The effect of canopy architecture on the patterning of "windflecks" within a wheat canopy.

Maxime Durand,Jonathon A Gibbs,Alexandra J Burgess,T Matthew Robson,Renata Retkute,Erik H Murchie

doi:10.1111/pce.14168

Maxime Durand, Jonathon A Gibbs + Show 4 more

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https://doi.org/10.1111/pce.14168

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Abstract

Under field conditions, plants are subject to wind-induced movement which creates fluctuations of light intensity and spectral quality reaching the leaves, defined here as windflecks. Within this study, irradiance within two contrasting wheat (Triticum aestivum) canopies during full sun conditions was measured using a spectroradiometer to determine the frequency, duration and magnitude of low- to high-light events plus the spectral composition during wind-induced movement. Similarly, a static canopy was modelled using three-dimensional reconstruction and ray tracing to determine fleck characteristics without the presence of wind. Corresponding architectural traits were measured manually and in silico including plant height, leaf area and angle plus biomechanical properties. Light intensity can differ up to 40% during a windfleck, with changes occurring on a sub-second scale compared to ~5min in canopies not subject to wind. Features such as a shorter height, more erect leaf stature and having an open structure led to an increased frequency and reduced time interval of light flecks in the CMH79A canopy compared to Paragon. This finding illustrates the potential for architectural traits to be selected to improve the canopy light environment and provides the foundation to further explore the links between plant form and function in crop canopies.

Highlights

Light intensities can differ 20- to 50-fold between the top and bottom of a canopy, with lower leaf layers often experiencing low levels of light interspersed with brief periods of high light termed “sunflecks” (Evans, 1956; Stadt, Gendron, Lieffers, Messier, & Comeau, 1999; Townsend et al, 2018)
A number of factors contribute to these light characteristics including canopy architectural traits, which develop with plant age, the biomechanical movement of the canopy, the optical properties
Whilst studies are beginning to arise that assess light interception within canopies of different crops subject to wind-induced movement (Durand et al, 2021), there is very little information on how specific architectural traits influence light patterning at the high-resolution required to assess windflecks

Summary

| INTRODUCTION

Light intensities can differ 20- to 50-fold between the top and bottom of a canopy, with lower leaf layers often experiencing low levels of light interspersed with brief periods of high light termed “sunflecks” (Evans, 1956; Stadt, Gendron, Lieffers, Messier, & Comeau, 1999; Townsend et al, 2018). More interest has arisen recently on the effect of fluctuating light in the agricultural setting, where the structure of a crop stand leads to very different patterns of radiation over smaller spatial, and often temporal, scales, with direct consequences in terms of photosynthetic productivity (Kromdijk et al, 2016; Murchie et al, 2018; Murchie, Pinto, & Horton, 2009; Slattery, Walker, Weber, & Ort, 2018; Wang et al, 2020) Wind affects both the plant canopy and its interactions with the environment, according to both the wind speed and the duration of gusts. Whilst studies are beginning to arise that assess light interception within canopies of different crops subject to wind-induced movement (Durand et al, 2021), there is very little information on how specific architectural traits influence light patterning at the high-resolution required to assess windflecks. By measuring the canopies subject to wind, and modelling the canopies using ray tracing techniques in a static formation, we aim to characterize the key features of light reaching leaves under field conditions

| MATERIALS AND METHODS

| RESULTS

| DISCUSSION

Findings

| CONCLUSION