| Autor: |
Urzay J; Department of Mechanical and Aerospace Engineering, Jacobs School of Engineering, University of California San Diego, La Jolla, CA 92093-0411, USA. jurzay@ucsd.edu, Llewellyn Smith SG, Thompson E, Glover BJ |
| Jazyk: |
angličtina |
| Zdroj: |
Journal of theoretical biology [J Theor Biol] 2009 Aug 21; Vol. 259 (4), pp. 785-92. Date of Electronic Publication: 2009 May 13. |
| DOI: |
10.1016/j.jtbi.2009.04.027 |
| Abstrakt: |
Plant reproduction depends on pollen dispersal. For anemophilous (wind-pollinated) species, such as grasses and many trees, shedding pollen from the anther must be accomplished by physical mechanisms. The unknown nature of this process has led to its description as the 'paradox of pollen liberation'. A simple scaling analysis, supported by experimental measurements on typical wind-pollinated plant species, is used to estimate the suitability of previous resolutions of this paradox based on wind-gust aerodynamic models of fungal-spore liberation. According to this scaling analysis, the steady Stokes drag force is found to be large enough to liberate anemophilous pollen grains, and unsteady boundary-layer forces produced by wind gusts are found to be mostly ineffective since the ratio of the characteristic viscous time scale to the inertial time scale of acceleration of the wind stream is a small parameter for typical anemophilous species. A hypothetical model of a stochastic aeroelastic mechanism, initiated by the atmospheric turbulence typical of the micrometeorological conditions in the vicinity of the plant, is proposed to contribute to wind pollination. |
| Databáze: |
MEDLINE |
| Externí odkaz: |
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