Developmental and Structural Section
Meicenheimer, Roger D. , Coffin, Douglas W. , Chapman, Eric M. .
To Break or Not To Break? – It's What's Inside that Counts!.
Differences in the flexibility of Pinus nigra and Pinus resinosa leaves can be used to discriminate these two similarly looking pine species from one another. When bent along the longitudinal axis, P. resinosa leaves "snap", while P. nigra leaves appear "flexible". This useful field test has had no known biophysical or anatomical explanation until now. Flexible leaves of P. nigra fail in compression, while brittle P. resinosa leaves fail in tension when subject to longitudinal bending. First order, mechanical analysis of bending and buckling was applied to the pine needles to elucidate the important anatomical differences between these two species, which can account for their different biophysical behavior when subject to bending. There was no significant difference in the cross section of the total leaf area, or the inner core (endodermis + transfusion tissue + vascular bundles) area between the two species. P. nigra had a thicker outer core (epidermis + hypodermis), but this could not account for the differences in the biophysical behavior of the two species leaves. Our investigation revealed that it was differences in the pattern of cell wall thickening and lignification of the endodermal layer of the inner core of the leaves that best explains the differences between bending behavior of the two species.
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1 - Miami University, Department of Botany, Oxford, Ohio, 45056, USA
2 - Miami University, Department of Paper and Chemical Engineering, Oxford, OH, 45056, USA
3 - Miami University, Department of Botany, Oxford, OH, 45056, USA
Presentation Type: Poster:Posters for Sections
Location: Ball Room & Party Room/SUB
Date: Monday, July 28th, 2008
Time: 12:30 PM