lodging—the permanent displacement of plants from their upright position—results in millions of dollars of lost revenue each year (Berry and Spink, 2012; USDA, 2013)
The leaf sheath was found to have a large effect on the stalk flexural rigidity and the stalk bending strength of wheat
The sheath increased the flexural rigidity of the wheat stalks an average of 27.6% (+/– 15.4% standard deviation) and increased the bending strength by 36.7%

Summary

Introduction

Wheat stalk lodging—the permanent displacement of plants from their upright position—results in millions of dollars of lost revenue each year (Berry and Spink, 2012; USDA, 2013). Numerous studies of lodging resistance, root anchorage strength, and stalk strength have been conducted previously in an effort to alleviate the problem of wheat stalk lodging (Berry et al, 2003b, 2004, 2007; Berry and Spink, 2012) These studies have focused on the role of chemical composition (Berry et al, 2003a; Kong et al, 2013), morphology (Keller et al, 1999; Zuber et al, 1999; Tripathi et al, 2002, 2003), weather (Easson et al, 1993; van der Velde et al, 2012; Mäkinen et al, 2018), disease (Loyce et al, 2008), and pests (Daamen et al, 1989). The mechanical role of the leaf sheath is not fully understood (Wu and Ma, 2019)

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