A Possible Mechanism for Sensing Crop Canopy Ventilation

Abstract

One approach that may help elucidate certain mechanisms of biological sensing is based on a concept developed by engineers in the 1940’s. Operations research seeks to describe the black box or functional behavior of a complex system without determining its exact relationship to the myriad behaviors and interactions of its many components. For example, using this perspective, it may be possible to identify the physical basis underlying sensory capability before identifying the biological pathway by which the sensing occurs at the cellular level. To illustrate this idea, the present Chapter describes a physical process, which provides filtered information that might allow the members of a plant community to monitor the effects of their collective wind-induced motion. Specifically, the energetics of crop canopy ventilation are studied for a wheat crop excited by a non-steady flow. In the model, the wind gust elicits large scale motions facilitating waste gas clearance out of the canopy and into the overlying airspace. As described below, the volumetric flow per unit time is found to be independent of gust velocity but varies in inverse proportion to stalk flexural stiffness. If waste gas clearance represents an important evolutionary constraint, healthy canopy plants may indeed sense intracanopy gas concentration and modulate their biomechanical properties accordingly.