A Possible Mechanism for Sensing Crop Canopy Ventilation

  • Tony Farquhar
  • Jiang Zhou
  • Henry W. HaslachJr.


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.


Large Scale Motion Wind Gust Flexural Stiffness Wind Tunnel Study Canopy Surface 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. Barlow PW (1995) Gravity perception in plants: a multiplicity of systems derived by evolution? Plant Cell Environment 18: 951–962CrossRefGoogle Scholar
  2. Biddington NL (1986) The effects of mechanically-induced stress in plants, a review. Plant Growth Regulation 4: 103–123CrossRefGoogle Scholar
  3. Brunet Y, Finnigan JJ, Raupach M (1995) A wind tunnel study of air flow in waving wheat: single point statistics. Bound Layer Meteo 70: 95–132CrossRefGoogle Scholar
  4. Bugbee B, Salisbury FB (1988) Exploring the limits of crop productivity. Plant Physiol 88: 869–878CrossRefGoogle Scholar
  5. Evans LT, Fischer RA (1999) Yield potential: its definition, measurement, and significance. Crop Science 39: 1544–1551CrossRefGoogle Scholar
  6. Farquhar T, Meyer H, van Beem J (2000 a) Effect of aeroelasticity on the aerodynamics of wheat. Matls Scien Engr C 7: 111–117CrossRefGoogle Scholar
  7. Farquhar T, Wood JZ, van Beem J (2000 b) The kinematics of wheat struck by a wind gust. J Applied Mechanics 67: 496–502CrossRefGoogle Scholar
  8. Farquhar T, Meyer-Phillips H (2001) Relative safety factors against global buckling, anchorage rotation, and tissue rupture in wheat. J Theoretical Biology 211: 55–65CrossRefGoogle Scholar
  9. Farquhar T, Zhou J (2002) Competing effects of buckling and anchorage strength on optimal wheat stem geometry. J Biomech Engr (in press)Google Scholar
  10. Farquhar T, Zhou J, Meyer H (2002) Rhtl dwarfing gene selectively decreases the material stiffness of wheat. J Biomech (in press)Google Scholar
  11. Finnigan JJ (1979) Turbulence in waving wheat. Mean statistics and Honami. Bound Layer Meteo 16: 181–236CrossRefGoogle Scholar
  12. Fischer RA, Stapper M (1987) Lodging effects on high-yielding crops of irrigated semidwarf wheat. Field Crops Research 17: 245–258CrossRefGoogle Scholar
  13. Fritig B, Legrand M (1993) Mechanisms of plant defense responses. Kluwer Acad Publ. Boston MACrossRefGoogle Scholar
  14. Gent MPN, Kiyomoto RK (1998) Physiological and agronomic consequences of Rht genes in wheat. In: Amarjit S. Basra (ed) Crop Science: Recent Advances. Hawthorne Press. Binghampton NYGoogle Scholar
  15. Inoue E (1955) Studies of the phenomenon of waving plants (Honami) caused by wind. J Agric Meteo (Japan) 11: 18–22CrossRefGoogle Scholar
  16. Jaffe MJ, Forbes S (1993) Thigmomorphogenesis: the effect of mechanical perturbation on plants. Plant Growth Regulation 12: 313–324PubMedCrossRefGoogle Scholar
  17. Mitchell C (1996) Recent advances in plant response to mechanical stress. HortScien 31: 31–35Google Scholar
  18. Shaw RH (1985) Gust penetration into plant canopies. Atmos Envir 5: 827–830CrossRefGoogle Scholar
  19. Speck T, Spatz HC, Vogellehner D (1990) Capabilities of plant stems with strengthening elements of different cross-sections against weight and wind forces. Botanica Acta, 103: 111–122Google Scholar
  20. Zebrowski J (1999) Dynamic behavior of inflorescence bearing triticale and triticum stems. Planta 207: 410–417PubMedCrossRefGoogle Scholar

Copyright information

© Springer-Verlag Wien 2003

Authors and Affiliations

  • Tony Farquhar
  • Jiang Zhou
  • Henry W. HaslachJr.

There are no affiliations available

Personalised recommendations