THE DISPERSAL EFFECTIVENESS OF THE ACHENE-PAPPUS UNITS OF SELECTED COMPOSITAE IN STEADY WINDS WITH CONVECTION.
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| Title: | THE DISPERSAL EFFECTIVENESS OF THE ACHENE-PAPPUS UNITS OF SELECTED COMPOSITAE IN STEADY WINDS WITH CONVECTION. |
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| Authors: | Sheldon, J. C.1, Burrows, F. M.2 |
| Source: | New Phytologist. May73, Vol. 72 Issue 3, p665-675. 11p. |
| Subjects: | Asteraceae, Fruit dispersal, Humidity, Effect of humidity on plants, Effect of wind on plants, Campanulales |
| Abstract: | The role of the involucral bracts of the Compositae capitulum in fruit dispersal, the behaviour of the pappus of composite fruits to changes in humidity, and the presentation of the achene- pappus units for wind dispersal, are briefly reviewed. Arguments put forward in the literature for and against the effectiveness of the pappus in facilitating wind dispersal are presented. A method is described for comparing the dispersal efficiency of achene-pappus units of selected composites. The computed trajectories for fruits of selected species under the independent effects of wind speed and plant height, wind speed and boundary layer, and the combination of these with convection velocity are given. It is shown that the efficiency of dispersal is determined more by the fine details of the pappus geometry, which directly affects its aerodynamic properties, than by the size ratio of pappus to achene. Under steady horizontal winds, increased height of fruit release increases dispersal distance. Reported patterns of wind dispersal are discussed in terms of air movement, flight path interference by neighbouring plants and, for some species, the fruit dissemination mechanism. While increased wind velocities increase the trajectory distance, dispersal of many composites is hampered by the pappus response to humidity. Increased dispersal distances are given by steady convection currents, whereas turbulence may either curtail or prolong transportation. The apparent inefficiency of wind dispersal reported under field conditions is explained by the combined effects of these various environmental factors upon the dispersal units during the period of dissemination. [ABSTRACT FROM AUTHOR] |
| Copyright of New Phytologist is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.) | |
| Database: | Engineering Source |
| FullText | Text: Availability: 0 |
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| Header | DbId: egs DbLabel: Engineering Source An: 12069979 AccessLevel: 6 PubType: Academic Journal PubTypeId: academicJournal PreciseRelevancyScore: 0 |
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| Items | – Name: Title Label: Title Group: Ti Data: THE DISPERSAL EFFECTIVENESS OF THE ACHENE-PAPPUS UNITS OF SELECTED COMPOSITAE IN STEADY WINDS WITH CONVECTION. – Name: Author Label: Authors Group: Au Data: <searchLink fieldCode="AR" term="%22Sheldon%2C+J%2E+C%2E%22">Sheldon, J. C.</searchLink><relatesTo>1</relatesTo><br /><searchLink fieldCode="AR" term="%22Burrows%2C+F%2E+M%2E%22">Burrows, F. M.</searchLink><relatesTo>2</relatesTo> – Name: TitleSource Label: Source Group: Src Data: <searchLink fieldCode="JN" term="%22New+Phytologist%22">New Phytologist</searchLink>. May73, Vol. 72 Issue 3, p665-675. 11p. – Name: Subject Label: Subjects Group: Su Data: <searchLink fieldCode="DE" term="%22Asteraceae%22">Asteraceae</searchLink><br /><searchLink fieldCode="DE" term="%22Fruit+dispersal%22">Fruit dispersal</searchLink><br /><searchLink fieldCode="DE" term="%22Humidity%22">Humidity</searchLink><br /><searchLink fieldCode="DE" term="%22Effect+of+humidity+on+plants%22">Effect of humidity on plants</searchLink><br /><searchLink fieldCode="DE" term="%22Effect+of+wind+on+plants%22">Effect of wind on plants</searchLink><br /><searchLink fieldCode="DE" term="%22Campanulales%22">Campanulales</searchLink> – Name: Abstract Label: Abstract Group: Ab Data: The role of the involucral bracts of the Compositae capitulum in fruit dispersal, the behaviour of the pappus of composite fruits to changes in humidity, and the presentation of the achene- pappus units for wind dispersal, are briefly reviewed. Arguments put forward in the literature for and against the effectiveness of the pappus in facilitating wind dispersal are presented. A method is described for comparing the dispersal efficiency of achene-pappus units of selected composites. The computed trajectories for fruits of selected species under the independent effects of wind speed and plant height, wind speed and boundary layer, and the combination of these with convection velocity are given. It is shown that the efficiency of dispersal is determined more by the fine details of the pappus geometry, which directly affects its aerodynamic properties, than by the size ratio of pappus to achene. Under steady horizontal winds, increased height of fruit release increases dispersal distance. Reported patterns of wind dispersal are discussed in terms of air movement, flight path interference by neighbouring plants and, for some species, the fruit dissemination mechanism. While increased wind velocities increase the trajectory distance, dispersal of many composites is hampered by the pappus response to humidity. Increased dispersal distances are given by steady convection currents, whereas turbulence may either curtail or prolong transportation. The apparent inefficiency of wind dispersal reported under field conditions is explained by the combined effects of these various environmental factors upon the dispersal units during the period of dissemination. [ABSTRACT FROM AUTHOR] – Name: AbstractSuppliedCopyright Label: Group: Ab Data: <i>Copyright of New Phytologist is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract.</i> (Copyright applies to all Abstracts.) |
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| RecordInfo | BibRecord: BibEntity: Identifiers: – Type: doi Value: 10.1111/j.1469-8137.1973.tb04415.x Languages: – Code: eng Text: English PhysicalDescription: Pagination: PageCount: 11 StartPage: 665 Subjects: – SubjectFull: Asteraceae Type: general – SubjectFull: Fruit dispersal Type: general – SubjectFull: Humidity Type: general – SubjectFull: Effect of humidity on plants Type: general – SubjectFull: Effect of wind on plants Type: general – SubjectFull: Campanulales Type: general Titles: – TitleFull: THE DISPERSAL EFFECTIVENESS OF THE ACHENE-PAPPUS UNITS OF SELECTED COMPOSITAE IN STEADY WINDS WITH CONVECTION. Type: main BibRelationships: HasContributorRelationships: – PersonEntity: Name: NameFull: Sheldon, J. C. – PersonEntity: Name: NameFull: Burrows, F. M. IsPartOfRelationships: – BibEntity: Dates: – D: 01 M: 05 Text: May73 Type: published Y: 1973 Identifiers: – Type: issn-print Value: 0028646X Numbering: – Type: volume Value: 72 – Type: issue Value: 3 Titles: – TitleFull: New Phytologist Type: main |
| ResultId | 1 |
